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# RealClimate

Climate science from climate scientists...

## Sitemaps

- [XML Sitemap](https://www.realclimate.org/sitemap.xml): Contains all public & indexable URLs for this website.

## Posts

- [Blog - realclimate.org - All Posts](https://www.realclimate.org/index.php/blog/) - RealClimate:
- [High-resolution ‘fingerprint’ images reveal a weakening Atlantic Ocean circulation (AMOC)](https://www.realclimate.org/index.php/archives/2025/10/high-resolution-fingerprint-images-reveal-a-weakening-atlantic-ocean-circulation-amoc/) - RealClimate: The #AMOC is the reason for Europe’s mild climate. Evidence that it is slowing has been piling up over the years – it now is likely at its weakest in at least a millennium, and it may even be approaching a tipping point. Here I will show you the latest high-resolution images – and also
- [What is happening in the Atlantic Ocean to the AMOC?](https://www.realclimate.org/index.php/archives/2023/07/what-is-happening-in-the-atlantic-ocean-to-the-amoc/) - RealClimate: For various reasons I'm motivated to provide an update on my current thinking regarding the slowdown and tipping point of the Atlantic Meridional Overturning Circulation (AMOC). I attended a two-day AMOC session at the IUGG Conference the week before last, there's been interesting new papers, and in the light of that I have been changing
- [Unforced Variations: Sep 2025](https://www.realclimate.org/index.php/archives/2025/09/unforced-variations-sep-2025/) - RealClimate: This month's open thread. As usual try to remain substantive and avoid insults and personal attacks on other commenters. Any sock-puppetry or abusive comments will just be deleted on sight. Also, please don't outsource your comments to ChatGPT - cut-and-pastes of long-winded LLM output are tedious and add precisely nothing to the conversation. There are
- [Unforced variations: Oct 2025](https://www.realclimate.org/index.php/archives/2025/10/unforced-variations-oct-2025/) - RealClimate: This month's open thread. Lots of salient stuff this month so please try and stay focused and constructive!
- ["But you said the ice was going to disappear in 10 years!"](https://www.realclimate.org/index.php/archives/2025/09/but-you-said-the-ice-was-going-to-disappear-in-10-years/) - RealClimate: Almost two decades ago, some scientists predicted that Arctic summer sea ice would 'soon' disappear. These predictions were mentioned by Al Gore and got a lot of press. However, they did not gain wide acceptance in the scientific community, and were swiftly disproven. Unsurprisingly, this still comes up a lot. Time for a deeper dive
- [Hurricanes and Global Warming - Is There a Connection? <lang_sp>Huracanes y calentamiento global ¿Hay conexión?</lang_sp><lang_fr>Ouragans et réchauffement global - existe t'il un lien ?</lang_fr>](https://www.realclimate.org/index.php/archives/2005/09/hurricanes-and-global-warming/) - RealClimate: by Stefan Rahmstorf, Michael Mann, Rasmus Benestad, Gavin Schmidt, and William Connolley On Monday August 29, Hurricane Katrina ravaged New Orleans, Louisiana and Missisippi, leaving a trail of destruction in her wake. It will be some time until the full toll of this hurricane can be assessed, but the devastating human and environmental impacts are
- [Live (almost) from AGU–Dispatch #2](https://www.realclimate.org/index.php/archives/2007/12/live-almost-from-agu-dispatch-2/) - RealClimate: Before I get started with a few hasty remarks on today's events, let me remind you that Lonnie Thompson's Frontiers in Geophysics lecture will be webcast live on Wednesday at 1815 Pacific time. A link to the webcast can be found here. The lecture is entitled "Abrupt Climate Change and Our Future". At the same
- [Time and Tide Gauges wait for no Voortman](https://www.realclimate.org/index.php/archives/2025/09/time-and-tide-gauges-wait-for-no-voortman/) - RealClimate: Here we go again. An obscure, methodologically poor, paper published with little to no review makes a convenient point and gets elevated into supposedly 'blockbusting' science by the merchants of bullshit, sorry, doubt. Actual scientists drop everything to respond, but not before the (convenient) nonsense has spread widely. Rebuttals are written and submitted, but by
- [Lil' NAS Express](https://www.realclimate.org/index.php/archives/2025/09/lil-nas-express/) - RealClimate: The fast-tracked update of the 2009 EPA Endangerment finding from the National Academies for Science, Engineering and Medicine (NASEM), has now been released. Unsurprisingly, it has come out strongly in favor of strengthening the conclusions of the 2009 finding. Specifically the conclude that: Emissions of greenhouse gases (GHGs) from human activities are increasing the concentration
- [DOE CWG Report "Moot"?](https://www.realclimate.org/index.php/archives/2025/09/doe-cwg-report-moot/) - RealClimate: Somewhat breaking news. A court filing (from 9/4) from DOE has noted that the Climate Working Group has been disbanded (as of 9/3). This was done to make the EDF/UCS lawsuit moot, but it also means that DOE is withdrawing the report, no-one will respond appropriately to the comments submitted, and (possibly) it becomes irrelevant
- [Climate Scientists response to DOE report](https://www.realclimate.org/index.php/archives/2025/09/climate-scientists-response-to-doe-report/) - RealClimate: As we've mentioned, Andrew Dessler and Robert Kopp have been coordinating a scientific peer review of the DOW 'CWG' Critique of Climate Science. It is now out. The comments are available here, and there is a press release that gives a summary. It has been picked up by some the media already: NY Times, The
- [Critique of Chapter 6 “Extreme Weather” in the DOE review](https://www.realclimate.org/index.php/archives/2025/09/critique-of-chapter-6-extreme-weather-in-the-doe-review/) - RealClimate: Guest commentary by Kerry Emanuel Executive Summary Chapter 6 of the draft DOE report examines whether global warming exacerbates extreme weather. It rightly notes that because events such as hurricanes are rare, detecting their response to climate change in short and imperfect historical records is extremely difficult—if not impossible. Yet the authors devote most of
- [Unforced Variations: Aug 2025](https://www.realclimate.org/index.php/archives/2025/08/unforced-variations-aug-2025/) - RealClimate: This month's open thread. Please try and stay focused on substance rather than personalities. There are many real issues that are particularly salient this month, and so maybe we can collectively try not to have the comments descend into tedium. Note: Moderation will be applied to over-frequent and pointless commenters (you know who you are,
- [Critiques of the 'Critical Review'](https://www.realclimate.org/index.php/archives/2025/08/critiques-of-the-critical-review/) - RealClimate: The first somewhat comprehensive reviews of the DOE critical review are now coming online. First out of the gate is a nice interactive from CarbonBrief based on direct input from scientists whose papers were cited, sometimes in misleading or false ways. They have a nice color-coding for which is which. There is a complementary effort
- [Are direct water vapor emissions endangering anyone?](https://www.realclimate.org/index.php/archives/2025/07/are-direct-water-vapor-emissions-endangering-anyone/) - RealClimate: In the EPA EF reconsideration document there is a section on p62 where they attempt to make the argument that the CO2 endangerment finding would also apply to direct water vapor emissions to the atmosphere, which is (according to them) obviously absurd. But both claims are bogus. First off, the definition of pollutant in the
- [Unforced variations: July 2025](https://www.realclimate.org/index.php/archives/2025/07/unforced-variations-july-2025/) - RealClimate: This month's open thread. Try to stick to climate topics.
- [The Endangerment of the Endangerment Finding?](https://www.realclimate.org/index.php/archives/2025/07/the-endangerment-of-the-endangerment-finding/) - RealClimate: The EPA, along with the "Climate Working Group" (CWG) of usual suspects (plus Judith Curry and Ross McKitrick) at DOE, have just put out a document for public comment their attempt to rescind the 2009 Endangerment Finding for greenhouse gas emissions. Here are some relevant links: Original Endangerment Finding (2009) Proposed rule (2025) DOE Critical
- [National Climate Assessment links](https://www.realclimate.org/index.php/archives/2025/07/national-climate-assessment-links/) - RealClimate: For some reason, it has become hard to locate the various National Climate Assessments (NCAs) that have been produced by the USGCRP over the decades (and it's pretty hard to find the USGRCP as well...). However, the reports are still accessible if you know where to look. So for future reference, here are all the
- [Ocean circulation going South?](https://www.realclimate.org/index.php/archives/2025/07/ocean-circulation-going-south/) - RealClimate: Some intriguing new measurements of salinity in the oceans around Antarctica have set off reams of sensationalist speculations. Maybe some context is helpful... What we've been seeing The climate change situation in the Southern Oceans (those seas surrounding Antarctica and connected by the massive Antarctic Circumpolar current) have been anomalous for many years, decades even.
- [Melange à Trois](https://www.realclimate.org/index.php/archives/2025/07/melange-a-trois/) - RealClimate: In honor of the revelation today, that Koonin, Christy and Spencer have been made Special Government Employees at the Dept. of Energy, we present a quick round up of our commentary on the caliber of their arguments we've posted here over the last decade or so. TL;DR? The arguments are not very good. Steve Koonin
- [Unforced variations: Jun 2025](https://www.realclimate.org/index.php/archives/2025/06/unforced-variations-jun-2025/) - RealClimate: This month's open thread. Please stay on climate topics and try to be constructive.
- [Predicted Arctic sea ice trends over time](https://www.realclimate.org/index.php/archives/2025/05/predicted-arctic-sea-ice-trends-over-time/) - RealClimate: Over multiple generations of CMIP models Arctic sea ice trend predictions have gone from much too stable to about right. Why? The diagnostics highlighted in our model-observations comparison page are currently all temperature based, and show overall that climate models have being doing well on these trends for decades. But there has been increasing attention
- [Unforced variations: May 2025](https://www.realclimate.org/index.php/archives/2025/05/unforced-variations-may-2025/) - RealClimate: This month's open thread. Note that the Nenana Ice challenge break up date graph has been updated, and the Yukon river ice break up is imminent (or may have already happened! [Update - it already had]). Please stay focused on climate issues.
- [2024 Hindsight](https://www.realclimate.org/index.php/archives/2025/01/2024-hindsight/) - RealClimate: To no-one's surprise 2024 was the warmest year on record - and by quite a clear margin. Another year, another data point. Unlike the previous year, 2024 was anticipated to be a record breaker even before it began (I predicted a record - despite the huge anomaly in 2023 - with a 55% probability). It
- [The most recent climate status](https://www.realclimate.org/index.php/archives/2025/05/the-most-recent-climate-status/) - RealClimate: The Arctic Council’s Arctic Monitoring and assessment Programme (AMAP) recently released a Summary for PolicyMakers’ Arctic Climate Change Update 2024. It is one of several stock taking exercises on the regional and global states of Earth's climate. The other reports include the 2024 European State of the Climate (ESOTC) report, NOAA’s Assessing the Global Climate
- [Unforced Variations: Apr 2025](https://www.realclimate.org/index.php/archives/2025/04/unforced-variations-apr-2025/) - RealClimate: This month's open thread for climate topics. Please try to stay focused on climate instead of generic (and tedious) political sniping.
- [Unforced Variations: Mar 2025](https://www.realclimate.org/index.php/archives/2025/03/unforced-variations-mar-2025/) - RealClimate: This month's open thread on climate topics. Despite everything going on, please avoid generic political arguments - there are many other places on line for that. Impacts on climate science or actions from the layoffs in the US federal government are, however, very much on topic.
- [WMO: Update on 2023/4 Anomalies](https://www.realclimate.org/index.php/archives/2025/03/wmo-update-on-2023-4-anomalies/) - RealClimate: The WMO released its (now) annual state of the climate report this week. As well as the (now) standard set of graphs related to increasing greenhouse gas concentrations, rising temperatures, reducing glacier mass, etc., Zeke Hausfather and I wrote up a short synthesis on the contributions to recent temperature anomalies. Readers will recall our previous
- [Andean glaciers have shrunk more than ever before in the entire Holocene](https://www.realclimate.org/index.php/archives/2025/03/andean-glaciers-have-shrunk-more-than-ever-before-in-the-holocene/) - RealClimate: Glaciers are important indicators of climate change. A recent study published in the leading journal Science shows that glaciers in the tropical Andes have now retreated further than at any other time in the entire Holocene - which covers the whole history of human civilisation since the invention of agriculture. These findings are likely to
- [Climate change in Africa](https://www.realclimate.org/index.php/archives/2025/03/climate-change-in-africa/) - RealClimate: [latexpage] While there have been some recent set-backs within science and climate research and disturbing news about NOAA, there is also continuing efforts on responding to climate change. During my travels to Mozambique and Ghana, I could sense a real appreciation for knowledge, and an eagerness to learn how to calculate risks connected to climate
- [We need NOAA now more than ever](https://www.realclimate.org/index.php/archives/2025/03/we-need-noaa-now-more-than-ever/) - RealClimate: Guest commentary by Robert Hart, Kerry Emanuel, & Lance Bosart The National Weather Service (NWS) and its parent agency, the National Oceanic and AtmosphericAdministration (NOAA), delivers remarkable value to the taxpayers. This efficiency can be demonstrated by its enormous return on investment. For example, the NWS costs only several dollars per citizen to operate each
- [Unforced Variations: Feb 2025](https://www.realclimate.org/index.php/archives/2025/02/unforced-variations-feb-2025/) - RealClimate: This month's open thread on climate-related topics.
- [How will media report on this new AMOC study?](https://www.realclimate.org/index.php/archives/2025/02/how-will-media-report-on-this-new-amoc-study/) - RealClimate: I’ve been getting a lot of media queries about a new paper on the AMOC (Atlantic Meridional Overturning Circulation), which has just been published. In my view this large media interest is perhaps due to confusing messages conveyed in the title of the paper and in press releases about it by the journal Nature and
- [Comparison Update 2024](https://www.realclimate.org/index.php/archives/2025/01/comparison-update-2024/) - RealClimate: One more dot on the graphs for our annual model-observations comparisons updates. Given how extraordinary the last two years have been, there are a few highlights to note. First, we have updated the versions of a few of the observational datasets: UAH TLT/TMT are now on version 6.1, and the NOAA NCEI surface temperature data
- [Much ado about acceleration](https://www.realclimate.org/index.php/archives/2024/04/much-ado-about-acceleration/) - RealClimate: There has been a lot of commentary about perceived disagreements among climate scientists about whether climate change is, or will soon, accelerate. As with most punditry, there is less here than it might seem.
- [Unforced Variations: Jan 2025](https://www.realclimate.org/index.php/archives/2025/01/unforced-variations-jan-2025/) - RealClimate: This month's open thread on climate topics. Please remember to be substantive, respectful and vaguely on topic. Note that we'll have an update to the various observational datasets after Jan 10th, and hopefully an update to all the model-observation comparisons the week following (depending on other things not getting in the way). Happy New Year
- [The AMOC is slowing, it's stable, it's slowing, no, yes, ...](https://www.realclimate.org/index.php/archives/2025/01/the-amoc-is-slowing-its-stable-its-slowing-no-yes/) - RealClimate: There's been a bit of media whiplash on the issue of AMOC slowing lately - ranging from the AMOC being "on the brink of collapse" to it being "more stable than previously thought". AMOC, of course, refers to the Atlantic Meridional Overturning Circulation, one of the worlds major ocean circulation systems which keeps the northern
- [What the IPCC models really say <lang_sp>Lo que dicen realmente los modelos del IPCC</lang_sp><lang_it>Cosa dicono realmente i modelli dell‘IPCC</lang_it>](https://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/) - RealClimate: Over the last couple of months there has been much blog-viating about what the models used in the IPCC 4th Assessment Report (AR4) do and do not predict about natural variability in the presence of a long-term greenhouse gas related trend. Unfortunately, much of the discussion has been based on graphics, energy-balance models and descriptions
- [How good have climate models been at truly predicting the future?](https://www.realclimate.org/index.php/archives/2019/12/how-good-have-climate-models-been-at-truly-predicting-the-future/) - RealClimate: A new paper from Hausfather and colleagues (incl. me) has just been published with the most comprehensive assessment of climate model projections since the 1970s. Bottom line? Once you correct for small errors in the projected forcings, they did remarkably well. Climate models are a core part of our understanding of our future climate. They
- [Non-condensable Cynicism in Santa Fe](https://www.realclimate.org/index.php/archives/2017/01/non-condensable-cynicism-in-santa-fe/) - RealClimate: Guest Post by Mark Boslough The Fourth Santa Fe Conference on Global & Regional Climate Change will be held on Feb 5-10, 2017. It is the fourth in a series organized and chaired by Petr Chylek of Los Alamos National Laboratory (LANL) and takes place intervals of 5 years or thereabouts. It is sponsored this
- [Update day](https://www.realclimate.org/index.php/archives/2019/02/update-day/) - RealClimate: So Wednesday was temperature series update day. The HadCRUT4, NOAA NCEI and GISTEMP time-series were all updated through to the end of 2018 (slightly delayed by the federal government shutdown). Berkeley Earth and the MSU satellite datasets were updated a couple of weeks ago. And that means that everyone gets to add a single additional
- [Update day 2020!](https://www.realclimate.org/index.php/archives/2020/01/update-day-2020/) - RealClimate: Following more than a decade of tradition (at least), I've now updated the model-observation comparison page to include observed data through to the end of 2019. As we discussed a couple of weeks ago, 2019 was the second warmest year in the surface datasets (with the exception of HadCRUT4), and 1st, 2nd or 3rd in
- [Update day 2021](https://www.realclimate.org/index.php/archives/2021/01/update-day-2021/) - RealClimate: As is now traditional, every year around this time we update the model-observation comparison page with an additional annual observational point, and upgrade any observational products to their latest versions. A couple of notable issues this year. HadCRUT has now been updated to version 5 which includes polar infilling, making the Cowtan and Way dataset
- [Another dot on the graphs (Part II)](https://www.realclimate.org/index.php/archives/2022/02/another-dot-on-the-graphs-part-ii/) - RealClimate: We've now made updates to all the model-observations plots for SAT and MSU TMT variables to include 2021 data.
- [Issues and Errors in a new Scafetta paper](https://www.realclimate.org/index.php/archives/2022/03/issues-and-errors-in-a-new-scafetta-paper/) - RealClimate: A recent paper discussing the CMIP6 models is fundamentally flawed.
- [The Scafetta Saga](https://www.realclimate.org/index.php/archives/2023/09/the-scafetta-saga/) - RealClimate: It has taken 17 months to get a comment published pointing out the obvious errors in the Scafetta (2022).
- [2022 updates to model-observation comparisons](https://www.realclimate.org/index.php/archives/2023/02/2022-updates-to-model-observation-comparisons/) - RealClimate: Our annual post related to the comparisons between long standing records and climate models.
- [Some new CMIP6 MSU comparisons](https://www.realclimate.org/index.php/archives/2023/03/some-new-cmip6-msu-comparisons/) - RealClimate: We add some CMIP6 models to the updateable MSU comparisons.
- [Not just another dot on the graph? Part II](https://www.realclimate.org/index.php/archives/2024/01/not-just-another-dot-on-the-graph-part-ii/) - RealClimate: Annual updates to the model-observation comparisons for 2023 are now complete. The comparisons encompass surface air temperatures, mid-troposphere temperatures (global and tropical, and 'corrected'), sea surface temperatures, and stratospheric temperatures. In almost every case, the addition of the 2023 numbers was in line with the long term expectation from the models. There were a few
- [Another dot on the graph](https://www.realclimate.org/index.php/archives/2022/01/another-dot-on-the-graph/) - RealClimate: Monitoring global temperatures and where the science goes next...
- [Comparing models to the satellite datasets](https://www.realclimate.org/index.php/archives/2016/05/comparing-models-to-the-satellite-datasets/) - RealClimate: How should one make graphics that appropriately compare models and observations? There are basically two key points (explored in more depth here) - comparisons should be 'like with like', and different sources of uncertainty should be clear, whether uncertainties are related to 'weather' and/or structural uncertainty in either the observations or the models. There are
- [NOAA temperature record updates and the 'hiatus'](https://www.realclimate.org/index.php/archives/2015/06/noaa-temperature-record-updates-and-the-hiatus/) - RealClimate: In a new paper in Science Express, describe the impacts of two significant updates to the NOAA NCEI (née NCDC) global temperature series. The two updates are: 1) the adoption of for the ocean temperatures (incorporating a number of corrections for biases for different methods), and 2) the use of the larger International Surface Temperature
- [2012 Updates to model-observation comparisons](https://www.realclimate.org/index.php/archives/2013/02/2012-updates-to-model-observation-comparions/) - RealClimate: Time for the 2012 updates! As has become a habit (2009, 2010, 2011), here is a brief overview and update of some of the most discussed model/observation comparisons, updated to include 2012. I include comparisons of surface temperatures, sea ice and ocean heat content to the CMIP3 and Hansen et al (1988) simulations. First, a
- [2011 Updates to model-data comparisons](https://www.realclimate.org/index.php/archives/2012/02/2011-updates-to-model-data-comparisons/) - RealClimate: And so it goes - another year, another annual data point. As has become a habit (2009, 2010), here is a brief overview and update of some of the most relevant model/data comparisons. We include the standard comparisons of surface temperatures, sea ice and ocean heat content to the AR4 and 1988 Hansen et al
- [2010 updates to model-data comparisons](https://www.realclimate.org/index.php/archives/2011/01/2010-updates-to-model-data-comparisons/) - RealClimate: As we did roughly a year ago (and as we will probably do every year around this time), we can add another data point to a set of reasonably standard model-data comparisons that have proven interesting over the years. First, here is the update of the graph showing the annual mean anomalies from the IPCC
- [Updates to model-data comparisons](https://www.realclimate.org/index.php/archives/2009/12/updates-to-model-data-comparisons/) - RealClimate: It's worth going back every so often to see how projections made back in the day are shaping up. As we get to the end of another year, we can update all of the graphs of annual means with another single datapoint. Statistically this isn't hugely important, but people seem interested, so why not? Una
- [¡AI Caramba!](https://www.realclimate.org/index.php/archives/2024/12/ai-caramba/) - RealClimate: Rapid progress in the use of machine learning for weather and climate models is evident almost everywhere, but can we distinguish between real advances and vaporware? First off, let's define some terms to maximize clarity. Machine Learning (ML) is a broad term to distinguish any kind of statistical fitting of large data sets to complicated
- [Unforced Variations: Dec 2024](https://www.realclimate.org/index.php/archives/2024/11/unforced-variations-dec-2024/) - RealClimate: This month's open thread on *climate* topics. Obviously, last month's events lent themselves to broader discussions, but this month (and going forward), we remind you that comments have to be climate-related. Note too that there are plenty of dying websites where you can troll to your heart's content and post tedious partisan talking points, but
- [New journal: <i>Nature 2023</i>?](https://www.realclimate.org/index.php/archives/2024/05/new-journal-nature-2023/) - RealClimate: [Last update Dec 6, 2024] There were a number of media reports today [May 11, 2024] related to , for instance, New Scientist, The Guardian etc. However, this is really just the beginning of what is likely to be a bit of a cottage industry in the next few months relating to possible causes/influences on
- [Nature 2023: Part II](https://www.realclimate.org/index.php/archives/2024/12/nature-2023-part-ii/) - RealClimate: This is a follow-on post to the previous summary of interesting work related to the temperatures in 2023/2024. I'll have another post with a quick summary of the AGU session on the topic that we are running on Tuesday Dec 10th, hopefully in the next couple of weeks. 6 Dec 2024: This is perhaps the
- [Unforced variations: Nov 2024](https://www.realclimate.org/index.php/archives/2024/11/unforced-variations-nov-2024/) - RealClimate: This month's open thread on climate change topics. How are we in November already? And why is it still so warm... ? Anyway, please stay on topic and avoid insulting other commenters.
- [Twenty years of blogging in hindsight](https://www.realclimate.org/index.php/archives/2024/11/twenty-years-of-blogging-in-hindsight/) - RealClimate: It’s 20 years since we started blogging on climate here on RealClimate (December 10, 2004). We wanted to counter disinformation about climate change that was spreading through various campaigns. In those days it was an unusual move that prompted a welcome from Nature. One thing that I didn’t anticipate then was the vast global scale
- [Operationalizing Climate Science](https://www.realclimate.org/index.php/archives/2024/11/operationalizing-climate-science/) - RealClimate: There is a need to make climate science more agile and more responsive, and that means moving (some of it) from research to operations.
- [Unforced Variations: Oct 2024](https://www.realclimate.org/index.php/archives/2024/10/unforced-variations-oct-2024/) - RealClimate: This month's open thread for climate topics. Please stay vaguely on topic and do not abuse other commenters.
- [Cold extremes do in fact decrease under global warming](https://www.realclimate.org/index.php/archives/2024/10/cold-extremes-do-in-fact-decrease-under-global-warming/) - RealClimate: The title of this post might seem like a truism, but for about a decade some people have claimed the opposite, and many people have spent much time and effort trying to understand why. Much of that effort was wasted. A decade ago, Nature Geoscience published , a review paper on potential connections between the
- [Science is not value free](https://www.realclimate.org/index.php/archives/2024/10/science-is-not-value-free/) - RealClimate: An interesting commentary addressing a rather odd prior commentary makes some very correct points. Back a few months there was a poorly argued and rather confusing commenary by Ulf Büntgen () that started: I am concerned by climate scientists becoming climate activists, because scholars should not have a priori interests in the outcome of their
- [The need for pluralism in climate modelling](https://www.realclimate.org/index.php/archives/2024/08/the-need-for-pluralism-in-climate-modelling/) - RealClimate: How should we allocate resources for climate modelling if the goal is to improve climate-related decisions? Higher resolution, machine learning and/or storylines? A call for a deeper discussion on how we should develop the climate modelling toolbox. Guest post by Marina Baldissera Pacchetti, Julie Jebeile and Erica Thompson The need for “km-scale” models able to
- [Oh My, Oh Miocene!](https://www.realclimate.org/index.php/archives/2024/08/oh-my-oh-miocene/) - RealClimate: A recent paper suggested that 'climate sensitivity' derived from a new paleo-CO2 record is around 7.2ºC (for equilibrium climate sensitivity ECS) and ~13.9ºC (Earth System Sensitivity - ESS) for a doubling of CO2. Some press has suggested that this means that "Earth’s Temperature Could Increase by 25 Degrees" (F). Huge if true! Fortunately these numbers
- [Phantastic Job!](https://www.realclimate.org/index.php/archives/2024/09/phantastic-job/) - RealClimate: A truly impressive paper was published this week with a new reconstruction of global temperatures over the last ~500 million years. There is something tremendously satisfying about seeing a project start, and then many years later see the results actually emerge and done better than you could have imagined. Especially one as challenging as accurately
- [Unforced Variations: Sep 2024](https://www.realclimate.org/index.php/archives/2024/09/unforced-variations-sep-2024/) - RealClimate: This month's open thread on climate topics. Try to be constructive!
- [Unforced variations: Aug 2024](https://www.realclimate.org/index.php/archives/2024/08/unforced-variations-aug-2024/) - RealClimate: This month's open thread on climate topics.
- [Unforced variations: July 2024](https://www.realclimate.org/index.php/archives/2024/06/unforced-variations-july-2024/) - RealClimate: This month's open thread on climate science topics.
- [Unforced variations: June 2024](https://www.realclimate.org/index.php/archives/2024/06/unforced-variations-june-2024/) - RealClimate: This month's open thread on climate topics. Please stay focused, minimize repetitive comments, and maintain a half-way decent level of decorum. Thanks!
- [Unforced Variations: May 2024](https://www.realclimate.org/index.php/archives/2024/04/unforced-variations-may-2024/) - RealClimate: This month's open thread on climate topics. Many eyes will be focused on whether April temperatures will be the 11th month in row of records... Note that we have updated the data and figures from the Nenana Ice Classic and Dawson City river ice break up pools (the nominal 13th and 5th earliest break-ups (or
- [Unforced variations: Apr 2024](https://www.realclimate.org/index.php/archives/2024/04/unforced-variations-apr-2024/) - RealClimate: This month's open thread on climate topics. Lots more discussion about 2023, aerosols, heat content and imbalances to come I expect... Note, comments should be substantive even if you are arguing with who you perceive to be the worst person in the world. Comments that are mainly personal attacks will just get deleted.
- [Unforced variations: March 2024](https://www.realclimate.org/index.php/archives/2024/03/unforced-variations-march-2024/) - RealClimate: The month's open thread on climate topics. More record monthly warmth, but only the second lowest Antarctic sea ice though (growing since 2023!).
- [More solar shenanigans*](https://www.realclimate.org/index.php/archives/2024/03/more-solar-shenanigans/) - RealClimate: It turns out the solar activity reconstruction beloved by contrarians is full of artifacts, and if it's updated, it's singular nature disappears.
- [The CO<sub>2</sub> problem in six easy steps (2022 Update)](https://www.realclimate.org/index.php/archives/2022/07/the-cos2-problem-in-six-easy-steps-2022-update/) - RealClimate: An update to one of most-read older posts.
- [Unforced variations: Feb 2024](https://www.realclimate.org/index.php/archives/2024/01/unforced-variations-feb-2024/) - RealClimate: This month's open thread for climate topics. This month's climate highlight will likely be the PACE launch at some point between Feb 6th and Feb 8th, that will hopefully provide information on aerosols and ocean color with more detail than ever before. Fingers crossed! A few notes on the blog and commenting. We have an
- [New study suggests the Atlantic overturning circulation AMOC “is on tipping course"](https://www.realclimate.org/index.php/archives/2024/02/new-study-suggests-the-atlantic-overturning-circulation-amoc-is-on-tipping-course/) - RealClimate: A new paper was published in Science Advances today. Its title says what it is about: "Physics-based early warning signal shows that AMOC is on tipping course." The study follows one by Danish colleagues which made headlines last July, likewise looking for early warning signals for approaching an AMOC tipping point (we discussed it here),
- [Responses to McShane and Wyner](https://www.realclimate.org/index.php/archives/2010/12/responses-to-mcshane-and-wyner/) - RealClimate: Gavin Schmidt and Michael Mann Readers may recall a flurry of excitement in the blogosphere concerning the McShane and Wyner paper in August. Well, the discussions on the McShane and Wyner paper in AOAS have now been put online. There are a stunning 13 different discussion pieces, an editorial and a rebuttal. The invited discussions
- [Spencer's Shenanigans](https://www.realclimate.org/index.php/archives/2024/01/spencers-shenanigans/) - RealClimate: A recent sensible-sounding piece by Roy Spencer for the Heritage foundation is full of misrepresentations. Let's play spot the fallacy.
- [Unforced variations: Jan 2024](https://www.realclimate.org/index.php/archives/2024/01/unforced-variations-jan-2024/) - RealClimate: New year, new open thread on climate topics. Note that summaries and updates to include 2023 data will be posted on the surface temperature graphics page and model-observations comparison page over the next couple of weeks as the data becomes available.
- [The Volcano Gambit](https://www.realclimate.org/index.php/archives/2016/04/the-volcano-gambit/) - RealClimate: Anyone reading pundits and politicians pontificating profusely about climate or environmental science will, at some point, have come across the "volcano gambit". During the discussion they will make a claim that volcanoes (or even a single volcano) produce many times more pollutant emissions than human activities. Often the factor is extremely precise to help give
- [Not just another dot on the graph?](https://www.realclimate.org/index.php/archives/2024/01/not-just-another-dot-on-the-graph/) - RealClimate: As the climate monitoring groups add an additional dot to their graphs this week, there is some disquiet among people paying attention about just how extraordinary 2023 really was.
- [Annual GMSAT predictions and ENSO](https://www.realclimate.org/index.php/archives/2024/01/annual-gmsat-predictions-and-enso/) - RealClimate: Predictions for next years annual global mean surface air temperature anomaly based on the long term trend and the state of ENSO have been quite skillful. Until 2023.
- [2023 appears to follow an upward trend in the North Atlantic/Caribbean named tropical cyclone count](https://www.realclimate.org/index.php/archives/2023/12/2023-appears-to-follow-an-upward-trend-in-the-north-atlantic-caribbean-named-tropical-cyclone-count/) - RealClimate: This year’s (2023) tropical cyclone season in the North Atlantic and Caribbean witnessed a relatively high number of named tropical cyclones: 20. In spite of the current El Niño, which tends to give lower numbers. But it appears to follow a historical trend for named tropical cyclones with an increasing number over time. The curve
- [Unforced Variations: Nov 2023](https://www.realclimate.org/index.php/archives/2023/11/unforced-variations-nov-2023/) - RealClimate: This month's open thread on climate topics.
- [Unforced Variations: Dec 2023](https://www.realclimate.org/index.php/archives/2023/12/unforced-variations-dec-2023/) - RealClimate: Well, that year went quickly. This month, there is the COP28 hoopla, the ongoing El Niño and the speculation about the 2023 temperature ranking (which will not be that surprising). An open thread for climate topics...
- [Science denial is still an issue ahead of COP28](https://www.realclimate.org/index.php/archives/2023/11/science-denial-is-still-an-issue-ahead-of-cop28/) - RealClimate: It is 33 years now since the IPCC in its first report in 1990 concluded that it is “certain” that greenhouse gas emissions from human activities “will enhance the greenhouse effect, resulting on average in an additional warming of the Earth's surface.” That has indeed happened as predicted, it has been confirmed by a zillion
- [Clauser-ology: Cloudy with a chance of meatballs](https://www.realclimate.org/index.php/archives/2023/11/clauser-ology-cloudy-with-a-chance-of-meatballs/) - RealClimate: John Clauser's theory of climate explained. Some of you will have heard of John Clauser because he was an awardee of the 2022 Nobel Prize in Physics for his role in the experimental verification of quantum entanglement. Some of you will have heard of him because the first thing that he did after winning the
- [A CERES of fortunate events...](https://www.realclimate.org/index.php/archives/2022/09/a-ceres-of-fortunate-events/) - RealClimate: The CERES estimates of the top-of-atmosphere radiative fluxes are available from 2001 to the present. That is long enough to see that there has been a noticeable trend in the Earth's Energy Imbalance (EEI), mostly driven by a reduction in the solar radiation reflected by the planet, while the outgoing long wave radiation does not appear to contribute much. But what can be causing this?
- [A distraction due to errors, misunderstanding and misguided Norwegian statistics](https://www.realclimate.org/index.php/archives/2023/11/a-distraction-due-to-errors-misunderstanding-and-misguided-norwegian-statistics/) - RealClimate: A friend asked me if a discussion paper published on Statistics Norway’s website, ‘To what extent are temperature levels changing due to greenhouse gas emissions?’, was purposely timed for the next climate summit (COP28). I don’t know the answer to his question. But this discussion paper is problematic for sure. It was, authored by Dagsvik
- [Unforced variations: Oct 2023](https://www.realclimate.org/index.php/archives/2023/10/unforced-variations-oct-2023/) - RealClimate: This month's open thread on climate topics. Please try to stay on topic and refrain from posting tedious, oft-debunked nonsense. Look out for more reports of ridiculously high global temperatures and intense rainfall, and more confident predictions of the budding El Niño event and annual temperature rankings...
- [The 5th International Conference on Regional Climate](https://www.realclimate.org/index.php/archives/2023/10/the-5th-international-conference-on-regional-climate/) - RealClimate: The fifth international conference on regional climate (ICRC 2023), organised by World Climate Research Programme's (WCRP) coordinated downscaling experiment (CORDEX), has just completed. It was a hybrid on-site/online conference with hubs in both Trieste/Italy (hosted by the International Centre on Theoretical Physics, ICTP) and Pune/India. The hybrid set-up, with video links between the two hubs
- [Unforced variations: Sep 2023](https://www.realclimate.org/index.php/archives/2023/09/unforced-variations-sep-2023/) - RealClimate: This month's open thread on climate science topics. It's been a warm summer, dontcha know? Expect ERA5, the satellite data and then the surface data products to confirm this in the next week or so. Sea ice minimum in the Arctic will also occur soon, as will a record low maximum in the Antarctic. El
- [Old habits](https://www.realclimate.org/index.php/archives/2023/09/old-habits/) - RealClimate: Media awareness about global warming and climate change has grown fairly steadily since 2004. My impression is that journalists today tend to possess a higher climate literacy than before. This increasing awareness and improved knowledge is encouraging, but there are also some common interpretations which could be more nuanced. Here are two examples, polar amplification
- [As Soon as Possible](https://www.realclimate.org/index.php/archives/2023/09/as-soon-as-possible/) - RealClimate: The latest contrarian crowd pleaser from is just the latest repetition of the old "it was the sun wot done it" trope that Soon and his colleagues have been pushing for decades. There is literally nothing new under the sun.
- [Unforced Variations: Aug 2023](https://www.realclimate.org/index.php/archives/2023/08/unforced-variations-aug-2023/) - RealClimate: This month’s open thread for climate topics. Has anyone noticed how warm it’s been? Someone should probably look into that…
- [The AMOC: tipping this century, or not?](https://www.realclimate.org/index.php/archives/2023/08/the-amoc-tipping-this-century-or-not/) - RealClimate: A few weeks ago, a study by Copenhagen University researchers Peter and Susanne Ditlevsen concluded that the Atlantic Meridional Overturning Circulation (AMOC) is likely to pass a tipping point already this century, most probably around mid-century. Given the catastrophic consequences of an AMOC breakdown, the study made quite a few headlines but also met some
- [Sea level in the 5th IPCC report](https://www.realclimate.org/index.php/archives/2013/10/sea-level-in-the-5th-ipcc-report/) - RealClimate: What is happening to sea levels? That was perhaps the most controversial issue in the 4th IPCC report of 2007. The new report of the Intergovernmental Panel on Climate Change is out now, and here I will discuss what IPCC has to say about sea-level rise (as I did here after the 4th report). Let
- [Unforced variations: July 2023](https://www.realclimate.org/index.php/archives/2023/07/unforced-variations-july-2023/) - RealClimate: This month's open thread for climate topics. Let the (northern hemisphere) heat wave and wildfire smoke season begin!
- [The summary for policymakers of the Intergovernmental Panel on Climate Change sixth assessment reports synthesis](https://www.realclimate.org/index.php/archives/2023/04/the-summary-for-policymakers-of-the-intergovernmental-panel-on-climate-change-sixth-assessment-reports-synthesis/) - RealClimate: The summary for policymakers of the Intergovernmental Panel on Climate Change (IPCC) sixth synthesis report was released on March 20th (available online as a PDF). There is a recording of the IPCC Press Conference - Climate Change 2023: Synthesis Report for those who are interested in watching an awkward release of the report. It strikes
- [Serious mistakes found in recent paper by Connolly et al.](https://www.realclimate.org/index.php/archives/2022/11/serious-mistakes-found-in-recent-paper-by-connolly-et-al/) - RealClimate: Guest post by Mark Richardson who is a Research Scientist in the Aerosol and Clouds Group at NASA’s Jet Propulsion Laboratory, California Institute of Technology. All opinions expressed are his own and do not in any way represent those of NASA, JPL or Caltech. Should scientists choose to believe provably false things? Even though that
- [New misguided interpretations of the greenhouse effect from William Kininmonth](https://www.realclimate.org/index.php/archives/2022/10/new-misguided-interpretations-of-the-greenhouse-effect-from-william-kininmonth/) - RealClimate: I have a feeling that we are seeing the start of a new wave of climate change denial and misrepresentation of science. At the same time, CEOs of gas and oil companies express optimism for further exploitation of fossil energy in the wake of Russia’s invasion of Ukraine, at least here in Norway. Another clue
- [Area-based global hydro-climatological indicators](https://www.realclimate.org/index.php/archives/2023/07/area-based-global-hydro-climatological-indicators/) - RealClimate: The World Meteorological Organisation (WMO) Global Climate Observing System (GCOS) and Copernicus Climate Change Services (C3S) both provide sets of global climate statistics to summarise the state of Earth’s climate. They are indeed valuable indicators for the global or regional mean temperature, greenhouse gas concentrations, both ice volume and area, ocean heat, acidification, and the
- [Back to basics](https://www.realclimate.org/index.php/archives/2023/07/back-to-basics/) - RealClimate: You can tell how worried the climate deniers are by how many fields of science they have to trash to try and have people not see what’s happening.
- [Unforced Variations: Jun 2023](https://www.realclimate.org/index.php/archives/2023/06/unforced-variations-jun-2023/) - RealClimate: This month's open thread on climate topics.
- [Turning a new page[s]](https://www.realclimate.org/index.php/archives/2023/06/turning-a-new-pages/) - RealClimate: The world is full of climate dashboards (and dashboards of dashboards), and so you might imagine that all datasets and comparisons are instantly available in whatever graphical form you like. Unfortunately, we often want graphics to emphasize a particular point or comparison, and generic graphs from the producers of the data often don't have the
- [Unforced variations: May 2023](https://www.realclimate.org/index.php/archives/2023/05/unforced-variations-may-2023/) - RealClimate: This month's open thread on climate topics. Please be succinct, courteous and on point.
- [Evaluation of GCM simulations with a regional focus.](https://www.realclimate.org/index.php/archives/2023/05/evaluation-of-gcm-simulations-with-a-regional-focus/) - RealClimate: Do the global climate models (GCMs) we use for describing future climate change really capture the change and variations in the region that we want to study? There are widely used tools for evaluating global climate models, such as the ESMValTool, but they don’t provide the answers that I seek. I use GCMs to provide
- [CMIP6: Not-so-sudden stratospheric cooling](https://www.realclimate.org/index.php/archives/2023/05/cmip6-not-so-sudden-stratospheric-cooling/) - RealClimate: As predicted in 1967 by Manabe and Wetherald, the stratosphere has been cooling.
- [Unforced Variations: Apr 2023](https://www.realclimate.org/index.php/archives/2023/04/unforced-variations-apr-2023/) - RealClimate: This month's open thread on climate topics (no joke).
- [A NOAA-STAR dataset is born...](https://www.realclimate.org/index.php/archives/2023/04/a-noaa-star-dataset-is-born/) - RealClimate: What does a new entrant in the lower troposphere satellite record stakes really imply?
- [Unforced variations: March 2023](https://www.realclimate.org/index.php/archives/2023/03/unforced-variations-march-2023/) - RealClimate: This month's open thread. Antarctic sea ice anyone?
- [How not to science](https://www.realclimate.org/index.php/archives/2023/03/how-not-to-science/) - RealClimate: A trip down memory lane and a lesson on scientific integrity.
- [Scafetta comes back for more](https://www.realclimate.org/index.php/archives/2022/10/scafetta-comes-back-for-more/) - RealClimate: A new paper from Scafetta and it's almost as bad as the last one.
- [Unforced variations: Feb 2023](https://www.realclimate.org/index.php/archives/2023/02/unforced-variations-feb-2023/) - RealClimate: This month's open thread for climate related topics. Please be constructive, polite, and succinct.
- [The established ground and new ideas](https://www.realclimate.org/index.php/archives/2023/02/the-established-ground-and-new-ideas/) - RealClimate: Science is naturally conservative and the scepticism to new ideas ensures high scientific quality. We have more confidence when different scholars arrive at the same conclusion independently of each other. But scientific research also brings about discoveries and innovations, and it typically takes time for such new understanding to receive acknowledgement and acceptance. In the
- [Unforced variations: Jan 2023](https://www.realclimate.org/index.php/archives/2023/01/unforced-variations-jan-2023/) - RealClimate: Starting a little slowly this new year, but here is this month's open thread. Look out for various updates of the annual 2022 numbers over the next week or so...
- [2022 updates to the temperature records](https://www.realclimate.org/index.php/archives/2023/01/2022-updates-to-the-temperature-records/) - RealClimate: Another January, another annual data point.
- [Unforced variations: Dec 2022](https://www.realclimate.org/index.php/archives/2022/12/unforced-variations-dec-2022/) - RealClimate: This month's open thread for climate discussions. Please be constructive and polite.
- [The long story of constraining ocean heat content](https://www.realclimate.org/index.php/archives/2018/11/the-long-story-of-constraining-ocean-heat-content/) - RealClimate: Scientists predicted in the 1980s that a key fingerprint of anthropogenic climate change would be found in the ocean. If they were correct that increases in greenhouse gases were changing how much heat was coming into the system, then the component with the biggest heat capacity, the oceans, is where most of that heat would
- [The water south of Greenland has been cooling, so what causes that?](https://www.realclimate.org/index.php/archives/2022/12/the-water-south-of-greenland-has-been-cooling-so-what-causes-that/) - RealClimate: Let’s compare two possibilities by a back-of-envelope calculation. (1) Is it due to a reduced heat transport of the Atlantic Meridional Overturning Circulation (AMOC)? (2) Or is it simply due to the influx of cold meltwater as the Greenland Ice Sheet is losing ice? The latter is often suggested. The meltwater also contributes indirectly to
- [Unforced variations: Nov 2022](https://www.realclimate.org/index.php/archives/2022/11/unforced-variations-nov-2022/) - RealClimate: This month's open thread. Anyone read Greta Thunberg's book? or have an opinion about soup? Be substantive, be polite, be talking about climate.
- [Ocean Cooling. Not. <lang_pt>Resfriamento Oceânico? Não.</lang_pt> <lang_fr>L'océan se refroidit. Pas.</lang_fr>](https://www.realclimate.org/index.php/archives/2007/04/ocean-cooling-not/) - RealClimate: A lot has been made of a paper (Lyman et al, 2006) that appeared last year that claimed that the oceans had, contrary to expectation, cooled over the period 2003-2005. At the time, we (correctly) pointed out that this result was going to be hard to reconcile with continued increases in sea level rise (driven
- [Unforced variations: Oct 2022](https://www.realclimate.org/index.php/archives/2022/10/unforced-variations-oct-2022/) - RealClimate: This month's open thread on climate-related topics (sorry for the slight delay in setting it up). As usual, try to limit yourself to one comment a day, don't be unnecessarily aggressive and try to be substantive.
- [The #ConcordOslo2022 workshop](https://www.realclimate.org/index.php/archives/2022/10/the-concordoslo2022-workshop/) - RealClimate: In recent years, the idea of climate change adaptation has received more and more attention and has become even more urgent with the unfolding of a number of extreme weather-related calamities. I wrote a piece on climate change adaptation last year here on RealClimate, and many of the issues that I pointed to then are
- [Watching the detections](https://www.realclimate.org/index.php/archives/2022/09/watching-the-detections/) - RealClimate: The detection and attribution of climate change are based on fundamentally different statistical frameworks and shouldn't be conflated.
- [Start here](https://www.realclimate.org/index.php/archives/2007/05/start-here/) - RealClimate: [Note this is page is updated regularly. Please notify us of any dead links. Last update: 10 May 2022.] We're often asked to provide a one stop link for resources that people can use to get up to speed on the issue of climate change, and so here is a selection. Unlike our other postings,
- [Unforced variations: Aug 2022](https://www.realclimate.org/index.php/archives/2022/08/unforced-variations-aug-2022/) - RealClimate: This month's open thread on climate-related topics. Please be substantive, one comment per person per day, no bickering.
- [Unforced variations: Sep 2022](https://www.realclimate.org/index.php/archives/2022/09/unforced-variations-sep-2022/) - RealClimate: This month's open thread on climate topics. Check out the new State of the Climate in 2021 report from NOAA and BAMS. A blast from the past, though yamal-age may vary... As always, please stay civil, on topic, and limit comments to one a day.
- [Hey Ya! (mal)](https://www.realclimate.org/index.php/archives/2009/09/hey-ya-mal/) - RealClimate: Is the Yamal tree-ring series really the basis of all climate science? Of course not. Discussion of the McIntyre, Yamal, Briffa and the highly predictable trajectory of climate-related blogstorms. Plus lots of non-Yamal based hockey sticks.
