There is a new critique of IPCC climate projections doing the rounds of the blogosphere from two ‘scientific forecasters’, Kesten Green and Scott Armstrong, who claim that since the IPCC projections are not ‘scientific forecasts’ they must perforce be wrong and that a naive model of no change in future is likely to be more accurate that any IPCC conclusion. This ignores the fact that IPCC projections have already proved themselves better than such a naive model, but their critique is novel enough to be worth a mention.
[Read more…] about Green and Armstrong’s scientific forecast
IPCC
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[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, we’ll amend this as we discover or are pointed to new resources. Different people have different needs and so we will group resources according to the level people start at.
For complete beginners:
NCAR: Weather and climate basics
Center for Climate and Energy Solutions: Climate basics
Wikipedia: Global Warming
NASA: Global Warming
National Academy of Science: America’s Climate Choices (2011)
Encyclopedia of Earth: Climate Change
Global Warming: Man or Myth? (Scott Mandia, SUNY Suffolk)
Open Learn: The Basics of Climate Prediction
There is a booklet on Climate Literacy from multiple agencies (NOAA, NSF, AAAS) available here (pdf).
The UK Govt. had a good site on The Science of Climate Change (archived).
The portal for climate and climate change of the ZAMG (Zentralaanstalt für Meteorologie und Geodynamik, Vienna, Austria). (In German) (added Jan 2011).
Those with some knowledge:
The IPCC Frequently Asked Questions are an excellent start (AR4 version here , updates were provided in the 5th Assessment report (pdf) and again for AR6).
The UK Royal Society and US National Academies of Science produced a joint Q&A on climate change in 2014, and an update in 2017.
RealClimate: Start with our index.
Informed, but in need of more detail:
Science: You can’t do better than the IPCC reports themselves (AR6 2021, AR5 2013, AR4 2007, TAR 2001). Also the Climate Science Special Report for the US National Climate Assessment.
History: Spencer Weart’s “Discovery of Global Warming” (AIP)
Informed, but seeking serious discussion of common contrarian talking points:
All of the below links have indexed debunks of most of the common points of confusion:
- Coby Beck’s How to talk to Global Warming Skeptic
- New Scientist: Climate Change: A guide for the perplexed
- RealClimate: Response to common contrarian arguments
- NERC (UK): Climate change debate summary (archived)
- UK Met Office: Climate Science
- Brian Angliss A Thorough Debunking
- John Cook Skeptical Science
- The Global Warming Debate (Presentations from around 2010 resurrected)
Please feel free to suggest other suitable resources, particularly in different languages, and we’ll try to keep this list up to date.
A Slovak translation is available here
Tłumaczenie na polski dostępne jest tutaj
A Bulgarian translation is available here (via Ivan Boreev).
Full IPCC AR4 report now available
The complete WG1 IPCC 4th Assessment report (AR4) is now available online. It’s missing the index and some supplemental data, but all should be available by May 7.
Over the next few weeks we’ll try and go through the report chapter by chapter, but since this is likely to the key reference for a number of years, we can take a little time to do it properly. Happy reading!
The IPCC sea level numbers
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) 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 Assessment Report, TAR). Some articles reported that IPCC had reduced its sea level projection from 88 cm to 59 cm (35 inches to 23 inches) , some even said it was reduced from 88 cm to 43 cm (17 inches), and there were several other versions as well (see “Broad Irony”). These statements are not correct and the new range up to 59 cm is not the full story. Here I will try to clarify what IPCC actually said and how these numbers were derived. (But if you want to skip the details, you can go straight to the critique or the bottom line).
[Read more…] about The IPCC sea level numbers
Aerosols: The Last Frontier?
) () Guest commentary from Juliane Fry, UC Berkeley
The recently released IPCC 2007 Fourth Assessment Report Summary for Policymakers reminds us that aerosols remain the least understood component of the climate system. Aerosols are solid or liquid particles suspended in the atmosphere, consisting of (in rough order of abundance): sea salt, mineral dust, inorganic salts such as ammonium sulfate (which has natural as well as anthropogenic sources from e.g. coal burning), and carbonaceous aerosol such as soot, plant emissions, and incompletely combusted fossil fuel. As should be apparent from this list, there are many natural sources of aerosol, but changes have been observed in particular, in the atmospheric loading of carbonaceous aerosol and sulphates, which originate in part from fossil fuel burning. While a relatively minor part of the overall aerosol