- [Climate impacts of the #IRA](https://www.realclimate.org/index.php/archives/2022/08/climate-impacts-of-the-ira/) - RealClimate: With the signing of the Inflation Reduction Act (IRA) on Tuesday Aug 16, the most significant climate legislation in US federal history (so far) became law. Despite the odd name (and greatly overused TLA), the IRA contains a huge number of elements, totalling roughly 0 billion of investment, in climate solutions over the next ten
- [Unforced Variations: July 2022](https://www.realclimate.org/index.php/archives/2022/07/unforced-variations-july-2022/) - RealClimate: This month's open thread. Please keep to climate-related issues, stay substantive, no abuse, no repetition, one-comment per day.
- [Michael E. Mann](https://www.realclimate.org/index.php/archives/2004/12/michael-mann/) - RealClimate: Dr. Michael E. Mann is Presidential Distinguished Professor in the Department of Earth and Environmental Science at the University of Pennsylvania, with a secondary appointment in the Annenberg School for Communication. He is director of the Penn Center for Science, Sustainability, and the Media (PCSSM). Dr. Mann received his undergraduate degrees in Physics and Applied
- [From blog to <i>Science</i>](https://www.realclimate.org/index.php/archives/2011/02/from-blog-to-science/) - RealClimate: There is a lot of talk around about why science isn't being done on blogs. It can happen though, and sometimes blog posts can even end up as (part of) a real Science paper. However, the process is non-trivial and the relatively small number of examples of such a transition demonstrate clearly why blog science
- [Unforced variations: June 2022](https://www.realclimate.org/index.php/archives/2022/06/unforced-variations-june-2022/) - RealClimate: This month's open thread. New commenting rules (as described last month) remain in effect. Basically, be substantive, one comment a day, remain polite.
- [Mmm-k scale climate models](https://www.realclimate.org/index.php/archives/2022/06/mmm-k-scale-climate-models/) - RealClimate: What's good (and what's not quite ready) about plans for 'k-scale' climate modeling? Two opinion pieces (, and ) and a supportive were published this week, extolling the prospects for what they call "k-scale" climate modeling. These are models that would have grid boxes around 1 to 2 km in the horizontal - some 50
- [Overselling k-scale? Hmm](https://www.realclimate.org/index.php/archives/2022/06/overselling-k-scale-hmm/) - RealClimate: Some of the authors of a recent commentary on k-scale climate modeling respond to RealClimate.
- [Digital Twinge](https://www.realclimate.org/index.php/archives/2022/04/digital-twinge/) - RealClimate: A couple of weeks ago the EU announced that they were funding a project called DestinE (Destination Earth) to build 'digital twins' of the Earth System to support policy making and rapid reaction to weather and climate events. While the term 'digitial twin' has a long history in the engineering world, it's only recently been
- [Unforced Variations: May 2022](https://www.realclimate.org/index.php/archives/2022/05/unforced-variations-may-2022/) - RealClimate: Sorry for delay posting this month, but we've been considering how (or if) to go forward with open threads and comments. Looking at the multitude of constructive comments on the "End of blog comments" thread, it's clear that many people appreciate the possibility of comments here, but that too often it disappoints by devolving into
- [River Ice break-up trends 2022](https://www.realclimate.org/index.php/archives/2022/05/river-ice-break-up-trends-2022/) - RealClimate: As in previous years, the spring break-up of river ice on the Tanana River at Nenana and the Yukon River at Dawson City in Canada (new! h/t Ed Wiebe), is a great opportunity to highlight phenology that indicates that the planet is in fact reacting to the ongoing global warming. As we've done in previous
- [Plimer's homework assignment](https://www.realclimate.org/index.php/archives/2009/08/plimers-homework-assignment/) - RealClimate: Some of you may be aware of George Monbiot's so-far-unsuccessful attempt to pin down Ian Plimer on his ridiculous compendium of non-science. In response to Monbiot's request for explanation and sources for some of Plimer's more bizarre claims, Plimer has responded with a homework assignment that is clearly beyond even his (claimed) prowess. This is
- [The end of blog comments?](https://www.realclimate.org/index.php/archives/2022/03/the-end-of-blog-comments/) - RealClimate: Over the last decade, commenting has dramatically moved from specific web-sites to general social media platforms, radically changing how people interact with longer-form content (such as blogs, substacks, newspapers and journalism). No single site can compete with the breadth of audience and engagement that is found on Facebook, Twitter, Reddit etc. This has led to
- [Unforced variations: Mar 2022](https://www.realclimate.org/index.php/archives/2022/03/unforced-variations-mar-2022/) - RealClimate: This month's open thread on climate science issues.
- [Forced responses: Mar 2022](https://www.realclimate.org/index.php/archives/2022/03/forced-responses-mar-2022/) - RealClimate: This month's open thread on climate solutions.
- [The modern demarcation problem](https://www.realclimate.org/index.php/archives/2022/04/the-modern-demarcation-problem/) - RealClimate: Defining (and enforcing) a clear line between information and mis-information is impossible, but that doesn't mean misinformation doesn't exist or that there is nothing to be done to combat it. I found myself caught in an 'interesting' set of exchanges on twitter a few weeks ago (I won't link to it to spare you the
- [The IPCC Sixth Assessment Report](https://www.realclimate.org/index.php/archives/2021/08/the-ipcc-sixth-assessment-report/) - RealClimate: Top level post for all IPCC AR6 posts.
- [The Future of Climate Modeling?](https://www.realclimate.org/index.php/archives/2022/03/the-future-of-climate-modeling/) - RealClimate: Day 2 (22nd March): (1h 54min) Day 3 (23rd March): (1h 33min) Day 4 (24th March): (1h 45min) Many of the presentations are also available. The organizers are working on a paper of some sort that digests what was said and will I think be reaching out to a wider audience for feedback. TL;DR. Summary:
- ["Don't Look Up"](https://www.realclimate.org/index.php/archives/2022/01/dont-look-up/) - RealClimate: I recommend diving in and seeing what folks (both climate professionals and civilians) are saying. Some personal thoughts Like Ayana, Mike, and Peter, I saw a number of elements that resonated clearly with my experience in climate #scicomm. The 'deer in the headlights on live TV' feeling you get when the interviewer starts to go
- [The definitive CO<sub>2</sub>/CH<sub>4</sub>  comparison post](https://www.realclimate.org/index.php/archives/2021/09/the-definitive-co2-ch4-comparison-post/) - RealClimate: There is a new push to reduce CH4 emissions as a possible quick 'win-win' for climate and air quality. To be clear this is an eminently sensible idea - as it has been for decades (remember the 'Methane-to-markets' initiative from the early 2000s?), but it inevitably brings forth a mish-mash of half-remembered, inappropriate or out-of-date
- [A Nobel pursuit](https://www.realclimate.org/index.php/archives/2021/10/a-nobel-pursuit/) - RealClimate: Last week, the Nobel physics prize was (half) awarded to Suki Manabe and Klaus Hasselmann for their work on climate prediction and the detection and attribution of climate change. This came as quite a surprise to the climate community - though it was welcomed warmly. We've discussed the early climate model predictions a lot (including
- [Making predictions with the CMIP6 ensemble](https://www.realclimate.org/index.php/archives/2021/12/making-predictions-with-the-cmip6-ensemble/) - RealClimate: The CMIP6 multi-model ensemble is a unique resource with input from scientists and modeling groups from around the world. [CMIP stands for the Coupled Model Intercomparison Project, and it is now in its 6th Phase]. But as we've discussed before (#NotAllModels) there are some specific issues that require users to be cautious in making predictions.
- [Forced responses: Jan 2022](https://www.realclimate.org/index.php/archives/2022/01/forced-responses-jan-2022/) - RealClimate: A bi-monthly open thread related to climate solutions. PS. New year, new moderation policy. Please be substantive – sniping, insults, and tedious repetition will just be culled. We want to maintain a civil and productive discourse here, but the comment threads may need to be re-evaluated if that doesn’t happen.
- [Of buckets and blogs](https://www.realclimate.org/index.php/archives/2008/06/of-buckets-and-blogs/) - RealClimate: This last week has been an interesting one for observers of how climate change is covered in the media and online. On Wednesday an interesting paper (Thompson et al) was published in Nature, pointing to a clear artifact in the sea surface temperatures in 1945 and associating it with the changing mix of fleets and
- [Future rainfall over Sahel and Sahara](https://www.realclimate.org/index.php/archives/2022/02/future-rainfall-over-sahel-and-sahara/) - RealClimate: Ethiopia is praying for rain according to a recent report from the Guardian, and ReliefWeb suggests that a lack of rain may be linked to malnutrition in Tchad, as well as reduced crops in Niger. The African rainfall deficit appears to be widespread: the Cairo Review reports severe droughts that have been experienced across the
- [Unforced Variations: Jan 2022](https://www.realclimate.org/index.php/archives/2022/01/unforced-variations-jan-2022/) - RealClimate: This month's open thread on climate science topics. Note that summaries of annual climate data from 2021 will start to appear in a couple of weeks, and updates to the model/observations comparisons will appear a week or so after that. PS. New year, new moderation policy. Please be substantive - sniping, insults, and tedious repetition
- [Unforced Variations: Feb 2022](https://www.realclimate.org/index.php/archives/2022/02/unforced-variations-feb-2022/) - RealClimate: This month's open thread on climate science issues. Please be constructive, non-abusive and on-topic.
- [Forced responses: Nov 2021](https://www.realclimate.org/index.php/archives/2021/11/forced-responses-nov-2021/) - RealClimate: A bi-monthly open thread related to climate solutions. This month will start off with COP-26 and many targets and plans and mechanisms will be proposed and discussed. Look out for the updated impacts of the evolving NDCs such as this one from Climate Resource, suggesting that the world could be on track for just a
- [Unforced Variations: Dec 2021](https://www.realclimate.org/index.php/archives/2021/12/unforced-variations-dec-2021/) - RealClimate: This month's open thread on climate science topics.
- [Unforced variations: Nov 2021](https://www.realclimate.org/index.php/archives/2021/11/unforced-variations-nov-2021/) - RealClimate: This month's open thread. The first two weeks will be dominated by COP-26, and various science updates that will be announced there, including this year's Global Carbon Project report. Curiously, there is some archival interest in the climategate affair possibly in connection to COP-26 (a BBC dramatization "The Trick", a BBC radio series on the
- [Net Zero/Not Zero](https://www.realclimate.org/index.php/archives/2021/11/net-zero-not-zero/) - RealClimate: Is net-zero an empty slogan or an important geophysical concept or both?
- [Forced responses: Sep 2021](https://www.realclimate.org/index.php/archives/2021/09/forced-responses-sep-2021/) - RealClimate: A bimonthly open thread for discussions related to climate solutions. Note that open discussions of climate science are here. Possible topics of interest are the trial carbon-capture effort in Iceland and the discussions in the lead up to COP26. Please be constructive and substantive.
- [Unforced Variations: Oct 2021](https://www.realclimate.org/index.php/archives/2021/10/unforced-variations-oct-2021/) - RealClimate: Fall is here (in the northern hemisphere at least), along with articles about the impact of climate change on autumnal colors. LandSat9 successfully launched to continue an almost 50 year long series of remote sensing (since 1972!), and the World Economic Forum has proposed and Earth Operations Center to monitor greenhouse gases and climate change.
- [A science-based move to climate change adaptation](https://www.realclimate.org/index.php/archives/2021/10/a-science-based-move-to-climate-change-adaptation/) - RealClimate: All countries in the world urgently need to adapt to climate change but are not yet in a good position to do so. It's urgent because we are not even adapted to the present climate. This fact is underscored by recent weather-related calamities, such as flooding in Central Europe and heatwaves over North America. It’s
- [Tributes to Geert Jan van Oldenborgh](https://www.realclimate.org/index.php/archives/2021/10/tributes-to-geert-jan-van-oldenborgh/) - RealClimate: As many of you will know, Geert Jan van Oldenborgh died on Oct 12, 2021, and in the last week a number of very touching tributes have appeared. Notably, a lovely obituary in the NY Times by Henry Fountain, a segment on the BBC's Inside Science from Roland Pease, a piece on Bloomberg News by
- [Unforced Variations: Sep 2021](https://www.realclimate.org/index.php/archives/2021/09/unforced-variations-sep-2021/) - RealClimate: This month's open thread for climate science topics. Not sure about you, but we are still reading the details of the IPCC report. We are watching the unfolding hurricane season with trepidation, with particular concern related to the impacts of compound events (and not just those associated with climate), and anticipating another low, if not
- [AR6 of the best](https://www.realclimate.org/index.php/archives/2021/08/ar6-of-the-best/) - RealClimate: Half a dozen takeaways from a first read of the new IPCC AR6 report. As climate scientists we tend to look at the IPCC reports a little differently than the general public might. Here are a few things that mark this report out from previous versions that relate to issues we've discussed here before: Extreme
- [Deciphering the ‘SPM AR6 WG1’ code](https://www.realclimate.org/index.php/archives/2021/08/deciphering-the-spm-ar6-wg1-code/) - RealClimate: I followed with great interest the launch of the sixth assessment report Working Group 1 (The Physical Science Basis) from the Intergovernmental Panel on Climate Change (IPCC) on August 9th. The main report is quite impressive (see earlier posts here, here, here, and here) but the press conference didn’t come across as being focused and
- [The Crank Shaft](https://www.realclimate.org/index.php/archives/2019/03/the-crank-shaft/) - RealClimate: This is a thread for collecting the oddball theories, tinfoil hat-level conspiracies and other climate-related nonsense in the comments that would otherwise derail substantive discussion. Keeping them all in one spot might be of interest to future researchers.
- [Worldwide glacier retreat <lang_fr>Recul mondial des glaciers</lang_fr>](https://www.realclimate.org/index.php/archives/2005/03/worldwide-glacier-retreat/) - RealClimate: One of the most visually compelling examples of recent climate change is the retreat of glaciers in mountain regions. In the U.S. this is perhaps most famously observed in Glacier National Park, where the terminus of glaciers have retreated by several kilometers in the past century, and could be gone before the next century (see
- [About <lang_fr>A propos</lang_fr>](https://www.realclimate.org/index.php/archives/2004/12/about/) - RealClimate: RealClimate is a commentary site on climate science by working climate scientists for the interested public and journalists and has been operating since Dec 2004. We aim to provide the context sometimes missing in mainstream commentary on climate science. The discussion here is mostly restricted to scientific topics though we maintain open threads for the
- [Bjørn Lomborg, just a scientist with a different opinion?](https://www.realclimate.org/index.php/archives/2015/08/bjorn-lomborg-just-a-scientist-with-a-different-opinion/) - RealClimate: Bjørn Lomborg is a well-known media personality who argues that there are more important priorities than reducing emissions to limit global warming. In a recent controversy centering on him, the Australian government (known for its contradictory position on climate change) offered the University of Western Australia (UWA) million to make Lomborg professor – which
- [Unforced Variations: Aug 2021](https://www.realclimate.org/index.php/archives/2021/08/unforced-variations-aug-2021/) - RealClimate: This month is IPCC month - the Sixth Assessment Report from Working Group 1 is out on Monday August 9. We'll have some detailed comments once it's out, but in the meantime, feel free to speculate widely (always considering that IPCC is restricted to assessing existing literature...). Open thread - please stick to climate science
- [Sea level in the IPCC 6th assessment report (AR6)](https://www.realclimate.org/index.php/archives/2021/08/sea-level-in-the-ipcc-6th-assessment-report-ar6/) - RealClimate: My top 3 impressions up-front: The sea level projections for the year 2100 have been adjusted upwards again. The IPCC has introduced a new high-end risk scenario, stating that a global rise “approaching 2 m by 2100 and 5 m by 2150 under a very high greenhouse gas emissions scenario cannot be ruled out due
- [Millennia of sea-level change](https://www.realclimate.org/index.php/archives/2016/02/millennia-of-sea-level-change/) - RealClimate: How has global sea level changed in the past millennia? And how will it change in this century and in the coming millennia? What part do humans play? Several new papers provide new insights. 2500 years of past sea level variations This week, a paper will appear in the Proceedings of the National Academy of
- [A deep dive into the IPCC’s updated carbon budget numbers](https://www.realclimate.org/index.php/archives/2021/08/a-deep-dive-into-the-ipccs-updated-carbon-budget-numbers/) - RealClimate: Guest post by Joeri Rogelj (Twitter: @joerirogelj) Since temperature targets became international climate goals, we have been trying to understand and quantify the implications for our global emissions. Carbon budgets play an important role in this translation. Carbon budgets tell us how much CO2 we can emit while keeping warming below specific limits. We can
- [Realclimate redesign](https://www.realclimate.org/index.php/archives/2021/08/realclimate-redesign/) - RealClimate: After more than 15 years with basically the same layout, the Realclimate website - while still functional - has become increasing anachronistic both in appearance and 'under the hood'. In order to take advantage of more up to date web-site designs and new features that have been developed since the early 2000s (!), we need
- [#NotAllModels](https://www.realclimate.org/index.php/archives/2021/08/notallmodels/) - RealClimate: The spread of climate sensitivity in the CMIP6 models is wider than previous model ensembles and wider than the assessed range. But #notallmodels are running hot.
- [A Tale of Two Hockey Sticks](https://www.realclimate.org/index.php/archives/2021/08/a-tale-of-two-hockey-sticks/) - RealClimate: Two decades ago, the so-called “Hockey Stick” curve, published in 1999 by me and my co-authors , was featured in the all-important “Summary for Policy Makers” (SPM) of the 2001 IPCC Third Assessment report. The curve, which depicted temperature variations over the past 1000 years estimated from “proxy data such as tree rings, corals, ice
- [We are not reaching 1.5ºC earlier than previously thought](https://www.realclimate.org/index.php/archives/2021/08/we-are-not-reaching-1-5oc-earlier-than-previously-thought/) - RealClimate: What does the new IPCC report say about the likelihood of meeting the Paris goal of 1.5ºC?
- [Contributors](https://www.realclimate.org/index.php/archives/2004/12/contributors/) - RealClimate: The current contributors to content on this site are: Gavin Schmidt Michael Mann Rasmus Benestad Stefan Rahmstorf Eric Steig William Connolley was a contributor, but has now left academia; Ray Bradley, David Archer, and Ray Pierrehumbert are no longer active; Jim Bouldin was a contributor from 2009 and Caspar Ammann and Thibault de Garidel were
- [Climate adaptation should be based on robust regional climate information](https://www.realclimate.org/index.php/archives/2021/07/climate-adaptation-should-be-based-on-robust-regional-climate-information/) - RealClimate: Climate adaptation steams forward with an accelerated speed that can be seen through the Climate Adaptation Summit in January (see previous post), the ECCA 2021 in May/June, and the upcoming COP26. Recent extreme events may spur this development even further (see previous post about attribution of recent heatwaves). To aid climate adaptation, Europe’s Climate-Adapt programme
- [The global cooling mole <lang_sp>La excusa del enfriamiento global</lang_sp>](https://www.realclimate.org/index.php/archives/2008/03/the-global-cooling-mole/) - RealClimate: By John Fleck and William Connolley To veterans of the Climate Wars, the old 1970s global cooling canard - "How can we believe climate scientists about global warming today when back in the 1970s they told us an ice age was imminent?" - must seem like a never-ending game of Whack-a-mole. One of us (WMC) has
- [Archives](https://www.realclimate.org/index.php/archives/2004/12/archives/) - RealClimate: Archives by Month: Archives by Category:
- [Rapid attribution of PNW heatwave](https://www.realclimate.org/index.php/archives/2021/07/rapid-attribution-of-pnw-heatwave/) - RealClimate: It was almost impossible for the temperatures seen recently in the Pacific North West heatwave to have occurred without global warming.
- [Forced Responses: May 2021](https://www.realclimate.org/index.php/archives/2021/05/forced-responses-may-2021/) - RealClimate: A bimonthly open thread on climate solutions. Perhaps unsurprisingly this is always the most contentious comment thread on the site, but please try and be constructive and avoid going off on wild tangents.
- [Unforced Variations: Jun 2021](https://www.realclimate.org/index.php/archives/2021/06/unforced-variations-jun-2021/) - RealClimate: This month's open thread for climate science. Start of the meteorological summer, official hurricane season (outlook), the final stretches of the IPCC AR6 review process and a rare conjunction of Father's Day and the summer solstice. Please stay on topic.
- [Forced Responses: July 2021](https://www.realclimate.org/index.php/archives/2021/07/forced-responses-july-2021/) - RealClimate: A new bi-monthly open thread for climate solutions discussions. Climate science threads go here.
- [Unforced Variations: July 2021](https://www.realclimate.org/index.php/archives/2021/07/unforced-variations-july-2021/) - RealClimate: This month's open thread for climate science. Probably a good time to discuss attribution for extreme heat, wildfires, hurricane intensity and intense precipitation.
- [Unforced Variations: May 2021](https://www.realclimate.org/index.php/archives/2021/05/unforced-variations-may-2021/) - RealClimate: This month's open thread for climate science topics.
- [Why is future sea level rise still so uncertain?](https://www.realclimate.org/index.php/archives/2021/05/why-is-future-sea-level-rise-still-so-uncertain/) - RealClimate: Why is sea level rise so hard? Data, modeling and projection challenges still exist even while we make incremental progress.
- [Forced responses: Mar 2021](https://www.realclimate.org/index.php/archives/2021/03/forced-responses-mar-2021/) - RealClimate: A bi-monthly open thread on climate solutions.
- [Unforced Variations: Apr 2021](https://www.realclimate.org/index.php/archives/2021/04/unforced-variations-apr-2021/) - RealClimate: This month's open thread for climate science discussions. Be nice, it's Earth month.
- [Something Harde to believe...](https://www.realclimate.org/index.php/archives/2017/02/something-harde-to-believe/) - RealClimate: A commenter brings news of an obviously wrong paper that has just appeared in Global and Planetary Change. purports to be a radical revision of our understanding of the carbon cycle by Hermann Harde. The key conclusions are (and reality in green): The average residence time of CO2 in the atmosphere is found to be
- [Nenana Ice Classic 2021](https://www.realclimate.org/index.php/archives/2021/04/nenana-ice-classic-2021/) - RealClimate: The Nenana Ice Classic continues its trend towards earlier break ups.
- [On arguing by analogy](https://www.realclimate.org/index.php/archives/2014/09/on-arguing-by-analogy/) - RealClimate: Climate blogs and comment threads are full of 'arguments by analogy'. Depending on what 'side' one is on, climate science is either like evolution/heliocentrism/quantum physics/relativity or eugenics/phrenology/Ptolemaic cosmology/phlogiston. Climate contrarians are either like flat-earthers/birthers/moon-landing hoaxers/vaccine-autism linkers or Galileo/stomach ulcer-Helicobacter proponents/Wegener/Copernicus. Episodes of clear misconduct or dysfunction in other spheres of life are closely parsed only
- [Two graphs show the path to 1.5 degrees](https://www.realclimate.org/index.php/archives/2021/04/two-graphs-show-the-path-to-1-5-degrees/) - RealClimate: In the Paris Agreement, just about all of the world's nations pledged to “pursue efforts to limit the temperature increase to 1.5 degrees Celsius above pre-industrial levels”. On Saturday, the top climate diplomats from the U.S. and China, John Kerry and Xie Zhenhua, reiterated in a joint statement that they want to step up their
- [Extreme metrics](https://www.realclimate.org/index.php/archives/2012/08/extreme-metrics/) - RealClimate: There has been a lot of discussion related to the paper and the accompanying op-ed in the Washington Post last week. But in this post, I'll try and make the case that most of the discussion has not related to the actual analysis described in the paper, but rather to proxy arguments for what people
- [Should the official Atlantic hurricane season be lengthened?](https://www.realclimate.org/index.php/archives/2021/04/should-the-official-atlantic-hurricane-season-be-lengthened/) - In 2020, the date of formation of every named storm, from Tropical Storm Arthur to Hurricane Iota was substantially earlier than normal. What is the evidence for a trend towards earlier and longer hurricane seasons?By Jim Kossin, Tim Hall, Mike Mann, and Stefan RahmstorfThe 2020 Atlantic hurricane season broke a number of records, with the formation of an unprecedented 30 "named storms" (storms that reach wind-speed intensity of at least 18 m/s and are then given an official name). The season also started earlier than normal. In fact, when
- [Unforced Variations: Mar 2021](https://www.realclimate.org/index.php/archives/2021/03/unforced-variations-mar-2021/) - RealClimate: This month's open thread. Northern Hemisphere Spring is on it's way, along with peak Arctic/minimum Antarctic sea ice, undoubtedly more discussion about the polar vortex, and the sharpening up of the (currently very uncertain) ENSO forecast for the rest of this year.
- [A potential rule of thumb for hourly rainfall?](https://www.realclimate.org/index.php/archives/2021/03/a-potential-rule-of-thumb-for-hourly-rainfall/) - RealClimate: [latexpage] Future global warming will be accompanied by more intense rainfall and flash floods due to increased evaporation, as a consequence of higher surface temperatures which also lead to a higher turn-around rate for the global hydrological cycle. In other words, we will see changing rainfall patterns. And if the global area of rainfall also
- [The Rise and Fall of the "Atlantic Multidecadal Oscillation"](https://www.realclimate.org/index.php/archives/2021/03/the-rise-and-fall-of-the-atlantic-multidecadal-oscillation/) - RealClimate: Two decades ago, in an interview with science journalist Richard Kerr for the journal Science, I coined the term the "Atlantic Multidecadal Oscillation" (AMO) to describe an internal oscillation in the climate system resulting from interactions between North Atlantic ocean currents and wind patterns. These interactions were thought to lead to alternating decades-long intervals of
- [Looking for help with an electricity tax-swap idea](https://www.realclimate.org/index.php/archives/2021/03/looking-for-help-with-an-electricity-tax-swap-idea/) - RealClimate: Guest commentary from Yoram Bauman Everyone from Treasury Secretary Janet Yellen to Elon Musk thinks that putting a price on carbon is an important step in tackling climate change. Politically, however, carbon taxes and cap-and-trade systems face an uphill battle, in part because they could drive up the prices of household basics like gasoline and
- [Forced Responses: Jan 2021](https://www.realclimate.org/index.php/archives/2021/01/forced-responses-jan-2021/) - RealClimate: A new open thread for climate solutions in the new year (and the soon-to-be new US administration actions). As for the climate science open threads, please try to renew your commitment to constructive dialog that prioritises light over heat (like LED bulbs for instance!). Thanks!
- [Unforced Variations: Feb 2021](https://www.realclimate.org/index.php/archives/2021/02/unforced-variations-feb-2021/) - RealClimate: This month's open thread on climate science topics. Discussions related to solutions should go here.
- [Laschamps-ing at the bit](https://www.realclimate.org/index.php/archives/2021/02/laschamps-ing-at-the-bit/) - RealClimate: A placeholder to provide some space to discuss the paper last week on the putative climate consequences of the Laschamps Geomagnetic Excursion, some 42,000 yrs ago. There was some rather breathless reporting on this paper, but there were also a lot of sceptical voices - not of the main new result (a beautiful new 14C
- [Regional information for society (RifS) and unresolved issues](https://www.realclimate.org/index.php/archives/2021/02/regional-information-for-society-rifs-and-unresolved-issues/) - RealClimate: It’s encouraging to note the growing interest for regional climate information for society and climate adaptation, such as recent advances in the World Climate Research Programme (WCRP), the climate adaptation summit CAS2021, and the new Digital Europe. These efforts are likely to boost the Global Framework for Climate Services (GFCS) needed as a guide to
- [Don't climate bet against the house](https://www.realclimate.org/index.php/archives/2021/02/dont-climate-bet-against-the-house/) - RealClimate: Decades ago (it seems) when perhaps it was still possible to have good faith disagreements about the attribution of current climate trends, James Annan wrote a post here summarizing the thinking and practice of Climate Betting. That led to spate of wagers on continued global warming (a summary of his bets through 2005 and attempts
- [Unforced Variations: Jan 2021](https://www.realclimate.org/index.php/archives/2021/01/unforced-variations-jan-2021/) - RealClimate: According to the somewhat arbitrary customs of our age, the 1st of January marks the beginning of a new year, a new decade and, by analogy, a new start in human affairs. So shall it be at RealClimate too.
- [Climate Adaptation Summit 2021](https://www.realclimate.org/index.php/archives/2021/01/climate-adaptation-summit-2021/) - RealClimate: The first ever Climate Adaptation Summit (#adaptationsummit) that I have heard about took place last week, on January 25-26. I think such a summit was a step in the right direction. It was adapted to the Covid-19 situation and therefore an online virtual summit streamed on YouTube. I watched a few of the streamed sessions,
- [Mind the Gap! <lang_it>Attenzione alla differenza!</lang_it>](https://www.realclimate.org/index.php/archives/2008/11/mind-the-gap/) - RealClimate: Confusion has continued regarding trends in global temperatures. The misconception 'the global warming has stopped' still lives on in some minds. We have already discussed why this argument is flawed. So why have we failed to convince ;-) ? Una traduzione in italiano è disponibile qui. The confused argument hinges on one data set -
- [2020 Hindsight](https://www.realclimate.org/index.php/archives/2021/01/2020-hindsight/) - RealClimate: Yesterday was the day that NASA, NOAA, the Hadley Centre and Berkeley Earth delivered their final assessments for temperatures in Dec 2020, and thus their annual summaries. The headline results have received a fair bit of attention in the media (NYT, WaPo, BBC, The Guardian etc.) and the conclusion that 2020 was pretty much tied
- [Flyer tipping](https://www.realclimate.org/index.php/archives/2021/01/flyer-tipping/) - RealClimate: You would be forgiven for not paying attention to the usual suspects of climate denial right now, but they are trying to keep busy anyway. Last week (January 8), Roy Spencer [Update Jan 13: now deleted] posted a series of Climate Change "flyers" on his personal blog that purported to be organised by David Legates
- [Unforced variations: Dec 2020](https://www.realclimate.org/index.php/archives/2020/12/unforced-variations-dec-2020/) - RealClimate: This month's open thread. Topics might include the record breaking hurricane season, odds for the warmest year horse race (and it's relevance or not), or indeed anything climate science related.
- [Forced responses: Dec 2020](https://www.realclimate.org/index.php/archives/2020/12/forced-responses-dec-2020/) - RealClimate: The bimonthly open thread on climate solution discussions. Topics might focus on the incoming Biden administration, the five year anniversary of the Paris Accords, and the challenge of making post-covid plans sustainable. Climate science issues should be raised here.
- [2020 vision](https://www.realclimate.org/index.php/archives/2020/12/2020-vision/) - RealClimate: No-one needs another litany of all the terrible things that happened this year, but there are three areas relevant to climate science that are worth thinking about: What actually happened in climate/weather (and how they can be teased apart). There is a good summary on the BBC radio Discover program covering wildfires, heat waves, Arctic
- [The number of tropical cyclones in the North Atlantic](https://www.realclimate.org/index.php/archives/2020/12/the-number-of-tropical-cyclones-in-the-north-atlantic/) - RealClimate: [latexpage]2020 has been an unusual and challenging year in many ways. One was the record-breaking number of named tropical cyclones in the North Atlantic (and the Carribean Sea). There has been 30 named North Atlantic tropical cyclones in 2020, beating the previous record of 28 from 2005 by two. A natural question then is whether
- [Do you want to share your views on climate change and reading blogs?](https://www.realclimate.org/index.php/archives/2019/10/do-you-want-to-share-your-views-on-climate-change-and-reading-blogs/) - RealClimate: A survey is being conducted by researchers of Cambridge University and Wageningen University. They have asked us to post information about it. Please share your views on climate change and reading blogs by filling out this survey. The data will be used to get a better understanding of climate change blog audiences’ views on climate
- [An ever more perfect dataset?](https://www.realclimate.org/index.php/archives/2020/12/an-ever-more-perfect-dataset/) - RealClimate: Do you remember when global warming was small enough for people to care about the details of how climate scientists put together records of global temperature history? Seems like a long time ago... Nonetheless, it's worth a quick post to discuss the latest updates in HadCRUT (the data product put together by the UK's Hadley
- [Unforced Variations: Nov 2020](https://www.realclimate.org/index.php/archives/2020/11/unforced-variations-nov-2020/) - RealClimate: This month's open thread for climate science. As if there wasn't enough going on, we have still more hurricanes in the Atlantic, temperature records tumbling despite La Niña, Arctic sea ice that doesn't want to reform, bushfire season kicking off in the Southern Hemisphere while we are barely done with it in the North... Welcome
- [Thinking, small and big](https://www.realclimate.org/index.php/archives/2020/11/thinking-small-and-big/) - RealClimate: The point that climate downscaling must pay attention to the law of small numbers is no joke. The World Climate Research Programme (WCRP) will become a 'new' WCRP with a “soft launch” in 2021. This is quite a big story since it coordinates much of the research and the substance on which the Intergovernmental Panel
- [Forced Responses: Oct 2020](https://www.realclimate.org/index.php/archives/2020/10/forced-responses-oct-2020/) - RealClimate: Bimonthly open thread for discussing climate policy and solutions. Climate science discussion should go here.
- [Unforced variations: Sep 2020](https://www.realclimate.org/index.php/archives/2020/09/unforced-variations-sep-2020/) - RealClimate: This month's open thread on climate science topics. Things to look for - Arctic sea ice minimum, boreal wildfires and the Atlantic hurricane season - you know, the usual...
- [Unforced Variations: Oct 2020](https://www.realclimate.org/index.php/archives/2020/10/unforced-variations-oct-2020/) - RealClimate: This month's open thread.
- [New studies confirm weakening of the Gulf Stream circulation (AMOC)](https://www.realclimate.org/index.php/archives/2020/09/new-studies-confirm-weakening-of-the-gulf-stream-circulation-amoc/) - RealClimate: Many of the earlier predictions of climate research have now become reality. The world is getting warmer, sea levels are rising faster and faster, and more frequent heat waves, extreme rainfall, devastating wildfires and more severe tropical storms are affecting many millions of people. Now there is growing evidence that another climate forecast is already
- [A New Take on an Old Millennium](https://www.realclimate.org/index.php/archives/2006/02/a-new-take-on-an-old-millennium/) - RealClimate: The subject of reconstructions of temperature variations of the past millennium has been discussed many times before on this site (see e.g. here, here, here, and here). Despite the apparent controversy, the basic conclusion--that the global and hemispheric-scale warmth of the past few decades appears anomalous in a very long-term context--has stood up remarkably well
- [First successful model simulation of the past 3 million years of climate change](https://www.realclimate.org/index.php/archives/2019/04/first-successful-model-simulation-of-the-past-3-million-years-of-climate-change/) - RealClimate: Guest post by Matteo Willeit, Potsdam Institute for Climate Impact Research A new study published in Science Advances shows that the main features of natural climate variability over the last 3 million years can be reproduced with an efficient model of the Earth system. The Quaternary is the most recent geological Period, covering the past
- [Unforced Variations: Aug 2020](https://www.realclimate.org/index.php/archives/2020/08/unforced-variations-aug-2020/) - RealClimate: This month's open thread for climate science issues. People might want to keep an eye on the Arctic sea ice...
- [Denial and Alarmism in the Near-Term Extinction and Collapse Debate](https://www.realclimate.org/index.php/archives/2020/08/denial-and-alarmism-in-the-near-term-extinction-and-collapse-debate/) - RealClimate: Guest article by Alastair McIntosh, honorary professor in the College of Social Sciences at the University of Glasgow in Scotland. This is an excerpt from his new book, Riders on the Storm: The Climate Crisis and the Survival of Being Mostly, we only know what we think we know about climate science because of the
- [Sensitive but unclassified: Part II](https://www.realclimate.org/index.php/archives/2020/06/sensitive-but-unclassified-part-ii/) - RealClimate: The discussion and analysis of the latest round of climate models continues - but not always sensibly. In a previous post, I discussed the preliminary results from the ongoing CMIP6 exercise - an international, multi-institutional, coordinated and massive suite of climate model simulations - and noted that they exhibited a wider range of equilibrium climate
- [How to spot "alternative scientists".](https://www.realclimate.org/index.php/archives/2020/08/how-to-spot-alternative-scientists/) - RealClimate: Recently, a so-called “white coat summit” gave me a sense of dejavu. It was held by a group that calls itself ‘America’s Frontline Doctors’ (AFD) that consisted of about a dozen people wearing white coats to the effect of achieving an appearance of being experts on medical matters. The AFD apparently wanted to address
- [Forced responses: Jun 2020](https://www.realclimate.org/index.php/archives/2020/06/forced-responses-jun-2020/) - RealClimate: Open thread on climate solutions. Please try and stay within a mile or two of the overall topic.
- [Forced Responses: Aug 2020](https://www.realclimate.org/index.php/archives/2020/08/forced-responses-aug-2020/) - RealClimate: This is the bimonthly thread on climate solutions. Climate Science discussions should go here.
- [Unforced Variations: July 2020](https://www.realclimate.org/index.php/archives/2020/07/unforced-variations-july-2020/) - RealClimate: This month's open thread for climate science topics.
- [Somebody read the comments...](https://www.realclimate.org/index.php/archives/2020/07/somebody-read-the-comments/) - RealClimate: This post is just to highlight an that's just been published that analyzed the comment threads here and at WUWT. In it, the authors analyze how the commenters interact, argue and attempt to persuade, mostly, to be fair, unsuccessfully. It may be that seeing how academics analyse the arguments, some commenters might want to modify
- [Climate Sensitivity: A new assessment](https://www.realclimate.org/index.php/archives/2020/07/climate-sensitivity-a-new-assessment/) - RealClimate: Not small enough to ignore, nor big enough to despair. There is a new review paper on climate sensitivity published today ( (preprint) that is the most thorough and coherent picture of what we can infer about the sensitivity of climate to increasing CO2. The paper is exhaustive (and exhausting - coming in at 166
- [Shellenberger's op-ad](https://www.realclimate.org/index.php/archives/2020/07/shellenbergers-op-ad/) - RealClimate: Guest commentary by Michael Tobis This is a deep dive into the form and substance of Michael Shellenberger's promotion for his new book "Apocalypse Never". Shorter version? It should be read as a sales pitch to a certain demographic rather than a genuine apology. Michael Shellenberger appears to have a talent for self-promotion. His book,
- [Unforced variations: Jun 2020](https://www.realclimate.org/index.php/archives/2020/06/unforced-variations-jun-2020/) - RealClimate: This month's open thread on climate science issues.
- ['2040'](https://www.realclimate.org/index.php/archives/2020/06/2040/) - RealClimate: After an absurd period with a real-life gloomy corona pandemic, lock-down and unrest, it was quite refreshing to see visions for a sustainable future in a new documentary '2040' (link to trailer). Its message, through the voice of Damon Gameau, is about hope and is based on rational thinking. The video takes us to twenty
- [Unforced variations: May 2020](https://www.realclimate.org/index.php/archives/2020/05/unforced-variations-may-2020/) - RealClimate: This month's climate science open thread.
- [Unforced Variations: Apr 2020](https://www.realclimate.org/index.php/archives/2020/04/unforced-variations-apr-2020/) - RealClimate: Open thread for climate science topics.
- [Nenana Ice Classic 2020](https://www.realclimate.org/index.php/archives/2020/04/nenana-ice-classic-2020/) - RealClimate: Readers may recall my interest in phenological indicators of climate change, and ones on which 0K rest are a particular favorite. The Nenana Ice Classic is an annual tradition since 1917, and provides a interesting glimpse into climate change in Alaska. This year's break-up of ice has just happened (unofficially, Apr 27, 12:56pm AKST), and,
- [Regional climate modeling and some common omissions](https://www.realclimate.org/index.php/archives/2020/04/regional-climate-modeling-and-some-common-omissions/) - RealClimate: There is a growing need for local climate information in order to update our understanding of risks connected to the changing weather and prepare for new challenges. This need has been an important motivation behind the World Meteorological Organisation’s (WMO) Global Framework for Climate Services (GFCS). There has also been a lot of work carried
- [A problem with YouTube](https://www.realclimate.org/index.php/archives/2020/04/a-problem-with-youtube/) - RealClimate: The American Geophysical Union (AGU) started to stream sessions at their annual meeting in San Francisco a few years ago. This kind of participation over the Internet is a nice alternative since many scholars are unable to attend the AGU meetings due to distance, time constraints, time difference and cost. I watched some of
- [Unbelievably, this is no April's fool joke](https://www.realclimate.org/index.php/archives/2020/03/unbelievably-this-is-no-aprils-fool-joke/) - RealClimate: Last week, a colleague shared a tweet with a link to a very unusual paper. I first thought it must be a joke, but then realised that since it was the last days in March when I read it, it could not be an April's fool joke. It seems to be a serious paper. So
- [Forced responses: Feb 2020](https://www.realclimate.org/index.php/archives/2020/02/forced-responses-feb-2020/) - RealClimate: This month’s open thread on climate solutions.
- [Unforced variations: Mar 2020](https://www.realclimate.org/index.php/archives/2020/03/unforced-variations-mar-2020/) - RealClimate: This month's open thread for climate science topics.
- [Forced variations: Apr 2020](https://www.realclimate.org/index.php/archives/2020/04/forced-variations-apr-2020/) - RealClimate: Open thread for climate solutions.
- [Further perspectives on pandemics and climate change](https://www.realclimate.org/index.php/archives/2020/03/further-perspectives-on-pandemics-and-climate-change/) - RealClimate: I have recently been asked whether the present corona pandemic will have any consequence on climate change. Gavin has already discussed the coronavirus and climate here on RealClimate, and I like to follow up on his post. Rather than emphasising analogies, I would highlight additional common denominators between the present world-wide Covid-19 pandemic and climate
- [Coronavirus and climate](https://www.realclimate.org/index.php/archives/2020/03/coronavirus-and-climate/) - RealClimate: As we collectively reel from the changes wrought by the current pandemic, people are being drawn by analogy to climate issues - but analogies can be tricky and often distort as much as they illuminate. For instance, in the Boston Globe, Jeff Jacoby's commentary was not particularly insightful and misquoted Mike Mann pretty egregiously. Mike's
- [Why not use a clever mathematical trick?](https://www.realclimate.org/index.php/archives/2020/03/why-not-use-a-clever-mathematical-trick/) - RealClimate: There is a clever mathematical trick for comparing different data sets, but it does not seem to be widely used. It is based on so-called empirical orthogonal functions (EOFs), which Edward Lorenz described in a Massachusetts Institute of Technology (MIT) scientific report from 1956. The EOFs are similar to principal component analysis (PCA). The EOFs
- [Resplandy et al. correction and response](https://www.realclimate.org/index.php/archives/2018/11/resplandy-et-al-correction-and-response/) - RealClimate: Guest commentary from Ralph Keeling (UCSD) I, with the other co-authors of , want to address two problems that came to our attention since publication of our paper in Nature last week. These problems do not invalidate the methodology or the new insights into ocean biogeochemistry on which it is based, but they do influence
- [Why are so many solar-climate papers flawed?](https://www.realclimate.org/index.php/archives/2020/03/why-are-so-many-solar-climate-papers-flawed/) - RealClimate: The paper that incorrectly purported to link solar-climate effects to movements of the Sun around the barycenter has been retracted. This paper generated an enormous thread on @PubPeer where the authors continued to defend the indefensible and even added in new errors (such as a claim that the Earth's seasonal cycles are due to variations
- [Unforced Variations: Feb 2020](https://www.realclimate.org/index.php/archives/2020/02/unforced-variations-feb-2020/) - RealClimate: This month's open thread. Focus on climate science. Be kind.
- [Surprised by the shallows - again](https://www.realclimate.org/index.php/archives/2020/02/surprised-by-the-shallows-again/) - RealClimate: Guest commentary from Jim Acker (GSFC/Adnet) Research on the ocean carbonate cycle published in 2019 supports results from the 1980s – in contrast to many papers published since then. During my graduate school education and research program in the 1980s, conducted at the Department of Marine Science (now the College of Oceanography) of the University
- [Unforced variations: Jan 2020](https://www.realclimate.org/index.php/archives/2020/01/unforced-variations-jan-2020/) - RealClimate: The new open thread on climate science for a new year, and a new decade - perhaps the Soaring Twenties? What precisely will be soaring is yet to be decided though. Two things will almost certainly go up - CO2 emissions and temperatures: https://twitter.com/ClimateOfGavin/status/1208748242596438018?s=20 But maybe also ambition, determination, and changes that will lead to
- [Temperature Variations in Past Centuries and the so-called "Hockey Stick"  <lang_fr>Variations de température sur les derniers siècles et la "crosse de hockey"</lang_fr>](https://www.realclimate.org/index.php/archives/2004/12/temperaturevariations-in-past-centuries-and-the-so-called-hockey-stick/) - RealClimate: Instrumental data describing large-scale surface temperature changes are only available for roughly the past 150 years. Estimates of surface temperature changes further back in time must therefore make use of the few long available instrumental records or historical documents and natural archives or "proxy" indicators, such as tree rings, corals, ice cores and lake sediments, to reconstruct patterns of past surface temperature change. Due to the paucity of data in the Southern Hemisphere, recent studies have emphasized the reconstruction of Northern Hemisphere (NH) mean, rather than global mean temperatures over roughly the past 1000 years. The term "Hockey Stick" was coined by former head of.....
- [What If ... the "Hockey Stick" Were Wrong? <lang_fr>Et si …. la "Crosse de Hockey" était fausse ? </lang_fr>](https://www.realclimate.org/index.php/archives/2005/01/what-if-the-hockey-stick-were-wrong/) - RealClimate: The “hockey stick” reconstruction of temperatures of the past millennium has attracted much attention – partly as it was high-lighted in the 2001 IPCC report as one of the important new results since the previous IPCC report of 1995, and partly as it has become the focus of a number of challenges. Discussion about the
- [Does a slow AMOC increase the rate of global warming?](https://www.realclimate.org/index.php/archives/2018/07/does-a-slow-amoc-increase-the-rate-of-global-warming/) - RealClimate: Established understanding of the AMOC (sometimes popularly called Gulf Stream System) says that a weaker AMOC leads to a slightly cooler global mean surface temperature due to changes in ocean heat storage. But now, a new paper in Nature claims the opposite and even predicts a phase of rapid global warming. What's the story? By
- [BAU wow wow](https://www.realclimate.org/index.php/archives/2020/01/bau-wow-wow/) - RealClimate: How should we discuss scenarios of future emissions? What is the range of scenarios we should explore? These are constant issues in climate modeling and policy discussions, and need to be reassessed every few years as knowledge improves. I discussed some of this in a post on worst case scenarios a few months ago, but
- [The best case for worst case scenarios](https://www.realclimate.org/index.php/archives/2019/02/the-best-case-for-worst-case-scenarios/) - RealClimate: The "end of the world" or "good for you" are the two least likely among the spectrum of potential outcomes.Stephen Schneider Scientists have been looking at best, middling and worst case scenarios for anthropogenic climate change for decades. For instance, himself took a turn back in 2009. And others have postulated both far more rosy
- [The climate has always changed. What do you conclude?](https://www.realclimate.org/index.php/archives/2017/07/the-climate-has-always-changed-what-do-you-conclude/) - RealClimate: Probably everyone has heard this argument, presented as objection against the findings of climate scientists on global warming: "The climate has always changed!" And it is true: climate has changed even before humans began to burn fossil fuels. So what can we conclude from that? A quick quiz Do you conclude... (1) that humans cannot
- [One more data point](https://www.realclimate.org/index.php/archives/2020/01/one-more-data-point/) - RealClimate: The climate summaries for 2019 are all now out. None of this will be a surprise to anyone who's been paying attention, but the results are stark. 2019 was the second warmest year (in analyses from GISTEMP, NOAA NCEI, ERA5, JRA55, Berkeley Earth and Cowtan & Way, RSS TLT), it was third warmest in the
- [Unforced variations: Dec 2019](https://www.realclimate.org/index.php/archives/2019/12/unforced-variations-dec-2019/) - RealClimate: This month’s open thread. December already?
- [AGU 2019](https://www.realclimate.org/index.php/archives/2019/12/agu-2019/) - RealClimate: Another year, another AGU. Back in San Francisco for the first time in 3 years, and with a massive assortment of talks, events and workshops. For those not able to go, there is an increasing, though not yet exhaustive, availability of streaming and online content. Notably, the AGU GO service is streaming 15 sessions live
- [Forced Responses: Dec 2019](https://www.realclimate.org/index.php/archives/2019/12/forced-responses-dec-2019/) - RealClimate: Open thread for climate solution discussion. Climate science discussions should remain on the Unforced Variations thread.
- [More than 500 people misunderstand climate change](https://www.realclimate.org/index.php/archives/2019/10/more-than-500-people-misunderstand-climate-change/) - RealClimate: A consensus is usually established when one explanation is more convincing than alternative accounts, convincing the majority. This is also true in science. However, science-based knowledge is also our best description of our world because it is built on testing hypotheses that are independently reexamined by colleagues. It is also typical that there are a
- [Unforced variations: Nov 2019](https://www.realclimate.org/index.php/archives/2019/11/unforced-variations-nov-2019/) - RealClimate: This month's open thread.
- [10 years on](https://www.realclimate.org/index.php/archives/2019/11/10-years-on/) - RealClimate: I woke up on Tuesday, 17 Nov 2009 completely unaware of what was about to unfold. I tried to log in to RealClimate, but for some reason my login did not work. Neither did the admin login. I logged in to the back-end via ssh, only to be inexplicably logged out again. I did it
- [Sensitive But Unclassified](https://www.realclimate.org/index.php/archives/2019/11/sensitive-but-unclassified/) - RealClimate: The US federal government goes to quite a lot of effort to (mostly successfully) keep sensitive but unclassified (SBU) information (like personal data) out of the hands of people who would abuse it. But when it comes to the latest climate models, quite a few are SBU as well. The results from climate models that
- [Unforced Variations: Oct 2019](https://www.realclimate.org/index.php/archives/2019/10/unforced-variations-oct-2019/) - RealClimate: This month's open thread. Please try to stick to climate science topics.
- [Noise on the Telegraph](https://www.realclimate.org/index.php/archives/2015/02/noise-on-the-telegraph/) - RealClimate: I was surprised by the shrill headlines from a British newspaper with the old fashioned name the Telegraph: “The fiddling with temperature data is the biggest science scandal ever”. So what is this all about? The story makes serious allegations, however Victor Venema explains why the Telegraph got it wrong in Variable Variability, and makes
- [2005 temperatures <lang_fr>Températures 2005</lang_fr>](https://www.realclimate.org/index.php/archives/2005/12/2005-temperatures/) - RealClimate: Due to a historical quirk (of unknown origin), the World Meterological Organisation releases its summary for each year based on the Dec to Nov 'meteorlogical year' means (rather than the more usual calendar year). Anyway, the WMO summary is now available, as is the NASA GISS analysis and the CRU summary. The point upon which
- [Forced responses: Oct 2019](https://www.realclimate.org/index.php/archives/2019/10/forced-responses-oct-2019/) - RealClimate: Bi-monthly open thread on climate solutions. Please try to be civil. Remember, climate science questions can be discussed on the Unforced Variations thread.
- [Forced responses: Aug 2019](https://www.realclimate.org/index.php/archives/2019/07/forced-responses-aug-2019/) - RealClimate: Bi-monthly thread on climate solutions and responses.
- [Unforced variations: Sep 2019](https://www.realclimate.org/index.php/archives/2019/09/unforced-variations-sep-2019/) - RealClimate: This month's open thread for climate science topics. A new two-part community assessment of tropical storms and climate change is online at BAMS: Knutson et al. ; . And for those interested in Arctic Sea Ice, there is always the NSIDC.
- [Background on the role of natural climate variability in West Antarctic ice sheet change.](https://www.realclimate.org/index.php/archives/2019/08/background-on-the-role-of-natural-climate-variability-in-west-antarctic-ice-sheet-change/) - RealClimate: This is a summary of some of the key details that underpin the discussion of anthropogenic vs. natural forcing in driving glacier change in West Antarctica. This is useful background for the paper by Holland et al. (2019), discussed in another post (here). We've known for some time that Pine Island Glacier (PIG) and Thwaites Glacier,
- [The Antarctic ice sheet is melting and, yeah, it's probably our fault.](https://www.realclimate.org/index.php/archives/2019/08/the-antarctic-ice-sheet-is-melting-and-yeah-its-probably-our-fault/) - RealClimate: Glaciers in West Antarctica have thinned and accelerated in the last few decades. A new paper provides some of the first evidence that this is due to human activities. by Eric Steig It’s been some time since I wrote anything for RealClimate. In the interim there’s been a lot of important new work in the area
- [Unforced variations: Aug 2019](https://www.realclimate.org/index.php/archives/2019/07/unforced-variations-aug-2019/) - RealClimate: This month's open thread on climate science topics. Arctic sea ice minimum is upcoming, global temperatures running at (or close) to record levels, heat waves, new reconstructions for the last 2000 years, etc... Surely something there to discuss?
- [Unforced variations: Nov 2014](https://www.realclimate.org/index.php/archives/2014/11/unforced-variations-nov-2014/) - RealClimate: This month's open thread. In honour of today's New York Marathon, we are expecting the fastest of you to read and digest the final IPCC Synthesis report in sub-3 hours. For those who didn't keep up with the IPCC training regime, the Summary for Policy Makers provides a more accessible target. Also in the news,
- [Just the facts?](https://www.realclimate.org/index.php/archives/2019/08/just-the-facts/) - RealClimate: In the wake of the appalling mass shootings last weekend, Neil DeGrasse Tyson (the pre-eminent scientist/communicator in the US) tweeted some facts that were, let's just say, not well received (and for which he kind of apologised). At least one of the facts he tweeted about was incorrect (deaths by medical errors are far smaller).
- [How much CO2 your country can still emit, in three simple steps](https://www.realclimate.org/index.php/archives/2019/08/how-much-co2-your-country-can-still-emit-in-three-simple-steps/) - RealClimate: Everyone is talking about emissions budgets – what are they and what do they mean for your country? Our CO2 emissions are causing global heating. If we want to stop global warming at a given temperature level, we can emit only a limited amount of CO2. That’s our emissions budget. I explained it here at
- [IPCC Special Report on Land](https://www.realclimate.org/index.php/archives/2019/08/ipcc-special-report-on-land/) - RealClimate: Thread for discussions of the new special report. [Boosting a comment from alan2102]. Climate Change and Land An IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems https://www.youtube.com/watch?v=g3HhAmjp-ME Land degradation accelerates global climate change. Al Jazeera EnglishPublished on Aug 8, 2019 https://www.youtube.com/watch?v=HZyRlpXLLq8 New
- [Can planting trees save our climate?](https://www.realclimate.org/index.php/archives/2019/07/can-planting-trees-save-our-climate/) - RealClimate: In recent weeks, a new study by researchers at ETH Zurich has hit the headlines worldwide (Bastin et al. 2019). It is about trees. The researchers asked themselves the question: how much carbon could we store if we planted trees everywhere in the world where the land is not already used for agriculture or cities?
- [Unforced variations: July 2019](https://www.realclimate.org/index.php/archives/2019/07/unforced-variations-july-2019/) - RealClimate: This month's open thread for climate science discussions.
- [The International Meeting on Statistical Climatology](https://www.realclimate.org/index.php/archives/2019/07/the-international-meeting-on-statistical-climatology/) - RealClimate: “The weather forecast looks sunny and particularly hot from Sunday to Friday, with afternoon temperatures above 30°C every day, and likely exceeding 35°C by the middle of the week. One consequence is that the poster sessions (Tuesday and Thursday) have been moved to the morning as they will be held outside under a marquee."
- [Unforced Variations: June 2019](https://www.realclimate.org/index.php/archives/2019/06/unforced-variations-june-2019/) - RealClimate: This month's open thread for climate science discussions. Remember discussion about climate solutions can be found here.
- [Absence and Evidence](https://www.realclimate.org/index.php/archives/2019/06/absence-and-evidence/) - RealClimate: Guest commentary by Michael Tobis, a retired climate scientist. He is a software developer and science writer living in Ottawa, Ontario. A recent opinion piece by economist Ross McKitrick in the Financial Post, which attracted considerable attention in Canada, carried the provocative headline “This scientist proved climate change isn’t causing extreme weather - so politicians
- [Koonin's case for yet another review of climate science](https://www.realclimate.org/index.php/archives/2019/06/koonins-case-for-yet-another-review-of-climate-science/) - RealClimate: We watch long YouTube videos so you don't have to. In the seemingly endless deliberations on whether there should be a 'red team' exercise to review various climate science reports, Scott Waldman reported last week that the original architect of the idea, Steve Koonin, had given a talk on touching on the topic at Purdue
- [Unforced Variations vs Forced Responses?](https://www.realclimate.org/index.php/archives/2019/06/unforced-variations-vs-forced-responses/) - RealClimate: Guest commentary by Karsten Haustein, U. Oxford, and Peter Jacobs (George Mason University). One of the perennial issues in climate research is how big a role internal climate variability plays on decadal to longer timescales. A large role would increase the uncertainty on the attribution of recent trends to human causes, while a small role
- [Unforced variations: May 2019](https://www.realclimate.org/index.php/archives/2019/05/unforced-variations-may-2019/) - RealClimate: This month's open thread about climate science topics. For discussions about solutions and policy, please use the Forced Responses open thread.
- [Unforced variations: April 2019](https://www.realclimate.org/index.php/archives/2019/04/unforced-variations-april-2019/) - RealClimate: This month's open thread on climate science issues. Remember that discussions about climate solutions go here.
- [Forced responses: May 2019](https://www.realclimate.org/index.php/archives/2019/05/forced-responses-may-2019/) - RealClimate: A bimonthly open thread on climate solutions and policies. If you want to discuss climate science, please use the Unforced Variations thread instead.
- [Nenana Ice Classic 2019](https://www.realclimate.org/index.php/archives/2019/04/nenana-ice-classic-2019/) - RealClimate: Wow. Perhaps unsurprisingly given the exceptional (relative) warmth in Alaska last month and in February, the record for the Nenana Ice Classic was shattered this year. The previous official record was associated with the exceptional conditions in El Niño-affected winter of 1939-1940, when the ice went out on April 20th 1940. Though since 1940 was
- [Curve-fitting and natural cycles: The best part](https://www.realclimate.org/index.php/archives/2011/12/curve-fitting-and-natural-cycles-the-best-part/) - RealClimate: It is not every day that I come across a scientific publication that so totally goes against my perception of what science is all about. present a study in the journal Global and Planetary Change, claiming that most of the temperature changes that we have seen so far are due to natural cycles. They claim
- [Warming, interrupted: Much ado about natural variability](https://www.realclimate.org/index.php/archives/2009/07/warminginterrupted-much-ado-about-natural-variability/) - RealClimate: A guest commentary by Kyle Swanson - University of Wisconsin-Milwaukee I am quite humbled by the interest that has been generated by our paper "Has the climate recently shifted?" (Swanson and Tsonis, 2009), and would like the thank the RealClimate editors for the opportunity to give my perspective on this piece. Before delving into the
- [Unforced variations: Mar 2019](https://www.realclimate.org/index.php/archives/2019/03/unforced-variations-mar-2019/) - RealClimate: This month's open thread on climate science topics.
- [Alpine glaciers: Another decade of loss](https://www.realclimate.org/index.php/archives/2019/03/alpine-glaciers-another-decade-of-loss/) - RealClimate: Guest Commentary by Mauri Pelto (Nichols College) Preliminary data reported from the reference glaciers of the World Glacier Monitoring Service (WGMS) in 2018 from Argentina, Austria, China, France, Italy, Kazakhstan, Kyrgyzstan, Nepal, Norway, Russia, Sweden, Switzerland and United States indicate that 2018 will be the 30th consecutive year of significant negative annual balance (> -200mm);
- [The Nenana Ice Classic and climate](https://www.realclimate.org/index.php/archives/2014/03/the-nenana-ice-classic-and-climate/) - RealClimate: I am always interested in non-traditional data sets that can shed some light on climate changes. Ones that I've discussed previously are the frequency of closing of the Thames Barrier and the number of vineyards in England. With the exceptional warmth in Alaska last month (which of course was coupled with colder temperatures elsewhere), I
- [Unforced variations: Feb 2019](https://www.realclimate.org/index.php/archives/2019/02/unforced-variations-feb-2019/) - RealClimate: This month's open thread for climate science discussions.
- [Whatevergate](https://www.realclimate.org/index.php/archives/2010/02/whatevergate/) - RealClimate: IPCC, glaciergate, climategate, UK media coverage, Jonathan Leake, David Rose, overton window
- [2005 Record Arctic Ozone Loss](https://www.realclimate.org/index.php/archives/2005/05/2005-arctic-ozone-loss/) - RealClimate: You read it here first! Update (09/05/05): Markus Rex was kind enough to send us the full figure from which Nature made their thumbnail, and which is a little clearer. He also cautions that the 2005 numbers are still preliminary, however there is a clear trend towards increasing potential for Arctic ozone loss, which is
- [Scientists respond to Barton](https://www.realclimate.org/index.php/archives/2005/07/barton-and-the-hockey-stick/) - RealClimate: by Gavin Schmidt and Stefan Rahmstorf Many readers will be aware that three scientists (two of which are contributors to this site, Michael Mann and Ray Bradley) have received letters from Representative Joe Barton (Texas), Chairman of the House Energy and Commerce Committee specifically requesting information about their work on the 'hockey stick' papers (Mann
- [Forced Responses: Feb 2019](https://www.realclimate.org/index.php/archives/2019/02/forced-responses-feb-2019/) - RealClimate: A bimonthly thread on societal responses to climate change. Note that there is another open thread for climate science topics. Please stick to specifics as opposed to arguments about ethics, politics or morality in general.
- [Forced Responses: Dec 2018](https://www.realclimate.org/index.php/archives/2018/12/forced-responses-dec-2018/) - RealClimate: A bimonthly thread for discussions on solutions and responses to climate change. For climate science topics, please comment on the Unforced Variations thread.
- [Unforced Variations: Jan 2019](https://www.realclimate.org/index.php/archives/2019/01/unforced-variations-jan-2019/) - RealClimate: This year’s first open thread on climate science topics. Usual rules apply - and let’s make a particular effort to stay substantive and not devolve into empty bickering (you still have Facebook for that). Any expectations or predictions for climate science in 2019?
- [Cold winter in a world of warming?](https://www.realclimate.org/index.php/archives/2010/12/cold-winter-in-a-world-of-warming/) - RealClimate: Last June, during the International Polar Year conference, James Overland suggested that there are more cold and snowy winters to come. He argued that the exceptionally cold snowy 2009-2010 winter in Europe had a connection with the loss of sea-ice in the Arctic. The cold winters were associated with a persistent 'blocking event', bringing in
- [What the 2018 climate assessments say about the Gulf Stream System slowdown](https://www.realclimate.org/index.php/archives/2019/01/what-the-2018-climate-assessments-say-about-the-gulf-stream-system-slowdown/) - RealClimate: Last year, twenty thousand peer reviewed studies on ‘climate change’ were published. No single person can keep track of all those – you’d have to read 55 papers every single day. (And, by the way, that huge mass of publications is why climate deniers will always find something to cherry-pick that suits their agenda.) That
- [Unforced variations: Dec 2018](https://www.realclimate.org/index.php/archives/2018/12/unforced-variations-dec-2018/) - RealClimate: This month's open thread for climate science topics. Please use the Forced Responses thread for solutions and politics.
- [Bending low with Bated breath](https://www.realclimate.org/index.php/archives/2018/12/bending-low-with-bated-breath/) - RealClimate: "Shall I bend low and in a bondman's key, With bated breath and whisp'ring humbleness...?"Shylock (Merchant of Venice, Act 1, Scene 3) As dark nights draw in, the venerable contrarians at the GWPF are still up late commissioning silly pseudo-rebuttals to mainstream science. The latest, [but see update below] which no-one was awaiting with any
- [The Climate Scientists are Alright](https://www.realclimate.org/index.php/archives/2019/01/the-climate-scientists-are-alright/) - RealClimate: Guest commentary from Eric Guilyardi (IPSL) and Valérie Masson-Delmotte (IPSL/IPCC) [This is a translation of an article in Le Monde (Jan 11).] In recent weeks in France, there has been a profusion of articles about the "climate scientist blues" (Le Monde 21/Dec, JDD 9/Dec, France Info 26/Sep), which has apparently affecting them "scientifically". This follows
- [New Ocean Heat Content Histories](https://www.realclimate.org/index.php/archives/2019/01/new-ocean-heat-content-histories/) - RealClimate: Guest commentary from Laure Zanna (U. Oxford) and G. Jake Gebbie (WHOI) Two recent papers, (hereafter ZKGIH19) and (hereafter GH19), independently reconstructed ocean heat content (OHC) changes prior to the instrumentally-based records (which start ~1950). The goals (and methodologies) of the two papers were quite different - ZKGIH19 investigated regional patterns of ocean warming and
- [Getting things right](https://www.realclimate.org/index.php/archives/2011/01/getting-things-right/) - RealClimate: Last Monday, I was asked by a journalist whether a claim in a new report from a small NGO made any sense. The report was mostly focused on the impacts of climate change on food production - clearly an important topic, and one where public awareness of the scale of the risk is low. However,
- [And the winner is...](https://www.realclimate.org/index.php/archives/2015/11/and-the-winner-is/) - RealClimate: Remember the forecast of a temporary global cooling which made headlines around the world in 2008? We didn't think it was reliable and offered a bet. The forecast period is now over: we were right, the forecast was not skillful. Back around 2007/8, two high-profile papers claimed to produce, for the first time, skilful predictions
- [Decluttering](https://www.realclimate.org/index.php/archives/2019/01/decluttering/) - RealClimate: Given some unexpected down time this month (and maybe next month too!), I've been trying to go through key old posts on this site. The basic idea is to update links to other sites, references and figures that over the years have died (site domains that were abandoned, site redesigns, deliberate deletions etc.). Most notably,
- [Revisiting historical ocean surface temperatures](https://www.realclimate.org/index.php/archives/2011/07/revisiting-historical-ocean-surface-temperatures/) - RealClimate: Readers may recall discussions of a paper by Thompson et al (2008) back in May 2008. This paper demonstrated that there was very likely an artifact in the sea surface temperature (SST) collation by the Hadley Centre (HadSST2) around the end of the second world war and for a few years subsequently, related to the
- [NOAA-thing burger officially confirmed](https://www.realclimate.org/index.php/archives/2019/01/noaa-thing-burger-officially-confirmed/) - RealClimate: Back in February 2017, I wrote about the tediously predictable arc of criticisms of the paper, and in particular the comments of John Bates at Judith Curry's blog. an initial claim of imperfection spiced up with insinuations of misconduct, coordination with a breathless hyping of the initial claim with ridiculous supposed implications, some sensible responses
- [Lindzen and Choi Unraveled](https://www.realclimate.org/index.php/archives/2010/01/lindzen-and-choi-unraveled/) - RealClimate: Lindzen and Choi, Trenberth Fasullo, O'Dell and Wang, tropical ocean temperatures, TOA radiative fluxes, climate sensitivity
- [Let's check your temperature](https://www.realclimate.org/index.php/archives/2018/12/lets-check-your-temperature/) - RealClimate: The underlying mission of my job is to safeguard lives and property through climate change adaptation based on science. In other words, to help society to prepare itself for risks connected with more extreme rainfall and temperatures. For many people, "climate" may seem to be an abstract concept. I have had many conversations about climate,
- [Misrepresentation from Lindzen](https://www.realclimate.org/index.php/archives/2012/03/misrepresentation-from-lindzen/) - RealClimate: Richard Lindzen is a very special character in the climate debate - very smart, high profile, and with a solid background in atmospheric dynamics. He has, in times past, raised interesting critiques of the mainstream science. None of them, however, have stood the test of time - but exploring the issues was useful. More recently
- [Fall AGU Week 2018](https://www.realclimate.org/index.php/archives/2018/12/fall-agu-week-2018/) - RealClimate: Fall AGU is in Washington DC. Follow #AGU18 for twitter discussions and highlights, and live streaming of keynotes and selected sessions. Use this thread to discuss anything arising from the meeting - or it's controversies.
- [IPCC Special Report on 1.5ºC](https://www.realclimate.org/index.php/archives/2018/10/ipcc-special-report-on-1-5oc/) - RealClimate: Responding to climate change is far more like a marathon than a sprint. The IPCC 1.5ºC Special report (#SR15) has been released: The press release Frequently Asked Questions The Summary For Policy Makers (SPM) The full report Thoughts It's well worth reading the SPM and FAQs before confidently pronouncing on the utility or impact of
- [A day when Hell was frozen](https://www.realclimate.org/index.php/archives/2008/02/a-day-when-hell-was-frozen/) - RealClimate: I was honoured to be invited to the annual regional conference for Norwegian journalists, taking place annually in a small town called ‘Hell’ (Try Earth Google 'Hell, Norway'). During this conference, I was asked to participate in a panel debate about the theme: ‘Climate – how should we [the media] deal with world’s most pressing
- [Climate sensitivity and aerosol forcings](https://www.realclimate.org/index.php/archives/2005/07/climate-sensitivity-and-aerosol-forcings/) - RealClimate: In a new review paper in Nature this week, Andreae, Jones and Cox expand on the idea that uncertainty in climate sensitivity is directly related to uncertainty in present day aerosol forcing (see also this New Scientist commentary). This was discussed here a couple of months back in the Global Dimming and the climateprediction.net posts,
- [Scientists: Resolve to Protect Yourself from Harassment in 2019](https://www.realclimate.org/index.php/archives/2018/12/scientists-resolve-to-protect-yourself-from-harassment-in-2019/) - RealClimate: Guest commentary by Lauren Kurtz The Climate Science Legal Defense Fund (CSLDF) protects the scientific endeavor from anti-science attacks. Since our founding in 2011, we’ve assisted hundreds of scientists with issues ranging from invasive open records requests to death threats. As part of this work, our staff will be at the American Geophysical Union Fall
- [Unforced variations: Nov 2018](https://www.realclimate.org/index.php/archives/2018/11/unforced-variations-nov-2018/) - RealClimate: This month's open thread on climate science issues. A lot of interest in the new Resplandy et al paper (WaPo), with some exploration of the implications on twitter i.e. https://twitter.com/Knutti_ETH/status/1057960390502608901 and https://twitter.com/jamesannan/status/1057944837163491328 Meanwhile, the CMIP6 model output is starting to come out...
- [4th National Climate Assessment report](https://www.realclimate.org/index.php/archives/2018/11/4th-national-climate-assessment-report/) - RealClimate: In possibly the biggest "Friday night news dump" in climate report history, the long awaited 4th National Climate Assessment (#NCA4) was released today (roughly two weeks earlier than everyone had been expecting). The summaries and FAQ (pdf) are good, and the ClimateNexus briefing is worth reading too. The basic picture is utterly unsurprising, but the
- [Ocean heat content increases update](https://www.realclimate.org/index.php/archives/2010/05/ocean-heat-content-increases-update/) - RealClimate: There is a new paper in Nature this week on recent trends in ocean heat content from a large group of oceanographers led by John Lyman at PMEL. Their target is the uncertainty surrounding the various efforts to create a homogenised ocean heat content data set that deals appropriately with the various instrument changes and
- [Planetary energy imbalance?](https://www.realclimate.org/index.php/archives/2005/05/planetary-energy-imbalance/) - RealClimate: The recent paper in Science Express by Hansen et al (on which I am a co-author) has garnered quite a lot of press attention and has been described as the 'smoking gun' for anthropogenic climate change. We have discussed many of the relevant issues here before, but it may be useful to go over the
- [Unforced variations: Oct 2018](https://www.realclimate.org/index.php/archives/2018/10/unforced-variations-oct-2018/) - RealClimate: This month's open thread on climate science topics. Dominant theme this month will probably be the release of the IPCC Special Report on 1.5ºC. The final report will be released later this week, and when it does we'll give a brief summary. The hastag to follow on Twitter is #SR15.
- [Climate Change and Extreme Summer Weather Events – The Future is still in Our Hands](https://www.realclimate.org/index.php/archives/2018/10/climate-change-and-extreme-summer-weather-events-the-future-is-still-in-our-hands/) - RealClimate: Summer 2018 saw an unprecedented spate of extreme weather events, from the floods in Japan, to the record heat waves across North America, Europe and Asia, to wildfires that threatened Greece and even parts of the Arctic. The heat and drought in the western U.S. culminated in the worst California wildfire on record. This is
- [Mercury, the other geologically persistent planetary poison](https://www.realclimate.org/index.php/archives/2018/10/mercury-the-other-geologically-persistent-planetary-poison/) - RealClimate: The thing that really gets me in the gut about global warming from fossil fuel combustion is how long it will last. Carbon mined from the deep Earth and injected into the “fast carbon cycle” of the atmosphere, ocean, and land surface will continue to affect atmospheric CO2 concentrations, and climate, for hundreds of thousands
- [Cracking the Climate Change Case](https://www.realclimate.org/index.php/archives/2018/10/cracking-the-climate-change-case/) - RealClimate: I have an op-ed in the New York Times this week: How Scientists Cracked the Climate Change Case The biggest crime scene on the planet is the planet. We know the earth is warming, but who or what is causing it? Many of you will recognise the metaphor from previous Realclimate pieces (this is earliest
- [Climate without Borders: putting changing climate into a new perspective](https://www.realclimate.org/index.php/archives/2018/10/climate-without-borders-putting-changing-climate-into-a-new-perspective/) - RealClimate: Guest post by Mike Favetta The goal of “Climate without Borders” (CwB) is to unite TV weather presenters from all over the world and bring scientific knowledge to a broader public. This, in turn, creates climate awareness and creates support for the urgent climate action needed. Although the name suggests a kind of connection with
- [Index](https://www.realclimate.org/index.php/archives/2004/12/index/) - RealClimate: In addition to the category indexing on the side bar, we have set out a more thematic index here to help you find your way through the content on the site. [Note: this was kept up-to-date through about 2008. For more recent articles, please use the search function.] Themes: Aerosols, Arctic and Antarctic climate, Atmospheric
- [Pre-industrial anthropogenic CO2 emissions: How large?](https://www.realclimate.org/index.php/archives/2018/10/pre-industrial-anthropogenic-co2-emissions-how-large/) - RealClimate: Guest article by William Ruddiman Fifteen years after publication of Ruddiman (2003), the early anthropogenic hypothesis is still debated, with relevant evidence from many disciplines continuing to emerge. Recent findings summarized here lend support to the claim that greenhouse-gas emissions from early agriculture (before 1850) were large enough to alter atmospheric composition and global climate
- [Unforced Variations: Sep 2018](https://www.realclimate.org/index.php/archives/2018/09/unforced-variations-sep-2018/) - RealClimate: This month's open thread on climate science topics. We are well into Arctic melt season (so keep track of Neven's Arctic Sea Ice blog for more info). Another link is the NY Times Daily podcast on the interesting-yet-flawed NYTimes Magazine "Losing Earth" piece (which is useful if you didn't get around to finishing the written
- [European climate services take an important leap forward ](https://www.realclimate.org/index.php/archives/2018/09/european-climate-services-take-an-important-leap-forward/) - RealClimate: An important milestone was passed during the second general assembly of the Copernicus Climate Change Service, which took place in Berlin on Sept 24-28 (twitter hashtag '#C3SGA18'). The European climate service has become operational, hosted by the European Centre for Medium-Range Forecasts (ECMWF). The results of the 'Master of climate codes' quiz. Note that the two
- [Does global warming make tropical cyclones stronger?](https://www.realclimate.org/index.php/archives/2018/05/does-global-warming-make-tropical-cyclones-stronger/) - RealClimate: By Stefan Rahmstorf, Kerry Emanuel, Mike Mann and Jim Kossin Friday marks the official start of the Atlantic hurricane season, which will be watched with interest after last year’s season broke a number of records and e.g. devastated Puerto Rico’s power grid, causing serious problems that persist today. One of us (Mike) is part of
- [Forced responses: Sep 2018](https://www.realclimate.org/index.php/archives/2018/09/forced-responses-sep-2018/) - RealClimate: This thread is the bimonthly open thread for discussion of climate solutions. A good starting point might be this clear description from Glen Peters on the feasibility of staying below 2ºC. Please stick to substantive points and refrain from attacking other commenters (as opposed to their ideas). The open thread for climate science issues is
- [A report from the European Meteorological Society’s annual meeting 2018](https://www.realclimate.org/index.php/archives/2018/09/a-report-from-the-european-meteorological-societys-annual-meeting-2018/) - RealClimate: If you want to make a difference as a scientist, you need to make sure that people understand the importance of your work. Conferences give you one opportunity to explain what you've found out. I sometimes wonder if the value of attending conferences is sufficiently appreciated. You can save time getting an overview over your
- [Forced Responses: Jul 2018](https://www.realclimate.org/index.php/archives/2018/07/forced-responses-jul-2018/) - RealClimate: Open thread for climate policy and responses.
- [Unforced Variations: Aug 2018](https://www.realclimate.org/index.php/archives/2018/08/unforced-variations-aug-2018/) - RealClimate: This month’s open thread for climate science issues.
- [Are the heatwaves caused by climate change? ](https://www.realclimate.org/index.php/archives/2018/08/are-the-heatwaves-caused-by-climate-change/) - RealClimate: [latexpage] I get a lot of questions about the connection between heatwaves and climate change these days. Particularly about the heatwave that has affected northern Europe this summer. If you live in Japan, South Korea, California, Spain, or Canada, you may have asked the same question. The raindrop analogy However, the question is inaccurate and
- [Musing about Losing Earth](https://www.realclimate.org/index.php/archives/2018/08/musing-about-losing-earth/) - RealClimate: The NY Times Magazine has a special issue this weekend on climate change. The main article is "Losing the Earth" by Nathaniel Rich, is premised on the idea that in the period 1979 to 1989 when we basically knew everything we needed to know that climate change was a risk, and the politics had not
- [Unforced Variations: July 2018](https://www.realclimate.org/index.php/archives/2018/07/unforced-variations-july-2018/) - RealClimate: This month's open thread for climate science related topics. The climate policy open thread is here.
- [Model Independence Day](https://www.realclimate.org/index.php/archives/2018/07/model-independence-day/) - RealClimate: We hold these truths to be self-evident, that all models are created equal, that they are endowed by their Creators with certain unalienable Rights, that among these are a DOI, Runability and Inclusion in the CMIP ensemble mean. Well, not quite. But it is Independence Day in the US, and coincidentally there is a new
- [Unforced variations: June 2018](https://www.realclimate.org/index.php/archives/2018/06/unforced-variations-june-2018/) - RealClimate: This month's open thread. We know people like to go off on tangents, but last month's thread went too far. There aren't many places to discuss climate science topics intelligently, so please stay focused on those.
- [Forced Responses: May 2018](https://www.realclimate.org/index.php/archives/2018/05/forced-responses-may-2018/) - RealClimate: The bimonthly open thread focused on climate solutions, mitigation and adaptation. Please keep this focused.
- [30 years after Hansen's testimony](https://www.realclimate.org/index.php/archives/2018/06/30-years-after-hansens-testimony/) - RealClimate: "The greenhouse effect is here." - Jim Hansen, 23rd June 1988, Senate Testimony The first transient climate projections using GCMs are 30 years old this year, and they have stood up remarkably well. We've looked at the skill in the (pdf) simulations before (back in 2008), and we said at the time that the simulations
- [Will climate change bring benefits from reduced cold-related mortality? Insights from the latest epidemiological research](https://www.realclimate.org/index.php/archives/2018/06/will-climate-change-bring-benefits-from-reduced-cold-related-mortality-insights-from-the-latest-epidemiological-research/) - RealClimate: Guest post by Veronika Huber Climate skeptics sometimes like to claim that although global warming will lead to more deaths from heat, it will overall save lives due to fewer deaths from cold. But is this true? Epidemiological studies suggest the opposite. Mortality statistics generally show a distinct seasonality. More people die in the colder
- [Unforced variations: May 2018](https://www.realclimate.org/index.php/archives/2018/05/unforced-variations-may-2018/) - RealClimate: This month's (slightly delayed) open thread on climate science topics.
- [If you doubt that the AMOC has weakened, read this](https://www.realclimate.org/index.php/archives/2018/05/if-you-doubt-that-the-amoc-has-weakened-read-this/) - RealClimate: A few weeks ago, we’ve argued in a paper in Nature that the Atlantic overturning circulation (sometimes popularly dubbed the Gulf Stream System) has weakened significantly since the late 19th Century, with most of the decline happening since the mid-20th Century. We have since received much praise for our study from colleagues around the world
- [Transparency in climate science](https://www.realclimate.org/index.php/archives/2018/05/transparency-in-climate-science/) - RealClimate: Good thing? Of course.* I was invited to give a short presentation to a committee at the National Academies last week on issues of reproducibility and replicability in climate science for a report they have been asked to prepare by Congress. My slides give a brief overview of the points I made, but basically the
- [Climate indicators](https://www.realclimate.org/index.php/archives/2018/05/climate-indicators/) - RealClimate: [latexpage] The climate system is complex, and a complete description of its state would require huge amounts of data. However, it is possible to keep track of its conditions through summary statistics. There are some nice resources which give an overview of a number for climate indicators. Some examples include NASA and The Climate Reality Project.
- [Unforced variations: Mar 2018](https://www.realclimate.org/index.php/archives/2018/02/unforced-variations-mar-2018/) - RealClimate: This month's open thread for climate science related items. The open thread for responses to climate change is here.
- [Forced responses: Mar 2018](https://www.realclimate.org/index.php/archives/2018/03/forced-responses-mar-2018/) - RealClimate: This month's open thread on responses to climate change (politics, adaptation, mitigation etc.). Please stay focused on the overall topic. Digressions into the nature and history of communism/feudal societies/anarchistic utopias are off topic and won't be posted. Thanks. The open thread for climate science topics is here.
- [Unforced Variations: Apr 2018](https://www.realclimate.org/index.php/archives/2018/04/unforced-variations-apr-2018/) - RealClimate: This month's open thread for general climate science discussions.
- [Nenana Ice Classic 2018](https://www.realclimate.org/index.php/archives/2018/05/nenana-ice-classic-2018/) - RealClimate: Another year, another ice out date. As in previous years, here's an update of the Nenana Ice Classic time series (raw date, and then with a small adjustment for the calendrical variations in 'spring'). One time series doesn't prove much, but this is of course part of a much larger archive of phenomenological climate-related data
- [The Alsup Aftermath](https://www.realclimate.org/index.php/archives/2018/04/the-alsup-aftermath/) - RealClimate: The presentations from the Climate Science tutorial last month have all been posted (links below), and Myles Allen (the first presenter for the plaintiffs) gives his impression of the events. Guest Commentary by Myles Allen A few weeks ago, I had an unusual — and challenging — assignment: providing a one-hour “tutorial" on the basic
- [Stronger evidence for a weaker Atlantic overturning circulation](https://www.realclimate.org/index.php/archives/2018/04/stronger-evidence-for-a-weaker-atlantic-overturning-circulation/) - RealClimate: Through two new studies in Nature, the weakening of the Gulf Stream System is back in the scientific headlines. But even before that, interesting new papers have been published - high time for an update on this topic. Let's start with tomorrow’s issue of Nature, which besides the two new studies (one of which I
- [Cockburn's form](https://www.realclimate.org/index.php/archives/2007/06/cockburns-form/) - RealClimate: Alexander Cockburn (writing in the Nation) has become the latest contrarian-de-jour, sallying forth with some rather novel arithmetic to show that human-caused global warming is nothing to be concerned about. This would be unworthy of comment in most cases, but Cockburn stands out as one of only a few left-wing contrarians, as opposed to the
- [The Silurian Hypothesis](https://www.realclimate.org/index.php/archives/2018/04/the-silurian-hypothesis/) - RealClimate: One of the benefits of working for NASA is that the enormous range of science the agency covers - from satellite records for the present day, to exoplanet climates, from early Mars and deep time on Earth to the far future - and the opportunity to think 'big'. This week sees the publication of a
- [Harde Times](https://www.realclimate.org/index.php/archives/2018/04/harde-times/) - RealClimate: Readers may recall a post a year ago about a nonsense paper by that appeared in Global and Planetary Change. We reported too on the crowd-sourced rebuttal led by that was published last October. Now comes by three members of the Editorial Board (Martin Grosjean, Joel Guiot and Zicheng Yu) reporting on what the circumstances
- [Plass and the Surface Budget Fallacy](https://www.realclimate.org/index.php/archives/2010/01/plass-and-the-surface-budget-fallacy/) - RealClimate: RealClimate is run by a rather loosely organized volunteer consortium of people with day jobs that in and of themselves can be quite consuming of attention. And so it came to pass that the first I learned about Gavin's interest in the work of Plass was -- by reading RealClimate! In fact, David Archer and
- [Alsup asks for answers](https://www.realclimate.org/index.php/archives/2018/03/alsup-asks-for-answers/) - RealClimate: Some of you might have read about the lawsuit by a number of municipalities (including San Francisco and Oakland) against the major oil companies for damages (related primarily to sea level rise) caused by anthropogenic climate change. The legal details on standing, jurisdiction, etc. are all very interesting (follow @ColumbiaClimate for those details), but somewhat
- [Forced Responses: Jan 2018](https://www.realclimate.org/index.php/archives/2018/01/forced-responses-jan-2018/) - RealClimate: This is a new class of open thread for discussions of climate solutions, mitigation and adaptation. As always, please be respectful of other commentators and try to avoid using repetition to make your points. Discussions related to the physical Earth System should be on the Unforced Variations threads.
- [Unforced variations: Feb 2018](https://www.realclimate.org/index.php/archives/2018/02/unforced-variations-feb-2018/) - RealClimate: This month’s open thread for climate science topics. Note that discussions about mitigation and/or adaptation should be on the Forced Responses thread. Let’s try and avoid a Groundhog Day scenario in the comments!
- [More ice-out and skating day data sets](https://www.realclimate.org/index.php/archives/2018/02/more-ice-out-and-skating-day-data-sets/) - RealClimate: The responses to the last post on the Rideau Canal Skateway season changes were interesting, and led to a few pointers to additional data sets that show similar trends and some rather odd counter-points from the usual suspects. Minnesotan Lakes The most comprehensive (and up-to-date) set of "ice out" data for lakes is, unsurprisingly perhaps,
- [Rideau Canal Skateway](https://www.realclimate.org/index.php/archives/2018/02/rideau-canal-skateway/) - RealClimate: I've been interested in indirect climate-related datasets for a while (for instance, the Nenana Ice Classic). One that I was reminded of yesterday is the 48-year series of openings and closings of the Rideau Canal Skateway in Ottawa. Since 1971, the National Capital Commission (NCC) in Ottawa has (once the ice is thick enough for
- [Unforced Variations: Jan 2018](https://www.realclimate.org/index.php/archives/2018/01/unforced-variations-jan-2018/) - RealClimate: Happy new year, and a happy new open thread. In response to some the comments we've been getting about previous open threads, we are going to try separating out OT comments on mitigation/saving the planet/theories of political action from ones related to the physical climate system. This thread remains a place for climate science issues,
- [The global CO2 rise: the facts, Exxon and the favorite denial tricks](https://www.realclimate.org/index.php/archives/2018/01/the-global-co2-rise-the-facts-exxon-and-the-favorite-denial-tricks/) - RealClimate: The basic facts about the global increase of CO2 in our atmosphere are clear and established beyond reasonable doubt. Nevertheless, I’ve recently seen some of the old myths peddled by “climate skeptics” pop up again. Are the forests responsible for the CO2 increase? Or volcanoes? Or perhaps the oceans? Let’s start with a brief overview
- [IPCC Communication handbook](https://www.realclimate.org/index.php/archives/2018/01/ipcc-communication-handbook/) - RealClimate: A new handbook on science communication came out from IPCC this week. Nominally it's for climate science related communications, but it has a wider application as well. This arose mainly out of an "Expert meeting on Communication" that IPCC held in 2016. 6 principles to help IPCC scientists better communicate their work https://www.youtube.com/watch?v=PlN6qs55NNE There was
- [The claim of reduced uncertainty for equilibrium climate sensitivity is premature](https://www.realclimate.org/index.php/archives/2018/01/the-claim-of-reduced-uncertainty-for-equilibrium-climate-sensitivity-is-premature/) - RealClimate: [latexpage] A recent story in the Guardian claims that new calculations reduce the uncertainty associated with a global warming: A revised calculation of how greenhouse gases drive up the planet’s temperature reduces the range of possible end-of-century outcomes by more than half, ... It was based on a study recently published in Nature , however,
- [2017 temperature summary](https://www.realclimate.org/index.php/archives/2018/01/2017-temperature-summary/) - RealClimate: This is a thread to discuss the surface temperature records that were all released yesterday (Jan 18). There is far too much data-vizualization on this to link to, but feel free to do so in the comments. Bottom line? It's still getting warmer. [Update: the page of model/observational data comparisons has now been updated too.]
- [What did NASA know? and when did they know it?](https://www.realclimate.org/index.php/archives/2017/12/what-did-nasa-know-and-when-did-they-know-it/) - RealClimate: If you think you know why NASA did not report the discovery of the Antarctic polar ozone hole in 1984 before the publication of in May 1985, you might well be wrong. One of the most fun things in research is what happens when you try and find a reference to a commonly-known fact and
- [Unforced Variations: Dec 2017](https://www.realclimate.org/index.php/archives/2017/12/unforced-variations-dec-2017/) - RealClimate: Last open-thread of the year. Tips for new books for people to read over the holidays? Highlights of Fall AGU (Dec 11-15, New Orleans)? Requests for what should be in the end of year updates? Try to be nice.
- [Fall AGU 2017](https://www.realclimate.org/index.php/archives/2017/12/fall-agu-2017/) - RealClimate: It's that time of year again. #AGU17 is from Dec 11 to Dec 16 in New Orleans (the traditional venue in San Francisco is undergoing renovations). As in previous years, there will be extensive live streams from "AGU On Demand" (free, but an online registration is required) of interesting sessions and the keynote lectures from
- [Unforced variations: Nov 2017](https://www.realclimate.org/index.php/archives/2017/11/unforced-variations-nov-2017/) - RealClimate: This month's open thread. Lawsuits about scientific disputes, the new Climate Science Special Report from the National Climate Assessment, and (imminently) the WMO State of the Climate statement for 2017.
- [A brief review of rainfall statistics](https://www.realclimate.org/index.php/archives/2017/11/a-brief-review-of-rainfall-statistics/) - RealClimate: [latexpage] There have been a number of studies which show that we can expect more extreme rainfall with a global warming . Hence, there is a need to increase our resilience to more rainfall in the future. We can say something about how the rainfall statistics will be affected by a global warming, even when
- [O Say can you See Ice...](https://www.realclimate.org/index.php/archives/2017/11/o-say-can-you-see-ice/) - RealClimate: Some concerns about continued monitoring of sea ice by remote sensing were raised this week in Nature News an article in the (UK) Observer: Donald Trump accused of obstructing satellite research into climate change. The last headline is not really correct, but the underlying issues are real. What is this about? Since the late seventies,
- [Unforced variations: Oct 2017](https://www.realclimate.org/index.php/archives/2017/10/unforced-variations-oct-2017/) - RealClimate: This month's open thread. Carbon budgets, Arctic sea ice minimum, methane emissions, hurricanes, volcanic impacts on climate... Please try and stick to these or similar topics.
- [El Niño and the record years 1998 and 2016](https://www.realclimate.org/index.php/archives/2017/11/el-nino-and-the-record-years-1998-and-2016/) - RealClimate: 2017 is set to be one of warmest years on record. Gavin has been making regular forecasts of where 2017 will end up, and it is now set to be #2 or #3 in the list of hottest years: With update thru September, ~80% chance of 2017 being 2nd warmest yr in the GISTEMP analysis
- [O Say Can You CO2…](https://www.realclimate.org/index.php/archives/2017/10/o-say-can-you-co2/) - RealClimate: Guest Commentary by Scott Denning The Orbiting Carbon Observatory (OCO-2) was launched in 2014 to make fine-scale measurements of the total column concentration of CO2 in the atmosphere. As luck would have it, the initial couple of years of data from OCO-2 documented a period with the fastest rate of CO2 increase ever measured, more
- [1.5ºC: Geophysically impossible or not?](https://www.realclimate.org/index.php/archives/2017/10/1-5oc-geophysically-impossible-or-not/) - RealClimate: Guest commentary by Ben Sanderson Millar et al’s recent paper in Nature Geoscience has provoked a lot of lively discussion, with the authors of the original paper releasing a statement to clarify that their paper did not suggest that “action to reduce greenhouse gas emissions is no longer urgent“, rather that 1.5ºC (above the pre-industrial)
- [Snow Water Ice and Water and Adaptive Actions for a Changing Arctic](https://www.realclimate.org/index.php/archives/2017/04/snow-water-ice-and-water-and-adaptive-actions-for-a-changing-arctic/) - RealClimate: The Arctic is changing fast, and the Arctic Council recently commissioned the Arctic Monitoring and Assessment Programme (AMAP) to write two new reports on the state of the Arctic cryosphere (snow, water, and ice) and how the people and the ecosystems in the Arctic can live with these changes. The two reports have now just
- [...the Harde they fall.](https://www.realclimate.org/index.php/archives/2017/10/the-harde-they-fall/) - RealClimate: Back in February we highlighted an obviously wrong paper by Harde which purported to scrutinize the carbon cycle. Well, thanks to a crowd sourced effort which we helped instigate, a comprehensive scrutiny of those claims has just been . Lead by Peter Köhler, this included scientists from multiple disciplines working together to clearly report on
- [Unforced Variations: Sep 2017](https://www.realclimate.org/index.php/archives/2017/09/unforced-variations-sep-2017/) - RealClimate: This month's open thread.... and let's stay on climate topics this month. It's not like there isn't anything climate-y to talk about (sea ice minimums, extreme events, climate model tunings, past 'hyperthermals'... etc.). Anything too far off-topic will get binned. Thanks!
- [Is there really still a chance for staying below 1.5 °C global warming?](https://www.realclimate.org/index.php/archives/2017/09/is-there-really-still-a-chance-for-staying-below-1-5-c-global-warming/) - RealClimate: There has been a bit of excitement and confusion this week about a new paper in Nature Geoscience, claiming that we can still limit global warming to below 1.5 °C above preindustrial temperatures, whilst emitting another ~800 Gigatons of carbon dioxide. That’s much more than previously thought, so how come? And while that sounds like
- [Data rescue projects](https://www.realclimate.org/index.php/archives/2017/08/data-rescue-projects/) - RealClimate: It's often been said that while we can only gather new data about the planet at the rate of one year per year, rescuing old data can add far more data more quickly. Data rescue is however extremely labor intensive. Nonetheless there are multiple data rescue projects and citizen science efforts ongoing, some of which
- [Impressions from the European Meteorological Society's annual meeting in Dublin ](https://www.realclimate.org/index.php/archives/2017/09/impressions-from-the-european-meteorological-societys-annual-meeting-in-dublin/) - RealClimate: The 2017 annual assembly of the European Meteorological Society (EMS) had a new set-up with a plenary keynote each morning. I though some of these keynotes were very interesting. There was a talk by Florence Rabier from the European Centre for Medium-range Weather Forecasts (ECMWF), who presented the story of ensemble forecasting. Keith Seitter, the
- [Why extremes are expected to change with a global warming](https://www.realclimate.org/index.php/archives/2017/09/why-extremes-are-expected-to-change-with-a-global-warming/) - RealClimate: Joanna Walters links extreme weather events with climate change in a recent article in the Guardian, however, some reservations have been expressed about such links in past discussions. For example, we discussed the connection between single storms and global warming in the post Hurricanes and Global Warming - Is there a connection?, the World Meteorological Organization (WMO)
- [Unforced Variations: August 2017](https://www.realclimate.org/index.php/archives/2017/08/unforced-variations-august-2017/) - RealClimate: This month's open thread.
- [Sensible Questions on Climate Sensitivity](https://www.realclimate.org/index.php/archives/2017/08/sensible-questions-on-climate-sensitivity/) - RealClimate: Guest Commentary by Cristian Proistosescu, Peter Huybers and Kyle Armour tl;dr Two recent papers help bridge a seeming gap between estimates of climate sensitivity from models and from observations of the global energy budget. Recognizing that equilibrium climate sensitivity cannot be directly observed because Earth’s energy balance is a long way from equilibrium, the studies
- [Observations, Reanalyses and the Elusive Absolute Global Mean Temperature](https://www.realclimate.org/index.php/archives/2017/08/observations-reanalyses-and-the-elusive-absolute-global-mean-temperature/) - RealClimate: One of the most common questions that arises from analyses of the global surface temperature data sets is why they are almost always plotted as anomalies and not as absolute temperatures. There are two very basic answers: First, looking at changes in data gets rid of biases at individual stations that don't change in time
- [Unforced variations: July 2017](https://www.realclimate.org/index.php/archives/2017/07/unforced-variations-july-2017/) - RealClimate: So, big news this week: The latest update to the RSS lower troposphere temperatures (Zeke at Carbon Brief, J. Climate paper) and, of course, more chatter about the red team/blue team concept. Comments?
- [Joy plots for climate change](https://www.realclimate.org/index.php/archives/2017/07/joy-plots-for-climate-change/) - RealClimate: This is joy as in 'Joy Division', not as in actual fun. Many of you will be familiar with the iconic cover of Joy Division's Unknown Pleasures album, but maybe fewer will know that it's a plot of signals from a pulsar (check out this Scientific American article on the history). The length of the
- [Red team/Blue team Day 1](https://www.realclimate.org/index.php/archives/2017/07/red-teamblue-team-day-1/) - RealClimate: From Russell Seitz:
- [Climate Sensitivity Estimates and Corrections](https://www.realclimate.org/index.php/archives/2017/07/climate-sensitivity-estimates-and-corrections/) - RealClimate: You need to be careful in inferring climate sensitivity from observations. Two climate sensitivity stories this week - both related to how careful you need to be before you can infer constraints from observational data. (You can brush up on the background and definitions here). Both cases - a "Brief Comment Arising" in Nature (that
- [Unforced Variations: June 2017](https://www.realclimate.org/index.php/archives/2017/06/unforced-variations-june-2017/) - RealClimate: Absolutely nothing of consequence happening today in climate news. Can't think of what people could discuss...
- [Nenana Ice Classic 2017](https://www.realclimate.org/index.php/archives/2017/05/nenana-ice-classic-2017/) - RealClimate: Artículo en español. As I've done for a few years, here is the updated graph for the Nenana Ice Classic competition, which tracks the break up of ice on the Tanana River near Nenana in Alaska. It is now a 101-year time series tracking the winter/spring conditions in that part of Alaska, and shows clearly
- [What do you need to know about climate?](https://www.realclimate.org/index.php/archives/2017/06/what-do-you-need-to-know-about-climate/) - RealClimate: What do you need to know about climate in order to be in the best position to adapt to future change? This question was discussed in a European workshop on Copernicus climate services during a heatwave in Barcelona, Spain (June 12-14). The answer is not clear-cut, even after having some information about user requirements from
- [How do we know that recent CO<sub>2</sub> increases are due to human activities? <lang_fr>Comment savons-nous que l'augmentation récente du CO<sub>2</sub> est due aux activités humaines ? (<em>mise-à-jour</em>)</lang_fr>](https://www.realclimate.org/index.php/archives/2004/12/how-do-we-know-that-recent-cosub2sub-increases-are-due-to-human-activities-updated/) - RealClimate: Note:This is an update to an earlier post, which many found to be too technical. The original, and a series of comments on it, can be found here. See also a more recent post here for an even less technical discussion. Over the last 150 years, carbon dioxide (CO2) concentrations have risen from 280 to
- [Why global emissions must peak by 2020](https://www.realclimate.org/index.php/archives/2017/06/why-global-emissions-must-peak-by-2020/) - RealClimate: (by Stefan Rahmstorf and Anders Levermann) In the landmark Paris Climate Agreement, the world’s nations have committed to “holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 °C above pre-industrial levels”. This goal is deemed necessary to
- [Unforced Variations: May 2017](https://www.realclimate.org/index.php/archives/2017/05/unforced-variations-may-2017/) - RealClimate: This month's open thread. Topics this month? What should a conservative contrarian be writing op-eds about that avoids strawman arguments, and getting facts wrong? What do you really think about geoengineering? Tracking the imminent conclusion of the Nenana Ice Classic (background)? Usual rules apply.
- [Unforced variations: Apr 2017](https://www.realclimate.org/index.php/archives/2017/04/unforced-variations-apr-2017/) - RealClimate: This month's open thread.
- [Nenana Ice Classic 2016](https://www.realclimate.org/index.php/archives/2016/04/nenana-ice-classic-2016/) - RealClimate: Just a quick note since I've been tracking this statistic for a few years, but the Nenana Ice Classic tripod went down this afternoon (Apr 23, 3:39 Alaska Standard Time). See the earlier post for what this is and why it says something about the climate (see posts on 2014 and 2015 results). With this
- [Judy Curry's attribution non-argument](https://www.realclimate.org/index.php/archives/2017/04/judy-currys-attribution-non-argument/) - RealClimate: Following on from the 'interesting' House Science Committee hearing two weeks ago, there was an excellent rebuttal curated by ClimateFeedback of the unsupported and often-times misleading claims from the majority witnesses. In response, Judy Curry has (yet again) declared herself unconvinced by the evidence for a dominant role for human forcing of recent climate changes.
- [Model projections and observations comparison page](https://www.realclimate.org/index.php/archives/2017/04/model-projections-and-observations-comparison-page/) - RealClimate: We should have done this ages ago, but better late than never! We have set up a permanent page to host all of the model projection-observation comparisons that we have monitored over the years. This includes comparisons to early predictions for global mean surface temperature from the 1980's as well as more complete projections from
- [What is the uncertainty in the Earth's temperature rise?](https://www.realclimate.org/index.php/archives/2017/04/what-is-the-uncertainty-in-the-earths-temperature-rise/) - RealClimate: Guest commentary by Shaun Lovejoy (McGill University) Below I summarize the key points of a that I think opens up new perspectives on understanding and estimating the relevant uncertainties. The main message is that the primary sources of error and bias are not those that have been the subject of the most attention - they
- [Unforced Variations: March 2017](https://www.realclimate.org/index.php/archives/2017/03/unforced-variations-march-2017/) - RealClimate: This month's open thread.
- [Current volcanic activity and climate?](https://www.realclimate.org/index.php/archives/2006/05/current-volcanic-activity-and-climate/) - RealClimate: There has been a lot in the news recently about current volcanic activity - Merapi in Indonesia and Bezymianny in the Kamchatka peninsula in Russia, but while most reports have focussed on the very real dangers to the local populace and air traffic, volcanoes can have important impacts on climate as well. However, there are
- [Is Climate Modelling Science? <lang_fr>La modélisation climatique est-elle de la science?</lang_fr>](https://www.realclimate.org/index.php/archives/2005/01/is-climate-modelling-science/) - RealClimate: At first glance this seems like a strange question. Isn't science precisely the quantification of observations into a theory or model and then using that to make predictions? Yes. And are those predictions in different cases then tested against observations again and again to either validate those models or generate ideas for potential improvements? Yes,
- [Carbon storage in WA state forests is too small and too risky to play a serious role as a climate change mitigation tool](https://www.realclimate.org/index.php/archives/2016/11/carbon-storage-in-wa-state-forests-is-too-small-and-too-risky-to-play-a-serious-role-as-a-climate-change-mitigation-tool/) - RealClimate: Guest post by John Crusius, Richard Gammon, and Steve Emerson The scientific community is almost universally in agreement that climate change (and ocean acidification) are severe threats that demand a rapid response, with putting a price on fossil fuel CO2 emissions being a top priority. Far and away the single biggest contributor to climate change
- [Predictable and unpredictable behaviour](https://www.realclimate.org/index.php/archives/2017/03/predictable-and-unpredictable-behaviour/) - RealClimate: Terms such as “gas skeptics” and “climate skeptics” aren’t really very descriptive, but they refer to sentiments that have something in common: unpredictable behaviour. Statistics is remarkably predictable The individual gas molecules are highly unpredictable, but the bulk properties of the gases are nevertheless very predictable thanks to physics. More specifically the laws of thermodynamics
- [The true meaning of numbers](https://www.realclimate.org/index.php/archives/2017/03/the-true-meaning-of-numbers/) - RealClimate: Gavin has already discussed John Christy’s misleading graph earlier in 2016, however, since the end of 2016, there has been a surge in interest in this graph in Norway amongst people who try to diminish the role of anthropogenic global warming. I think this graph is warranted some extra comments in addition to Gavin’s points
- [Unforced Variations: Feb 2017](https://www.realclimate.org/index.php/archives/2017/02/unforced-variations-feb-2017/) - RealClimate: "O brave new world, that has such people in 't!" This month's open thread. Usual rules apply.
- [Someone C.A.R.E.S.](https://www.realclimate.org/index.php/archives/2017/02/someone-c-a-r-e-s/) - RealClimate: Do we need a new venue for post-publication comments and replications? Social media is full of commentary (of varying degrees of seriousness) on the supposed replication crisis in science. Whether this is really a crisis, or just what is to be expected at the cutting edge is unclear (and may well depend on the topic
- [Introducing PubPeer.com](https://www.realclimate.org/index.php/archives/2013/05/introducing-pubpeer-com/) - RealClimate: Guest post from PubPeer.com The process of reviewing published science is constantly occurring and is now commonly being called post-publication peer review. It occurs in many places including on blogs such as this one, review articles, at conferences around the world, and has even been encouraged on the websites of some journals. However, the process
- [Stefan Rahmstorf](https://www.realclimate.org/index.php/archives/2004/12/stefan-rahmstorf/) - RealClimate: A physicist and oceanographer by training, Stefan Rahmstorf has moved from early work in general relativity theory to working on climate issues. He has done research at the New Zealand Oceanographic Institute, at the Institute of Marine Science in Kiel and since 1996 at the Potsdam Institute for Climate Impact Research in Germany (in Potsdam
- [Serving up a NOAA-thing burger](https://www.realclimate.org/index.php/archives/2017/02/serving-up-a-noaa-thing-burger/) - RealClimate: I have mostly been sitting back and watching the John Bates story go through the predictable news-cycle of almost all supposed 'scandalous' science stories. The patterns are very familiar - an initial claim of imperfection spiced up with insinuations of misconduct, coordination with a breathless hyping of the initial claim with ridiculous supposed implications, some
- [Fake news, hacked mail, alternative facts – that's old hat for climate scientists](https://www.realclimate.org/index.php/archives/2017/02/fake-news-hacked-mail-alternative-facts-thats-old-hat-for-climate-scientists/) - RealClimate: Distortion? False information? Conspiracy theories? Hacked email? Climate scientists have known all this for decades. What can be learned from their rich experience with climate propaganda. The world is slowly waking up. "Post-truth" was declared the word of the year 2016 by the Oxford Dictionaries. Finally, people start to widely appreciate how dangerous the epidemic
- [1934 and all that](https://www.realclimate.org/index.php/archives/2007/08/1934-and-all-that/) - RealClimate: Another week, another ado over nothing. Last Saturday, Steve McIntyre wrote an email to NASA GISS pointing out that for some North American stations in the GISTEMP analysis, there was an odd jump in going from 1999 to 2000. On Monday, the people who work on the temperature analysis (not me), looked into it and
- [New report: Climate change, impacts and vulnerability in Europe 2016](https://www.realclimate.org/index.php/archives/2017/02/new-report-climate-change-impacts-and-vulnerability-in-europe-2016/) - RealClimate: Another climate report is out - what's new? Many of the previous reports have presented updated status on the climate and familiar topics such as temperature, precipitation, ice, snow, wind, and storm activities. The latest report Climate change, impacts and vulnerability in Europe 2016 from the European Environment Agency (EEA) also includes an assessment of
- [Unforced Variations: Jan 2017](https://www.realclimate.org/index.php/archives/2017/01/unforced-variations-jan-2017/) - RealClimate: The first open thread of the new year. Your resolution will be to keep the comments focused on science. Try to keep it longer than your resolution to exercise more...
- [There was no pause](https://www.realclimate.org/index.php/archives/2017/01/there-was-no-pause/) - RealClimate: I think that the idea of a pause in the global warming has been a red herring ever since it was suggested, and we have commented on this several times here on RC: On how data gaps in some regions (eg. the Arctic) may explain an underestimation of the recent warming. We have also explained
- [The NASA data conspiracy theory and the cold sun](https://www.realclimate.org/index.php/archives/2017/01/the-nasa-data-conspiracy-theory-and-the-cold-sun/) - RealClimate: When climate deniers are desperate because the measurements don’t fit their claims, some of them take the final straw: they try to deny and discredit the data. The years 2014 and 2015 reached new records in the global temperature, and 2016 has done so again. Some don’t like this because it doesn’t fit their political
- [2016 Temperature Records](https://www.realclimate.org/index.php/archives/2017/01/2016-temperature-records/) - RealClimate: To nobody's surprise, all of the surface datasets showed 2016 to be the warmest year on record. Barely more surprising is that all of the tropospheric satellite datasets and radiosonde data also have 2016 as the warmest year. Coming as this does after the record warm 2015, and (slightly less definitively) record warm 2014, the
- [The underestimated danger of a breakdown of the Gulf Stream System](https://www.realclimate.org/index.php/archives/2017/01/the-underestimated-danger-of-a-breakdown-of-the-gulf-stream-system/) - RealClimate: A new model simulation of the Gulf Stream System shows a breakdown of the gigantic overturning circulating in the Atlantic after a CO2 doubling. A new study in Science Advances by Wei Liu and colleagues at the Scripps Institution of Oceanography in San Diego and the University of Wisconsin-Madison has important implications for the future stability of the
- [Unforced variations: Dec 2016](https://www.realclimate.org/index.php/archives/2016/12/unforced-variations-dec-2016/) - RealClimate: This month's open thread. Roll on 2017...
- [A trigger action from sea-level rise?](https://www.realclimate.org/index.php/archives/2017/01/a-trigger-action-from-sea-level-rise/) - RealClimate: Can a rising sea level can act as a boost for glaciers calving into the sea and trigger a surge of ice into the oceans? I finally got round to watch the documentary Chasing Ice over the Christmas and New Year’s break, and it made a big impression. I also was left with this question
- [Climatology and meteorology are your friends](https://www.realclimate.org/index.php/archives/2016/12/climatology-and-meteorology-are-your-friends/) - RealClimate: The Norwegian Meteorological institute has celebrated its 150th anniversary this year. It was founded to provide weather data and tentative warnings to farmers, sailors, and fishermen. The inception of Norwegian climatology in the mid-1800s started with studies of geographical climatic variations to adapt important infrastructure to the ambient climate. The purpose of the meteorology and
- [What has science done for us?](https://www.realclimate.org/index.php/archives/2016/12/what-has-science-done-for-us/) - RealClimate: Where would we be without science? Today, we live longer than ever before according to the Royal Geographical Society, thanks to pharmaceutical, medical, and health science. Vaccines saves many lives. Physics and electronics have given us satellites, telecommunications, and the Internet. You would not read this blog without them. Chemistry and biology have provided use
- [AGU 2016](https://www.realclimate.org/index.php/archives/2016/12/agu-2016/) - RealClimate: It's that time of year again. Fall AGU is the biggest gathering of geophysical scientists in the world (~24,000 attendees) and while it includes planetary science, seismology and magnetophysics, it is swamped by earth scientists, whose work covers the atmosphere, oceans, cryosphere, climate, natural hazards and paleoclimate. As in previous years, many sessions and most
- [Defending Climate Science](https://www.realclimate.org/index.php/archives/2016/12/defending-climate-science/) - RealClimate: Guest commentary from Lauren Kurtz The Climate Science Legal Defense Fund (CSLDF) was founded in September 2011 to defend climate scientists from harassing and invasive attacks via the legal system. Five years in, we’re expanding our efforts to reflect the new challenges scientists face, including increasing education and outreach work. Now more than ever, it’s
- [Unforced variations: Nov 2016](https://www.realclimate.org/index.php/archives/2016/11/unforced-variations-nov-2016/) - RealClimate: This month's open thread. Usual rules apply...
- [Trump carbon and the Paris agreement](https://www.realclimate.org/index.php/archives/2016/11/trump-carbon-and-the-paris-agreement/) - RealClimate: The recent US election has prompted cries that the decision on Earth’s climate has now been irrevocably made, that the US has unilaterally decided to scrap the peak warming target from the Paris agreement of 1.5 oC. What do the numbers say? Is Earth’s climate now irrevocably fracked? The short answer is that, strictly speaking,
- [Record heat despite a cold sun](https://www.realclimate.org/index.php/archives/2016/11/record-heat-despite-a-cold-sun/) - RealClimate: Global temperature goes from heat record to heat record, yet the sun is at its dimmest for half a century. For a while, 2010 was the hottest year on record globally. But then it got overtopped by 2014. And 2014 was beaten again by 2015. And now 2016 is so warm that it is certain
- [Unforced Variations: Oct 2016](https://www.realclimate.org/index.php/archives/2016/10/unforced-variations-oct-2016/) - RealClimate: Here's hoping for no October climate surprises... Carry on. Usual rules.
- [Don’t make a choice that your children will regret](https://www.realclimate.org/index.php/archives/2016/11/dont-make-a-choice-that-your-children-will-regret/) - RealClimate: Dear US voters, the world is holding its breath. The stakes are high in the upcoming US elections. At stake is a million times more than which email server one candidate used, or how another treated women. The future of humanity will be profoundly affected by your choice, for many generations to come. The coming
- [Tuning in to climate models](https://www.realclimate.org/index.php/archives/2016/10/tuning-in-to-climate-models/) - RealClimate: There is an interesting news article ($) in Science this week by Paul Voosen on the increasing amount of transparency on climate model tuning. (Full disclosure, I spoke to him a couple of times for this article and I'm working on tuning description paper for the US climate modeling centers). The main points of the
- [AMOC slowdown: Connecting the dots](https://www.realclimate.org/index.php/archives/2016/05/amoc-slowdown-connecting-the-dots/) - RealClimate: I want to revisit a fascinating study that recently came from (mainly) the Geophysical Fluid Dynamics Lab in Princeton. It looks at the response of the Atlantic Ocean circulation to global warming, in the highest model resolution that I have seen so far. That is in the CM2.6 coupled climate model, with 0.1° x 0.1°
- [Q & A about the Gulf Stream System slowdown and the Atlantic ‘cold blob’](https://www.realclimate.org/index.php/archives/2016/10/q-a-about-the-gulf-stream-system-slowdown-and-the-atlantic-cold-blob/) - RealClimate: Last weekend, in Reykjavik the Arctic Circle Assembly was held, the large annual conference on all aspects of the Arctic. A topic of this year was: What's going on in the North Atlantic? This referred to the conspicuous ‘cold blob’ in the subpolar Atlantic, on which there were lectures and a panel discussion (Reykjavik University
- [The Snyder Sensitivity Situation](https://www.realclimate.org/index.php/archives/2016/09/the-snyder-sensitivity-situation/) - RealClimate: Nature published a great new reconstruction of global temperatures over the past 2 million years today. uses 61 temperature reconstructions from 59 globally diverse sediment cores and a correlation structure from model simulations of the last glacial maximum to estimate (with uncertainties) the history of global temperature back through the last few dozen ice ages
- [Unforced variations: Sep 2016](https://www.realclimate.org/index.php/archives/2016/09/unforced-variations-sep-2016/) - RealClimate: To come this month: Arctic sea ice minimum, decisions from the IPCC scoping meeting on a report focused on the 1.5ºC target, interesting paleo-climate science at #ICP12 and a chance to stop arguing about politics perhaps. Usual rules apply.
- [Why correlations of CO2 and Temperature over ice age cycles don't define climate sensitivity](https://www.realclimate.org/index.php/archives/2016/09/why-correlations-of-co2-and-temperature-over-ice-age-cycles-dont-define-climate-sensitivity/) - RealClimate: We've all seen how well temperature proxies and CO2 concentrations are correlated in the Antarctic ice cores - this has been known since the early 1990's and has featured in many high-profile discussions of climate change. EPICA Dome C ice core greenhouse gas and isotope records. The temperature proxies are water isotope ratios that can
- [650,000 years of greenhouse gas concentrations <lang_fr>650 000 années de concentrations de gaz à effet de serre</lang_fr>](https://www.realclimate.org/index.php/archives/2005/11/650000-years-of-greenhouse-gas-concentrations/) - RealClimate: The latest results from the EPICA core in Antarctica have just been published this week in Science (Siegenthaler et al. and Spahni et al.). This ice core extended the record of Antarctic climate back to maybe 800,000 years, and the first 650,000 years of ice have now been analysed for greenhouse gas concentrations saved in
- [Can a blanket violate the second law of thermodynamics?](https://www.realclimate.org/index.php/archives/2016/09/can-a-blanket-violate-the-second-law-of-thermodynamics/) - RealClimate: One of the silliest arguments of climate deniers goes like this: the atmosphere with its greenhouse gases cannot warm the Earth's surface, because it is colder than the surface. But heat always flows from warm to cold and never vice versa, as stated in the second law of thermodynamics. The freshly baked Australian Senator Malcolm
- [What is new in European climate research?](https://www.realclimate.org/index.php/archives/2016/09/what-is-new-in-european-climate-research/) - RealClimate: What did I learn from the 2016 annual European Meteorological Society (EMS) conference that last week was hosted in Trieste (Italy)? I think the biggest news from the conference was that new reanalyses are soon to be released by the European Centre for Medium-ranged Weather Forecasts (ECMWF). One new product known as ERA-5 will replace
- [Predicting annual temperatures a year ahead](https://www.realclimate.org/index.php/archives/2016/09/predicting-annual-temperatures-a-year-ahead/) - RealClimate: I have a post at Nate Silver's 538 site on how we can predict annual surface temperature anomalies based on El Niño and persistence - including a (by now unsurprising) prediction for a new record in 2016 and a slightly cooler, but still very warm, 2017. The key results are summarized in the figures that
- [An update on mid-latitude cyclones and climate change](https://www.realclimate.org/index.php/archives/2016/09/an-update-on-mid-latitude-cyclones-and-climate-change/) - RealClimate: Why is it so hard to say what the future North European climate will look like? A recent review paper by explains the reason in persuasive terms. The weather over Northern Europe is strongly shaped by low and high barotropic pressure, associated with so-called mid-latitude cyclones. Most people refer to the most extreme cyclones as
- [Unforced variations: Aug 2016](https://www.realclimate.org/index.php/archives/2016/08/unforced-variations-aug-2016/) - RealClimate: Sorry for the low rate of posts this summer. Lots of offline life going on. ;-) Meantime, this paper by Hourdin et al on climate model tuning is very interesting and harks back to the FAQ we did on climate models a few years ago (Part I, Part II). Maybe it's worth doing an update?
- [Boomerangs versus Javelins: The Impact of Polarization on Climate Change Communication](https://www.realclimate.org/index.php/archives/2016/06/boomerangs-versus-javelins-the-impact-of-polarization-on-climate-change-communication/) - RealClimate: Guest commentary by Jack Zhou, Nicholas School of the Environment, Duke University For advocates of climate change action, communication on the issue has often meant “finding the right message” that will spur their audience to action and convince skeptics to change their minds. This is the notion that simply connecting climate change to the right
- [Australian silliness and July temperature records](https://www.realclimate.org/index.php/archives/2016/08/australian-silliness-and-july-temperature-records/) - RealClimate: Some of you that follow my twitter account will have already seen this, but there was a particularly amusing episode of Q&A on Australian TV that pitted Prof. Brian Cox against a newly-elected politician who is known for his somewhat fringe climate 'contrarian' views. The resulting exchanges were fun: https://twitter.com/QandA/status/765155774234439680 The insinuation that NASA data
- [Unforced variations: July 2016](https://www.realclimate.org/index.php/archives/2016/07/unforced-variations-july-2016/) - RealClimate: A week is a long time in politics climate science: Nonsense debunked in WaPo, begininngs of recovery in the ozone hole, revisiting the instrumental record constraints on climate sensitivity... Lots of lessons there. Usual rules apply.
- [Unforced Variations: June 2016](https://www.realclimate.org/index.php/archives/2016/06/unforced-variations-june-2016/) - RealClimate: June already? Cripes... Usual rules apply.
- [Unforced variations: May 2016](https://www.realclimate.org/index.php/archives/2016/05/unforced-variations-may-2016/) - RealClimate: This month's open thread. Usual rules apply.
- [Scientists getting organized to help readers sort fact from fiction in climate change media coverage](https://www.realclimate.org/index.php/archives/2016/05/scientists-getting-organized-to-sort-fact-from-fiction-in-climate-change-media-coverage/) - RealClimate: Guest post by Emmanuel Vincent While 2016 is on track to easily surpass 2015 as the warmest year on record, some headlines, in otherwise prestigious news outlets, are still claiming that “2015 Was Not Even Close To Hottest Year On Record” (Forbes, Jan 2016) or that the “Planet is not overheating...” (The Times of London,
- [Do regional climate models add value compared to global models?](https://www.realclimate.org/index.php/archives/2016/05/do-regional-climate-models-add-value-compared-to-global-models/) - RealClimate: Global climate models (GCM) are designed to simulate earth's climate over the entire planet, but they have a limitation when it comes to describing local details due to heavy computational demands. There is a nice TED talk by Gavin that explains how climate models work. We need to apply downscaling to compute the local details.
- [Recycling Carbon?](https://www.realclimate.org/index.php/archives/2016/05/recycling-carbon/) - RealClimate: Guest commentary by Tony Patt, ETH Zürich This morning I was doing my standard reading of the New York Times, which is generally on the good side with climate reporting, and saw the same old thing: an article about a potential solution, which just got the story wrong, at least incomplete. The particular article was
- [Unforced Variations: Apr 2016](https://www.realclimate.org/index.php/archives/2016/04/unforced-variations-apr-2016/) - RealClimate: This month's open thread. Standard rules apply...
- [Limiting global warming to 2 °C – why Victor and Kennel are wrong + update](https://www.realclimate.org/index.php/archives/2014/10/limiting-global-warming-to-2-c-why-victor-and-kennel-are-wrong/) - RealClimate: In a comment in Nature titled Ditch the 2 °C warming goal, political scientist David Victor and retired astrophysicist Charles Kennel advocate just that. But their arguments don’t hold water. It is clear that the opinion article by Victor & Kennel is meant to be provocative. But even when making allowances for that, the arguments
- [What drives uncertainties in adapting to sea-level rise?](https://www.realclimate.org/index.php/archives/2016/03/what-drives-uncertainties-in-adapting-to-sea-level-rise/) - RealClimate: Guest article by Sally Brown, University of Southampton Let me get this off my chest – I sometimes get frustrated at climate scientists as they love to talk about uncertainties! To be sure, their work thrives on it. I’m someone who researches the projected impacts and adaptation to sea-level rise and gets passed ‘uncertain’ climate
- [The Early Anthropocene Hypothesis: An Update](https://www.realclimate.org/index.php/archives/2016/03/the-early-anthropocene-hypothesis-an-update/) - RealClimate: Guest post from Bill Ruddiman, University of Virginia For over a decade, paleoclimate scientists have argued whether the warmth of the last several thousand years was natural or anthropogenic. This brief comment updates that debate, also discussed earlier at RC: Debate over the Early Anthropogenic Hypothesis (2005) and An Emerging View on Early Land Use
- [Marvel et al (2015) Part III: Response to Nic Lewis](https://www.realclimate.org/index.php/archives/2016/02/marvel-et-al-2015-part-iii-response-to-nic-lewis/) - RealClimate: The first post in this series gave the basic summary of (henceforth MEA15) and why I think it is an important paper. The second discussed some of the risible immediate media coverage. But there has also been an 'appraisal' of the paper by Nic Lewis that has appeared in no fewer than three other climate
- [Unforced Variations: Feb 2016](https://www.realclimate.org/index.php/archives/2016/02/unforced-variations-feb-2016/) - RealClimate: This month's open thread. Just so you know, a lot of people have complained that these threads have devolved - particularly when the discussion has turned to differing visions of solutions - and have therefore become much less interesting. Some suggestions last month were for a side thread for that kind of stuff that wouldn't
- [Unforced Variations: Mar 2016](https://www.realclimate.org/index.php/archives/2016/03/unforced-variations-mar-2016/) - RealClimate: This month's open thread. Pros and cons of celebrity awareness-raising on climate? The end of the cherry-picking of 'pauses' in the satellite data? Continuing impacts of El Niño? Your choice (except for the usual subjects to be avoided...).
- [What is the best description of the greenhouse effect?](https://www.realclimate.org/index.php/archives/2016/02/what-is-the-best-description-of-the-greenhouse-effect/) - RealClimate: What exactly is the greenhouse effect? And what does it look like if we view it from a new angle? Of course, we know the answer, and Raymond Pierrehumbert has written an excellent paper about it (Infrared radiation and planetary temperature). Computer code used in climate models contain all the details. But is it possible
- [New On-line Classes and Models](https://www.realclimate.org/index.php/archives/2016/02/new-on-line-classes-and-models/) - RealClimate: My free online class on Coursera.org entitled Global Warming I: The Science and Modeling of Climate Change has already served 45,000 people (started, not finished) in the four times that it's run. Now it's set up in a new format, called "on demand mode", which allows people to start, progress, and finish on their own
- [Anti-scientists](https://www.realclimate.org/index.php/archives/2016/02/anti-scientists/) - RealClimate: Ross McKitrick was so upset about a paper ‘Learning from mistakes in climate research’ that he has written a letter of complaint and asked for immediate retraction of the pages discussing his work. This is an unusual step in science, as most disagreements and debate involve a comment or a response to the original article.
- [Unforced variations: Jan 2016](https://www.realclimate.org/index.php/archives/2016/01/unforced-variations-jan-2016/) - RealClimate: Happy New Year, and happy new open thread. As per usual, nuclear energy is off-topic - it's not that it's uninteresting, but it ends up dominating conversation to the total exclusion of everything else and just becomes repetitive and dull. Recent excursions on this topic shows what happens when we relax the moderation, so back
- [The evolution of radiative forcing bar-charts](https://www.realclimate.org/index.php/archives/2013/10/the-evolution-of-radiative-forcing-bar-charts/) - RealClimate: As part of the IPCC WG1 SPM (pdf) released last Friday, there was a subtle, but important, change in one of the key figures - the radiative forcing bar-chart (Fig. SPM.4). The concept for this figure has been a mainstay of summaries of climate change science for decades, and the evolution over time is a
- [Blizzard Jonas and the slowdown of the Gulf Stream System](https://www.realclimate.org/index.php/archives/2016/01/blizzard-jonas-and-the-slowdown-of-the-gulf-stream-system/) - RealClimate: Blizzard Jonas on the US east coast has just shattered snowfall records. Both weather forecasters and climate experts have linked the high snowfall amounts to the exceptionally warm sea surface temperatures off the east coast. In this post I will examine a related question: why are sea surface temperatures so high there, as shown in
- [How Likely Is The Observed Recent Warmth?](https://www.realclimate.org/index.php/archives/2016/01/how-likely-is-the-observed-recent-warmth/) - RealClimate: With the official numbers now in 2015 is, by a substantial margin, the new record-holder, the warmest year in recorded history for both the globe and the Northern Hemisphere. The title was sadly short-lived for previous record-holder 2014. And 2016 could be yet warmer if the current global warmth persists through the year. One might
- [2015 Temperatures](https://www.realclimate.org/index.php/archives/2016/01/2015-temperatures/) - RealClimate: To no-one's great surprise, 2015 was clearly a record year in all the surface temperature analyses (GISTEMP, NOAA, HadCRUT4, Cowtan&Way, JMA + Berkeley Earth). There is a lot of discussion of this in the press, and on the relevant websites, so not much to add here. A few figures didn't make it into the official
- [Marvel et al (2015) Part 1: Reconciling estimates of climate sensitivity](https://www.realclimate.org/index.php/archives/2016/01/marvel-et-al-2015-part-1-reconciling-estimates-of-climate-sensitivity/) - RealClimate: This post is related to the substantive results of the new Marvel et al (2015) study. There is a separate post on the media/blog response. The by Kate Marvel and others (including me) in Nature Climate Change looks at the different forcings and their climate responses over the historical period in more detail than any
- [Marvel et al (2015) Part 2: Media responses](https://www.realclimate.org/index.php/archives/2016/01/marvel-et-al-2015-part-2-media-responses/) - RealClimate: This is a second post related to the new paper. The first post dealing with the substantive content is here. What with #AGU15 going on, and a little bit of overlap in content with Shindell (2014), NASA wasn't particularly keen to put out a press release for the paper, but we did get a 'web
- [Unforced Variations: Dec 2015](https://www.realclimate.org/index.php/archives/2015/12/unforced-variations-dec-2015/) - RealClimate: This is a belated open thread for this month, for anything non-COP21 and non-AGU related.
- [Unforced Variations: Nov 2015](https://www.realclimate.org/index.php/archives/2015/11/unforced-variations-nov-2015/) - RealClimate: This month's open thread.
- [#AGU15](https://www.realclimate.org/index.php/archives/2015/12/agu15/) - RealClimate: So this week it's the biggest Earth Science meeting on the planet… There is a lot of great science that will be freely streamed via AGU On-Demand (registration required), and there'll be a lot of commentary using the hashtag #AGU15. Many posters will be available online too. A few highlights have already been discussed by
- [#COP21](https://www.realclimate.org/index.php/archives/2015/11/cop21/) - RealClimate: Apparently there is a climate conference of some sort going on. Happy to answer any science questions as they arise...
- [Hiatus or Bye-atus?](https://www.realclimate.org/index.php/archives/2015/11/hiatus-or-bye-atus/) - RealClimate: Guest commentary by Stephan Lewandowsky, James Risbey and Naomi Oreskes The idea that global warming has “stopped” has long been a contrarian talking point. This framing has found entry into the scientific literature and there are now numerous articles that address a presumed recent “pause” or “hiatus” in global warming. Moreover, the “hiatus” also featured
- [Reports of our demise…](https://www.realclimate.org/index.php/archives/2015/11/reports-of-our-demise/) - RealClimate: … have of course been greatly exaggerated. But we are having some issues with our domain name. The back story is perhaps interesting to others, so here is quick summary of the situation. Update: The account details have been restored and the domains renewed. We should be back to normal in a couple of days.
- [So what is <i>really</i> happening in Antarctica?](https://www.realclimate.org/index.php/archives/2015/11/so-what-is-really-happening-in-antarctica/) - RealClimate: The recent paper by Zwally et al. in the Journal of Glaciology has been widely reported as evidence that Antarctic is gaining mass, and hence lowering sea level. Is it? Expert Jonathan Bamber weighs in. Guest post by Jonathan Bamber, University of Bristol There have been quite few big media stories related to Antarctica recently,
- [So how did that global cooling bet work out?](https://www.realclimate.org/index.php/archives/2010/11/so-how-did-that-global-cooling-bet-work-out/) - RealClimate: Evaluation of decadal projections of 'global cooling' by Keenlyside et al (2008), climate betting and the importance of clearly communicating to the public.
- [Unforced variations: Oct 2015](https://www.realclimate.org/index.php/archives/2015/10/unforced-variations-oct-2015/) - RealClimate: This month's open thread. Since most climate related discussion this month will be focussed on the COP21... What is (or should be) the role of climate science in the upcoming negotiations? Discuss.
- [Climate change is coming to a place near you ](https://www.realclimate.org/index.php/archives/2015/10/climate-change-is-coming-to-a-place-near-you/) - RealClimate: What are the local consequences of a continued global warming? And what kind of future climate can you expect for you children? Do we expect more extreme events, and will a global warming affect the statistics of storms? Another question is how the local changes matters for local communities and the ecosystem. It may be
- [Unforced Variations: Sept. 2015](https://www.realclimate.org/index.php/archives/2015/09/unforced-variations-sept-2015/) - RealClimate: This month's open thread.
- [Recent Warming But No Trend  in Galactic Cosmic Rays ](https://www.realclimate.org/index.php/archives/2004/12/recent-warming-but-no-trend-in-galactic-cosmic-rays/) - RealClimate: There is little evidence for a connection between solar activity (as inferred from trends in galactic cosmic rays) and recent global warming. Since the paper by Friis-Christensen and Lassen (1991), there has been an enhanced controversy about the role of solar activity for earth's climate. Svensmark (1998) later proposed that changes in the inter-planetary magnetic
- [Unforced variations: Aug 2015](https://www.realclimate.org/index.php/archives/2015/08/unforced-variations-aug-2015/) - RealClimate: This month's open thread. A traditional time to discuss the Arctic sea ice minimum. But NH summer heatwaves, and to be fair, snow in the southern hemisphere, are also fair game...
- [Let’s learn from mistakes](https://www.realclimate.org/index.php/archives/2015/08/lets-learn-from-mistakes/) - RealClimate: The publication ‘Learning from mistakes in climate research’ is the result of a long-winded story with a number of surprises. At least to me. I have decided to share this story with our readers, since it in some aspects is closely linked with RealClimate. The core of this story is the reproduction and assessment of
- [Was the record Amazon drought caused by warm seas?](https://www.realclimate.org/index.php/archives/2006/01/is-the-amazonian-drought-caused-by-gw/) - RealClimate: On December 11, 2005, The New York Times ran a story on record drought conditions in the Amazonas region of Brasil, linking it to global warming, and specifically the warm ocean temperatures in the North Atlantic that have also been linked to the ferocity of the 2005 Atlantic hurricane season. This prompted a response from
- [Ice-core dating corroborates tree ring chronologies](https://www.realclimate.org/index.php/archives/2015/08/ice-core-dating-corroborates-tree-ring-chronologies/) - RealClimate: Guest commentary from Jonny McAneney You heard it here first... Back in February, we wrote a post suggesting that Greenland ice cores may have been incorrectly dated in prior to AD 1000. This was based on research by which compared the spacing between frost ring events (physical scarring of living growth rings by prolonged sub-zero
- [Unforced variations: July 2015](https://www.realclimate.org/index.php/archives/2015/07/unforced-variations-july-2015/) - RealClimate: This month's open thread. How about a focus on cimate science this time? Data visualizations anyone?
- [Polar Amplification](https://www.realclimate.org/index.php/archives/2006/01/polar-amplification/) - RealClimate: Guest commentary by Cecilia Bitz, University of Washington "Polar amplification'' usually refers to greater climate change near the pole compared to the rest of the hemisphere or globe in response to a change in global climate forcing, such as the concentration of greenhouse gases (GHGs) or solar output (see e.g. Moritz et al 2002). Polar
- [Unforced Variations: June 2015](https://www.realclimate.org/index.php/archives/2015/06/unforced-variations-june-2015/) - RealClimate: This month's open thread. Some interesting trends in ocean heat content, surface temperatures, multiple oddly reported papers (which are often linked to ambiguous press releases...) etc. But at least we aren't working in political science...
- [Heaven belongs to us all - the new papal encyclical](https://www.realclimate.org/index.php/archives/2015/06/heaven-belongs-to-us-all-the-new-papal-encyclical/) - RealClimate: Guest post by Brigitte Knopf With his encyclical "Laudato Si" the Pope has written more than a moral appeal without obligation. He has presented a pioneering political analysis with great explosive power, which will probably determine the public debate on climate change, poverty and inequality for years to come. Thus, the encyclical is also highly
- [Irreversible Does Not Mean Unstoppable <lang_fi>Peruuttamaton, ei pysäyttämätön</lang_fi><lang_it>Irreversibile non significa inarrestabile</lang_it><lang_sp>Irreversible no significa imparable</lang_sp>](https://www.realclimate.org/index.php/archives/2009/02/irreversible-does-not-mean-unstoppable/) - RealClimate: Susan Solomon, ozone hole luminary and chair of the Nobel Prize winning IPCC, and her colleagues, have just published a paper entitled “Irreversible climate change because of carbon dioxide emissions” in the Proceedings of the National Academy of Sciences. We at realclimate have been getting a lot of calls from journalists about this paper, and
- [Debate in the noise](https://www.realclimate.org/index.php/archives/2015/06/debate-in-the-noise/) - RealClimate: Last week there was an international media debate on climate data which appeared to be rather surreal to me. It was claimed that the global temperature data had so far shown a "hiatus" of global warming from 1998-2012, which was now suddenly gone after a data correction. So what happened? One of the data centers
- [The Soon fallacy ](https://www.realclimate.org/index.php/archives/2015/02/the-soon-fallacy/) - RealClimate: As many will have read, there were a number of press reports (NYT, Guardian, InsideClimate) about the non-disclosure of Willie Soon's corporate funding (from Southern Company (an energy utility), Koch Industries, etc.) when publishing results in journals that require such disclosures. There are certainly some interesting questions to be asked (by the OIG!) about adherence
- [Unforced Variations: May 2015](https://www.realclimate.org/index.php/archives/2015/05/unforced-variations-may-2015/) - RealClimate: This month's open thread.
- [Global warming and unforced variability: Clarifications on recent Duke study](https://www.realclimate.org/index.php/archives/2015/05/global-warming-and-unforced-variability-clarifications-on-recent-duke-study/) - RealClimate: Guest Commentary from Patrick Brown and Wenhong Li, Duke University We recently published a study in Scientific Reports titled . Our study seemed to generated a lot of interest and we have received many inquires regarding its findings. We were pleased with some of coverage of our study (e.g., here) but we were disappointed that
- [Unforced Variations: April 2015](https://www.realclimate.org/index.php/archives/2015/04/unforced-variations-april-2015/) - RealClimate: April already? Time for a new climate science open thread...
- [How long does it take Antarctica to notice the Northern Hemisphere is warming?](https://www.realclimate.org/index.php/archives/2015/04/how-long-does-it-take-antarctica/) - RealClimate: Eric Steig A series of large and abrupt climate changes occurred during the last ice age, most clearly expressed in ice cores from Greenland and other paleoclimate data from the circum-North-Atlantic region. Since the discovery of these events, we’ve been trying to pin down the timing of abrupt climate changes elsewhere on the globe. Were
- [Nenana Ice Classic 2015](https://www.realclimate.org/index.php/archives/2015/04/nenana-ice-classic-2015/) - RealClimate: Unsurprisingly to anyone looking at the exceptionally warm winter on the West Coast of North America, the Nenana Ice Classic had another near-record early breakup on Friday, netting some lucky winner(s) around 0,000 in prizes. As I've discussed previously (last year and an update), the Ice Classic is a lottery that has been run every
- [The return of the iris effect?](https://www.realclimate.org/index.php/archives/2015/04/the-return-of-the-iris-effect/) - RealClimate: Guest commentary from Andy Dessler (TAMU) When a new scientific hypothesis is published, two questions always occur to me: Did the authors convincingly show the hypothesis was correct? If not, is the hypothesis actually correct? The answers to these two questions may not be the same. A good example is Wegener's theory of continental drift
- [An Online University Course on the Science of Climate Science Denial](https://www.realclimate.org/index.php/archives/2015/04/an-online-university-course-on-the-science-of-climate-science-denial/) - RealClimate: Guest post from John Cook, University of Queensland For many years, RealClimate has been educating the public about climate science. The value of climate scientists patiently explaining the science and rebutting misinformation directly with the public cannot be overestimated. When I began investigating this issue, my initial searches led me here, which was invaluable in
- [A failure in communicating the impact of new findings](https://www.realclimate.org/index.php/archives/2013/12/a-failure-in-communicating-the-impact-of-new-findings/) - RealClimate: I was disappointed by the recent summary for policymakers (SPM) of the intergovernmental panel on climate change (IPCC) assessment report 5, now that I finally got around to read it. Not so much because of the science, but because the way it presented the science. The report was written by top scientists, so what went
- [A Scientific Debate](https://www.realclimate.org/index.php/archives/2015/04/a-scientific-debate/) - RealClimate: Guest posting from Bill Ruddiman, University of Virginia Recently I’ve read claims that some scientists are opposed to AGW but won’t speak out because they fear censure from a nearly monolithic community intent on imposing a mainstream view. Yet my last 10 years of personal experience refute this claim. This story began late in 2003
- [Unforced variations: March 2015](https://www.realclimate.org/index.php/archives/2015/03/unforced-variations-march-2015/) - RealClimate: This month's open thread. We've burned out on mitigation topics (again), so please focus on climate science issues this month...
- [A hypothesis about the cold winter in eastern North America + Update](https://www.realclimate.org/index.php/archives/2015/03/a-hypothesis-about-the-cold-winter-in-eastern-north-america/) - RealClimate: The past winter was globally the warmest on record. At the same time it set a new cold record in the subpolar North Atlantic – and it was very cold in the eastern parts of North America. Are these things related? Two weeks ago NOAA published the following map of temperature anomalies for the past
- [Reflections on Ringberg](https://www.realclimate.org/index.php/archives/2015/04/reflections-on-ringberg/) - A review of last weeks workshop on climate sensitivity with a focus on structural challenges and cloud feedbacks.
- [What's going on in the North Atlantic?](https://www.realclimate.org/index.php/archives/2015/03/whats-going-on-in-the-north-atlantic/) - RealClimate: The North Atlantic between Newfoundland and Ireland is practically the only region of the world that has defied global warming and even cooled. Last winter there even was the coldest on record - while globally it was the hottest on record. Our recent study (Rahmstorf et al. 2015) attributes this to a weakening of the
- [Climate Sensitivity Week](https://www.realclimate.org/index.php/archives/2015/03/climate-sensitivity-week/) - RealClimate: Some of you will be aware that there is a workshop on Climate Sensitivity this week at Schloss Ringberg in southern Germany. The topics to be covered include how sensitivity is defined (and whether it is even meaningful (Spoiler, yes it is)), what it means, how it can be constrained, what the different flavours signify
- [Severe Tropical Cyclone Pam and Climate Change](https://www.realclimate.org/index.php/archives/2015/03/severe-tropical-cyclone-pam-and-climate-change/) - RealClimate: Guest post by Kerry Emanuel In the past 16 months, two exceptionally intense tropical cyclones, Haiyan and Pam, have struck the western Pacific with devastating effect. Haiyan may have had the highest wind speeds of any tropical cyclone on record, but we will never know for sure because we do a poor job estimating the
- [Unforced Variations: Feb 2015](https://www.realclimate.org/index.php/archives/2015/02/unforced-variations-feb-2015/) - RealClimate: This month's open thread.
- [Climate Oscillations and the Global Warming Faux Pause](https://www.realclimate.org/index.php/archives/2015/02/climate-oscillations-and-the-global-warming-faux-pause/) - RealClimate: No, climate change is not experiencing a hiatus. No, there is not currently a "pause" in global warming. Despite widespread such claims in contrarian circles, human-caused warming of the globe proceeds unabated. Indeed, the most recent year (2014) was likely the warmest year on record. It is true that Earth's surface warmed a bit less
- [How Soon is now?](https://www.realclimate.org/index.php/archives/2011/07/how-soon-is-now/) - RealClimate: Willie Soon is a name that pops up every so often in climate 'debate'. He was the lead author on the Soon and Baliunas (2003) paper (the only paper that has ever led to the resignation of 6 editors in protest at the failure of peer-review that led to its publication). He was a recent
- [The mystery of the offset chronologies: Tree rings and the volcanic record of the 1st millennium](https://www.realclimate.org/index.php/archives/2015/02/the-mystery-of-the-offset-chronologies-tree-rings-and-the-volcanic-record-of-the-1st-millennium/) - RealClimate: Guest commentary by Jonny McAneney Volcanism can have an important impact on climate. When a large volcano erupts it can inject vast amounts of dust and sulphur compounds into the stratosphere, where they alter the radiation balance. While the suspended dust can temporarily block sunlight, the dominant effect in volcanic forcing is the sulphur, which
- [The lure of solar forcing](https://www.realclimate.org/index.php/archives/2005/07/the-lure-of-solar-forcing/) - RealClimate: It's obvious. The sun provides 99.998% of the energy to the Earth's climate (the rest coming from geothermal heat sources). The circulation patterns of the tropical Hadley Cell, the mid latitude storm tracks the polar high and the resulting climate zones are all driven by the gradients of solar heating as a function of latitude.
- [536 AD and all that <lang_sp>530 AD y todo eso</lang_sp>](https://www.realclimate.org/index.php/archives/2008/03/536-ad-and-all-that/) - RealClimate: "during this year a most dread portent took place. For the sun gave forth its light without brightness… and it seemed exceedingly like the sun in eclipse, for the beams it shed were not clear." Eine deutsche Übersetzung dieses Artikels ist hier. This quote from Procopius of Caesarea is matched by other sources from around
- [Unforced Variations: Jan 2015](https://www.realclimate.org/index.php/archives/2015/01/unforced-variations-jan-2015/) - RealClimate: This month's open thread. Sorry for the slow start - you know what it's like after the holidays...
- [Dummies guide to the latest "Hockey Stick" controversy <lang_fr>Guide pratique pour comprendre la dernière controverse sur la « crosse de hockey »</lang_fr>](https://www.realclimate.org/index.php/archives/2005/02/dummies-guide-to-the-latest-hockey-stick-controversy/) - RealClimate: by Gavin Schmidt and Caspar Amman Due to popular demand, we have put together a 'dummies guide' which tries to describe what the actual issues are in the latest controversy, in language even our parents might understand. A pdf version is also available. More technical descriptions of the issues can be seen here and here.
- [Peer Review: A Necessary But <em>Not</em> Sufficient Condition <lang_fr>Evaluation par des pairs : une condition nécessaire mais <em>pas</em> suffisante</lang_fr>](https://www.realclimate.org/index.php/archives/2005/01/peer-review-a-necessary-but-not-sufficient-condition/) - RealClimate: by Michael Mann and Gavin Schmidt On this site we emphasize conclusions that are supported by "peer-reviewed" climate research. That is, research that has been published by one or more scientists in a scholarly scientific journal after review by one or more experts in the scientists' same field ('peers') for accuracy and validity. What is
- [Thoughts on 2014 and ongoing temperature trends](https://www.realclimate.org/index.php/archives/2015/01/thoughts-on-2014-and-ongoing-temperature-trends/) - RealClimate: Last Friday, NASA GISS and NOAA NCDC had a press conference and jointly announced the end-of-year analysis for the 2014 global surface temperature anomaly which, in both analyses, came out top. As you may have noticed, this got much more press attention than their joint announcement in 2013 (which wasn't a record year). In press
- [A new sea level curve](https://www.realclimate.org/index.php/archives/2015/01/a-new-sea-level-curve/) - RealClimate: The "zoo" of global sea level curves calculated from tide gauge data has grown - tomorrow a new reconstruction of our US colleagues around Carling Hay from Harvard University will appear in Nature . That is a good opportunity for an overview over the available data curves. The differences are really in the details, the
- [Diagnosing Causes of Sea Level Rise](https://www.realclimate.org/index.php/archives/2015/01/diagnosing-causes-of-sea-level-rise/) - RealClimate: Guest post by Sarah G. Purkey and Gregory C. Johnson, University of Washington / NOAA I solicited this post from colleagues at the University of Washington. I found particularly interesting because it gets at the question of sea level rise from a combination of ocean altimetry and density (temperature + salinity) data. This kind of
- [Unforced variations: Dec 2014](https://www.realclimate.org/index.php/archives/2014/12/unforced-variations-dec-2014/) - RealClimate: This month's open thread. Think history, Lima, and upcoming additions of a single data point to timeseries based on arbitrary calendrical boundaries.
- [Absolute temperatures and relative anomalies](https://www.realclimate.org/index.php/archives/2014/12/absolute-temperatures-and-relative-anomalies/) - RealClimate: Most of the images showing the transient changes in global mean temperatures (GMT) over the 20th Century and projections out to the 21st C, show temperature anomalies. An anomaly is the change in temperature relative to a baseline which usually the pre-industrial period, or a more recent climatology (1951-1980, or 1980-1999 etc.). With very few
- [Clarity on Antarctic sea ice.](https://www.realclimate.org/index.php/archives/2014/12/clarity-on-antarctic-sea-ice/) - RealClimate: I've always been a skeptic when it comes to Antarctic sea ice. I'm not referring here to the tiresome (and incorrect) claim that the expansion of sea ice around Antarctica somehow cancels out the dramatic losses of sea ice in the Arctic (NB: polar bears don't really care if there is sea ice in Antarctica
- [Eric Steig](https://www.realclimate.org/index.php/archives/2004/12/eric-steig/) - RealClimate: Eric Steig is an isotope geochemist at the University of Washington in Seattle. His primary research interest is use of ice core records to document climate variability in the past. He also works on the geological history of ice sheets, on ice sheet dynamics, on statistical climate analysis, and on atmospheric chemistry. He received a
- [AGU 2014](https://www.realclimate.org/index.php/archives/2014/12/agu-2014/) - RealClimate: Once more unto the breach! Fall AGU this year will be (as last year) ...the largest Earth Science conference on the planet, and is where you will get previews of new science results, get a sense of what other experts think about current topics, and indulge in the more social side of being a scientist.
- [Ten Years of RealClimate: Where now?](https://www.realclimate.org/index.php/archives/2014/12/ten-years-of-realclimate-where-now/) - RealClimate: The landscape for science blogging, the public discourse on climate and our own roles in the scientific community have all changed radically over the last 10 years. Blogging is no longer something that stands apart from professional communications, the mainstream media or new online start-ups. The diversity of voices online has also increased widely: scientists
- [Ten years of RealClimate: Thanks](https://www.realclimate.org/index.php/archives/2014/12/ten-years-of-realclimate-thanks/) - RealClimate: As well as the current core team - David Archer, Eric Steig, Gavin Schmidt, Mike Mann, Rasmus Benestad, Ray Bradley, Ray Pierrehumbert, Stefan Rahmstorf - this blog has had input from many others over the years: The 90+ guest contributors and previous team members who bring a necessary diversity of experience and expertise to the
- [Good news for the earth's climate system?](https://www.realclimate.org/index.php/archives/2010/02/good-news-for-the-earths-climate-system/) - RealClimate: Frank et al, Nature, carbon cycle sensitivity to global warming.
- [Linking the climate-ecology attribution chain](https://www.realclimate.org/index.php/archives/2009/02/linking-the-climate-ecology-attribution-chain/) - RealClimate: Guest commentary by Jim Bouldin, Department of Plant Sciences, UC Davis Linking the regional climate-ecology attribution chain in the western United States Many are obviously curious about whether certain current regional environmental changes are traceable to global climate change. There are a number of large-scale changes that clearly qualify—rapid warming of the arctic/sub-arctic regions for
- [Ten years of Realclimate: By the numbers](https://www.realclimate.org/index.php/archives/2014/12/ten-years-of-realclimate-by-the-numbers/) - RealClimate: Start date: 10 December 2004 Number of posts: 914 Number of comments: ~172,000 Number of comments with inline responses: 14,277 Minimum number of total unique page visits, and unique views, respectively: 19 Million, 35 Million Number of guest posts: 100+ Number of mentions in newspaper sources indexed by LexisNexis: 225 Minimum number of contributors and
- [Ten Years of RealClimate](https://www.realclimate.org/index.php/archives/2014/12/ten-years-of-realclimate/) - RealClimate: In the spring of 2004, when we (individually) first started talking to people about starting a blog on climate science, almost everyone thought it was a great idea, but very few thought it was something they should get involved in. Today, scientists communicating on social media is far more commonplace. On the occasion of our
- [Recent global warming trends: significant or paused or what?  ](https://www.realclimate.org/index.php/archives/2014/12/recent-global-warming-trends-significant-or-paused-or-what/) - RealClimate: As the World Meteorological Organisation WMO has just announced that “The year 2014 is on track to be the warmest, or one of the warmest years on record”, it is timely to have a look at recent global temperature changes. I’m going to use Kevin Cowtan’s nice interactive temperature plotting and trend calculation tool to
- [Water vapour: feedback or forcing?](https://www.realclimate.org/index.php/archives/2005/04/water-vapour-feedback-or-forcing/) - RealClimate: Whenever three or more contrarians are gathered together, one will inevitably claim that water vapour is being unjustly neglected by 'IPCC' scientists. "Why isn't water vapour acknowledged as a greenhouse gas?", "Why does anyone even care about the other greenhouse gases since water vapour is 98% of the effect?", "Why isn't water vapour included in
- [How do trees change the climate?](https://www.realclimate.org/index.php/archives/2014/10/how-do-trees-change-the-climate/) - RealClimate: Guest commentary from Abby Swann (U. Washington) This past month, an op-ed by Nadine Unger appeared in the New York Times with the headline “To save the climate, don’t plant trees”. The author’s main argument is that UN programs to address climate change by planting trees or preserving existing forests are “high risk” and a
- [New developments: Climate services for health](https://www.realclimate.org/index.php/archives/2014/10/new-developments-climate-services-for-health/) - RealClimate: I recently received a joint email from the World Meteorological and Health organisations (WMO & WHO) which I like to bring to the attention of our readers. Both because it shows the direction of some new developments, but also because the WMO and WHO are inviting people to share their experience with health and climate.
- [The most popular deceptive climate graph](https://www.realclimate.org/index.php/archives/2014/12/the-most-popular-deceptive-climate-graph/) - RealClimate: The "World Climate Widget" from Tony Watts' blog is probably the most popular deceptive image among climate “skeptics”. We'll take it under the microscope and show what it would look like when done properly. So called "climate skeptics" deploy an arsenal of misleading graphics, with which the human influence on the climate can be down
- [A new experiment with science publication](https://www.realclimate.org/index.php/archives/2013/06/a-new-experiment-with-science-publication/) - RealClimate: A while ago, I received a request to publish a paper on a post that I had written here on RealClimate, exposing the flaws in the analysis of . Instead of writing a comment to one paper, however, I thought it might be useful to collect a sample of papers that I found unconvincing (usual
- [Statistics and Climate](https://www.realclimate.org/index.php/archives/2013/11/statistics-and-climate/) - RealClimate: Do different climate models give different results? And if so, why? The answer to these questions will increase our understanding of the climate models, and potentially the physical phenomena and processes present in the climate system. We now have many different climate models, many different methods, and get a range of different results. They provide
- [Weighing change in Antarctica](https://www.realclimate.org/index.php/archives/2012/11/weighing-change-in-antarctica/) - RealClimate: Guest commentary by Matt King, Michael Bentley and Pippa Whitehouse Determining whether polar ice sheets are shrinking or growing, and what their contribution is to changes in sea level, has motivated polar scientists for decades. Genuine progress began in the early 1990s when satellite observations started to provide (nearly) spatially comprehensive sets of observations. Three
- [Cows, Carbon and the Anthropocene: Commentary on Savory TED Video](https://www.realclimate.org/index.php/archives/2013/11/cows-carbon-and-the-anthropocene-commentary-on-savory-ted-video/) - RealClimate: Guest post by Jason West and David Briske Allan Savory delivered a highly publicized talk at a “Technology, Entertainment, Design (TED)” conference in February of this year (2013) entitled “How to fight desertification and reverse climate change.” Here we address one of the most dramatic claims made – that a specialized grazing method alone can
- [A clearer picture how climate change affects El Niño?](https://www.realclimate.org/index.php/archives/2014/11/a-clearer-picture-how-climate-change-affects-el-nino/) - RealClimate: I still remember the first time I was asked about how climate change affects El Niño. It was given as a group exercise during a winter school in Les Houghes (in France) back in February 1996. Since then, I have kept thinking about this question, and I have not been the only one wondering about
- [Unforced variations: Oct 2014](https://www.realclimate.org/index.php/archives/2014/10/unforced-variations-oct-2014/) - RealClimate: This month's open thread.
- [Storm surge: Hurricane Sandy](https://www.realclimate.org/index.php/archives/2014/10/storm-surge-hurricane-sandy/) - Excerpt from "Storm Surge: Hurricane Sandy, Our Changing Climate, and Extreme Weather of the Past and Future" by Adam Sobel
- [Gavin A. Schmidt](https://www.realclimate.org/index.php/archives/2004/12/gavin-schmidt/) - RealClimate: Gavin Schmidt is a climate modeller at the NASA Goddard Institute for Space Studies and Earth Institute at Columbia University in New York and is interested in modeling past, present and future climate. He works on developing and improving coupled climate models and, in particular, is interested in how their results can be compared to
- [Ocean heat storage: a particularly lousy policy target + Update](https://www.realclimate.org/index.php/archives/2014/10/ocean-heat-storage-a-particularly-lousy-policy-target/) - RealClimate: The New York Times, 12 December 2027: After 12 years of debate and negotiation, kicked off in Paris in 2015, world leaders have finally agreed to ditch the goal of limiting global warming to below 2 °C. Instead, they have agreed to the new goal of limiting global ocean heat content to 1024 Joules. The
- [Climate response estimates from Lewis & Curry](https://www.realclimate.org/index.php/archives/2014/10/climate-response-estimates-from-lewis-curry/) - RealClimate: Guest commentary from Richard Millar (U. Oxford) The recent study of climate sensitivity estimated from the transient surface temperature record is being lauded as something of a game-changer – but how much of a game-changer is it really? The method at the heart of the new study is essentially identical to that used in the
- [Unforced variations: September 2014](https://www.realclimate.org/index.php/archives/2014/09/unforced-variations-september-2014/) - RealClimate: This month's open thread. People could waste time rebunking predictable cherry-picked claims about the upcoming Arctic sea ice minimum, or perhaps discuss a selection of 10 climate change controversies from ICSU... Anything! (except mitigation).
- [The lag between temperature and CO<sub>2</sub>.  (Gore's got it right.)](https://www.realclimate.org/index.php/archives/2007/04/the-lag-between-temp-and-co2/) - RealClimate: When I give talks about climate change, the question that comes up most frequently is this: “Doesn’t the relationship between CO2 and temperature in the ice core record show that temperature drives CO2, not the other way round?" On the face of it, it sounds like a reasonable question. It is no surprise that it
- [Free climate science / modeling class beginning Sept. 29](https://www.realclimate.org/index.php/archives/2014/09/free-climate-science-modeling-class-beginning-sept-29/) - RealClimate: Global Warming: The Science and Modeling of Climate Change is a free online adaptation of a college-level class for non-science majors at the University of Chicago (textbook, video lectures). The class includes 33 short exercises for playing with on-line models, 5 "number-cruncher" problems where you create simple models from scratch in a spreadsheet or programming
- [The story of methane in our climate, in five pie charts](https://www.realclimate.org/index.php/archives/2014/09/the-story-of-methane-in-our-climate-in-five-pie-charts/) - RealClimate: methane_pie
- [Unforced variations: Aug 2014](https://www.realclimate.org/index.php/archives/2014/08/unforced-variations-aug-2014/) - RealClimate: This month's open thread. Keeping track of the Arctic sea ice minimum is interesting but there should be plenty of other climate science topics to discuss (if people can get past the hype about the Ebola outbreak or imaginary claims about anomalous thrusting). As with last month, pleas no discussion of mitigation strategies - it
- [Sherwood Rowland, CFCs, ozone depletion and the public role of scientists](https://www.realclimate.org/index.php/archives/2012/03/sherwood-roland-cfcs-ozone-depletion-and-the-public-role-of-scientists/) - RealClimate: Many of you will have read the obituaries of the Nobel Prize-winning chemist Sherwood Rowland (Nature, BBC) who sadly died over the weekend. DotEarth has a good collection of links to papers, videos and tributes. We have sometimes commented on the connections between the issue of CFC-driven ozone depletion and anthropogenic global warming. In both
- [IPCC attribution statements redux: A response to Judith Curry](https://www.realclimate.org/index.php/archives/2014/08/ipcc-attribution-statements-redux-a-response-to-judith-curry/) - RealClimate: I have written a number of times about the procedure used to attribute recent climate change (here in 2010, in 2012 (about the AR4 statement), and again in 2013 after AR5 was released). For people who want a summary of what the attribution problem is, how we think about the human contributions and why the
- [How much methane came out of that hole in Siberia?](https://www.realclimate.org/index.php/archives/2014/08/how-much-methane-came-out-of-that-hole-in-siberia/) - RealClimate: Siberia has explosion holes in it that smell like methane, and there are newly found bubbles of methane in the Arctic Ocean. As a result, journalists are contacting me assuming that the Arctic Methane Apocalypse has begun. However, as a climate scientist I remain much more concerned about the fossil fuel industry than I am
- [Unforced variations: July 2014](https://www.realclimate.org/index.php/archives/2014/07/unforced-variations-july-2014/) - RealClimate: This month's open thread. Topics of potential interest: The successful OCO-2 launch, continuing likelihood of an El Niño event this fall, predictions of the September Arctic sea ice minimum, Antarctic sea ice excursions, stochastic elements in climate models etc. Just for a change, no discussion of mitigation efforts please!
- [Rossby waves and surface weather extremes](https://www.realclimate.org/index.php/archives/2014/07/rossby-waves-and-surface-weather-extremes/) - RealClimate: A new study by Screen and Simmonds demonstrates the statistical connection between high-amplitude planetary waves in the atmosphere and extreme weather events on the ground. Guest post by Dim Coumou There has been an ongoing debate, both in and outside the scientific community, whether rapid climate change in the Arctic might affect circulation patterns in
- [Release of the International Surface Temperature Initiative’s (ISTI’s) Global Land Surface Databank, an expanded set of fundamental surface temperature records](https://www.realclimate.org/index.php/archives/2014/07/release-of-the-international-surface-temperature-initiatives-istis-global-land-surface-databank-an-expanded-set-of-fundamental-surface-temperature-records/) - RealClimate: Guest post by Jared Rennie, Cooperative Institute for Climate and Satellites, North Carolina on behalf of the databank working group of the International Surface Temperature Initiative In the 21st Century, when multi-billion dollar decisions are being made to mitigate and adapt to climate change, society rightly expects openness and transparency in climate science to enable
- [Unforced variations: June 2014](https://www.realclimate.org/index.php/archives/2014/06/unforced-variations-june-2014/) - RealClimate: June is the month when the Arctic Sea Ice outlook gets going, when the EPA releases its rules on power plant CO2 emissions, and when, hopefully, commenters can get back to actually having constructive and respectful conversations about climate science (and not nuclear energy, impending apocalypsi (pl) or how terrible everyone else is). Thanks.
- [Labels for climate data](https://www.realclimate.org/index.php/archives/2014/04/labels-for-climate-data/) - RealClimate: "These results are quite strange", my colleague told me. He analysed some of the recent climate model results from an experiment known by the cryptic name 'CMIP5'. It turned out that the results were ok, but we had made an error when reading and processing the model output. The particular climate model that initially gave
- [Unforced variations: May 2014](https://www.realclimate.org/index.php/archives/2014/05/unforced-variations-may-2014/) - RealClimate: This month's open thread. In order to give everyone a break, no discussion of mitigation options this month - that has been done to death in previous threads. Anything related to climate science is totally fine: Carbon dioxide levels maybe, or TED talks perhaps...
- [Jim Bouldin](https://www.realclimate.org/index.php/archives/2004/12/jim-bouldin/) - RealClimate: Jim Bouldin is a currently unaffiliated research ecologist, holding a BS in Wildlife Management from Ohio State University and a PhD in Plant Science from UCD. His primary research background/interest relates to forest change in response to human activity over the last ~ 200 years, and associated vegetation analysis methods issues, focusing on North America.
- [El Niño or Bust](https://www.realclimate.org/index.php/archives/2014/05/el-nino-or-bust/) - RealClimate: Guest commentary from Michelle L'Heureux, NOAA Climate Prediction Center Much media attention has been directed at the possibility of an El Niño brewing this year. Many outlets have drawn comparison with the 1997-98 super El Niño. So, what are the odds that El Niño will occur? And if it does, how strong will it be?
- [Faking it](https://www.realclimate.org/index.php/archives/2014/04/faking-it/) - RealClimate: Every so often contrarians post old newspaper quotes with the implication that nothing being talked about now is unprecedented or even unusual. And frankly, there are lots of old articles that get things wrong, are sensationalist or made predictions without a solid basis. And those are just the articles about the economy. However, there are
- [Nenana Ice Classic: Update](https://www.realclimate.org/index.php/archives/2014/04/nenana-ice-classic-update/) - RealClimate: Somewhat randomly, my thoughts turned to the Nenana Ice Classic this evening, only to find that the ice break up had only just occurred (3:48 pm Alaskan Standard Time, April 25). This is quite early (the 7th earliest date, regardless of details associated with the vernal equinox or leap year issues), though perhaps unsurprising after
- [Mitigation of Climate Change - Part 3 of the new IPCC report](https://www.realclimate.org/index.php/archives/2014/04/mitigation-of-climate-change-part-3-of-the-new-ipcc-report/) - RealClimate: Guest post by Brigitte Knopf Global emissions continue to rise further and this is in the first place due to economic growth and to a lesser extent to population growth. To achieve climate protection, fossil power generation without CCS has to be phased out almost entirely
- [Shindell: On constraining the Transient Climate Response](https://www.realclimate.org/index.php/archives/2014/04/shindell-on-constraining-the-transient-climate-response/) - RealClimate: Guest commentary from Drew Shindell There has been a lot of discussion of my recent paper in Nature Climate Change . That study addressed a puzzle, namely that recent studies using the observed changes in Earth's surface temperature suggested climate sensitivity is likely towards the lower end of the estimated range. However, studies evaluating model
- [Unforced variations: Mar 2014](https://www.realclimate.org/index.php/archives/2014/03/unforced-variations-mar-2014/) - RealClimate: This month's open thread.
- [Unforced variations: Apr 2014](https://www.realclimate.org/index.php/archives/2014/04/unforced-varaitions-apr-2014/) - RealClimate: More open thread. Unusually, we are keeping the UV Mar 2014 thread open for more Diogenetic conversation and to keep this thread open for more varied fare.
- [Unforced variations: Mar 2014. Part II](https://www.realclimate.org/index.php/archives/2014/03/unforced-variations-mar-2014-part-ii/) - RealClimate: This is mid-month open-thread for all discussions, except those related to Diogenes' comments. People wanting to discuss with commenter Diogenes should stick to the previous UV thread. All such discussion on this thread will be moved over. Thanks.
- [Impacts of Climate Change – Part 2 of the new IPCC Report has been approved](https://www.realclimate.org/index.php/archives/2014/04/impacts-of-climate-change-part-2-of-the-new-ipcc-report-has-been-approved/) - RealClimate: The second part of the new IPCC Report has been approved – as usual after lengthy debates – by government delegations in Yokohama (Japan) and is now public. Perhaps the biggest news is this: the situation is no less serious than it was at the time of the previous report 2007. Nonetheless there is progress
- [The most common fallacy in discussing extreme weather events + Update](https://www.realclimate.org/index.php/archives/2014/03/the-most-common-fallacy-in-discussing-extreme-weather-events/) - RealClimate: Does global warming make extreme weather events worse? Here is the #1 flawed reasoning you will have seen about this question: it is the classic confusion between absence of evidence and evidence for absence of an effect of global warming on extreme weather events. Sounds complicated? It isn’t. I’ll first explain it in simple terms
- [IPCC WG2 report now out](https://www.realclimate.org/index.php/archives/2014/03/ipcc-wg2-report-now-out/) - RealClimate: Instead of speculations based on partial drafts and attempts to spin the coverage ahead of time, you can now download the final report of the IPCC WG2: "Climate Change 2014:Impacts, Adaptation, and Vulnerability" directly. The Summary for Policy Makers is here, while the whole report is also downloadable by chapter. Notably there are FAQ for
- [PBS: Climate of Doubt](https://www.realclimate.org/index.php/archives/2012/10/pbs-climate-of-doubt/) - RealClimate: The video of Tuesday's PBS show on the politics of the climate debate is available - I make a minor appearance... The PBS website has more background.
- [How Many Cans?](https://www.realclimate.org/index.php/archives/2014/03/how-many-cans/) - RealClimate: XKCD, the brilliant and hilarious on-line comic, attempts to answer the question How much CO2 is contained in the world's stock of bottled fizzy drinks? How much soda would be needed to bring atmospheric CO2 back to preindustrial levels? The answer is, enough to cover the Earth with 10 layers of soda cans. However, the
- [Can we make better graphs of global temperature history?](https://www.realclimate.org/index.php/archives/2014/03/can-we-make-better-graphs-of-global-temperature-history/) - RealClimate: I'm writing this post to see if our audience can help out with a challenge: Can we collectively produce some coherent, properly referenced, open-source, scalable graphics of global temperature history that will be accessible and clear enough that we can effectively out-compete the myriad inaccurate and misleading pictures that continually do the rounds on social
- [Thibault de Garidel](https://www.realclimate.org/index.php/archives/2004/12/thibault-de-garidel/) - RealClimate: Dr. Thibault de Garidel-Thoron is currently a researcher at CEREGE in France. He was post-doctoral associate at the Institute of Marine and Coastal Sciences at Rutgers University. His main scientific interest is to reconstruct past tropical climate changes using micropaleontological and geochemical proxies from oceanic sediment records. Dr. de Garidel received his Bachelor’s degree in
- [Caspar Ammann](https://www.realclimate.org/index.php/archives/2004/12/caspar-ammann/) - RealClimate: Caspar Ammann is a climate scientist working at the National Center for Atmospheric Research (NCAR). Dr. Ammann is interested in the reconstruction of natural climate forcings, natural climate variability, coupled modeling of natural and anthropogenic climate change, and data/model intercomparison. Dr. Ammann got his B.S. from Gymnasium Koeniz (Switzerland), his M.S. from the University of
- [William M. Connolley](https://www.realclimate.org/index.php/archives/2004/12/william-m-connolley/) - RealClimate: When I joined RC, I was a climate modeller with the British Antarctic Survey. Now I'm a software engineer for CSR. I'm still interested in communicating the science of climate change, but can no longer do so at a professional level. I'm also elsewhere: the wikipedia project is developing into a useful resource, and my
- [New daily temperature dataset from Berkeley](https://www.realclimate.org/index.php/archives/2014/03/new-daily-temperature-dataset-from-berkeley/) - RealClimate: Guest commentary from Zeke Hausfather and Robert Rohde Daily temperature data is an important tool to help measure changes in extremes like heat waves and cold spells. To date, only raw quality controlled (but not homogenized) daily temperature data has been available through GHCN-Daily and similar sources. Using this data is problematic when looking at
- [It never rains but it pause](https://www.realclimate.org/index.php/archives/2014/03/it-never-rains-but-it-pause/) - RealClimate: There has been a veritable deluge of new papers this month related to recent trends in surface temperature. There are analyses of the CMIP5 ensemble, new model runs, analyses of complementary observational data, attempts at reconciliation all the way to commentaries on how the topic has been covered in the media and on twitter. We
- [Unforced variations: Feb 2014](https://www.realclimate.org/index.php/archives/2014/02/unforced-variations-feb-2014/) - RealClimate: A little late starting this month's open thread - must be the weather...
- [Bubkes](https://www.realclimate.org/index.php/archives/2009/06/bubkes/) - RealClimate: Some parts of the blogosphere, headed up by CEI ("CO2: They call it pollution, we call it life!"), are all a-twitter over an apparently "suppressed" document that supposedly undermines the EPA Endangerment finding about human emissions of carbon dioxide and a basket of other greenhouse gases. Well a draft of this "suppressed" document has been
- [Going with the wind](https://www.realclimate.org/index.php/archives/2014/02/going-with-the-wind/) - RealClimate: A new paper in Nature Climate Change out this week by England and others joins a number of other recent papers seeking to understand the climate dynamics that have led to the so-called "slowdown" in global warming. As we and others have pointed out previously (e.g. here), the fact that global average temperatures can deviate
- [Unforced Variations: Jan 2014](https://www.realclimate.org/index.php/archives/2014/01/unforced-variations-jan-2014/) - RealClimate: First open thread of the new year. A time for 'best of's of climate science last year and previews for the this year perhaps? We will have an assessment of the updates to annual indices and model/data comparisons later in the month.
- [Exploring CRUTEM4 with Google Earth ](https://www.realclimate.org/index.php/archives/2014/02/exploring-crutem4-with-google-earth/) - RealClimate: Guest commentary by Tim Osborn and Phil Jones The Climatic Research Unit (CRU) land surface air temperature data set, CRUTEM4, can now be explored using Google Earth. Access is via this portal together with instructions for using it (though it is quite intuitive). We have published a short paper in Earth System Science Data to
- [New climate science MOOCs](https://www.realclimate.org/index.php/archives/2014/02/new-climate-science-moocs/) - RealClimate: Along with David's online class a number of new climate science Massive Online Open Courses (MOOCs) are now coming online. A new online course from MIT, "Global Warming Science", introduces the basic science underpinning our knowledge of the climate system, how climate has changed in the past, and how it may change in the future.
- [Global temperature 2013](https://www.realclimate.org/index.php/archives/2014/01/global-temperature-2013/) - RealClimate: The global temperature data for 2013 are now published. 2010 and 2005 remain the warmest years since records began in the 19th Century. 1998 ranks third in two records, and in the analysis of Cowtan & Way, which interpolates the data-poor region in the Arctic with a better method, 2013 is warmer than 1998 (even
- [If You See Something, Say Something](https://www.realclimate.org/index.php/archives/2014/01/if-you-see-something-say-something/) - RealClimate: Gavin provided a thoughtful commentary about the role of scientists as advocates in his RealClimate piece a few weeks ago. I have weighed in with my own views on the matter in my op-ed today in this Sunday's New York Times. And, as with Gavin, my own views have been greatly influenced and shaped by
- [Thames Barrier raised again](https://www.realclimate.org/index.php/archives/2014/01/thames-barrier-raised-again/) - RealClimate: Back in 2007 I wrote a post looking at the closures of the Thames Barrier since construction finished in 1983. Since then there has been another 7 years of data* and given that there was a spate of closures last week due to both river and tidal flooding, it seems a good time to revisit
- [A Bit More Sensitive...](https://www.realclimate.org/index.php/archives/2014/01/a-bit-more-sensitive/) - RealClimate: by Michael E. Mann and Gavin Schmidt This time last year we gave an overview of what different methods of assessing climate sensitivity were giving in the most recent analyses. We discussed the three general methods that can be used: The first is to focus on a time in the past when the climate was
- [On sensitivity: Part I](https://www.realclimate.org/index.php/archives/2013/01/on-sensitivity-part-i/) - RealClimate: Climate sensitivity is a perennial topic here, so the multiple new papers and discussions around the issue, each with different perspectives, are worth discussing. Since this can be a complicated topic, I'll focus in this post on the credible work being published. There'll be a second part from Karen Shell, and in a follow-on post
- [AGU talk on science and advocacy](https://www.realclimate.org/index.php/archives/2013/12/agu-talk-on-science-and-advocacy/) - RealClimate: We have often discussed issues related to science communication on this site, and the comment threads frequently return to the issue of advocacy, the role of scientists and the notion of responsibility. Some videos from the recent AGU meeting are starting to be uploaded to the AGU Youtube channel and, oddly, the first video of
- [The global temperature jigsaw](https://www.realclimate.org/index.php/archives/2013/12/the-global-temperature-jigsaw/) - RealClimate: Since 1998 the global temperature has risen more slowly than before. Given the many explanations for colder temperatures discussed in the media and scientific literature (La Niña, heat uptake of the oceans, arctic data gap, etc.) one could jokingly ask why no new ice age is here yet. This fails to recognize, however, that the
- [AGU 2013 preview and participation](https://www.realclimate.org/index.php/archives/2013/12/agu-2013-preview-and-participation/) - RealClimate: So, it's that time of year again. Fall AGU is the largest Earth Science conference on the planet, and is where you will get previews of new science results, get a sense of what other experts think about current topics, and indulge in the more social side of being a scientist. The full scientific program
- [Our Books](https://www.realclimate.org/index.php/archives/2008/01/our-books/) - RealClimate: This post is a list of books since 2005 (in reverse chronological order) that we have been involved in, accompanied by the publisher's official description, and some comments of independent reviewers of the work. We will try and keep this list up to date as and when new books appear. We have also added links
- [Geo-engineering in vogue...](https://www.realclimate.org/index.php/archives/2006/06/geo-engineering-in-vogue/) - RealClimate: There was an interesting article in the NY Times this week on possible geo-engineering solutions to the global warming problem. The story revolves around a paper that Paul Crutzen (Nobel Prize winner for chemistry related to the CFC/ozone depletion link) has written about deliberately adding sulphate aerosols in the stratosphere to increase the albedo and
- [Unforced Variations: Nov 2013](https://www.realclimate.org/index.php/archives/2013/11/unforced-variations-nov-2013/) - RealClimate: This month's open thread...
- [Unforced Variations: Dec 2013](https://www.realclimate.org/index.php/archives/2013/12/unforced-variations-dec-2013/) - RealClimate: This month's open thread. It's coming to the end of the year and that means updates to the annual time series of observations and models relatively soon. Suggestions for what you'd like to see assessed are welcome... or any other climate science related topic.
- [Arctic and American Methane in Context](https://www.realclimate.org/index.php/archives/2013/11/arctic-and-american-methane-in-context/) - RealClimate: Lots of interesting methane papers this week. In Nature Geoscience, have published a substantial new study of the methane cycle on the Siberian continental margin of the Arctic Ocean. This paper will get a lot of attention, because it follows by a few months a paper from last summer, , which claimed a strong (and
- [Sea-level rise: What the experts expect](https://www.realclimate.org/index.php/archives/2013/11/sea-level-rise-what-the-experts-expect/) - RealClimate: In the long run, sea-level rise will be one of the most serious consequences of global warming. But how fast will sea levels rise? Model simulations are still associated with considerable uncertainty - too complex and varied are the processes that contribute to the increase. A just-published survey of 90 sea-level experts from 18 countries
- [Simple physics and climate](https://www.realclimate.org/index.php/archives/2013/11/simple-physics-and-climate/) - RealClimate: No doubt, our climate system is complex and messy. Still, we can sometimes make some inferences about it based on well-known physical principles. Indeed, the beauty of physics is that a complex systems can be reduced into simple terms that can be quantified, and the essential aspects understood. A recent paper by provides an example
- [Global Warming Since 1997 Underestimated by Half](https://www.realclimate.org/index.php/archives/2013/11/global-warming-since-1997-underestimated-by-half/) - RealClimate: A new study by British and Canadian researchers shows that the global temperature rise of the past 15 years has been greatly underestimated. The reason is the data gaps in the weather station network, especially in the Arctic. If you fill these data gaps using satellite measurements, the warming trend is more than doubled in
- [State of Antarctica: red or blue? <lang_it>Lo stato dell’Antartide: più caldo o più freddo?</lang_it>](https://www.realclimate.org/index.php/archives/2009/01/state-of-antarctica-red-or-blue/) - RealClimate: A couple of us (Eric and Mike) are co-authors on a paper coming out in Nature this week (Jan. 22, 09). We have already seen misleading interpretations of our results in the popular press and the blogosphere, and so we thought we would nip such speculation in the bud. The paper shows that Antarctica has
- [From global climate change to local consequences](https://www.realclimate.org/index.php/archives/2013/11/from-global-climate-change-to-local-consequences/) - RealClimate: Some will be luckier than others when it comes to climate change. The effects of a climate change on me will depend on where I live. In some regions, changes may not be as noticeable as in others. So what are the impacts in my region? In other to understand the local impacts of a
- [Unforced Variations: Oct 2013](https://www.realclimate.org/index.php/archives/2013/10/unforced-variations-oct-2013/) - RealClimate: This month's open thread. We're going to guess that most of what people want to talk about is related to the IPCC WG1 AR5 report... Have at it!
- [Science of Climate Change online class starting next week on Coursera](https://www.realclimate.org/index.php/archives/2013/10/science-of-climate-change-online-class-starting-next-week-on-coursera/) - RealClimate: Maybe you remember the rollout a few years ago of Open Climate 101, a massive open online class (MOOC) that was served sort of free-range from a computer at the University of Chicago. Now the class has been entirely redone as Global Warming: The Science of Climate Change within the far slicker Coursera platform. Beginning
- [A new European report on climate extremes is out](https://www.realclimate.org/index.php/archives/2013/10/a-new-european-report-on-climate-extremes-is-out/) - RealClimate: A new report on extreme climate events in Europe is just published: 'Extreme Weather Events in Europe: preparing for climate change adaptation'. It was launched in Oslo on October 24th by the Norwegian Academy of Science and Letters, and the report is now available online. What's new? The new report provides information that is more
- [On mismatches between models and observations ](https://www.realclimate.org/index.php/archives/2013/09/on-mismatches-between-models-and-observations/) - RealClimate: It is a truism that all models are wrong. Just as no map can capture the real landscape and no portrait the true self, numerical models by necessity have to contain approximations to the complexity of the real world and so can never be perfect replications of reality. Similarly, any specific observations are only partial
- [The new IPCC climate report](https://www.realclimate.org/index.php/archives/2013/09/the-new-ipcc-climate-report/) - RealClimate: The time has come: the new IPCC report is here! After several years of work by over 800 scientists from around the world, and after days of extensive discussion at the IPCC plenary meeting in Stockholm, the Summary for Policymakers was formally adopted at 5 o’clock this morning. Congratulations to all the colleagues who were
- [Tropical SSTs: Natural variations or Global warming?](https://www.realclimate.org/index.php/archives/2006/09/tropical-ssts-natural-variations-or-global-warming/) - RealClimate: by Michael Mann and Gavin Schmidt Roughly a year ago, we summarized the state of play in the ongoing scientific debate over the role of anthropogenic climate change in the observed trends in hurricane activity. This debate (as carefully outlined by Curry et al recently) revolves around a number of elements - whether the hurricane
- [The IPCC AR5 attribution statement](https://www.realclimate.org/index.php/archives/2013/10/the-ipcc-ar5-attribution-statement/) - RealClimate: Last year I discussed the basis of the AR4 attribution statement: Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. In the new AR5 SPM (pdf), there is an analogous statement: It is extremely likely that more than
- [Climate Change on Film](https://www.realclimate.org/index.php/archives/2013/10/climate-change-on-film/) - RealClimate: Making a film about climate change is difficult, especially if you want it to reach a wide audience. One problem is the long time scale of climate change, which fits badly with the time scale of a typical film narrative. That was the reason why in the Hollywood blockbuster The Day After Tomorrow some laws
- [What ocean heating reveals about global warming](https://www.realclimate.org/index.php/archives/2013/09/what-ocean-heating-reveals-about-global-warming/) - RealClimate: The heat content of the oceans is growing and growing. That means that the greenhouse effect has not taken a pause and the cold sun is not noticeably slowing global warming. NOAA posts regularly updated measurements of the amount of heat stored in the bulk of the oceans. For the upper 2000 m (deeper than
- [Paleoclimate: The End of the Holocene](https://www.realclimate.org/index.php/archives/2013/09/paleoclimate-the-end-of-the-holocene/) - RealClimate: Recently a group of researchers from Harvard and Oregon State University has published the first global temperature reconstruction for the last 11,000 years – that’s the whole Holocene (Marcott et al. 2013). The results are striking and worthy of further discussion, after the authors have already commented on their results in this blog. Eine Übersetzung
- [The inevitability of sea level rise](https://www.realclimate.org/index.php/archives/2013/08/the-inevitability-of-sea-level-rise/) - RealClimate: Guest post by Anders Levermann [via The Conversation] Small numbers can imply big things. Global sea level rose by a little less than 0.2 metres during the 20th century – mainly in response to the 0.8 °C of warming humans have caused through greenhouse gas emissions. That might not look like something to worry about.
- [Unforced variations: August 2013](https://www.realclimate.org/index.php/archives/2013/08/unforced-variations-august-2013/) - RealClimate: This month's open thread. Since there are two main topics (Advocacy and Methane bombs) buzzing around the blogo-twitter-sphere this week, perhaps those are our starters for ten... (Feel free to populate the comments with links to various commentaries - we will chime in as we find time).
- [Unforced variations: Sept. 2013](https://www.realclimate.org/index.php/archives/2013/09/unforced-variations-sept-2013/) - RealClimate: This month's open thread... Expect pre-IPCC report discussion (SPM due on Sep 27, full report (pre-copy-editing) Sep 30th), analysis of this years Arctic ice cover minimum, and a host of the usual distractions.
- [Sea-level rise: Where we stand at the start of 2013](https://www.realclimate.org/index.php/archives/2013/01/sea-level-rise-where-we-stand-at-the-start-of-2013/) - RealClimate: Progress has been made in recent years in understanding the observed past sea-level rise. As a result, process-based projections of future sea-level rise have become dramatically higher and are now closer to semi-empirical projections. However, process-based models still underestimate past sea-level rise, and they still project a smaller rise than semi-empirical models. Sea-level projections were
- [Unforced Variations: July 2013](https://www.realclimate.org/index.php/archives/2013/07/unforced-variations-july-2013/) - RealClimate: This month's open thread... We have just updated the blog software, and are taking a little time to assess how up-to-date some the content is (including the theme, mobile theme, blogroll, about pages and the RC wiki etc.). So this might be a good time to chime in with your suggestions as well as discussing
- [Arctic Methane on the Move?](https://www.realclimate.org/index.php/archives/2010/03/arctic-methane-on-the-move/) - RealClimate: Methane is like the radical wing of the carbon cycle, in today's atmosphere a stronger greenhouse gas per molecule than CO2, and an atmospheric concentration that can change more quickly than CO2 can. There has been a lot of press coverage of a new paper in Science this week called “Extensive methane venting to the
- [The Guardian disappoints](https://www.realclimate.org/index.php/archives/2010/02/the-guardian-disappoints/) - RealClimate: The Guardian, Fred Pearce, Douglas Keenan, Tom Wigley, Phil Jones, Mike Mann, Keith Briffa, Chinese weather stations, fraud, peer review
- [AGU Chapman Conference on Climate Science Communication](https://www.realclimate.org/index.php/archives/2013/07/agu-chapman-conference-on-climate-science-communication/) - RealClimate: A couple of weeks ago, there was a small conference on Climate Science communication run by the AGU. Both Mike and I attended, but it was very notable that it wasn't just scientists attending - there were also entertainers, psychologists, film-makers and historians. There were a lot of quite diverse perspectives and many discussions about
- [Arctic misrepresentations](https://www.realclimate.org/index.php/archives/2013/07/arctic-misrepresentations/) - RealClimate: At the weekend, Christopher Booker at the Daily Telegraph made another attempt (see previous) to downplay the obvious decreases in Arctic sea ice by (mis-)quoting a statement from Arctic oceanographer Ken Drinkwater and colleagues: Panic over Arctic ice – what else can the warmists get wrong? As evidence to support their belief system continues to
- [A warming pause?](https://www.realclimate.org/index.php/archives/2009/10/a-warming-pause/) - RealClimate: The blogosphere (and not only that) has been full of the "global warming is taking a break" meme lately. Although we have discussed this topic repeatedly, it is perhaps worthwhile reiterating two key points about the alleged pause here. (1) This discussion focuses on just a short time period - starting 1998 or later -
- [Unforced Variations: June 2013](https://www.realclimate.org/index.php/archives/2013/06/unforced-variations-june-2013/) - RealClimate: June's open thread...
- [Yamalian yawns](https://www.realclimate.org/index.php/archives/2012/05/yamalian-yawns/) - RealClimate: Steve McIntyre is free to do any analysis he wants on any data he can find. But when he ladles his work with unjustified and false accusations of misconduct and deception, he demeans both himself and his contributions. The idea that scientists should be bullied into doing analyses McIntyre wants and delivering the results to
- [Should regional climate models take the blame?](https://www.realclimate.org/index.php/archives/2013/04/should-regional-climate-models-take-the-blame/) - RealClimate: recently provided a critical review of regional climate models ("RCMs"). I think his views have caused a stir in the regional climate model community. So what's the buzz all about? RCMs provide important input to many climate services, for which there is a great deal of vested interest on all levels. On the international stage,
- [The PAGES-2k synthesis](https://www.realclimate.org/index.php/archives/2013/04/the-pages-2k-synthesis/) - RealClimate: Guest commentary by Darrell Kaufman (N. Arizona U.) In a major step forward in proxy data synthesis, the PAst Global Changes (PAGES) 2k Consortium has just a suite of continental scale reconstructions of temperature for the past two millennia in Nature Geoscience. More information about the study and its implications are available at the FAQ
- [Seeing Red](https://www.realclimate.org/index.php/archives/2010/10/seeing-red/) - RealClimate: NOTE: The hijacking and spread of misinformation and slander by certain commenters has led to the closing of further comments on this article. I am however, very thankful to those many who made good points, asked good questions and provided further references, thus contributing to better public education. Jim. Note: This is the first of
- [Yamal and Polar Urals: a research update](https://www.realclimate.org/index.php/archives/2013/06/yamal-and-polar-urals-a-research-update/) - RealClimate: Guest commentary from Tim Osborn, Tom Melvin and Keith Briffa, Climatic Research Unit, UEA Records of tree-ring characteristics such as their width (TRW) and density (usually the maximum density of the wood formed towards the end of the growing season – the “maximum latewood density” - MXD) are widely used to infer past variations in
- [Unforced Variations: May 2013](https://www.realclimate.org/index.php/archives/2013/05/unforced-variations-may-2013/) - RealClimate: This month's open thread.
- [The scientific debate on climate change](https://www.realclimate.org/index.php/archives/2013/05/the-scientific-debate-on-climate-change/) - RealClimate: by Jill and David Archer
- [The answer is blowing in the wind: The warming went into the deep end](https://www.realclimate.org/index.php/archives/2013/04/the-answer-is-blowing-in-the-wind-the-warming-went-into-the-deep-end/) - RealClimate: There has been an unusual surge of interest in the climate sensitivity based on the last decade's worth of temperature measurements, and a lengthy story in the Economist tries to argue that the climate sensitivity may be lower than previously estimated. I think its conclusion is somewhat misguided because it missed some important pieces of
- [Unforced Variations: Apr 2013](https://www.realclimate.org/index.php/archives/2013/03/unforced-variations-apr-2013/) - RealClimate: Open thread for April...
- [Rasmus E. Benestad](https://www.realclimate.org/index.php/archives/2004/12/rasmus-e-benestad/) - RealClimate: I am a physicist by training and have affiliations with the Norwegian Meteorological Institute [My views here are personal and may not necessarily represent those of Met Norway]. I have a D.Phil in physics from Atmospheric, Oceanic & Planetary Physics at Oxford University in the United Kingdom. Recent work involve a good deal of statistics
- [Ice hockey](https://www.realclimate.org/index.php/archives/2013/04/ice-hockey/) - RealClimate: Eric Steig It is well known that ice shelves on the Antarctic Peninsula have collapsed on several occasions in the last couple of decades, that ice shelves in West Antarctica are thinning rapidly, and that the large outlet glaciers that drain the West Antarctic ice sheet (WAIS) are accelerating. The rapid drainage of the WAIS
- [Verification of regional model trends](https://www.realclimate.org/index.php/archives/2013/04/verification-of-regional-model-trends/) - RealClimate: Guest post by Geert Jan van Oldenborgh, Francisco Doblas-Reyes, Sybren Drijfhout and Ed Hawkins Climate information for the future is usually presented in the form of scenarios: plausible and consistent descriptions of future climate without probability information. This suffices for many purposes, but for the near term, say up to 2050, scenarios of emissions of
- [Movie review: SWITCH](https://www.realclimate.org/index.php/archives/2013/04/movie-review-switch/) - RealClimate: This year, the Geological Society of America is rolling out their SWITCH Energy Awareness campaign . The centerpiece of the campaign is a documentary film, SWITCH, which purports to be about the need for a transformation in the world's energy systems. Recently, I attended the Chicago premier of the film, presented as part of the
- [Thin Ice --- the movie](https://www.realclimate.org/index.php/archives/2013/04/thin-ice-the-movie/) - RealClimate: Some of my friends have made a film, Thin Ice, which tells the story of CO2 and climate from the standpoint of the climate scientists who are out there in the trenches trying to figure out what is going on. I have a small role in the film myself, and I am sure RealClimate readers
- [Unforced Variations: March 2013](https://www.realclimate.org/index.php/archives/2013/03/unforced-variations-march-2013/) - RealClimate: A new open thread - hopefully for some new climate science topics...
- [Response by Marcott <i>et al</i>.](https://www.realclimate.org/index.php/archives/2013/03/response-by-marcott-et-al/) - RealClimate: Readers will be aware of the paper by Shaun Marcott and colleagues, that they published a couple weeks ago in the journal Science. That paper sought to extend the global temperature record back over the entire Holocene period, i.e. just over 11 kyr back time, something that had not really been attempted before. The paper
- [Climate change and consequences on the ground](https://www.realclimate.org/index.php/archives/2013/03/climate-change-and-consequences-on-the-groud/) - RealClimate: The link between extreme weather events, climate change, and national security is discussed in Extreme Realities, a new episode in PBS' series Journey To Planet Earth hosted by Matt Damon. The video features a number of extreme weather phenomena: hurricanes, tornadoes, floods, wild fires, and flooding. The discussion is about climate change and the consequences
- [Sea-level rise: Where we stand at the start of 2013 -- Part 2](https://www.realclimate.org/index.php/archives/2013/01/sea-level-rise-where-we-stand-at-the-start-of-2013-part-2/) - RealClimate: This is Part 2 of my thoughts on the state of sea-level research. Here is Part 1. Sea-level cycles? A topic that keeps coming up in the literature is the discussion on a (roughly) 60-year cycle in sea level data; a nice recent paper on this is . One thing I like about this paper
- [Unforced Variations: Feb 2013](https://www.realclimate.org/index.php/archives/2013/02/unforced-variations-feb-2013/) - RealClimate: This month's open thread on climate science...
- [Urban Heat Islands and U.S. Temperature Trends](https://www.realclimate.org/index.php/archives/2013/02/urban-heat-islands-and-u-s-temperature-trends/) - RealClimate: US temperature trends are not rising because of Urban Heat Island effects. New research using multiple datasets from Zeke Hausfather and other bloggers in collaboration with NCDC scientists.
- [Carl Wunsch, The Economist and the Gulf Stream](https://www.realclimate.org/index.php/archives/2006/10/carl-wunsch-the-economist-and-the-gulf-stream/) - RealClimate: Carl Wunsch usually has very interesting things to say about the climate system, and although his arguments don't necessarily win everyone completely over, they often generate an improvement in the level of scientific discussion. In this week's Economist, he has a letter printed concerning the mis-definition of the 'Gulf Stream' concept in the magazine's climate
- [The heat is on in West Antarctica](https://www.realclimate.org/index.php/archives/2012/12/the-heat-is-on-in-west-antarctica/) - RealClimate: Eric Steig Regular followers of RealClimate will be aware of our publication in 2009 in Nature, showing that West Antarctica -- the part of the Antarctic ice sheet that is currently contributing the most to sea level rise, and which has the potential to become unstable and contribute a lot more (3 meters!) to sea
- [Unforced Variations: Jan 2013](https://www.realclimate.org/index.php/archives/2013/01/unforced-variations-jan-2013/) - RealClimate: A new year... so comments reflecting the past year in climate science, or looking forward to the next are particularly apropos.
- [The Greenland melt](https://www.realclimate.org/index.php/archives/2013/01/the-greenland-melt/) - RealClimate: Eric Steig Last July (2012), I heard from a colleagues working at the edge of the Greenland ice sheet, and from another colleague working up at the Summit. Both were independently writing to report the exceptional conditions they were witnessing. The first was that the bridge over the Watson river by the town of Kangerlussuaq,
- [The IPCC sea level numbers <lang_po>Os números do nível do mar do IPCC</lang_po>](https://www.realclimate.org/index.php/archives/2007/03/the-ipcc-sea-level-numbers/) - RealClimate: The sea level rise numbers published in the new IPCC report (the Fourth Assessment Report, AR4) have already caused considerable confusion. Many media articles and weblogs suggested there is good news on the sea level issue, with future sea level rise expected to be a lot less compared to the previous IPCC report (the Third
- [The Moscow Warming Hole](https://www.realclimate.org/index.php/archives/2011/10/the-moscow-warming-hole/) - RealClimate: This week, PNAS published our paper Increase of Extreme Events in a Warming World, which analyses how many new record events you expect to see in a time series with a trend. It does that with analytical solutions for linear trends and Monte Carlo simulations for nonlinear trends. A key result is that the number
- [What to study?](https://www.realclimate.org/index.php/archives/2013/01/what-to-study/) - RealClimate: I recently got an email from newly graduated Math(s) major (mildly edited): I am someone with a deep-seated desire to help the planet remain as habitable as possible in the face of the trials humanity is putting it through. I'd like to devote my career to this cause, but am young and haven't chosen a
- [Antarctic Peninsula warming: natural variability or "global warming"?](https://www.realclimate.org/index.php/archives/2012/08/antarctic-peninsula-warming-natural-variability-of-global-warming/) - RealClimate: Most people know that the Antarctic Peninsula is one of the most rapidly warming places on earth. But like everywhere else in Antarctica, the length of available temperature data is short -- most records begin in 1957 (when stations were put in place during the International Geophysical Year); a few start in the late 1940s.
- [On Sensitivity Part II: Constraining Cloud Feedback without Cloud Observations](https://www.realclimate.org/index.php/archives/2013/01/on-sensitivity-part-ii-constraining-cloud-feedback-without-cloud-observations/) - RealClimate: Guest Commentary by Karen M. Shell, Oregon State University Link to Part I. Clouds are very pesky for climate scientists. Due to their high spatial and temporal variability, as well as the many processes involved in cloud droplet formation, clouds are difficult to model. Furthermore, clouds have competing effects on solar and terrestrial radiation. Increases
- [What is signal and what is noise?](https://www.realclimate.org/index.php/archives/2012/12/what-is-signal-and-what-is-noise/) - RealClimate: The recent warming has been more pronounced in the Arctic Eurasia than in many other regions on our planet, but argues that only one out of 109 temperature records from this region exhibits a significant warming trend. I think that his conclusions were based on misguided analyses. The analysis did not sufficiently distinguish between signal
- [Unforced variations: Dec 2012](https://www.realclimate.org/index.php/archives/2012/12/unforced-variations-dec-2012/) - RealClimate: A new meteorological season, perhaps some new science topics to discuss...
- [A review of cosmic rays and climate: a cluttered story of little success](https://www.realclimate.org/index.php/archives/2012/12/a-review-of-cosmic-rays-and-climate-a-cluttered-story-of-little-success/) - RealClimate: A number of blogs were excited after having leaked the second-order draft of IPCC document, which they interpreted as a "game-changing admission of enhanced solar forcing". However, little evidence remains for a link between galactic cosmic rays (GCR) and variations in Earth's cloudiness. recently provided an extensive review of the study of the GCR and
- [Ice age constraints on climate sensitivity](https://www.realclimate.org/index.php/archives/2011/11/ice-age-constraints-on-climate-sensitivity/) - RealClimate: There is a new paper on Science Express that examines the constraints on climate sensitivity from looking at the last glacial maximum (LGM), around 21,000 years ago (SEA). The headline number (2.3ºC) is a little lower than IPCC's "best estimate" of 3ºC global warming for a doubling of CO2, but within the likely range (2-4.5ºC)
- [Online video lectures on climate change](https://www.realclimate.org/index.php/archives/2012/12/online-video-lectures-on-climate-change/) - RealClimate: For those who’d like to get the basics of climate change explained first-hand by a climate scientist, here are two video lectures. In the first, I show some of the basic data sets and findings about global warming, including some comments on historic land marks of our science. The second lecture deals with the impacts
- [Improving the Tropical Cyclone Climate Record](https://www.realclimate.org/index.php/archives/2012/12/improving-the-tropical-cyclone-climate-record/) - RealClimate: Guest Commentary by Christopher Hennon (UNC Asheville) Get involved in a new citizen science project at CycloneCenter.org. The poor quality of the tropical cyclone (TC) data record provides severe constraints on the ability of climate scientists to: a) determine to what degree TCs have responded to shifts in climate, b) evaluate theories on how TCs
- [IPCC draft: No comment.](https://www.realclimate.org/index.php/archives/2006/05/ipcc-draft-no-comment/) - RealClimate: As everyone has now realised, the second-order draft of the new IPCC report has become very widely available and many of the contributors to this site, commenters and readers will have seen copies. Part of the strength of the IPCC process are the multiple stages of review - the report is already significantly improved (in
- [IPCC draft (redux)](https://www.realclimate.org/index.php/archives/2012/12/ipcc-draft-redux/) - RealClimate: Amid the manufactured spin and excitement of the unofficial release of the IPCC WG1 Second Order Draft, it is worth remembering that this happened last time too: IPCC draft: No comment May 4, 2006 As everyone has now realised, the second-order draft of the new IPCC report has become very widely available and many of
- [Some AGU highlights](https://www.realclimate.org/index.php/archives/2012/12/some-agu-highlights/) - RealClimate: Here a few of the videos of the named lectures from last week that are worth watching. There are loads more videos from selected sessions on the AGU Virtual Meeting site (the AGU YouTube channel has quite a lot more from past meetings too). All well worth the time. Charney Lecture: Drew Shindell "Mitigating Near-Term
- [The Physics of Climate Modelling <lang_fr>La physique de la modélisation du climat</lang_fr>](https://www.realclimate.org/index.php/archives/2007/01/the-physics-of-climate-modelling/) - RealClimate: This is just a pointer to a 'Quick Study' guide on The physics of climate modelling that appears in Physics Today this month, and to welcome anyone following through from that magazine. Feel free to post comments or questions about the article here and I'll try and answer as many as I can. Cet article
- [AGU time again... ](https://www.realclimate.org/index.php/archives/2012/12/agu-time-again/) - RealClimate: This week is Fall AGU, the biggest climate-related conference around. Not everything is related to climate - there is a lot of other geophysics and astrophysics, but it is generally the place to go if you want to see and be seen (and incidentally, be crushed, be excited, be friendly and be frustrated that you
- [Unforced Variations: Nov 2012](https://www.realclimate.org/index.php/archives/2012/11/unforced-variations-nov-2012/) - RealClimate: I can't think what people might want to talk about this month...
- [Responses to volcanoes in tree rings and models](https://www.realclimate.org/index.php/archives/2012/11/responses-to-volcanoes-in-tree-rings-and-models/) - RealClimate: Houston, we have a problem. Admittedly, not a huge problem and not one that most people, or even most climatologists, are particularly fascinated by, but one which threads together many topics (climate models, tree rings, paleo-climate) which have been highlighted here in the past. The problem is that we have good evidence in the ice
- [Don’t estimate acceleration by fitting a quadratic…](https://www.realclimate.org/index.php/archives/2012/11/dont-estimate-acceleration-by-fitting-a-quadratic/) - RealClimate: … if your data do not look like a quadratic! This is a post about global sea-level rise, but I put that message up front so that you’ve got it even if you don’t read any further. The reputable climate-statistics blogger Tamino, who is a professional statistician in real life and has published a couple
- [El Nino's effect on CO2 causes confusion about CO2's role for climate change](https://www.realclimate.org/index.php/archives/2012/09/el-ninos-effect-onco2-causes-confusion/) - RealClimate: Are the rising atmospheric CO2-levels a result of oceans warming up? And does that mean that CO2 has little role in the global warming? Moreover, are the rising levels of CO2 at all related to human activity? These are claims made in a fresh publication by . However, when seeing them in the context of
- [Stronger regional differences due to large-scale atmospheric flow.](https://www.realclimate.org/index.php/archives/2012/11/stronger-regional-differences-due-to-large-scale-atmospheric-flow/) - RealClimate: A new paper by (free access) is likely to have repercussions on discussions of local climate change adaptation. I think it caught some people by surprise, even if the results perhaps should not be so surprising. The range of possible local and regional climate outcomes may turn out to be larger than expected for regions
- [ClimateDialogue: Exploring different views on climate change](https://www.realclimate.org/index.php/archives/2012/11/climatedialogue-exploring-different-views-on-climate-change/) - RealClimate: This is a guest posting from some Dutch colleagues on a new online experiment in fostering dialogue on climate change. Bart Verheggen has asked us to host this quick introduction. We are interested to hear if you think this is a good idea. Guest Commentary by Bart Strengers (PBL) ClimateDialogue.org offers a platform for discussions
- [Trying to shoot the messenger](https://www.realclimate.org/index.php/archives/2012/11/trying-to-shoot-the-messenger/) - RealClimate: Does this sound familiar? A quantitative prediction is inconvenient for some heavily invested folks. Legitimate questions about methodology morph quickly into accusations that the researchers have put their thumb on the scale and that they are simply making their awkward predictions to feather their own nest. Others loudly proclaim that the methodology could never work
- [Short term trends: Another proxy fight](https://www.realclimate.org/index.php/archives/2012/11/short-term-trends-another-proxy-fight/) - RealClimate: One might assume that people would be happy that the latest version of the Hadley Centre and CRU combined temperature index is now being updated on a monthly basis. The improvements over the previous version in terms of coverage and error estimates is substantial. One might think that these advances - albeit incremental - would
- [Unforced variations: Oct 2012](https://www.realclimate.org/index.php/archives/2012/10/unforced-variations-oct-2012/) - RealClimate: This month's open thread. Try to keep it at least vaguely focused on climate science...!
- [Betting on climate change](https://www.realclimate.org/index.php/archives/2005/06/betting-on-climate-change/) - RealClimate: Guest contribution by James Annan of FRCGC/JAMSTEC. "The more unpredictable the world, the more we rely on predictions" (Steve Rivkin). The uncertainty of an unknown future imposes costs and risks on us in many areas of life. A cereal-growing farmer risks a big financial loss if the price of grain is low at harvest time,
- [A sea level Golden Horseshoe nominee<sup>*</sup>](https://www.realclimate.org/index.php/archives/2012/10/a-sea-level-golden-horseshoe-nominee/) - RealClimate: I was reading a sign high on the wall behind the bar: 'Only genuine pre-war British and American whiskeys served here' I was trying to count how many lies could be found in those nine words, and had reached four, with promise of more …" Dashiell Hammett, "The Golden Horseshoe" Google News occasionally throws up
- [Climate Change videos: Part I](https://www.realclimate.org/index.php/archives/2012/10/climate-change-videos-part-i/) - RealClimate: The US National Research Council has been doing a lot recently to expand background knowledge of the climate system and of climate change. In tandem with a new report discussing strategies for advancing climate modeling, they have put up a an introductory web site on climate models (including some interviews with some actual climate modelers).
- [Unforced variations: Sep 2012](https://www.realclimate.org/index.php/archives/2012/09/unforced-variations-sep-2012/) - RealClimate: Open thread - a little late because of the holiday. But everyone can get back to work now!
- [Embargos and confidentiality](https://www.realclimate.org/index.php/archives/2012/09/embargos-and-confidentiality/) - RealClimate: This post is not about climate science, but rather about the science/media interface. As many of you may be aware, papers that are scheduled to appear in high-profile journals (Science, Nature and a few others) are often released a few days early to journalists under embargo in order to give them a chance to do
- [Why bother trying to attribute extreme events?](https://www.realclimate.org/index.php/archives/2012/09/why-bother-trying-to-attribute-extreme-events/) - RealClimate: Nature has an interesting editorial this week on the state of the science for attributing extreme events. This was prompted by a workshop in Oxford last week where, presumably, strategies, observations and results were discussed by a collection of scientists interested in the topic (including Myles Allen, Peter Stott and other familiar names). Rather less
- [Climate indices to watch](https://www.realclimate.org/index.php/archives/2012/08/climate-indices-to-watch/) - RealClimate: What is the most important climate condition to keep tabs on? We have recently mentioned the record-low Arctic sea-ice extent, but hurricanes this year seem to be getting the most attention because of timing ofHurricane Isaac (I know of no evidence suggesting that the Arctic sea-ice has such a direct impact on U.S. politics!). In
- [An update on the Arctic sea-ice](https://www.realclimate.org/index.php/archives/2012/08/an-update-on-the-arctic-sea-ice/) - RealClimate: We noted earlier that the Artic sea-ice is approaching a record minimum. The record is now broken, almost a month before the annual sea-ice minima usually is observed, and there is probably more melting in store before it reaches the minimum for 2012 - before the autumn sea-ice starts to form. The figure shows annual
- [Language Intelligence - Lessons on persuasion from Jesus, Shakespeare, Lincoln, and Lady Gaga: A Review](https://www.realclimate.org/index.php/archives/2012/08/language-intelligence-lessons-on-persuasion-from-jesus-shakespeare-lincoln-and-lady-gaga-a-review/) - RealClimate: Any book that manages to link together the lessons of the Bible, Shakespeare, Abraham Lincoln, and Lady Gaga (not to mention Martin Luther King, Winston Churchill, Bob Dylan, and Jerry Seinfeld), can't be all bad. With Joe Romm's new book Language Intelligence, it is, in fact, ALL good. There are lessons galore for the scientists
- [Arctic sea ice minimum 2012...](https://www.realclimate.org/index.php/archives/2012/08/arctic-sea-ice-minimum-2012/) - RealClimate: By popular demand, a thread devoted to the continuing decline of Arctic sea ice, and a potential new record minimum this year. As before, the figures are hot-linked and will update day-by-day. JAXA Sea ice extent: Cryosphere Today sea ice concentration (interactive chart): Estimated sea ice volume from UW PIOMAS (updated every month): Other links:
- [Let the games begin!](https://www.realclimate.org/index.php/archives/2012/08/let-the-games-begin/) - RealClimate: I picked a good weekend to be out of cell phone range and unconnected to the internet - and judging from how the rest of the week has gone, I'd have been minded to stay there... As most readers are probably aware, there was an op-ed in the Saturday New York Times from Richard Muller
- [Unforced Variations: July 2012](https://www.realclimate.org/index.php/archives/2012/07/unforced-variations-july/) - RealClimate: Have at it.
- [Unforced Varations: Aug 2012](https://www.realclimate.org/index.php/archives/2012/08/unforced-varations-aug-2012/) - RealClimate: Once more with feeling...
- [Tree Rings and Climate: Some Recent Developments](https://www.realclimate.org/index.php/archives/2012/07/tree-rings-and-climate-some-recent-developments/) - RealClimate: by Michael E. Mann, Gavin Schmidt, and Eric Steig Update 7/12/12: Media Matters comments on the latest misrepresentations of the Esper et al study discussed in our article: 'Surprise: Fox News Fails Paleoclimatology' Update 7/13/12: Further comment from Bob Ward of the Grantham Institute in Huffington Post UK "The World's Most Visited Newspaper Website Continues
- [Far out in North Carolina](https://www.realclimate.org/index.php/archives/2012/06/far-out-in-north-carolina/) - RealClimate: The extensive salt marshes on the Outer Banks of Carolina offer ideal conditions for unravelling the mysteries of sea level change during past centuries. Here is a short report from our field work there – plus some comments on strange North Carolina politics as well as two related new papers published today in Nature Climate
- [My oh Miocene!](https://www.realclimate.org/index.php/archives/2012/07/my-oh-miocene/) - RealClimate: Guest commentary by Sarah Feakins Our recent study in reconstructed conditions at the Antarctic coast during a warm period of Earth’s history. Today the Ross Sea has an ice shelf and the continent is ice covered; but we found the Antarctic coast was covered with tundra vegetation for some periods between 20 million and 15.5
- [Methane game upgrade](https://www.realclimate.org/index.php/archives/2012/06/methane-game-upgrade/) - RealClimate: Walter Anthony et al (2012) have made a major contribution to the picture of methane emissions from thawing Arctic regions. Not a game-changer exactly, but definitely a graphics upgrade, bringing the game to life in stunningly higher resolution (/joke). Katey Walter Anthony draws upon her previous field findings that methane emissions from the Arctic landscape
- [Fresh hockey sticks from the Southern Hemisphere](https://www.realclimate.org/index.php/archives/2012/05/fresh-hockey-sticks-from-the-southern-hemisphere/) - RealClimate: In the Northern Hemisphere, the late 20th / early 21st century has been the hottest time period in the last 400 years at very high confidence, and likely in the last 1000 - 2000 years (or more). It has been unclear whether this is also true in the Southern Hemisphere. Three studies out this week
- [What makes sea-level rise?](https://www.realclimate.org/index.php/archives/2012/06/what-makes-sea-level-rise/) - RealClimate: Last week the science community was shocked by the claim that 42% of the sea-level rise of the past decades is due to groundwater pumping for irrigation purposes. What could this mean for the future – and is it true? The causes of global sea level rise can be roughly split into three categories: (1)
- [Unforced variations: May 2012](https://www.realclimate.org/index.php/archives/2012/05/unforced-variations-may-2012/) - RealClimate: New open thread for this month: misrepresentations of wind farm impacts on local climate? Clouds and contrarians? or whatever...
- [Unforced Variations; June 2012](https://www.realclimate.org/index.php/archives/2012/06/unforced-variations-june-2012/) - RealClimate: This month's open thread...
- [Real Video](https://www.realclimate.org/index.php/archives/2012/05/real-video/) - RealClimate: Guest post by Kelly Levin, WRI; Paul Higgins, AMS; Brian Helmuth, University of South Carolina; and Andy Dessler, Texas A&M Scientists have made massive progress in understanding the climate system and how human activities are altering it. Despite that progress, decision makers continue to struggle with climate change risk management. RealClimate and other initiatives have
- [OHC Model/Obs Comparison Errata](https://www.realclimate.org/index.php/archives/2012/05/ohc-modelobs-comparison-errata/) - RealClimate: This is just a brief note to point out that a few graphs that I have put together showing Ocean Heat Content changes in recent decades had an incorrect scaling for the GISS model data. My error was in assuming that the model output (which were in units W yr/m2) were scaled for the ocean
- [Another fingerprint](https://www.realclimate.org/index.php/archives/2012/05/another-fingerprint/) - RealClimate: When my kids were younger, they asked me why the ocean was blue. I would answer that the ocean mirrors the blue sky. However, I would not think much more about it, even though it is well-known that the oceans represent the most important source for atmospheric moisture. They also play an important role for
- [The legend of the Titanic](https://www.realclimate.org/index.php/archives/2012/05/the-legend-of-the-titanic/) - RealClimate: It's 100 years since the Titanic sank in the North Atlantic, and it's still remembered today. It was one of those landmark events that make a deep impression on people. It also fits a pattern of how we respond to different conditions, according to a recent book about the impact of environmental science on the
- [Plugging the leaks](https://www.realclimate.org/index.php/archives/2012/05/plugging-the-leaks/) - RealClimate: Guest commentary by Beate Liepert, NWRA Clouds and water vapor accounts for only a tiny fraction of all water on Earth, but in spite of it, this moisture in the atmosphere is crucially important to replenishing drinking water reservoirs, crop yields, distribution of vegetation zones, and so on. This is the case because in the
- [Greenland Glaciers -- not so fast!](https://www.realclimate.org/index.php/archives/2012/05/greenland-glaciers-not-so-fast/) - RealClimate: There have been several recent papers on ice sheets and sea level that have gotten a bit of press of the journalistic whiplash variety ("The ice is melting faster than we thought!" "No, its not!"). As usual the papers themselves are much better than the press about them, and the results less confusing. They add
- [Unforced variations: April 2012](https://www.realclimate.org/index.php/archives/2012/04/unforced-variations-april-2012/) - RealClimate: This month's open thread - a day late for obvious reasons... Have at it.
- [Unlocking the secrets to ending an Ice Age](https://www.realclimate.org/index.php/archives/2012/04/unlocking-the-secrets-to-ending-an-ice-age/) - RealClimate: Guest Commentary by Chris Colose, SUNY Albany It has long been known that characteristics of the Earth’s orbit (its eccentricity, the degree to which it is tilted, and its “wobble”) are slightly altered on timescales of tens to hundreds of thousands of years. Such variations, collectively known as Milankovitch cycles, conspire to pace the timing
- [Another well-deserved honor: Oeschger medal awarded to Michael Mann](https://www.realclimate.org/index.php/archives/2012/04/another-well-deserved-honor-oeschger-medal-awarded-to-michael-mann/) - RealClimate: As many will have already heard, our colleague, RC co-founder and friend Michael Mann will receive the Oeschger medal from the European Geosciences Union this week in Vienna. We are delighted to announce this and to congratulate Mike. Hans Oeschger was a Swiss scientist originally trained as a nuclear physicist. His name is well known
- [HadCRUT4 data now available](https://www.realclimate.org/index.php/archives/2012/04/hadcrut4-data-now-available/) - RealClimate: Just a quick note to point out that the HadCRUT4 data are now fully available for download. Feel free to discuss (or point to) any analyses you'd like to see done in the comments, and perhaps we'll update this post with the more interesting ones.
- [Arctic Sea Ice Volume:  PIOMAS, Prediction, and the Perils of Extrapolation](https://www.realclimate.org/index.php/archives/2012/04/arctic-sea-ice-volume-piomas-prediction-and-the-perils-of-extrapolation/) - RealClimate: Guest Commentary by Axel Schweiger, Ron Lindsay, and Cecilia Bitz We have just passed the annual maximum in Arctic sea ice extent which always occurs sometime in March. Within a month we will reach the annual maximum in Arctic sea ice volume. After that, the sea ice will begin its course towards its annual minimum
- ['Wrong sign paradox' finally resolved?](https://www.realclimate.org/index.php/archives/2012/04/wrong-sign-paradox-finally-resolved/) - RealClimate: A group of colleagues has all but solved one of the greatest remaining puzzles in climate science. But the story is not one of scientific triumph – rather, it is so embarrassing that we had controversial discussions in our group whether to break this to a wider public at all. The puzzle is known amongst
- [Evaluating a 1981 temperature projection](https://www.realclimate.org/index.php/archives/2012/04/evaluating-a-1981-temperature-projection/) - RealClimate: Guest commentary from Geert Jan van Oldenborgh and Rein Haarsma, KNMI Sometimes it helps to take a step back from the everyday pressures of research (falling ill helps). It was in this way we stumbled across (pdf). In 1981 the first author of this post was in his first year at university and the other
- [Extremely hot](https://www.realclimate.org/index.php/archives/2012/03/extremely-hot/) - RealClimate: By Stefan Rahmstorf and Dim Coumou One claim frequently heard regarding extreme heat waves goes something like this: ”Since this heat wave broke the previous record by 5 °C, global warming can’t have much to do with it since that has been only 1 °C over the 20th century”. Here we explain why we find
- [The IPCC SREX: the report is finally out.](https://www.realclimate.org/index.php/archives/2012/03/the-ipcc-srex-the-report-is-finally-out/) - RealClimate: Some of us have been waiting quite a while now, especially since the 'road tour' meant to present the Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation starting in Oslo on January 24th this year. The summary for policymakers (SPM) was released already in 18 November 2011
- [Data presentation: A trend lesson](https://www.realclimate.org/index.php/archives/2012/03/data-presentation-a-trend-lesson/) - RealClimate: I just came across an interesting way to eliminate the impression of a global warming. A trick used to argue that the global warming had stopped, and the simple recipe is as follows: Cut off parts of the measurements and only keep the last 17 years. Plot all the months of these 17 years to
- [Updating the CRU and HadCRUT temperature data](https://www.realclimate.org/index.php/archives/2012/03/updating-the-cru-and-hadcrut-temperature-data/) - RealClimate: The latest incarnation of the CRUTEM land surface temperatures and the HadCRUT global temperatures are out this week. This is the 4th version of these products, which have undergone a number of significant changes over that time and so this is a good opportunity to discuss how and why data products evolve and what that
- [Recent trends in CO<sub>2</sub> emissions](https://www.realclimate.org/index.php/archives/2010/06/recent-trends-in-co2-emissions/) - RealClimate: CO2 emissions, growth rates, SRES scenarios, LeQuere and Manning
- [Unforced Variations: March 2012](https://www.realclimate.org/index.php/archives/2012/03/unforced-variations-march-2012/) - RealClimate: This month's open thread - for appetizers we have: William Nordhaus's extremely impressive debunking in the NY Review of Books of the WSJ 16 letter and public polling on the issue of climate change. Over to you...
- [Unforced Variations: February 2012](https://www.realclimate.org/index.php/archives/2012/02/unforced-variations-february-2012/) - RealClimate: This month's open thread. Current topics are focused on the laughingly bad Daily Mail article by David Rose, the fallout from the Wall Street Journal's latest regurgitation of why no-one should ever do anything ever. And perhaps someone might want to audit some of David Whitehouse's arithmetic and reading comprehension... Or anything else. Within reason.
- [Bickmore on the WSJ response](https://www.realclimate.org/index.php/archives/2012/02/bickmore-on-the-wsj-response/) - RealClimate: Guest commentary from Barry Bickmore (repost) The Wall Street Journal posted yet another op-ed by 16 scientists and engineers, which even include a few climate scientists(!!!). Here is the editor’s note to explain the context. Editor’s Note: The authors of the following letter, listed below, are also the signatories of“No Need to Panic About Global
- [Free speech and academic freedom](https://www.realclimate.org/index.php/archives/2012/02/free-speech-and-academic-freedom/) - RealClimate: Update: Some related concerns from deepclimate.org, if these claims can be verified. In a recent interview for a Norwegian magazine (Teknisk Ukeblad, 0412), the IPCC chair Rajendra Kumar Pachauri told the journalist that he had received death threats in connection with his role as a head for the IPCC. There have also been recent reports
- [Global Temperatures, Volcanic Eruptions, and Trees that Didn't Bark](https://www.realclimate.org/index.php/archives/2012/02/global-temperatures-volcanic-eruptions-and-trees-that-didnt-bark/) - RealClimate: My co-authors and I have just published an article in Nature Geoscience (advance online publication here; associated press release here) which seeks to explain certain enigmatic features of tree-ring reconstructions of Northern Hemisphere (NH) temperatures of the past millennium. Most notable is the virtual absence of cooling in the tree-ring reconstructions during what ice core
- [So What’s A Teacher to Do?](https://www.realclimate.org/index.php/archives/2012/02/so-whats-a-teacher-to-do/) - RealClimate: Guest Commentary by Eugenie Scott, National Center for Science Education Imagine you’re a middle-school science teacher, and you get to the section of the course where you’re to talk about climate change. You mention the “C” words, and two students walk out of the class. Or you mention global warming and a hand shoots up.
- [Unforced variations: Jan 2012](https://www.realclimate.org/index.php/archives/2012/01/unforced-variations-jan-2012/) - RealClimate: First open thread of 2012, so perhaps some discussion of the highlights and lowlights of 2011 are in order? Top 5 lists welcome...
- [The AR4 attribution statement](https://www.realclimate.org/index.php/archives/2012/01/the-ar4-attribution-statement/) - RealClimate: What the IPCC AR4 attribution statement meant for the anthropogenic contribution to recent global warming.
- [The dog is the weather](https://www.realclimate.org/index.php/archives/2012/01/the-dog-is-the-weather/) - RealClimate: Update January 27: There is also another recent dog-based animations from Victoria (southeast Australia) explaining some of the key drivers of our climate and how some are changing. A TV series that ran on Norwegian TV (NRK) last year included a simple and fun cartoon that demonstrates some important concepts relative to weather and climate:
- ["Vision Prize", an online poll of scientists about climate risk](https://www.realclimate.org/index.php/archives/2012/01/the-vision-prize/) - RealClimate: A group of researchers at Carnegie Mellon University is trying to get a better understanding of the views of earth scientists regarding various climate change topics. They have set up an ongoing poll to do this, called Vision Prize. It's a short (10 question) poll, covering topics like the rate of CO2 increase, predicted future
- [Open Climate 101 Online](https://www.realclimate.org/index.php/archives/2012/01/open-climate-101-online/) - RealClimate: Almost 3000 non-science major undergraduates at the University of Chicago have taken PHSC13400, Global Warming: Understanding the Forecast, since Ray Pierrehumbert and I (David Archer) first developed it back in 1995. Since the publication of the textbook for the class in 2005 (and a much-cleaned-up 2nd edition now shipping), enrollment has gone through the roof,
- [The sky IS falling <lang_fr>Le ciel nous tombe vraiment sur la tête</lang_fr>](https://www.realclimate.org/index.php/archives/2006/11/the-sky-is-falling/) - RealClimate: A timely perspective article in Science this week addresses the issues of upper atmosphere change. 'Upper' atmosphere here is the stratosphere up to the ionosphere (~20 to 300 km). Laštovička et al point out that cooling trends are exactly as predicted by increasing greenhouse gas trends, and that the increase in density that this implies
- [An online model of methane in the atmosphere](https://www.realclimate.org/index.php/archives/2012/01/an-online-model-of-methane-in-the-atmosphere/) - RealClimate: I've put together an easy-to-play-with online model of methane in the atmosphere. I'm going to use it for teaching along with the rest of the Understanding the Forecast webmodels, but it was designed to be relevant to the issue of abrupt new methane burps as we've been ruminating about lately on Realclimate. The model runs
- [An Arctic methane worst-case scenario](https://www.realclimate.org/index.php/archives/2012/01/an-arctic-methane-worst-case-scenario/) - RealClimate: Let's suppose that the Arctic started to degas methane 100 times faster than it is today. I just made that number up trying to come up with a blow-the-doors-off surprise, something like the ozone hole. We ran the numbers to get an idea of how the climate impact of an Arctic Methane Nasty Surprise would
- [Much ado about methane](https://www.realclimate.org/index.php/archives/2012/01/much-ado-about-methane/) - RealClimate: Methane is a powerful greenhouse gas, but it also has an awesome power to really get people worked up, compared to other equally frightening pieces of the climate story. What methane are we talking about? The largest methane pools that people are talking about are in sediments of the ocean, frozen into hydrate or clathrate
- [Recycling](https://www.realclimate.org/index.php/archives/2011/12/recycling/) - RealClimate: Two slightly off-center topics that Realclimate has covered in the past have recently come up again. The first is an analysis of Freakonomics by statisticians Andrew Gelman and Kaiser Fung in American Scientist, while the second is a recent reimagining of Washington crossing the Delaware. The Gelman and Fung piece goes through a number of
- [Copernicus and Arrhenius: Physics Then and <i>Physics Today</i>](https://www.realclimate.org/index.php/archives/2011/12/copernicus-and-arrhenius-physics-then-and-physics-today/) - RealClimate: There was a really interesting
- [Climate cynicism at the Santa Fe conference](https://www.realclimate.org/index.php/archives/2011/12/climate-cynicism-at-the-santa-fe-conference/) - RealClimate: Guest commentary by Mark Boslough* The Third Santa Fe Conference on Global and Regional Climate Change was held during Halloween week. It was most notable for the breadth of opinion — and the span of credibility — of its speakers. I have long complained about the lack of willingness of most contrarians to attend and
- [Global warming and ocean heat content](https://www.realclimate.org/index.php/archives/2011/10/global-warming-and-ocean-heat-content/) - RealClimate: The connection between global warming and the changes in ocean heat content has long been a subject of discussion in climate science. This was explicitly discussed in Hansen et al, 1997 where they predicted that over the last few decades of the 20th Century, there should have been a significant increase in ocean heat content
- [AGU 2011: Day 1](https://www.realclimate.org/index.php/archives/2011/12/agu-2011-day-1/) - RealClimate: A number of us are at the big AGU meeting in San Francisco this week (among 20,000 other geophysicists). We will try to provide a daily summary of interesting talks and posters we come across, but obviously this won't be complete or comprehensive. Other bloggers are covering the event (twitter #AGU11). A small number of
- [AGU Days 3&4](https://www.realclimate.org/index.php/archives/2011/12/agu-days-34/) - RealClimate: (Day 1)(Day 2) Sorry for the slow blogging, but with the AGU fun run starting at 6.15am, and the Awards ending at around ~10pm, and the actual science portion of the day squeezed in the middle, little time was available on Wednesday for reporting. Thursday seemed equally busy. So today you get two days in
- [AGU 2011: Day 2](https://www.realclimate.org/index.php/archives/2011/12/agu-2011-day-2/) - RealClimate: (Day 1) Tuesday There were two interesting themes in the solar sessions this morning. The first was a really positive story about how instrumental differences between rival (and highly competitive) teams can get resolved. This refers to the calibration of measurements of the Total Solar Irradiance (TSI). As is relatively well known, the different satellite
- [Les Chevaliers de l'Ordre de la Terre Plate, Part I: Allègre and Courtillot](https://www.realclimate.org/index.php/archives/2007/11/les-chevaliers-de-lordre-de-la-terre-plate-part-i-allgre-and-courtillot/) - RealClimate: France has a per capita carbon emission of 1.64 tonnes, compared to 2.67 tonnes for the U.K and 5.61 tonnes for the US. So, if anybody has earned the right to rest on their laurels and pontificate to the rest of the developed world about what they should be doing, you'd think it would be
- [Les Chevaliers de l’Ordre de la Terre Plate, Part II: Courtillot's Geomagnetic Excursion](https://www.realclimate.org/index.php/archives/2007/12/les-chevaliers-de-lordre-de-la-terre-plate-part-ii-courtillots-geomagnetic-excursion/) - RealClimate: This article continues the critique of writings on climate change by Allègre and Courtillot, started in Part I . If you would like to read either post in French, please click on the flag icon beside the post title above. Cet article poursuit la critique des écrits sur le climat d'Allègre et Courtillot, commencée dans
- [AGU 2011: Day 5 and wrap-up](https://www.realclimate.org/index.php/archives/2011/12/agu-2011-day-5-and-wrap-up/) - RealClimate: (Day 1)(Day 2)(Days 3&4) After 5 days, there is a definite slowdown in energy, desire to ask questions and attendance. But there were still a lot of good talks to be seen. Perhaps most relevant here were a few sessions talking about initial results from the CMIP5 models and the data with which they are
- [Global Temperature News](https://www.realclimate.org/index.php/archives/2011/12/global-temperature-news/) - RealClimate: There are two interesting pieces of news on the global temperature evolution. First, today a paper by was published by Environmental Research Letters, providing a new analysis of the five available global (land+ocean) temperature time series. Foster and Rahmstorf tease out and remove the short-term variability due to ENSO, solar cycles and volcanic eruptions and
- [Unforced variations: Dec 2011](https://www.realclimate.org/index.php/archives/2011/12/unforced-variations-dec-2011/) - RealClimate: Open thread for December...
- [Two-year old turkey](https://www.realclimate.org/index.php/archives/2011/11/two-year-old-turkey/) - RealClimate: The blogosphere is abuzz with the appearance of a second tranche of the emails stolen from CRU just before thanksgiving in 2009. Our original commentary is still available of course (CRU Hack, CRU Hack: Context, etc.), and very little appears to be new in this batch. Indeed, even the out-of-context quotes aren't that exciting, and
- [The IPCC report on extreme climate and weather events](https://www.realclimate.org/index.php/archives/2011/11/the-ipcc-report-on-extreme-climate-and-weather-events/) - RealClimate: The IPCC recently released the policy-maker's summary (SREX-SPM) on extreme weather and climate events. The background for this report is a larger report that is due to be published in the near future, and one gets a taste of this in the 'wordle' figure below. By the way, the phrase 'ET' in this context does
- [Scientific confusion](https://www.realclimate.org/index.php/archives/2011/11/scientific-confusion/) - RealClimate: "We have not succeeded in answering all our problems. The answers we have found only serve to raise a whole set of new questions. In some ways we feel we are as confused as ever, but we believe we are confused on a higher level and about more important things." I read this quote on
- [Keystone XL: Game over?](https://www.realclimate.org/index.php/archives/2011/11/keystone-xl-game-over/) - RealClimate: The impending Obama administration decision on the Keystone XL Pipeline, which would tap into the Athabasca Oil Sands production of Canada, has given rise to a vigorous grassroots opposition movement, leading to the arrests so far of over a thousand activists. At the very least, the protests have increased awareness of the implications of developing
- [Times Atlas map of Greenland to be corrected](https://www.realclimate.org/index.php/archives/2011/11/times-atlas-map-of-greenland-to-be-corrected/) - RealClimate: We were pleased to hear from the University of Arizona's Jeff Kargel that the Times Atlas folks are now updating their atlas of Greenland. As we reported earlier, the first edition was completely in error, and led to some rather bizarre claims about the amount of ice loss in Greenland. Kargel reports that HarperCollins (publisher
- [On record-breaking extremes](https://www.realclimate.org/index.php/archives/2011/11/on-record-breaking-extremes/) - RealClimate: It is a good tradition in science to gain insights and build intuition with the help of thought-experiments. Let’s perform a couple of thought-experiments that shed light on some basic properties of the statistics of record-breaking events, like unprecedented heat waves. I promise it won’t be complicated, but I can’t promise you won’t be surprised.
- [Conference conversations](https://www.realclimate.org/index.php/archives/2011/11/conference-conversations/) - RealClimate: Rasmus & Gavin The reason why scientists like going to conferences (despite them often being held in stuffy hotel basements) is because of the conversations. People can be found who know what they are talking about, and discussions can be focused clearly on what is important, rather than what is trivial. The atmosphere at these
- [MJO Conversations](https://www.realclimate.org/index.php/archives/2011/11/mjo-conversations/) - RealClimate: There is a (relatively) new blog from scientists involved in a big research program (DYNAMO) looking into the Madden-Julian Oscillation (MJO). Called Madden-Julian Conversations, it is run by Adam Sobel and Daehyun Kim (Columbia), Zhiming Kuang (Harvard) and Eric Maloney (Colorado State). A schematic of the MJO from cmmap.org The MJO can be seen in
- [Unforced variations: Nov 2011](https://www.realclimate.org/index.php/archives/2011/10/unforced-variations-nov-2011/) - RealClimate: Once more unto the open thread...
- [A bit of philosophy](https://www.realclimate.org/index.php/archives/2007/05/a-bit-of-philosophy/) - RealClimate: Eric Steig and Gavin Schmidt The two of us participated last week in an interesting meeting at the University of Washington on Ethics and Climate Change. Other scientists in attendance included Dennis Hartmann, who gave an overview of the current state of the science, and sometime RealClimate contributor Cecilia Bitz. Organized by Associate Professor of
- [The Climate Data Guide](https://www.realclimate.org/index.php/archives/2011/10/the-climate-data-guide/) - RealClimate: The National Center for Atmospheric Research (NCAR) has, in the last few months, developed an interesting and potentially very useful website The Climate Data Guide devoted to the ins and outs of obtaining and analyzing the various existing climatic data sets. The site describes itself as "...a focal point for expert-user guidance, commentary, and questions
- [NPP lift off](https://www.realclimate.org/index.php/archives/2011/10/npp-lift-off/) - RealClimate: The launch of the NASA/NOAA NPP satellite seems to have gone off without a hitch this morning which is great news. This satellite has instruments that are vital to continuing data streams that were pioneered on the aging TERRA (1999), AQUA (2002) and AURA (2004), satellites - including the CERES instrument for monitoring the Earth's
- [Berkeley earthquake called off](https://www.realclimate.org/index.php/archives/2011/10/berkeley-earthquake-called-off/) - RealClimate: Anybody expecting earthshaking news from Berkeley, now that the Berkeley Earth Surface Temperature group being led by Richard Muller has released its results, had to be content with a barely perceptible quiver. As far as the basic science goes, the results could not have been less surprising if the press release had said "Man Finds
- [A Well Deserved Honor](https://www.realclimate.org/index.php/archives/2011/10/a-well-deserved-honor/) - RealClimate: The rest of us here would like to congratulate Gavin on a well-deserved honor. He is the recipient of the inaugural AGU Climate Communication Prize. Since co-founding RealClimate back in 2004, Gavin has emerged as the de facto leader of RealClimate, having written the majority of our posts--and many of our best ones. One of
- [The high cost of inaction](https://www.realclimate.org/index.php/archives/2011/10/the-cost-of-inaction/) - RealClimate: In 2004 Stephen Pacala and Robert Socolow published a paper in Science in which they argued that a pragmatic, but still difficult, way of stabilizing atmospheric CO2 levels over the long term was via the implementation of seven "stabilization wedges" over the next 50 years. The idea was very simple: each wedge represented one in-hand
- [What is a first-order climate forcing?](https://www.realclimate.org/index.php/archives/2005/09/what-is-a-first-order-climate-forcing/) - RealClimate: Roger Pielke Sr. (Colorado State) has a blog (Climate Science) that gives his personal perspective on climate change issues. In it, he has made clear that he feels that apart from greenhouse gases, other climate forcings (the changes that affect the energy balance of the planet) are being neglected in the scientific discussion. Specifically, he
- [Are the CRU data "suspect"?   An objective assessment.](https://www.realclimate.org/index.php/archives/2009/12/are-the-cru-data-suspect-an-objective-assessment/) - RealClimate: Kevin Wood, Joint Institute for the Study of the Atmosphere and Ocean, University of Washington Eric Steig, Department of Earth and Space Sciences, University of Washington In the wake of the CRU e-mail hack, the suggestion that scientists have been hiding the raw meteorological data that underpin global temperature records has appeared in the media.
- [Who ya gonna call?](https://www.realclimate.org/index.php/archives/2007/08/who-ya-gonna-call/) - RealClimate: Gavin Schmidt and Michael Mann Scientific theories gain credence from successful predictions. Similarly, scientific commentators should gain credibility from whether their comments on new studies hold up over time. Back in 2005 we commented on the Bryden et al study on a possible ongoing slowdown in the North Atlantic overturning circulation. In our standard, scientifically
- [Art and climate](https://www.realclimate.org/index.php/archives/2006/03/art-and-climate/) - RealClimate: As anecdotal evidence of past climate change goes, some of the most pleasant to contemplate involve paintings of supposedly typical events that involve the weather. Given the flourishing of secular themes in European art from the Renaissance on, most of this art comes from the 16th to 19th centuries. As readers here will know, this
- [Speculative polar cartography](https://www.realclimate.org/index.php/archives/2011/10/speculative-polar-cartography/) - RealClimate: Guest commentary from Kevin Brown The curious mismapping of Greenland’s ice sheet cover by the venerable Times Atlas recently has excited a lot of outraged commentary. But few people noted that this follows an old tradition of speculative cartography of the polar regions. 'Modern' mapmakers as early as the 16th century combined real facts and
- [Unforced Variations: Sep 2011](https://www.realclimate.org/index.php/archives/2011/09/unforced-variations-sep-2011/) - RealClimate: This month's open thread...
- [Unforced variations: Oct 2011](https://www.realclimate.org/index.php/archives/2011/10/unforced-variations-oct-2011/) - RealClimate: Open thread for October...
- [ Cosmic rays and clouds: Potential mechanisms](https://www.realclimate.org/index.php/archives/2011/09/cosmic-rays-and-clouds-potential-mechanisms/) - RealClimate: Guest Commentary by Jeffrey Pierce (Dalhousie U.) I've written this post to help readers understand potential physical mechanisms behind cosmic-ray/cloud connections. But first I briefly want to explain my motivation. Prior to the publication of the aerosol nucleation results from the CLOUD experiment at CERN in Nature several weeks ago , I was asked by
- [Greenland meltdown](https://www.realclimate.org/index.php/archives/2011/09/greenland-meltdown/) - RealClimate: After a record-breaking 2010 in terms of surface melt area in Greenland , numbers from 2011 have been eagerly awaited. Marco Tedseco and his group have now just reported their results. This is unrelated to other Greenland meltdown this week that occurred at the launch of the new Times Atlas. The melt index anomaly is
- [Chaos and Climate](https://www.realclimate.org/index.php/archives/2005/11/chaos-and-climate/) - RealClimate: By James Annan and William Connolley In this post, we will try to explain a little about chaos theory, and its relevance to our attempts to understand and forecast the climate system. The chaotic nature of atmospheric solutions of the Navier-Stokes equations for fluid flow has great impact on weather forecasting (which we discuss first),
- [Hooked on 'theWeather'](https://www.realclimate.org/index.php/archives/2011/09/hooked-on-theweather/) - RealClimate: During the annual European Meteorological Society's (EMS) annual meeting in Berlin, I was pleasantly surprised by a magazine called 'theWeather', issued by the theWeather Club, an outreach activity associated with the Royal Meteorological Society. TheWeather Club was awarded the EMS outreach & Communication award 2011 for this magazine. TheWeather is a source rich with different
- [The unnoticed melt](https://www.realclimate.org/index.php/archives/2011/09/the-unnoticed-melt/) - RealClimate: Guest commentary from Dirk Notz, MPI Hamburg “Well, it’s not really good timing to write about global warming when the summer feels cold and rainy”, a journalist told me last week. Hence, at least here in Germany, there hasn’t been much reporting about the recent evolution of Arctic sea ice – despite the fact that
- [Unforced variations: Mar 2011](https://www.realclimate.org/index.php/archives/2011/03/unforced-variations-mar-2011/) - RealClimate: This month's open thread for climate science discussions.
- [Unforced variations: Apr 2011](https://www.realclimate.org/index.php/archives/2011/04/unforced-variations-apr-2011/) - RealClimate: This months open thread. There are some Items of potential interest:: The fallout (and falling out) from the climate hearings yesterday (video) (liveblog) A good paper on science communication in Nature Climate Change A set of articles on the Medieval Climate Anomaly (MCA) in this month's PAGES newsletter. or whatever you like.
- [Unforced variations: May 2011](https://www.realclimate.org/index.php/archives/2011/05/unforced-variations-may-2011/) - RealClimate: This month's open thread. Seed topics: The genealogy of climate models, how to compare different greenhouse gases, whether a 2 deg C temperature target makes sense (Stoat has already weighed in), or reflections on the Nenana Ice classic (which has just concluded for this year). But you decide.
- [Unforced Variations: June 2011](https://www.realclimate.org/index.php/archives/2011/06/unforced-variations-june-2011/) - RealClimate: A new open thread...
- [Unforced Variations: Aug 2011](https://www.realclimate.org/index.php/archives/2011/08/unforced-variations-aug-2011/) - RealClimate: This month's open thread. Your starter for 2010, the 2010 State of the Climate report....
- [Resignations, retractions and the process of science](https://www.realclimate.org/index.php/archives/2011/09/resignations-retractions-and-the-process-of-science/) - RealClimate: Much is being written about the very public resignation of Wolfgang Wagner from the editorship of Remote Sensing over the publication of Spencer and Braswell (2011) - and rightly so. It is a very rare situation that an editor resigns over the failure of peer review, and to my knowledge it has only happened once
- [An exercise about meaningful numbers: examples from celestial "attribution studies"](https://www.realclimate.org/index.php/archives/2011/08/an-exercise-about-meaningful-numbers-examples-from-celestial-attribution-studies/) - RealClimate: Is the number 2.14159 (here rounded off to 5 decimal points) a fundamentally meaningful one? Add one, and you get π = 3.14159 = 2.14159 + 1. Of course, π is a fundamentally meaningful number, but you can split up this number in infinite ways, as in the example above, and most of the different
- [Arctic sea ice minimum discussions](https://www.realclimate.org/index.php/archives/2011/09/arctic-sea-ice-minimum-discussions/) - RealClimate: Here is a continuation of the last Arctic sea ice discussion as we get closer to the 2011 minimum. All figures will update continuously. JAXA Sea ice extent and area: Cryosphere Today sea ice concentration: Estimated sea ice volume from UW PIOMAS (updated every month):
- [The CERN/CLOUD results are surprisingly interesting...](https://www.realclimate.org/index.php/archives/2011/08/the-cerncloud-results-are-surprisingly-interesting/) - RealClimate: The long-awaited first paper from the CERN/CLOUD project has just been published in Nature. The paper, by Kirkby et al, describes changes in aerosol nucleation as a function of increasing sulphates, ammonia and ionisation in the CERN-based 'CLOUD' chamber. Perhaps surprisingly, the key innovation in this experimental set up is not the presence of the
- [How large were the past changes in the sun?](https://www.realclimate.org/index.php/archives/2011/08/how-large-were-the-past-changes-in-the-sun/) - RealClimate: We only have direct observations of total solar irradiance (TSI) since the beginning of the satellite era and substantial evidence for variations in the level of solar activity (from cosmogenic isotopes or sunspot records) in the past. Tying those factors together in order to estimate solar irradiance variations in the past is crucial for attributing
- [CMIP5 simulations](https://www.realclimate.org/index.php/archives/2011/08/cmip5-simulations/) - RealClimate: Climate modeling groups all across the world are racing to add their contributions to the CMIP5 archive of coupled model simulations. This coordinated project, proposed, conceived and specified by the climate modeling community itself, will be an important resource for analysts and for the IPCC AR5 report (due in 2013), and beyond. There have been
- [Volcanic vs. Anthropogenic CO2](https://www.realclimate.org/index.php/archives/2011/08/volcanic-vs-anthropogenic-co2/) - RealClimate: Guest Commentary by Terry Gerlach* TV screen images of erupting and exploding volcanoes spewing forth emissions are typically spectacular, awesome, and vividly suggestive of huge additions of gas to the atmosphere. By comparison, the smokestack and exhaust pipe venting of anthropogenic emissions is comparatively unexciting, unimpressive, and commonplace. Consequently, it easy to get traction with
- [Raymond T. Pierrehumbert](https://www.realclimate.org/index.php/archives/2004/12/raymond-t-pierrehumbert/) - RealClimate: Raymond Pierrehumbert is the Louis Block Professor in Geophysical Sciences at the University of Chicago, having earlier served on the atmospheric science faculties of MIT and Princeton. He is principally interested in the formulation of idealized models which can be brought to bear on fundamental phenomena governing present and past climates of the Earth and
- [Unforced variations, July 2011](https://www.realclimate.org/index.php/archives/2011/07/unforced-variations-july-2011/) - RealClimate: The RC open thread. With a reminder that this is not a dumping ground for anything under the sun, but is rather for discussing climate science topics that don't fit neatly into ongoing discussions.
- ["Misdiagnosis of Surface Temperature Feedback"](https://www.realclimate.org/index.php/archives/2011/07/misdiagnosis-of-surface-temperature-feedback/) - RealClimate: Guest commentary by Kevin Trenberth and John Fasullo The hype surrounding a new paper by Roy Spencer and Danny Braswell is impressive (see for instance Fox News); unfortunately the paper itself is not. News releases and blogs on climate denier web sites have publicized the claim from the paper's news release that “Climate models get
- [CRUTEM3 data release (except Poland)](https://www.realclimate.org/index.php/archives/2011/07/crutem3-data-release-except-poland/) - RealClimate: The entire CRUTEM3 database of station temperature measurements has just been released. This comes after a multi-year process to get permissions from individual National Weather Services to allow the passing on of data to third parties and from a ruling from the UK ICO. All the NWSs have now either agreed or not responded (except
- [Reanalyses 'R' Us](https://www.realclimate.org/index.php/archives/2011/07/reanalyses-r-us/) - RealClimate: There is an interesting new wiki site, Reanalyses.org, that has been developed by a number of groups dedicated to documenting the various reanalysis products for atmosphere and ocean that are increasingly being made available. For those that don't know, a 'reanalysis' is a climate or weather model simulation of the past that includes data assimilation
- [Learning from a simple model](https://www.realclimate.org/index.php/archives/2007/04/learning-from-a-simple-model/) - RealClimate: A lot of what gets discussed here in relation to the greenhouse effect is relatively simple, and yet can be confusing to the lay reader. A useful way of demonstrating that simplicity is to use a stripped down mathematical model that is complex enough to include some interesting physics, but simple enough so that you
- [Cuckoo Science <lang_fr>La Science Coucou</lang_fr>](https://www.realclimate.org/index.php/archives/2006/11/cuckoo-science/) - RealClimate: Traduit par Etienne Pesnelle Sometimes on Realclimate we discuss important scientific uncertainties, and sometimes we try and clarify some subtle point or context, but at other times, we have a little fun in pointing out some of the absurdities that occasionally pass for serious 'science' on the web and in the media. These pieces look
- [Is Sea-Level Rise Accelerating?](https://www.realclimate.org/index.php/archives/2011/07/is-sea-level-rise-accelerating/) - RealClimate: A few months ago a paper by Jim Houston and Bob Dean in the Journal of Coastal Research (JCR) cast doubt on whether global sea level rise has accelerated over the past century or so. As things go these days, ‘climate sceptics’ websites immediately heralded this as a “bombshell”. A rebuttal by myself and Martin
- [Arctic sea ice discussions](https://www.realclimate.org/index.php/archives/2011/07/arctic-sea-ice-discussions/) - RealClimate: This is a thread to discuss issues related to the 2011 Arctic sea ice minimum. The following graphs will update every day: JAXA Sea ice extent: Cryosphere Today sea ice concentration:
- [Coldest Winter in 1000 Years Cometh. Not.](https://www.realclimate.org/index.php/archives/2010/12/coldest-winter-in-1000-years/) - RealClimate: This claim circulates in the internet and in many mainstream media as well: Scientists have allegedly predicted the coldest winter in 1,000 years for Europe. What is behind it? Nothing – no scientist has predicted anything like it. A Polish tabloid made up the story. An interesting lesson about today´s media. By Stefan Rahmstorf and
- [A brief history of knowledge about Antarctic temperatures](https://www.realclimate.org/index.php/archives/2010/12/a-brief-history-of-knowledge-about-antarctic-temperatures/) - RealClimate: Sources in italics. Early 20th Century: Scott: It's cold here. The media: Scott is a hero! Scott: It's really really cold here. The media: Scott is a hero! Amundsen: It's not that cold. The media: Scott is a hero. Oh, and Amundsen. Public: Shackleton is a hero, but please shut up, there's a war on.
- [Michael Crichton's State of Confusion <lang_fr>L'état de confusion de Michael Crichton</lang_fr>](https://www.realclimate.org/index.php/archives/2004/12/michael-crichtons-state-of-confusion/) - RealClimate: In a departure from normal practice on this site, this post is a commentary on a piece of out-and-out fiction (unlike most of the other posts which deal with a more subtle kind). Michael Crichton's new novel "State of Fear" is about a self-important NGO hyping the science of the global warming to further the
- [Lu: from 'interesting but incorrect' to just wrong](https://www.realclimate.org/index.php/archives/2011/07/lu-from-interesting-but-incorrect-to-just-wrong/) - RealClimate: Some readers might recall a story from a couple of years of ago relating polar ozone depletion to cosmic rays and the subsequent failure of predictions made using that theory. The idea came from from a Qian-B. Lu (U. Waterloo), and initially seemed interesting (at least to those of us who were not specialists). Perhaps
- [Climate change commitments](https://www.realclimate.org/index.php/archives/2010/03/climate-change-commitments/) - RealClimate: Climate change commitment, Matthews and Weaver, adaptation and mitigation. CO2 emissions and concentrations.
- [2000 Years of Sea Level (+updates)](https://www.realclimate.org/index.php/archives/2011/06/2000-years-of-sea-level/) - RealClimate: A group of colleagues have succeeded in producing the first continuous proxy record of sea level for the past 2000 years. According to this reconstruction, 20th-Century sea-level rise on the U.S. Atlantic coast is faster than at any time in the past two millennia. Good data on past sea levels is hard to come by.
- [What if the Sun went into a new Grand Minimum?](https://www.realclimate.org/index.php/archives/2011/06/what-if-the-sun-went-into-a-new-grand-minimum/) - RealClimate: Guest commentary by Georg Feulner During a meeting of the Solar Physics Division of the American Astronomical Society, solar physicists have just announced a prediction that the Sun might enter an extended period of low activity (a 'grand minimum') similar to the Maunder Minimum in the 17th century. In this post I will explore the
- [The age of Aquarius](https://www.realclimate.org/index.php/archives/2011/06/the-age-of-aquarius/) - RealClimate: Seawater salinity and NASA's Aquarius satellite.
- [Unfinished Business](https://www.realclimate.org/index.php/archives/2011/06/unfinished-business/) - RealClimate: A paper in the scientific literature has to have some minimum level of content to be worth publishing (and regrettably, the search for the 'Least Publishable Unit' (LPU) of work is occasionally apparent for those wishing to pad their CVs). But what happens when someone has something worth saying that falls below that level? This
- [An incremental step blown up](https://www.realclimate.org/index.php/archives/2011/05/an-incremental-step-blown-up/) - RealClimate: New results from the University of Aarhus in Denmark and the Danish National Space Institute allegedly show that particles from space create cloud cover, according to a recent press release. And the Physics World magazine (May, 2011) report that the researchers say this is the best experimental evidence yet that the Sun influences the climate
- [Nobel Laureates Speak Out](https://www.realclimate.org/index.php/archives/2011/05/nobel-laureates-speak-out-2/) - RealClimate: On Wednesday, 17 Nobel laureates who gathered in Stockholm have published a remarkable memorandum, asking for “fundamental transformation and innovation in all spheres and at all scales in order to stop and reverse global environmental change”. The Stockholm Memorandum concludes that we have entered a new geological era: the Anthropocene, where humanity has become the
- [Handbook in Denialism](https://www.realclimate.org/index.php/archives/2011/05/handbook-in-denialism/) - RealClimate: It would not surprise me if the denialists would deny the existence of the new book by Haydn Washington and John Cook (skepticalscience.com) ‘Climate Change Denial: Heads in the Sand‘. Somehow, I don’t think they will read it – but they are not target group of this book either. Anyway, denialism is, according to the
- [Health on a Changing Planet](https://www.realclimate.org/index.php/archives/2011/05/a-changing-planet/) - RealClimate: by Jim and Rasmus NOTE: The authors of the book are following this post. If you have questions on this broad topic, ask them! In the big, wide-ranging world of global change effects, one would be hard pressed to find a topic that is more important--or of more interest to more people--than effects on human
- [Review of Spencer's 'Great Global Warming Blunder'](https://www.realclimate.org/index.php/archives/2011/04/review-of-spencers-great-global-warming-blunder/) - RealClimate: Guest commentary from Steve Ghan A good writer knows their audience, and Roy Spencer knows his. There are plenty of people who would love to hear a compelling argument for why no action is needed to mitigate global warming, and Spencer's book "The Great Global Warming Blunder: How Mother Nature Fooled the World's Top Climate
- [Steve Schneider's first letter to the editor](https://www.realclimate.org/index.php/archives/2011/04/steve-schneiders-first-letter-to-the-editor/) - RealClimate: There was a time at NASA when writing a letter to the paper without your director's permission could get you fired. And no, I'm not talking about the last Bush administration. It was 1971. Steve Schneider at the time was a postdoc at NASA GISS, working for the then director, Robert Jastrow (later of the
- [Rescuing data...](https://www.realclimate.org/index.php/archives/2011/04/rescuing-data/) - RealClimate: Guest commentary by Vicky Slonosky One of the lesser-known branches of climatology is historical climatology, the study of past climates from historical records of instrumental observations and weather descriptions, with “historical” often loosely taken to mean “pre-government-organized-meteorological or weather service” observations. In the last ten years or so, with the development of digital imaging, increased
- [An Emerging View on Early Land Use](https://www.realclimate.org/index.php/archives/2011/04/an-emerging-view-on-early-land-use/) - RealClimate: Guest article by William Ruddiman More than 20 years ago, analyses of greenhouse gas concentrations in ice cores showed that downward trends in CO2 and CH4 that had begun near 10,000 years ago subsequently reversed direction and rose steadily during the last several thousand years. Competing explanations for these increases have invoked either natural changes
- [Fracking methane](https://www.realclimate.org/index.php/archives/2011/04/fracking-methane/) - RealClimate: The Howarth et al paper estimating the climatic impact of shale gas extraction by hydraulic fracturing (fracking) has provoked a number of responses across the media. Since the issue of natural gas vs. coal or oil, and the specifics of fracking itself are established and growing public issues, most commentary has served to bolster any
- [Losing time, not buying time](https://www.realclimate.org/index.php/archives/2010/12/losing-time-not-buying-time/) - RealClimate: Control of methane, soot, and other short-lived climate-forcing agents has often been described as a cheap way to "buy time" to get carbon dioxide emissions under control. But is it really? Expectations for the outcome of the Cancun climate talks seem to be running low, and the suggestion has emerged that maybe we should forget
- [The warm beer chart](https://www.realclimate.org/index.php/archives/2011/04/the-warm-beer-chart/) - RealClimate: Perhaps a way to connect with Joe Sixpack? Tagline: If we can pay as much attention to the Earth as we do to our beer, we probably wouldn't need to worry about global warming. Design by S. Han, loosely based on IPCC (2007), courtesy of the "Artist as Citizen" initiative. (Full size pdf version)
- [English vineyards again....](https://www.realclimate.org/index.php/archives/2006/11/english-vineyards-again/) - RealClimate: Readers may recall a thorough examination of the history of English wine here a few months ago - chiefly because the subject tends to come up as a contrarian climate talking point every now and again. The bottom line from that post was that the English wine industry is currently thriving and has a geographical
- [Making climate science more useful](https://www.realclimate.org/index.php/archives/2011/03/making-climate-science-more-useful/) - RealClimate: Last week, there was a CORDEX workshop on regional climate modelling at International Centre for Theoretical Physics (ICTP), near Trieste, Italy. The CORDEX initiative, as the abbreviation 'COordinated Regional climate Downscaling Experiment' suggests, tries to bring together the community of regional climate modellers. At least, this initiative has got a blessing from the World Climate
- [Friday round-up](https://www.realclimate.org/index.php/archives/2011/03/friday-round-up-5/) - RealClimate: Last week, Nature published another strong statement addressing the political/economic attack on climate science in an editorial titled "Into Ignorance". It specifically criticized the right wing element of the U.S. Congress that is attempting to initiate legislation that would strip the US EPA of its powers to regulate greenhouse gases as pollutants. In so doing,
- [Under and over the ice](https://www.realclimate.org/index.php/archives/2011/03/under-and-over-the-ice/) - RealClimate: Antarctica, Greenland, ice sheet dynamics, mass balance and sea level rise. Underestimate of IPCC projections.
- [Blogging climate scientists](https://www.realclimate.org/index.php/archives/2011/03/blogging-climate-scientists/) - RealClimate: The newest arrival in the climate science blogosphere is Isaac Held. This is notable in a number of respects. First, Isaac is a top-tier climate scientist who is hugely respected in the community. For him to decide that it is worth his time to blog on the science should be an important signal for other
- [Con Allègre, ma non troppo](https://www.realclimate.org/index.php/archives/2006/10/con-allegre-ma-non-troppo/) - RealClimate: Guest Commentary by Georg Hoffmann (LSCE) Climate change denial is not necessarily a speciality of Washington DC think tanks - sometimes it can also be found in old Europe. Right now there is a little media storm passing by in France evoked by an article from Claude Allègre in L’Express. Who is Claude Allègre? He
- [Will spring 2005 be a bad one for Arctic ozone? <lang_fr>Le printemps 2005 comptera-t-il parmi les mauvais pour l’ozone arctique ?</lang_fr>](https://www.realclimate.org/index.php/archives/2005/03/will-spring-2005-be-a-bad-one-for-arctic-ozone/) - RealClimate: Guest Commentary by Drew Shindell (NASA GISS) The current winter and early spring have been extremely cold in the Arctic stratosphere, leading to the potential for substantial ozone depletion there. This has been alluded to recently in the press (Sitnews, Seattle Post Intelligencer), but what’s the likely outcome, and why is it happening? Par Drew
- [Introduction to feedbacks](https://www.realclimate.org/index.php/archives/2010/09/introduction-to-feedbacks/) - RealClimate: Guest blog by Chris Colose (e-mail: colose-at-wisc.edu) UPDATE: This is Part 1 of two posts by Chris. Part 2 is here RealClimate has recently featured a series of posts on the greenhouse effect and troposphere, articulating some of the more important physics of global warming from first principles. It is worthwhile reviewing these elements every
- [Wahl-to-Wahl coverage](https://www.realclimate.org/index.php/archives/2011/03/wahl-to-wahl-coverage/) - RealClimate: Eugene Wahl asked us to post a statement related to some incorrect claims circulating in the blogosphere: The Daily Caller blog yesterday contained an inaccurate story regarding a correspondence that was part of the emails hacked from East Anglia University Climate Research Unit (CRU) in November 2009. For the record, while I received the email
- [On Yet Another False Claim by McIntyre and McKitrick](https://www.realclimate.org/index.php/archives/2005/01/on-yet-another-false-claim-by-mcintyre-and-mckitrick/) - RealClimate: McIntyre and McKitrick (MM), in one of their many false claims regarding the Mann et al (MBH98) temperature reconstruction, assert that the "Hockey Stick" shape of the reconstruction is an artifact of the "non-centered" Principal Components Analysis (PCA) convention used by MBH98 in representing the North American International Tree Ring Data Bank (ITRDB) data series.
- [Myth vs. Fact Regarding the "Hockey Stick"](https://www.realclimate.org/index.php/archives/2004/12/myths-vs-fact-regarding-the-hockey-stick/) - RealClimate: Numerous myths regarding the so-called "hockey stick" reconstruction of past temperatures, can be found on various non-peer reviewed websites, internet newsgroups and other non-scientific venues. The most widespread of these myths are debunked below: Una traducción está disponible aquí. MYTH #0: Evidence for modern human influence on climate rests entirely upon the "Hockey Stick" Reconstruction
- [Live-blogging the climate science hearings](https://www.realclimate.org/index.php/archives/2011/03/live-blogging-the-climate-science-hearings/) - RealClimate: I will be live-blogging the House Energy and Commerce committee hearings on climate science with Eli Kintisch. The details are available here, and there should be a live feed from the committee website from 10am. Eli and I did this last year for the last Democrat-run hearings, and it went quite well - a little
- [What we do not know in terms of adaptation](https://www.realclimate.org/index.php/archives/2011/03/what-we-do-not-know-in-terms-of-adaptation/) - RealClimate: A recent paper by Oreskes et al. in the journal Philosophy of Science asserts that "there is a gap between the scale on which models produce consistent information and the scale on which humans act". While the large scales, such as the global mean, provide the best indicators of the state of earth's climate, it
- [Glory (not to) be](https://www.realclimate.org/index.php/archives/2011/03/glory-not-to-be/) - RealClimate: This morning one of the most important (and most delayed) satellite launches in ages took place. The mission was to launch the Glory satellite into a polar orbit, where three key instruments would have been looking at solar irradiance, aerosols and clouds. Unfortunately, one of the stages failed to separate and the satellite did not
- [Requiem for the Younger Dryas impact hypothesis?](https://www.realclimate.org/index.php/archives/2011/03/requiem-for-the-younger-dryas-impact-hypothesis/) - RealClimate: This is the strong conclusion of a new paper in the Earth Science Reviews by Pinter et al (via Scribd). From their abstract: The Younger Dryas (YD) impact hypothesis is a recent theory that suggests that a cometary or meteoritic body or bodies hit and/or exploded over North America 12,900 years ago, causing the YD
- [Unforced variations: Feb 2011](https://www.realclimate.org/index.php/archives/2011/02/unforced-variations-feb-2011/) - RealClimate: This month's open thread... ... continued here.
- [Revisiting the Younger Dryas](https://www.realclimate.org/index.php/archives/2010/07/revisiting-the-younger-dryas/) - RealClimate: Younger Dryas, North Atlantic circulation, MOC, abrupt climate change, last glacial maximum
- [RealClimate In the News](https://www.realclimate.org/index.php/archives/2006/07/realclimate-in-the-news/) - RealClimate: The Guardian, Feb 25 2011, RealClimate faces libel suit Salt Lake Tribune, Nov 27, 2010, Separating truth and fiction in climate debate (op-ed) The Observer, Nov 14 2010, Climate Change Email Scandal Vetenskapens Varld (Swedish Television), Nov 2010 Climategate - otextad Providence Journal, 21 Jan 2010 Continued partly cloudy Die Zeit, 8 Dec 2009 Skeptiker
- [How easy it is to get fooled](https://www.realclimate.org/index.php/archives/2011/02/how-easily-it-is-to-get-fooled/) - RealClimate: When you analyse your data, you usually assume that you know what the data really represent. Or do you? This has been a question that over time has marred studies on solar activity and climate, and more recently cosmic rays and clouds. And yet again, this issue pops up in two recent papers; One by
- [E&E threatens a libel suit ](https://www.realclimate.org/index.php/archives/2011/02/ee-threatens-a-libel-suit/) - RealClimate: Abuse of the UK libel laws is so commonplace as to require no real introduction (but see the Campaign for libel reform for more details). Because of the ridiculous costs and pro-plaintiff assumptions, it has been (ab)used by many and fought against successfully only by a few. In the realm of discussions about science, Simon
- [Going to extremes](https://www.realclimate.org/index.php/archives/2011/02/going-to-extremes/) - RealClimate: There are two new papers in Nature this week that go right to the heart of the conversation about extreme events and their potential relationship to climate change. This is a complex issue, and one not well-suited to soundbite quotes and headlines, and so we'll try and give a flavour of what the issues are
- [West Antarctica: still warming](https://www.realclimate.org/index.php/archives/2011/02/west-antarctica-still-warming-2/) - RealClimate: The temperature reconstruction of O'Donnell et al. (2010) confirms that West Antarctica is warming -- but underestimates the rate Eric Steig At the end of my post last month on the history of Antarctic science I noted that I had an initial, generally favorable opinion of the paper by O'Donnell et al. in the Journal
- [O'Donnellgate](https://www.realclimate.org/index.php/archives/2011/02/odonnellgate/) - RealClimate: or...Some thoughts on Personal Responsibility and the Peer Review Process Eric Steig Ryan O'Donnell made a series of serious of allegations against me at ClimateAudit, in the context of our friendly dispute about whether his new paper in the Journal of Climate supports or 'refutes' my own results, published in Nature. To his credit, Ryan
- [The Starship vs. Spaceship Earth](https://www.realclimate.org/index.php/archives/2011/02/the-starship-vs-spaceship-earth/) - RealClimate: Eric Steig & Ray Pierrehumbert One of my (Eric's) favorite old books is The Starship and the Canoe by Kenneth Brower It's a 1970s book about a father (Freeman Dyson, theoretical physicist living in Princeton) and son (George Dyson, hippy kayaker living 90 ft up in a fir tree in British Columbia) that couldn't be
- [Unforced variations: Jan 2011](https://www.realclimate.org/index.php/archives/2011/01/unforced-variations-jan-2011/) - RealClimate: Open thread.
- [Friday round-up](https://www.realclimate.org/index.php/archives/2011/01/friday-round-up-4/) - RealClimate: A few items of interest this week. Paleoclimate: 1. A new study by Spielhagen and co-authors in Science reconstructs temperatures of North Atlantic source waters to the Arctic for the past two millennia, adding another very long-handled Hockey Stick to the ever-growing league. 2. From last week, an article in Science Express by Buntgen et
- [The obvious answer](https://www.realclimate.org/index.php/archives/2011/01/the-obvious-answer/) - RealClimate: Climate science appears to be just like any other science. At least, this is the conclusion from a fresh publication by Marianne Ryghaug and Tomas Moe Skjølsvold ("The global warming of climate science: Climategate and the construction of scientific facts" in International studies in the philosophy of science). This finding is not news to the
- [Comment policy](https://www.realclimate.org/index.php/archives/2004/12/comment-policy/) - RealClimate: Comments are moderated. Comments are periodically reviewed, but especially at weekends, evenings and holidays, there may be some delay in approving otherwise non-contentious posts. Please be patient. Questions, clarifications and serious rebuttals and discussions are welcomed. Only comments that are germane to the post will be approved. Comments that are "off-topic" should be made on
- [Overheard in the newsroom](https://www.realclimate.org/index.php/archives/2011/01/overheard-in-the-newsroom/) - RealClimate: Reporter doing a phone interview: “Please slow down, professor. You’ve been researching this topic for a decade. I’ve been researching it since lunchtime.” From here (h/t Josh).
- [The Bore Hole](https://www.realclimate.org/index.php/archives/2004/12/the-bore-hole/) - RealClimate: A place for comments that would otherwise disrupt sensible conversations.
- [Reflections on funding panels](https://www.realclimate.org/index.php/archives/2011/01/reflections-on-funding-panels/) - RealClimate: Climate science funding
- [Forbes' rich list of nonsense](https://www.realclimate.org/index.php/archives/2011/01/forbes-rich-list-of-nonsense/) - RealClimate: Larry Bell's rich list of nonsense about climate in Forbes magazine gets fact-checked and is found wanting.
- [Feedback on Cloud Feedback](https://www.realclimate.org/index.php/archives/2010/12/feedback-on-cloud-feedback/) - RealClimate: Guest article by Andrew Dessler I have a paper in this week’s issue of Science on the cloud feedback that may be of interest to realclimate readers. As you may know, clouds are important regulators of the amount of energy in and out of the climate system. Clouds both reflect sunlight back to space and
- [David Archer](https://www.realclimate.org/index.php/archives/2004/12/david-archer/) - RealClimate: David Archer is a computational ocean chemist at the University of Chicago. He has published research on the carbon cycle of the ocean and the sea floor, at present, in the past, and in the future. Dr. Archer has worked on the ongoing mystery of the low atmospheric CO2 concentration during glacial time 20,000 years
- [Blog updates and suggestions](https://www.realclimate.org/index.php/archives/2011/01/blog-updates-and-suggestions/) - RealClimate: New Year, new blog software. You'll notice the new preview function for comments, the AddThis button for distributing our content to your favorite social media sites, and various updates to the plugins and functionality you won't notice at all. This is always a work in progress, so feel free to comment on the blog as
- [Science is self-correcting: Lessons from the arsenic controversy](https://www.realclimate.org/index.php/archives/2010/12/science-is-self-correcting-lessons-from-the-arsenic-controversy/) - RealClimate: Arsenic in DNA, the nature of the scientific debate, how science is self-correcting.
- [Post-holiday round-up](https://www.realclimate.org/index.php/archives/2010/12/post-holiday-round-up/) - RealClimate: What with holiday travel, and various other commitments, we've missed a few interesting stories over the last week or so. First off, AGU has posted highlights from this year's meeting - mainly the keynote lectures, and there are a few interesting presentations for instance from Tim Palmer on how to move climate modelling forward, Ellen
- [On replication](https://www.realclimate.org/index.php/archives/2009/02/on-replication/) - RealClimate: This week has been dominated by questions of replication and of what standards are required to serve the interests of transparency and/or science (not necessarily the same thing). Possibly a recent example of replication would be helpful in showing up some of the real (as opposed to manufactured) issues that arise. The paper I'll discuss
- [Green and Armstrong's scientific forecast](https://www.realclimate.org/index.php/archives/2007/07/green-and-armstrongs-scientific-forecast/) - RealClimate: J. Scott Armstrong and Kesten Green, scientific forecasting of global warming.
- [The AGU Q & A Service--Open for Business](https://www.realclimate.org/index.php/archives/2010/12/the-agu-q-a-service-open-for-business/) - RealClimate: This is just a brief notice for those members of the media who may not be aware of the American Geophysical Union's (AGU) re-vamped question and answer service for climate science questions. There are about 700 participating AGU scientists, with several answering questions at any given time. This service should be highly useful for getting
- [The new post-partisan world](https://www.realclimate.org/index.php/archives/2010/11/the-new-post-partisan-world/) - RealClimate: From Russell Seitz: (with apologies to Jen Sorensen at Slowpoke comics).
- [Sea level rise: The New York Times got the story](https://www.realclimate.org/index.php/archives/2010/11/sea-level-rise-the-new-york-times-got-the-story/) - RealClimate: Yesterday, the New York Times ran an excellent cover story on sea level rise, together with two full pages inside the paper, fancy graphs and great photographs (online version here). The author, Justin Gillis, researched the piece for months, visited Greenland and talked to most of the leading scientists in the field – many of
- [One year later](https://www.realclimate.org/index.php/archives/2010/11/one-year-later/) - RealClimate: Recalling the impact of the climate scientist email hack, 'Climategate', CRU and the RealClimate response.
- [The A-train](https://www.realclimate.org/index.php/archives/2010/11/the-a-train/) - RealClimate: A little behind schedule, I finally found time to read the article in the July 2010 edition of Physics Today "Touring the atmosphere aboard the A-Train" by Tristan S. L’Ecuyer and Jonathan H. Jiang. I think this article is a worth-while read, telling a fascinating story about how new satellite missions lead to greater understanding
- [Global Cooling-Wanna Bet? <lang_sp>Enfriamiento Global, ¿Quieres apostar?</lang_sp><lang_it>Raffreddamento Globale - scommettiamo?</lang_it>](https://www.realclimate.org/index.php/archives/2008/05/global-cooling-wanna-bet/) - RealClimate: By Stefan Rahmstorf, Michael Mann, Ray Bradley, William Connolley, David Archer, and Caspar Ammann Por Stefan Rahmstorf, Michael Mann, Ray Bradley, William Connolley, David Archer y Caspar Ammann (Traducido por Angela Carosio) Dieser Beitrag erscheint zeitgleich auf deutsch auf KlimaLounge Una traduzione in italiano è disponibile qui Global cooling appears to be the “flavour of
- [Warmer and warmer](https://www.realclimate.org/index.php/archives/2010/09/warmer-and-warmer/) - RealClimate: Are the heat waves really getting more extreme? This question popped up after the summer of 2003 in Europe, and yet again after this hot Russian summer. The European Centre for Medium-range Weather Forecasts (ECMWF), which normally doesn't make much noise about climate issues, has since made a statement about July global mean temperature being
- [Science, narrative and heresy](https://www.realclimate.org/index.php/archives/2010/11/science-narrative-and-heresy/) - RealClimate: Recent blog discussions have starkly highlighted the different values and priorities for scientists, bloggers and (some parts) of the mainstream media. For working scientists, the priority in any discussion about science should be accuracy. Methods, results, and interpretations must be clear, logically connected and replicable by others. For people who haven't experienced a joint editing
- [More on feedbacks](https://www.realclimate.org/index.php/archives/2010/11/more-on-feedbacks/) - RealClimate: Guest post by Chris Colose (e-mail: colose-at-wisc.edu) This post is a more technical version of Part 1, meant to quantify and expand upon some of the feedback concepts laid out previously. Additionally, the role of the water vapor feedback in planetary climate is discussed. By convention, climate scientists define a feedback parameter, λ, to encompass
- [MY Review of Books](https://www.realclimate.org/index.php/archives/2006/05/my-review-of-books/) - RealClimate: I've finally got round to reading a number of the many climate change-related books that have been published in recent months. These books seem to have caught the public imagination in ways that are different than in the past, and so it's worth examining how they do. The three I've read are; Eugene Linden's The
- [Climate code archiving: an open and shut case?](https://www.realclimate.org/index.php/archives/2010/10/climate-code-archiving-an-open-and-shut-case/) - RealClimate: How can climate code archiving help the community actually do science?
- [Unforced variations 3](https://www.realclimate.org/index.php/archives/2010/10/unforced-variations-3-2/) - RealClimate: Here's an open thread for various climate science related discussions, to prevent more off-topic clutter everywhere else. We have some good posts coming up, but if you want to discuss something you read in the media, saw in a press release or just wanted to ask about, this is the time. Some interesting things we've
- [Making sense of Greenland's ice](https://www.realclimate.org/index.php/archives/2007/07/making-sense-of-greenlands-ice/) - RealClimate: A widely publicised paper in Science last week discussed the recovery ancient DNA from the base of the Dye-3 ice core (in southern Greenland). This was an impressive technical feat and the DNA recovered may well be the oldest pure DNA ever, dating back maybe half a million years. However much of the press coverage
- [Solar spectral stumper](https://www.realclimate.org/index.php/archives/2010/10/solar-spectral-stumper/) - RealClimate: Solar forcing of climate. SORCE mission, SIM data.
- [False Claims by McIntyre and McKitrick regarding the Mann et al. (1998) reconstruction ](https://www.realclimate.org/index.php/archives/2004/12/false-claims-by-mcintyre-and-mckitrick-regarding-the-mann-et-al-1998reconstruction/) - RealClimate: A number of spurious criticisms regarding the Mann et al (1998) proxy-based temperature reconstruction have been made by two individuals McIntyre and McKitrick ( McIntyre works in the mining industry, while McKitrick is an economist). These criticisms are contained in two manuscripts (McIntyre and McKitrick 2003 and 2004--the latter manuscript was rejected by Nature; both
- [PCA details](https://www.realclimate.org/index.php/archives/2004/11/pca-details/) - RealClimate: PCA of the 70 North American ITRDB Tree-ring Proxy Series used by Mann et al (1998) a. Eigenvalue spectrum for Mann et al (1998) PCA analysis (1902-1980 zero reference period, data normalized by detrended 1902-1980 standard deviation): Rank Explained Variance Cumulative Variance 1 0.3818 0.3818 2 0.0976 0.4795 _______________________________________________ 3 0.0491 0.5286 4 0.0354 0.5640
- [Cuccinelli goes fishing again](https://www.realclimate.org/index.php/archives/2010/10/cuccinelli-goes-fishing-again/) - RealClimate: Cuccinelli witch hunts and abuse of power against UVa
- [Happy 35th birthday, global warming!](https://www.realclimate.org/index.php/archives/2010/07/happy-35th-birthday-global-warming/) - RealClimate: Global warming is turning 35! Not only has the current spate of global warming been going on for about 35 years now, but also the term “global warming” will have its 35th anniversary next week. On 8 August 1975, Wally Broecker published his paper “Are we on the brink of a pronounced global warming?” in
- [The Key to the Secrets of the Troposphere](https://www.realclimate.org/index.php/archives/2010/08/the-key-to-the-secrets-of-the-troposphere/) - RealClimate: Update: It seems that the UNFCCC background page referred to below has changed and the link no longer works - see table of contents. A response from Justin Wood, writing to me from Australia after my previous post (cited with permission below), has prompted me to write a follow-up on the story of the greenhouse
- [Younger Dry-as dust?](https://www.realclimate.org/index.php/archives/2007/10/younger-dry-as-dust/) - RealClimate: The Younger Dryas is so called because it corresponds, in the pollen record from Europe, to the latest (i.e. youngest) appearance of the Dryas octopetala pollen, an alpine flower in regions that are now far from alpine. It marks a clear period towards the end of the last ice age when the warming trend of
- [IPCC report card](https://www.realclimate.org/index.php/archives/2010/08/ipcc-report-card/) - RealClimate: Update: Nature has just published a thoughtful commentary on the report The Inter-Academy Council report on the processes and governance of the IPCC is now available. It appears mostly sensible and has a lot of useful things to say about improving IPCC processes - from suggesting a new Executive to be able to speak for
- [An icy retreat](https://www.realclimate.org/index.php/archives/2010/07/an-icy-retreat/) - RealClimate: Guest Commentary by Dirk Notz, MPI Hamburg It's almost routine by now: Every summer, many of those interested in climate change check again and again the latest data on sea-ice evolution in the Arctic. Such data are for example available on a daily basis from the US National Snow and Ice Data Center. And again
- [Doing it yourselves](https://www.realclimate.org/index.php/archives/2010/08/doing-it-yourselves/) - RealClimate: Surface temperature data sets, surfactemperatures.org, Hadley, Broberg, GSOD, McShane and Wyner, paleoclimate reconstructions, BAMS State of the Climate 2009
- [The Montford Delusion](https://www.realclimate.org/index.php/archives/2010/07/the-montford-delusion/) - RealClimate: Guest commentary by Tamino Update: Another review of the book has been published by Alistair McIntosh in the Scottish Review of Books (scroll down about 25% through the page to find McIintosh's review) Update #2 (8/19/10): The Guardian has now weighed in as well. If you don't know much about climate science, or about the
- [Monckton makes it up](https://www.realclimate.org/index.php/archives/2010/08/monckton-makes-it-up/) - RealClimate: Christopher Monckton, Lord Monckton, Viscount of Brenchley, making stuff up.
- [Expert Credibility in Climate Change - Responses to Comments](https://www.realclimate.org/index.php/archives/2010/08/expert-credibility-in-climate-change-responses-to-comments/) - RealClimate: Expert credibility in climate science, consensus and the Anderegg PNAS study
- [Global cooling, again](https://www.realclimate.org/index.php/archives/2006/10/global-cooling-again/) - RealClimate: The ice age is coming, the sun’s zooming in / Engines stop running and the wheat is growing thin /A nuclear error, but I have no fear /’Cause London is drowning, and I live by the river (chorus from London's Calling, by Strummer/Jones, 1979). These lines rather sum up the confused media response in the
- [On attribution](https://www.realclimate.org/index.php/archives/2010/05/on-attribution/) - RealClimate: Attribution of climate change, volcanoes, greenhouse gases and the need for models.
- [Why the continued interest?](https://www.realclimate.org/index.php/archives/2009/10/why-the-continued-interest/) - RealClimate: I believe the idea that galactic cosmic rays (GCR) play a role for the present global warming is unlikely to fade soon, despite a growing number of scientific arguments that normally would falsify a hypothesis and lay it dead (see links here and here). Despite all the arguments against the role of GCR, there was
- [Why Levitt and Dubner like geo-engineering and why they are wrong](https://www.realclimate.org/index.php/archives/2009/10/why-levitt-and-dubner-like-geo-engineering-and-why-they-are-wrong/) - RealClimate: A review of the science of geoengineering featured in Superfreakonomics by Levitt and Dubner
- [Climate Cover-Up: A (Brief) Review](https://www.realclimate.org/index.php/archives/2009/10/climate-cover-up-a-brief-review/) - RealClimate: We often allude to the industry-funded attacks against climate change science, and the dubious cast of characters involved, here at RealClimate. In recent years, for example, we've commented on disinformation efforts by industry front groups such as the "Competitive Enterprise Institute, the Cato Institute, the Fraser Institute, and a personal favorite, The Heartland Institute, and
- [350](https://www.realclimate.org/index.php/archives/2009/10/350/) - RealClimate: I was quoted by Andrew Revkin in the New York Times on Sunday in a piece about the 350.org International Day of Climate Action (involving events in 181 countries). The relevant bit is: Gavin A. Schmidt, a climate scientist who works with Dr. Hansen and manages a popular blog on climate science, realclimate.org, said those
- [An open letter to Steve Levitt](https://www.realclimate.org/index.php/archives/2009/10/an-open-letter-to-steve-levitt/) - RealClimate: Dear Mr. Levitt, The problem of global warming is so big that solving it will require creative thinking from many disciplines. Economists have much to contribute to this effort, particularly with regard to the question of how various means of putting a price on carbon emissions may alter human behavior. Some of the lines of
- [Muddying the peer-reviewed literature](https://www.realclimate.org/index.php/archives/2009/11/muddying-the-peer-reviewed-literature/) - RealClimate: We've often discussed the how's and why's of correcting incorrect information that is occasionally found in the peer-reviewed literature. There are multiple recent instances of heavily-promoted papers that contained fundamental flaws that were addressed both on blogs and in submitted comments or follow-up papers (e.g. McLean et al, Douglass et al., Schwartz). Each of those
- [It's all about me (thane)!](https://www.realclimate.org/index.php/archives/2009/11/its-all-about-me-thane/) - RealClimate: The impact of indirect impacts of methane emissions on ozone, aerosols and stratospheric water vapour increase the historical attribution of climate forcing to methane, but CO2 is still the dominant forcing and will continue to be for many decades.
- [A Treeline Story](https://www.realclimate.org/index.php/archives/2009/11/a-treeline-story/) - RealClimate: Some of the highest growing trees in the world are also the oldest—bristlecone pines (Pinus longaeva) from the Great Basin in the western United States (eastern California, Nevada and Utah). The oldest example is more than 4800 years old. Because of their longevity and growth at high elevations (where the growth of trees is generally
- [A problem of multiplicity](https://www.realclimate.org/index.php/archives/2009/11/a-problem-of-multiplicity/) - RealClimate: One thing a scientist doesn't want to mess up is the problem of multiplicity (also known as 'field significance'). It's just like rolling a die 600 times, and then getting excited about getting roughly 100 sixes. However, sometimes it's much more subtle than just rolling dice. This problem seems to be an issue in a
- [An offering](https://www.realclimate.org/index.php/archives/2009/11/an-offering/) - RealClimate: I video-taped and posted all the lectures from my Global Warming class this quarter. The class is part of our core science curriculum for non-science majors at the University of Chicago, and interest has been strong enough that the class has kind of taken over my teaching life. The lectures are based on my textbook,
- [Where's the data?](https://www.realclimate.org/index.php/archives/2009/11/wheres-the-data/) - RealClimate: Much of the discussion in recent days has been motivated by the idea that climate science is somehow unfairly restricting access to raw data upon which scientific conclusions are based. This is a powerful meme and one that has clear resonance far beyond the people who are actually interested in analysing data themselves. However, many
- [Something Is X in the State of Denmark](https://www.realclimate.org/index.php/archives/2009/11/something-is-x-in-the-state-of-denmark/) - RealClimate: We received a letter with the title 'Climate Change: The Role of Flawed Science' which may be of interest to the wider readership. The author, Peter Laut, is Professor (emeritus) of physics at The Technical University of Denmark and former scientific advisor on climate change for The Danish Energy Agency. He has long been a
- [CRU Hack: More context](https://www.realclimate.org/index.php/archives/2009/12/cru-hack-more-context/) - RealClimate: Continuation of the older threads. Please scan those (even briefly) to see whether your point has already been dealt with. Let me know if there is something worth pulling from the comments to the main post. In the meantime, read about why peer-review is a necessary but not sufficient condition for science to be worth
- [Unsettled Science](https://www.realclimate.org/index.php/archives/2009/12/unsettled-science/) - RealClimate: Unusually, I'm in complete agreement with a recent headline on the Wall Street Journal op-ed page: "The Climate Science Isn't Settled" The article below is the same mix of innuendo and misrepresentation that its author normally writes, but the headline is correct. The WSJ seems to think that the headline is some terribly important pronouncement
- [AGU Fall 2009](https://www.realclimate.org/index.php/archives/2009/12/agu-fall-2009/) - RealClimate: 16,000 attendees, thousands of cups of coffee and thousands of interesting conversations (and debates) about science. That would be San Francisco, not Copenhagen of course. There are a few of the RC crew there, so hopefully we'll get some updates, but keep track of some other attending bloggers as well: Michael Tobis Steve Easterbrook Update:
- [Please, show us your code](https://www.realclimate.org/index.php/archives/2009/12/please-show-us-your-code/) - RealClimate: The 1991 Science paper by Friis-Christensen & Lassen, work by Henrik Svensmark (Physical Review Letters), and calculations done by Scafetta & West (in the journals Geophysical Research Letters, Journal of Geophysical Research, and Physics Today) have inspired the idea that the recent warming is due to changes in the sun, rather than greenhouse gases. We
- [Unforced variations 2](https://www.realclimate.org/index.php/archives/2010/01/unforced-variations-2/) - RealClimate: Open thread on climate science issues. Knorr 2009 CO2 airborne fraction changes, John Coleman, KUSI, NCDC and NASA 'manipulation' of temperature data
- [The carbon dioxide theory of Gilbert Plass](https://www.realclimate.org/index.php/archives/2010/01/the-carbon-dioxide-theory-of-gilbert-plass/) - RealClimate: Gilbert Plass, Lewis Kaplan, the history of the "carbon dioxide theory", climate sensitivity and how well it stands up 50 years later.
- [First published response to Lindzen and Choi](https://www.realclimate.org/index.php/archives/2010/01/first-published-response-to-lindzen-and-choi/) - RealClimate: Lindzen and Choi, Trenberth, Fasullo, O'Dell and Wong, climate sensitivity and how the scientific literature deals with anomalies.
- [L&C, GRL, comments on peer review and peer-reviewed comments](https://www.realclimate.org/index.php/archives/2010/01/lc-grl-comments-on-peer-review-and-peer-reviewed-comments/) - RealClimate: Lindzen and Choi (2009), GRL, peer review
- [2009 temperatures by Jim Hansen](https://www.realclimate.org/index.php/archives/2010/01/2009-temperatures-by-jim-hansen/) - RealClimate: Jim Hansen, 2009 temperature summary, GISTEMP, HadCRUT, Arctic Oscillation, El Niño, global warming, and the difference between weather and climate
- [The IPCC is not infallible (shock!)](https://www.realclimate.org/index.php/archives/2010/01/the-ipcc-is-not-infallible-shock/) - RealClimate: Like all human endeavours, the IPCC is not perfect. Despite the enormous efforts devoted to producing its reports with the multiple levels of peer review, some errors will sneak through. Most of these will be minor and inconsequential, but sometimes they might be more substantive. As many people are aware (and as John Nieslen-Gammon outlined
- [The wisdom of Solomon](https://www.realclimate.org/index.php/archives/2010/01/the-wisdom-of-solomon/) - RealClimate: Solomon et al, Science express, stratospheric water vapour
- [IPCC errors: facts and spin](https://www.realclimate.org/index.php/archives/2010/02/ipcc-errors-facts-and-spin/) - RealClimate: IPCC AR4 errors, glaciergate, amazongate
- [Daily Mangle](https://www.realclimate.org/index.php/archives/2010/02/daily-mangle/) - RealClimate: Yesterday, the Daily Mail of the UK published a predictably inaccurate article entitled "Climategate U-turn as scientist at centre of row admits: There has been no global warming since 1995". The title itself is a distortion of what Jones actually said in an interview with the BBC. What Jones actually said is that, while the
- [Throw your iPhone into the climate debate](https://www.realclimate.org/index.php/archives/2010/02/throw-your-iphone-into-the-climate-debate/) - RealClimate: Who says that the climate debate is not evolving? According to the daily newspaper the Guardian, a new application ('app') has been written for iPhones that provides a list of climate dissidents' arguments, and counter arguments based on more legitimate scientific substance. The app is developed by John Cook from 'Skeptical Science'. It's apparently enough
- [Close Encounters of the Absurd Kind](https://www.realclimate.org/index.php/archives/2010/02/close-encounters-of-the-absurd-kind/) - RealClimate: Ben Santer, IPCC, SAR, Chapter 8, discernible influence, "scientific cleasning", Guardian, Fred Pearce, Douglass and Christy
- [A mistaken message from IoP?](https://www.realclimate.org/index.php/archives/2010/03/a-mistaken-message-from-iop/) - RealClimate: Institute of Physics, CRU inquiry, transparency
- [More on sun-climate relations](https://www.realclimate.org/index.php/archives/2010/03/more-on-sun-climate-relations/) - RealClimate: Four new papers discuss the relatiosnhip between solar activity and climate: one by Judith Lean (2010) in WIREs Climate Change, a GRL paper by Calogovic et al. (2010), Kulmala et al. (2010), and an on-line preprint by Feulner and Rahmstorf (2010). They all look at different aspects of how changes in solar activity may influence
- [Sealevelgate](https://www.realclimate.org/index.php/archives/2010/03/ippc-sealevel-gate/) - RealClimate: Imagine this. In its latest report, the IPCC has predicted up to 3 meters of sea level rise by the end of this century. But “climate sceptics” websites were quick to reveal a few problems (or “tricks”, as they called it). First, although the temperature scenarios of IPCC project a maximum warming of 6.4 ºC
- [Why we bother](https://www.realclimate.org/index.php/archives/2010/03/why-we-bother/) - RealClimate: A letter from a reader (reproduced with permission): Dear RealClimate team: I have a background in biology and studied at post-grad level in the area of philosophy of science. For the last few years, I have been working on a book about the logic of argument used in debates between creationists and evolutionists. About a
- [Unforced variations 3](https://www.realclimate.org/index.php/archives/2010/03/unforced-variations-3/) - RealClimate: Another open thread. OT comments from the Amazon drying thread have been moved over. As usual, substantive comments only please and no abuse.
- [The Guardian responds](https://www.realclimate.org/index.php/archives/2010/03/the-guardian-responds/) - RealClimate: Guardian, "climategate", hacked emails, Realclimate, Gavin Schmidt, Fred Pearce
- [First CRU inquiry report released](https://www.realclimate.org/index.php/archives/2010/03/first-cru-inquiry-report-released/) - RealClimate: UK Parliamentary Select Committee, climategate, phil jones
- [Climate and network connections](https://www.realclimate.org/index.php/archives/2010/04/climate-and-network-connections/) - RealClimate: by Rasmus & Jim Who would think that Internet, ideas, disease, money, birds, and climate literacy have anything in common? Recent progress on complex systems and network theory suggests that they all can be described in terms of a 'Levy flight'. A recent and lengthy paper with the title 'A study on interconnections between climate
- [Science Story: the Making of a Sea Level Study](https://www.realclimate.org/index.php/archives/2010/04/science-story-the-making-of-a-sea-level-study/) - RealClimate: Sea level rise, semi-empirical models, peer review, Vermeer and Rahmstorf, getting published
- [Climate scientist bashing](https://www.realclimate.org/index.php/archives/2010/04/climate-scientist-bashing/) - RealClimate: A new popular sport in some media these days is “climate scientist bashing”. Instead of dealing soberly with the climate problem they prefer to attack climate scientists, i.e. the bearers of bad news. The German magazine DER SPIEGEL has played this game last week under the suggestive heading “Die Wolkenschieber” – which literally translated can
- [Krugman weighs in](https://www.realclimate.org/index.php/archives/2010/04/krugman-weighs-in/) - RealClimate: After weeks and months of press coverage seemingly Through the Looking Glass, Paul Krugman has sent us a breath of fresh air this morning in the New York Times Magazine, entitled "Building a Green Economy". Krugman now joins fellow NYT columnist Tom Friedman as required reading in my Global Warming for English Majors class at
- [Second CRU inquiry reports](https://www.realclimate.org/index.php/archives/2010/04/second-cru-inquiry-reports/) - RealClimate: The Oxburgh report on the science done at the CRU has now been published and..... as in the first inquiry, they find no scientific misconduct, no impropriety and no tailoring of the results to a preconceived agenda, though they do suggest more statisticians should have been involved. They have also some choice words to describe
- [Claude Allègre: The Climate Imposter](https://www.realclimate.org/index.php/archives/2010/04/claude-allegre-the-climate-imposter/) - RealClimate: Guest Commentary by Georg Hoffmann In mathematical proofs, it's a well-known fact that if at some point you divide by zero accidentally or on purpose, then you end up being able to prove absolutely anything you want - for instance, that 2+2=5 or that 1+1=0. The same phenomena appears to govern any number of publications
- [Solar](https://www.realclimate.org/index.php/archives/2010/05/solar/) - RealClimate: The new novel Solar by Ian McEwan, Britain’s “national author” (as many call him) tackles the issue of climate change. I should perhaps start my review with a disclosure: I’m a long-standing fan of McEwan and have read all of his novels, and I am also mentioned in the acknowledgements of Solar. I met McEwan
- [What we can learn from studying the last millennium (or so)](https://www.realclimate.org/index.php/archives/2010/05/what-we-can-learn-from-studying-the-last-millennium-or-so/) - RealClimate: With all of the emphasis that is often placed on hemispheric or global mean temperature trends during the past millennium, and the context they provide for interpreting modern warming trends, one thing is often lost in the discussion: space matters as much as time. Indeed, it is likely that the regional patterns of past climate
- [Climate Change Commitment II](https://www.realclimate.org/index.php/archives/2010/06/climate-change-commitment-ii/) - RealClimate: Climate change commitment, zero emissions, short-lived climate forcings, CO2 and other GHGs
- [A conclusion of the 4th International Polar Year](https://www.realclimate.org/index.php/archives/2010/06/a-conclusion-of-the-4th-international-polar-year/) - RealClimate: This week, the "Oslo Science conference" the largest conference ever -it was claimed - was held on polar sciences at Lillestrøm, just outside Oslo. Some of the web-casts from that meeting are worth watching, and I found especially the talk by David Barber ("On Thin Ice: The Arctic and Climate Change", video link here) both
- [Atlantic Tropical Cyclone Records – Trends and Ephemerality](https://www.realclimate.org/index.php/archives/2010/06/atlantic-tropical-cyclone-records-trends-and-ephemerality/) - RealClimate: Guest Commentary from Urs Neu To understand the influence of climate change on tropical cyclone and hurricane activity, it is crucial to know how this activity has varied in the past. There have been a number of interesting new studies of Atlantic tropical cyclones (TCs) and hurricanes (tropical cyclones with maximum sustained winds exceeding 74
- [Five Thousand Gulf Oil Spills](https://www.realclimate.org/index.php/archives/2010/06/five-thousand-gulf-oil-spills/) - RealClimate: That’s the rate that people are releasing carbon to the atmosphere from fossil fuel combustion and deforestation today. I know, it’s apples and oranges; carbon in the form of oil is more immediately toxic to the environment than it is as CO2 (although CO2 may be more damaging on geologic time scales). But think of
- [Leakegate: A retraction](https://www.realclimate.org/index.php/archives/2010/06/leakegate-a-retraction/) - RealClimate: Amazongate retraction, Jonathan Leake, Simon Lewis, IPCC
- [What do climate scientists think?](https://www.realclimate.org/index.php/archives/2010/06/what-do-climate-scientists-think/) - RealClimate: by Gavin and Eric. ... and why does it matter? Una traducción en español está disponible aquí. There is a lot of discussion this week about a new paper in PNAS (Anderegg et al, 2010) that tries to assess the credibility of scientists who have made public declarations about policy directions. This come from a
- [A Eulogy to Stephen Schneider](https://www.realclimate.org/index.php/archives/2010/07/a-eulogy-to-stephen-schneider/) - RealClimate: We were greatly saddened to learn that our revered colleague Stephen Schneider passed away this morning. We are posting a personal account by Ben Santer of Steve's amazing accomplishments and contributions. Ben's account provides a glimpse into what made Steve so special, and why he will be so deeply missed: Today the world lost a
- [A simple recipe for GHE](https://www.realclimate.org/index.php/archives/2010/07/a-simple-recipe-for-ghe/) - RealClimate: According to some recent reports (e.g. PlanetArk; The Guardian), the public concern about global warming may be declining. It's not clear whether this is actually true: a poll conducted by researchers at Stanford suggests otherwise. In any case, the science behind climate change has not changed (also see America's Climate Choices), but there certainly remains
- [Information levels](https://www.realclimate.org/index.php/archives/2010/07/information-levels/) - RealClimate: Rasmus' recent post on the greenhouse effect raised some interesting points concerning the technical level at which posts or other public communications should be written. This was a relatively technical article as these things go, eschewing the very basic 'the greenhouse effect is like a blanket' but not really approaching the level of a technical
- [The Muir Russell report](https://www.realclimate.org/index.php/archives/2010/07/the-muir-russell-report/) - RealClimate: Muir-Russell report, climategate, climate science emails and the exoneration of the Phil Jones and the other scientists at CRU.
- [Penn State reports ](https://www.realclimate.org/index.php/archives/2010/07/penn-state-reports/) - RealClimate: The last part of the Penn State inquiry has now reported unanimously that Mike Mann did not engage in any activity that violated scientific norms. Quoting from the report conclusions, Conclusion of the Investigatory Committee as to whether research misconduct occurred: The Investigatory Committee, after careful review of all available evidence, determined that there is
- [The uncertainty prayer](https://www.realclimate.org/index.php/archives/2010/06/the-uncertainty-prayer/) - RealClimate: Seen at a meeting yesterday: Grant us... The ability to reduce the uncertainties we can; The willingness to work with the uncertainties we cannot; And the scientific knowledge to know the difference. (Drawn from a white paper on the use of climate models for water managers). Discuss.
- [Groundhog Day](https://www.realclimate.org/index.php/archives/2006/02/groundhog-day/) - RealClimate: Living in central Pennsylvania, it would seem remiss of me not to comment on Groundhog Day today. For those not familiar with the event, Groundhog Day, which takes place on February 2 every year, is the modern American version of an age-old tradition originating in Europe centuries ago. The modern Groundhog Day is celebrated in
- [11ºC warming, climate crisis in 10 years? <lang_fr>11ºC de réchauffement, une crise climatique dans 10 ans ?</lang_fr>](https://www.realclimate.org/index.php/archives/2005/01/climatepredictionnet-climate-challenges-and-climate-sensitivity/) - RealClimate: by Gavin Schmidt and Stefan Rahmstorf Two stories this week, a paper in Nature (Stainforth et al, 2005) describing preliminary results of the climateprediction.net experiments, and the Meeting the Climate Challenge report from a high level political group have lead to dramatic headlines. On the Nature paper, BBC online reported that "temperatures around the world
- [Strange Bedfellows <lang_fr>En Etrange Compagnie</lang_fr>](https://www.realclimate.org/index.php/archives/2005/02/strange-bedfellows/) - RealClimate: Here's a curious observation. Some commentators who for years have been vocally decrying the IPCC consensus are lining up to support the 'Ruddiman' hypothesis. A respected paleoceanographer, Bill Ruddiman has recently argued that humans have been altering the level of important greenhouse gases since the dawn of agriculture (5 to 8000 years ago), and in
- [<i>The Economist</i> does not disappoint](https://www.realclimate.org/index.php/archives/2010/04/the-economist-does-not-disappoint/) - RealClimate: The March 20th -26th cover story of The Economist, "Spin, science and climate change," deftly bypasses the politics surrounding ‘climategate’, to tackle the more important issue: whether any of this has any bearing on climate change science and policy. This is a refreshing bit of journalism that everyone should read. It is no secret that
- [Up is Down, Brown is Green (with apologies to Orwell)](https://www.realclimate.org/index.php/archives/2010/03/up-is-down-brown-is-green-with-apologies-to-orwell/) - RealClimate: In the alternate universe of Fox News, Anthony Watts, and many others, up is down. Now, it appears, brown is green. Following the total confusion over the retraction of a paper on sea level, claims of another "mistake" by the IPCC are making the rounds of the blogosphere. This time, the issue is the impact
- [Saleska Responds (<font color = 'green'>green</font> is <font color = 'green'>green</font>)](https://www.realclimate.org/index.php/archives/2010/03/saleska-responds-green-is-green/) - RealClimate: In a recent post here at RealClimate, Simon Lewis wrote regarding a 2010 paper by Samanta et al. on the effect of single-year drought conditions on the Amazon. Samanta et al. claimed to have contradicted a 2007 paper by Scott Saleska et al., and to have thereby overturned some IPCC conclusions. Lewis showed why Samanta’s
- [How not to attribute climate change](https://www.realclimate.org/index.php/archives/2006/10/how-not-to-attribute-climate-change/) - RealClimate: In an earlier post, we discussed a review article by Frohlich et al. on solar activity and its relationship with our climate. We thought that paper was quite sound. This September saw a new article in the Geophysical Research Letters with the title «Phenomenological solar signature in 400 years of reconstructed Northern Hemisphere temperature record»
- [Moberg et al: Highly variable Northern Hemisphere temperatures?     <lang_fr>Moberg et coll. : une plus grande variabilité climatique passée dans l'Hémisphere Nord ?</lang_fr>](https://www.realclimate.org/index.php/archives/2005/02/moberg-et-al-highly-variable-northern-hemisphere-temperatures/) - RealClimate: by William Connolley and Eric Steig The 10th Feb edition of Nature has a nice paper "Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data" by Anders Moberg, DM. Sonechkin, K Holmgren, NM Datsenko, & W Karlin (doi:10.1038/nature03265). This paper takes a novel approach to the problem of reconstructing past temperatures from
- [Global warming on Mars? <lang_fr>Réchauffement global sur Mars ? </lang_fr>](https://www.realclimate.org/index.php/archives/2005/10/global-warming-on-mars/) - RealClimate: Guest contribution by Steinn Sigurdsson. Recently, there have been some suggestions that "global warming" has been observed on Mars (e.g. here). These are based on observations of regional change around the South Polar Cap, but seem to have been extended into a "global" change, and used by some to infer an external common mechanism for
- [Tropical Glacier Retreat](https://www.realclimate.org/index.php/archives/2005/05/tropical-glacier-retreat/) - RealClimate: In a previous post entitled Worldwide Glacier Retreat, we highlighted the results of a study by J. Oerlemans, who compiled glacier data from around the world and used them to estimate temperature change over the last ~400 years. A question that arose in subsequent online discussion was to what extent Oerlemans had relied on glaciers
- [Aerosol effects and climate, Part II: the role of nucleation and cosmic rays](https://www.realclimate.org/index.php/archives/2009/04/aerosol-effects-and-climate-part-ii-the-role-of-nucleation-and-cosmic-rays/) - RealClimate: Guest post by Bart Verheggen, Department of Air Quality and Climate Change , Energy research Institute of the Netherlands (ECN) In Part I, I discussed how aerosols nucleate and grow. In this post I'll discuss how changes in nucleation and ionization might impact the net effects. Cosmic rays Galactic cosmic rays (GCR) are energetic particles
- [Who you gonna call?](https://www.realclimate.org/index.php/archives/2009/12/who-you-gonna-call/) - RealClimate: The problem of ‘false balance’ in reporting -- the distortions that can result from trying give equal time to the two perceived sides of an issue -- is well known. In an excellent editorial a few years ago, the Seattle Post-Intelligencer called for a greater emphasis on truth, rather than 'balance'. Unfortunately, this basic element
- [The CRU hack: Context](https://www.realclimate.org/index.php/archives/2009/11/the-cru-hack-context/) - RealClimate: CRU hack, "climategate" context, fudge factors, Kevin Trenberth travesty, Wigley, hide the decline, Mann's Nature trick, UEA emails, Climate Research, Soon and Baliunas, peer-review
- [Transparency of the IPCC process](https://www.realclimate.org/index.php/archives/2007/08/transparency-of-the-ipcc-process-2/) - RealClimate: Recently, a Financial Times op-ed criticised the IPCC for having contributors and peers drawn from a narrow professional circle. I don't think this is fair, unless one regards a whole discipline as 'narrow'. Furthermore, recent public disclosure of both comments and response suggests a different story to the allegations in the FT op-ed of 'refusing
- [Jim Hansen's opinion](https://www.realclimate.org/index.php/archives/2009/12/jim-hansens-opinion/) - RealClimate: Several people have written saying that it would be useful to have an expert opinion on the state of the surface temperature data from someone other than RealClimate members. Here you go: TemperatureOfScience.pdf You don't get more expert than Jim Hansen. Una traducción está disponible aquí
- [Unforced variations](https://www.realclimate.org/index.php/archives/2009/12/unforced-variations/) - RealClimate: Open thread for various climate science-related discussions. Suggestions for potential future posts are welcome. (Continued here).
- [Just what is this Consensus anyway? <lang_fr>En quoi consiste le "Consensus" ?</lang_fr>](https://www.realclimate.org/index.php/archives/2004/12/just-what-is-this-consensus-anyway/) - RealClimate: We've used the term "consensus" here a bit recently, without ever really defining what we mean by it. In normal practice, there is no great need to define it - no science depends on it. But its useful to record the core that most scientists agree on, for public presentation. The consensus that exists is that of the IPCC reports, in particular the working group I report
- [Kim Cobb's view](https://www.realclimate.org/index.php/archives/2009/12/kim-cobbs-view/) - RealClimate: Guest Commentary: An Open Essay on “ClimateGate" Kim Cobb, Georgia Tech Since the widespread distribution of stolen e-mails originating from the University of East Anglia, I have become increasingly distressed by the way that the internet and media machinery has digested their content. As a climate scientist, I have always been sensitive to the direction
- [More independent views: Myles Allen and Ben Santer](https://www.realclimate.org/index.php/archives/2009/12/more-independent-views-myles-allen-and-ben-santer/) - RealClimate: Three more commentaries by experts not associated with RealClimate. Ben Santer, Lawrence Livermore National Laboratory Ben Santer again Myles Allen, University of Oxford It's worth noting that Allen has published commentary that is critical of RealClimate. Comments on this should be posted under the Hansen post.
- [Friday roundup](https://www.realclimate.org/index.php/archives/2007/07/friday-roundup/) - RealClimate: An eclectic round-up of the week's climate science happenings (and an effort to keep specific threads clear of clutter). It's the sun! (not) As regular readers here will know, the big problem for blaming the sun for the recent global warming is that there hasn't been a trend in any index of solar activity since
- [The CRU hack](https://www.realclimate.org/index.php/archives/2009/11/the-cru-hack/) - RealClimate: As many of you will be aware, a large number of emails from the Climatic Research Unit (CRU) at the University of East Anglia webmail server were hacked recently (Despite some confusion generated by Anthony Watts, this has absolutely nothing to do with the Hadley Centre which is a completely separate institution). As people are
- [The Guardian's Editorial](https://www.realclimate.org/index.php/archives/2009/12/the-guardians-editorial/) - RealClimate: The following editorial was published today by 56 newspapers around the world in 20 languages including Chinese, Arabic and Russian. The text was drafted by a Guardian team during more than a month of consultations with editors from more than 20 of the papers involved. Like The Guardian most of the newspapers have taken the
- [Greenspan, Einstein and Reich <lang_fr>Greenspan, Einstein et Reich</lang_fr>](https://www.realclimate.org/index.php/archives/2008/10/greenspan-einstein-and-reich/) - RealClimate: Les lettres que je reçois vont de l'affirmation amusante que nous ignorons des changements du champ magnétique aux histoires abracadabrantes à propos du “poids“ du dioxide de carbone qui le retiendrait "près du sol". Si l'auteur semble sérieux, alors je le traite sérieusement et tente de lui offrir une réponse utile. Bien souvent, par contre,
- [The CO<sub>2</sub> problem in 6 easy steps](https://www.realclimate.org/index.php/archives/2007/08/the-co2-problem-in-6-easy-steps/) - RealClimate: We often get requests to provide an easy-to-understand explanation for why increasing CO2 is a significant problem without relying on climate models and we are generally happy to oblige. The explanation has a number of separate steps which tend to sometimes get confused and so we will try to break it down carefully. Step 1:
- [Copenhagen](https://www.realclimate.org/index.php/archives/2009/11/copenhagen/) - RealClimate: Nov. 24th, 2009 The 'Copenhagen Diagnosis', a report by 26 scientists from around the world was released today. The report is intended as an update to the IPCC 2007 Working Group 1 report. Like the IPCC report, everything in the Copenhagen Diagnosis is from the peer-reviewed literature, so there is nothing really new. But the
- [Is Pine Island Glacier the Weak Underbelly of the West Antarctic Ice Sheet?  ](https://www.realclimate.org/index.php/archives/2009/11/is-pine-island-glacier-the-weak-underbelly-of-the-west-antarctic-ice-sheet/) - RealClimate: Guest post by Mauri Pelto It is popularly understood that glaciologists consider West Antarctica the biggest source of uncertainty in sea level projections. The base of the 3000-m thick West Antarctic Ice Sheet (WAIS) - unlike the much larger East Antarctic Ice Sheet - lies below sea level, and it has been recognized for a
- [Putting the recent Antarctic snowmelt minimum into context](https://www.realclimate.org/index.php/archives/2009/10/putting-the-recent-antarctic-snowmelt-minimum-into-context/) - RealClimate: Guest Commentary by Andrew Monaghan and Marco Tedesco Our study published in mid October in Geophysical Research Letters (Tedesco and Monaghan, 2009) documents record minimum snowmelt for Antarctica during austral summer 2008-2009 and lower-than-normal melt for several recent years, based on a 30-year satellite microwave record. Numerous blogs have cited the results as a challenge
- [A biased economic analysis of geoengineering](https://www.realclimate.org/index.php/archives/2009/08/a-biased-economic-analysis-of-geoengineering/) - RealClimate: Guest commentary by Alan Robock - Rutgers University Bjorn Lomborg’s Climate Consensus Center just released an un-refereed report on geoengineering, An Analysis of Climate Engineering as a Response to Global Warming, by J Eric Bickel and Lee Lane. The “consensus” in the title of Lomborg's center is based on a meeting of 50 economists last
- [Ups and downs of sea level projections](https://www.realclimate.org/index.php/archives/2009/08/ups-and-downs-of-sea-level-projections/) - RealClimate: By Stefan Rahmstorf and Martin Vermeer The scientific sea level discussion has moved a long way since the last IPCC report was published in 2007 (see our post back then). The Copenhagen Synthesis Report recently concluded that “The updated estimates of the future global mean sea level rise are about double the IPCC projections from
- [Climate Services](https://www.realclimate.org/index.php/archives/2009/09/climate-services/) - RealClimate: I recently attended the World Climate Conference-3 (WCC-3), hosted by the World Meteorological Organization (WMO) in Geneva. Most of the talk was of providing "climate services" (CS) and coordinating these globally. But what are climate services, and how much of what was envisaged is scientifically doable? Climate services is a fairly new term that involves
- [Communicating Science: Not Just Talking the Talk](https://www.realclimate.org/index.php/archives/2009/09/communicating-science-not-just-talking-the-talk/) - RealClimate: Reviews of 'Don't be such a scientist' by Randy Olson, Greg Craven's "What's the worst that can happen?" and the prospects for more media-savvy scientists.
- [Decadal predictions](https://www.realclimate.org/index.php/archives/2009/09/decadal-predictions/) - RealClimate: Decadal predictions of climate based on assimilated ocean initial conditions may help reduce uncertainty in climate forecasts, but how do they really work and do they justify the hype?
- [Past reconstructions: problems, pitfalls and progress](https://www.realclimate.org/index.php/archives/2007/12/past-reconstructions/) - RealClimate: Many people hold the mistaken belief that reconstructions of past climate are the sole evidence for current and future climate change. They are not. However, they are very interesting and useful for all sorts of reasons: for modellers to test out theories of climate change, for geographers, archaeologists and historians to examine the impact of
- [Resolving technical issues in science](https://www.realclimate.org/index.php/archives/2009/08/resolving-technical-issues-in-science/) - RealClimate: One of the strengths of science is its capacity to resolve controversies by generally accepted procedures and standards. Many scientific questions (especially more technical ones) are not matters of opinion but have a correct answer. Scientists document their procedures and findings in the peer-reviewed literature in such a way that they can be double-checked and
- [The Global Cooling Bet - Part 2 <lang_sp>Apuesta al Enfriamiento Global – Segunda Parte</lang_sp><lang_it>La scommessa sul raffreddamento globale - II parte</lang_it>](https://www.realclimate.org/index.php/archives/2008/05/the-global-cooling-bet-part-2/) - RealClimate: Last week we proposed a bet against the "pause in global warming" forecast in Nature by Keenlyside et al. and we promised to present our scientific case later - so here it is. Una traduzione in italiano è disponibile qui Dieser Beitrag erscheint zeitgleich auf deutsch auf Klimalounge Traducido por Angela Carosio La semana pasada
- [PETM Weirdness](https://www.realclimate.org/index.php/archives/2009/08/petm-weirdness/) - RealClimate: Paleocene-Eocene thermal maximum, climate sensitivity, PETM, Earth System Sensitivity, methane hydrates, climate models.
- [Still not convincing](https://www.realclimate.org/index.php/archives/2009/08/still-not-convincing/) - RealClimate: In a new GRL paper, Svensmark et al., claim that liquid water content in low clouds is reduced after Forbush decreases (FD), and for the most influential FD events, the liquid water content in the oceanic atmosphere can diminish by as much as 7%. In particular, they argue that there is a substantial decline in
- [Friday round-up](https://www.realclimate.org/index.php/archives/2009/07/friday-round-up-3/) - RealClimate: Debunking the claim that long-term temperature trends are related to ENSO (El Niño - Southern Oscillation) by McLean, de Freitas and Carter. Pointer to the ICSU visioning earth science open call for discussion
- [Sea ice minimum forecasts](https://www.realclimate.org/index.php/archives/2009/07/summer-sea-ice-round-up/) - RealClimate: Arctic sea ice minimum september forecasts 2009
- ['Unscientific America': A Review](https://www.realclimate.org/index.php/archives/2009/07/unscientific-america-a-review/) - RealClimate: Author Chris Mooney (of "Storm World" fame) and fellow "Intersection" blogger, scientist, and writer Sheril Kirshenbaum have written an extraordinary, if rather sobering book entitled 'Unscientific America'. What I found most refreshing about the book is that it not only isolates the history behind, and source of, the problem in question---the pervasiveness and dangerousness of
- [Science at the bleeding edge](https://www.realclimate.org/index.php/archives/2009/07/science-at-the-bleeding-edge/) - RealClimate: Discussion of how surprising new science often turns out to be wrong or at least incomplete, specifically looking at Polar ozone depletion, North Atlantic ocean circulation change, methane from plants.
- [Groundhog day](https://www.realclimate.org/index.php/archives/2009/06/groundhog-day-2/) - RealClimate: Alert readers will have noticed the fewer-than-normal postings over the last couple of weeks. This is related mostly to pressures associated with real work (remember that we do have day jobs). In my case, it is because of the preparations for the next IPCC assessment and the need for our group to have a functioning
- [Two degrees](https://www.realclimate.org/index.php/archives/2009/07/two-degrees/) - RealClimate: The countries of the G8 today approved a target of 2° C rise in global average temperature above the natural, preanthropogenic climate, that they resolve should be avoided. The Europeans have been pushing for 2 degrees as a target maximum temperature for several years, but this is something of a development for the Americans. We
- [Science at the bleating edge](https://www.realclimate.org/index.php/archives/2009/07/science-at-the-bleating-edge/) - RealClimate: New complexities in the sheep-albedo hypothesis for climate change.
- [More bubkes](https://www.realclimate.org/index.php/archives/2009/07/more-bubkes/) - RealClimate: Roger Pielke Sr. has raised very strong allegations against RealClimate in a recent blog post. Since they come from a scientific colleague, we consider it worthwhile responding directly. The statement Pielke considers “misinformation” is a single sentence from a recent posting: Some aspects of climate change are progressing faster than was expected a few years
- [Introducing RC forum](https://www.realclimate.org/index.php/archives/2006/07/introducing-rc-forum/) - RealClimate: It's clear that there is a need to have some posts and discussions that specifically deal with up-to-the-minute articles and issues that we don't necessarily want to cover in our usual detail. This might be related to a recent op-ed which just repeats the same talking-points as usual, or pointers to good discussions on other
- [Exeter conference: Avoiding Dangerous  Climate Change <lang_fr> Conférence d'Exeter (G-B): éviter un changement climatique dangereux </lang_fr>](https://www.realclimate.org/index.php/archives/2005/02/exeter-conference-avoiding-dangerous-climate-change/) - RealClimate: The conference last week in Exeter on "Avoiding Dangerous Climate Change" grew out of a speech by UK Prime Minister Tony Blair. He asked "What level of greenhouse gases in the atmosphere is self-evidently too much?" and "What options do we have to avoid such levels?". The first question is very interesting, but also very
- [Of tempests, barren ground and a thousand furlongs of sea](https://www.realclimate.org/index.php/archives/2009/05/of-tempests-barren-ground-and-a-thousand-furlongs-of-sea/) - RealClimate: Guest commentary by Ron Miller, NASA GISS Several studies have shown that hurricane activity is generally reduced during years when there is a thick aerosol haze over the subtropical Atlantic. The haze is comprised mainly of soil particles, stripped by wind erosion from the barren ground over the Sahara and Sahel. These particles are lifted
- [On overfitting](https://www.realclimate.org/index.php/archives/2009/06/on-overfitting/) - RealClimate: I don’t tend to read other blogs much, despite contributing to RealClimate. And I'm especially uninterested in spending time reading blogs full of ad hominem attacks. But a handful of colleagues apparently do read this stuff, and have encouraged me to take a look at the latest commentaries on our Antarctic temperature story. Since I
- [A warning from Copenhagen](https://www.realclimate.org/index.php/archives/2009/06/a-warning-from-copenhagen/) - RealClimate: In March the biggest climate conference of the year took place in Copenhagen: 2500 participants from 80 countries, 1400 scientific presentations. Last week, the Synthesis Report of the Copenhagen Congress was handed over to the Danish Prime Minister Rasmussen in Brussels. Denmark will host the decisive round of negotiations on the new climate protection agreement
- [Wilkins ice shelf collapse](https://www.realclimate.org/index.php/archives/2009/04/wilkins-ice-shelf-collapse/) - RealClimate: Since people are wanting to talk about the latest events on the Antarctic Peninsula, this is a post for that discussion. The imagery from ESA (animation here) tells the recent story quite clearly - the last sliver of ice between the main Wilkins ice shelf and Charcot Island is currently collapsing in a very interesting
- [Breaking the silence about Spring](https://www.realclimate.org/index.php/archives/2009/04/breaking-the-silence-about-spring/) - RealClimate: Did you know that in 1965 the U.S. Department of Agriculture planted a particular variety of lilac in more than seventy locations around the U.S. Northeast, to detect the onset of spring --- in turn to be used to determine the appropriate timing of corn planting and the like? The records the USDA have kept
- [Aerosol formation and climate, Part I](https://www.realclimate.org/index.php/archives/2009/04/aerosol-formation-and-climate-part-i/) - RealClimate: Guest post by Bart Verheggen, Department of Air Quality and Climate Change , Energy research Institute of the Netherlands (ECN) The impacts of aerosols on climate are significant, but also very uncertain. There are several reasons for this, one of which is the uncertainty in how and how fast they are formed in the atmosphere
- [Friday round-up](https://www.realclimate.org/index.php/archives/2009/04/friday-round-up-2/) - RealClimate: They knew all along? A recent story in NYT: 'Industry Ignored Its Scientists on Climate' has caught our attention. Update: Marc Roberts' take: Latest skeptical song from Singer This week, the annual European Geophysical Union (EGU)'s general assembly was held in Vienna. Friday afternoon, I went to one of the conference's last talks to learn
- [Hit the brakes hard](https://www.realclimate.org/index.php/archives/2009/04/hit-the-brakes-hard/) - RealClimate: There is a climate splash in Nature this week, including a cover showing a tera-tonne weight, presumably meant to be made of carbon (could it be graphite?), dangling by a thread over the planet, and containing two new articles (Allen et al and Meinshausen et al), a "News & Views" piece written by two of
- [Welcome to the fray](https://www.realclimate.org/index.php/archives/2009/05/welcome-to-the-fray/) - RealClimate: As imitation is the sincerest form of flattery, we've naturally been delighted that a number of sites have sprung up over the past few years with missions complementary to our own focussing on the science of climate change. Last year, we were introduced to "climate ethics", whose mission it is to focus on the ethical
- [Monckton's deliberate manipulation](https://www.realclimate.org/index.php/archives/2009/05/moncktons-deliberate-manipulation/) - RealClimate: Our favorite contrarian, the potty peer Christopher Monckton has been indulging in a little aristocratic artifice again. Not one to be constrained by mere facts or observable reality, he has launched a sally against Andy Revkin for reporting the shocking news that past industry disinformation campaigns were not sincere explorations of the true uncertainties in
- [ACRIM vs PMOD](https://www.realclimate.org/index.php/archives/2009/05/acrim-vs-pmod/) - RealClimate: Two recent papers (Lockwood & Fröhlich, 2008 - 'LF08'; Scafetta & Willson, 2009 - 'SW09') compare the analysis of total solar irradiance (TSI) and the way the TSI measurements are combined to form a long series consisting of data from several satellite missions. The two papers come to completely opposite conclusions regarding the long term
- [Winds of change](https://www.realclimate.org/index.php/archives/2009/06/winds-of-change/) - RealClimate: Gavin Schmidt and Michael Mann There was an interesting AP story this week about possible changes in wind speed over the continental US. The study (by Pryor et al (sub.)), put together a lot of observational data, reanalyses (from the weather forecasting models) and regional models, and concluded that there was some evidence for a
- [The tragedy of climate commons](https://www.realclimate.org/index.php/archives/2009/05/the-tragedy-of-climate-commons/) - RealClimate: Imagine a group of 100 fisherman faced with declining stocks and worried about the sustainability of their resource and their livelihoods. One of them works out that the total sustainable catch is about 20% of what everyone is catching now (with some uncertainty of course) but that if current trends of increasing catches (about 2%
- [Air Capture <lang_sp>Captura de Aire</lang_sp>](https://www.realclimate.org/index.php/archives/2008/03/air-capture/) - RealClimate: Guest Commentary by Frank Zeman [This is one of an occasional series on the science of mitigation/adaptation/geo-engineering that we hope to continue. Since this isn't our core expertise, we'd especially appreciate balanced contributions from other scientists.] One of the central challenges of controlling anthropogenic climate change is developing technologies that deal with emissions from small,

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## Tags

- [sea ice](https://www.realclimate.org/index.php/archives/tag/sea-ice/)
- [Arctic](https://www.realclimate.org/index.php/archives/tag/arctic/)
- [Book review](https://www.realclimate.org/index.php/archives/tag/book-review/)
- [solar activity](https://www.realclimate.org/index.php/archives/tag/solar-activity/)
- [weather extremes](https://www.realclimate.org/index.php/archives/tag/weather-extremes/)
- [Arctic amplification](https://www.realclimate.org/index.php/archives/tag/arctic-amplification/)
- [climate change](https://www.realclimate.org/index.php/archives/tag/climate-change/)
- [aerosols](https://www.realclimate.org/index.php/archives/tag/aerosols/)
- [greenhouse warming](https://www.realclimate.org/index.php/archives/tag/greenhouse-warming/)
- [early anthropocene](https://www.realclimate.org/index.php/archives/tag/early-anthropocene/)
- [co2](https://www.realclimate.org/index.php/archives/tag/co2/)
- [greenhouse gases](https://www.realclimate.org/index.php/archives/tag/greenhouse-gases/)
- [AMOC](https://www.realclimate.org/index.php/archives/tag/amoc/)
- [Gulf Stream](https://www.realclimate.org/index.php/archives/tag/gulf-stream/)
- [IPCC](https://www.realclimate.org/index.php/archives/tag/ipcc/)
- [emissions](https://www.realclimate.org/index.php/archives/tag/emissions/)
- [budget](https://www.realclimate.org/index.php/archives/tag/budget/)
- [climate models](https://www.realclimate.org/index.php/archives/tag/climate-models/)
- [sea level rise](https://www.realclimate.org/index.php/archives/tag/sea-level-rise/)
- [extremes](https://www.realclimate.org/index.php/archives/tag/extremes/)
- [drought](https://www.realclimate.org/index.php/archives/tag/drought/)
- [Nobel prize](https://www.realclimate.org/index.php/archives/tag/nobel-prize/)
- [Manabe](https://www.realclimate.org/index.php/archives/tag/manabe/)
- [Hasselmann](https://www.realclimate.org/index.php/archives/tag/hasselmann/)
- [CERES](https://www.realclimate.org/index.php/archives/tag/ceres/)
- [CMIP](https://www.realclimate.org/index.php/archives/tag/cmip/)
- [WCRP](https://www.realclimate.org/index.php/archives/tag/wcrp/)
- [Scafetta](https://www.realclimate.org/index.php/archives/tag/scafetta/)
- [CMIP6](https://www.realclimate.org/index.php/archives/tag/cmip6/)
- [misinformation](https://www.realclimate.org/index.php/archives/tag/misinformation/)
- [digital twin](https://www.realclimate.org/index.php/archives/tag/digital-twin/)
- [cloud computing](https://www.realclimate.org/index.php/archives/tag/cloud-computing/)
- [DestinE](https://www.realclimate.org/index.php/archives/tag/destine/)
- [nenana](https://www.realclimate.org/index.php/archives/tag/nenana/)
- [yukon](https://www.realclimate.org/index.php/archives/tag/yukon/)
- [k-scale](https://www.realclimate.org/index.php/archives/tag/k-scale/)
- [digital twins](https://www.realclimate.org/index.php/archives/tag/digital-twins/)
- [open thread](https://www.realclimate.org/index.php/archives/tag/open-thread/)
- [Inflation Reduction Act](https://www.realclimate.org/index.php/archives/tag/inflation-reduction-act/)
- [IRA](https://www.realclimate.org/index.php/archives/tag/ira/)
- [extreme events](https://www.realclimate.org/index.php/archives/tag/extreme-events/)
- [detection](https://www.realclimate.org/index.php/archives/tag/detection/)
- [attribution](https://www.realclimate.org/index.php/archives/tag/attribution/)
- [EEI](https://www.realclimate.org/index.php/archives/tag/eei/)
- [energy imblance](https://www.realclimate.org/index.php/archives/tag/energy-imblance/)
- [Downscaling](https://www.realclimate.org/index.php/archives/tag/downscaling/)
- [Climate Change adaptation](https://www.realclimate.org/index.php/archives/tag/climate-change-adaptation/)
- [REgional climate modelling](https://www.realclimate.org/index.php/archives/tag/regional-climate-modelling/)
- [Impacts](https://www.realclimate.org/index.php/archives/tag/impacts/)
- [greta thunberg](https://www.realclimate.org/index.php/archives/tag/greta-thunberg/)
- [GISTEMP](https://www.realclimate.org/index.php/archives/tag/gistemp/)
- [NOAA NCEI](https://www.realclimate.org/index.php/archives/tag/noaa-ncei/)
- [HadCRUT](https://www.realclimate.org/index.php/archives/tag/hadcrut/)
- [Berkeley Earth](https://www.realclimate.org/index.php/archives/tag/berkeley-earth/)
- [RSS](https://www.realclimate.org/index.php/archives/tag/rss/)
- [UAH](https://www.realclimate.org/index.php/archives/tag/uah/)
- [AIRS](https://www.realclimate.org/index.php/archives/tag/airs/)
- [TMT](https://www.realclimate.org/index.php/archives/tag/tmt/)
- [SAT](https://www.realclimate.org/index.php/archives/tag/sat/)
- [MSU](https://www.realclimate.org/index.php/archives/tag/msu/)
- [Satellite temperature](https://www.realclimate.org/index.php/archives/tag/satellite-temperature/)
- [John Christy](https://www.realclimate.org/index.php/archives/tag/john-christy/)
- [Corrected-TMT](https://www.realclimate.org/index.php/archives/tag/corrected-tmt/)
- [AMSU](https://www.realclimate.org/index.php/archives/tag/amsu/)
- [NOAA STAR](https://www.realclimate.org/index.php/archives/tag/noaa-star/)
- [SSU](https://www.realclimate.org/index.php/archives/tag/ssu/)
- [CMIP5](https://www.realclimate.org/index.php/archives/tag/cmip5/)
- [climate dashboard](https://www.realclimate.org/index.php/archives/tag/climate-dashboard/)
- [North Atlantic](https://www.realclimate.org/index.php/archives/tag/north-atlantic/)
- [urban heating](https://www.realclimate.org/index.php/archives/tag/urban-heating/)
- [Willie Soon](https://www.realclimate.org/index.php/archives/tag/willie-soon/)
- [Nicola Scafetta](https://www.realclimate.org/index.php/archives/tag/nicola-scafetta/)
- [Clauser](https://www.realclimate.org/index.php/archives/tag/clauser/)
- [CMIP3](https://www.realclimate.org/index.php/archives/tag/cmip3/)
- [Roy Spencer](https://www.realclimate.org/index.php/archives/tag/roy-spencer/)
- [acceleration](https://www.realclimate.org/index.php/archives/tag/acceleration/)
- [2023](https://www.realclimate.org/index.php/archives/tag/2023/)
- [marine shipping](https://www.realclimate.org/index.php/archives/tag/marine-shipping/)
- [Miocene](https://www.realclimate.org/index.php/archives/tag/miocene/)
- [paleo-CO2](https://www.realclimate.org/index.php/archives/tag/paleo-co2/)
- [ECS](https://www.realclimate.org/index.php/archives/tag/ecs/)
- [km-scale](https://www.realclimate.org/index.php/archives/tag/km-scale/)
- [GCMs](https://www.realclimate.org/index.php/archives/tag/gcms/)
- [Machine Learning](https://www.realclimate.org/index.php/archives/tag/machine-learning/)
- [ESS](https://www.realclimate.org/index.php/archives/tag/ess/)
- [replication](https://www.realclimate.org/index.php/archives/tag/replication/)
- [Phanerozoic](https://www.realclimate.org/index.php/archives/tag/phanerozoic/)
- [reproduction](https://www.realclimate.org/index.php/archives/tag/reproduction/)
- [advocacy](https://www.realclimate.org/index.php/archives/tag/advocacy/)
- [activism](https://www.realclimate.org/index.php/archives/tag/activism/)
- [CMIP7](https://www.realclimate.org/index.php/archives/tag/cmip7/)
- [ERA5](https://www.realclimate.org/index.php/archives/tag/era5/)
- [AI/ML](https://www.realclimate.org/index.php/archives/tag/ai-ml/)
- [1.5ºC](https://www.realclimate.org/index.php/archives/tag/1-5oc/)
- [Atlantic Meridional Overturning Circulation](https://www.realclimate.org/index.php/archives/tag/atlantic-meridional-overturning-circulation/)
- [NOAA](https://www.realclimate.org/index.php/archives/tag/noaa/)
- [NWS](https://www.realclimate.org/index.php/archives/tag/nws/)
- [RWE](https://www.realclimate.org/index.php/archives/tag/rwe/)
- [Huaraz](https://www.realclimate.org/index.php/archives/tag/huaraz/)
- [Andes](https://www.realclimate.org/index.php/archives/tag/andes/)
- [Glacial](https://www.realclimate.org/index.php/archives/tag/glacial/)
- [outburst](https://www.realclimate.org/index.php/archives/tag/outburst/)
- [flood](https://www.realclimate.org/index.php/archives/tag/flood/)
- [2024](https://www.realclimate.org/index.php/archives/tag/2024/)
- [Steve Koonin](https://www.realclimate.org/index.php/archives/tag/steve-koonin/)
- [Southern Ocean](https://www.realclimate.org/index.php/archives/tag/southern-ocean/)
- [salinity](https://www.realclimate.org/index.php/archives/tag/salinity/)
- [National Climate Assessment](https://www.realclimate.org/index.php/archives/tag/national-climate-assessment/)
- [NCA](https://www.realclimate.org/index.php/archives/tag/nca/)
- [USGCRP](https://www.realclimate.org/index.php/archives/tag/usgcrp/)
- [EPA](https://www.realclimate.org/index.php/archives/tag/epa/)
- [Endangerment Finding](https://www.realclimate.org/index.php/archives/tag/endangerment-finding/)
- [DOE](https://www.realclimate.org/index.php/archives/tag/doe/)
- [Water vapor](https://www.realclimate.org/index.php/archives/tag/water-vapor/)
- [CWG](https://www.realclimate.org/index.php/archives/tag/cwg/)
- [predictions](https://www.realclimate.org/index.php/archives/tag/predictions/)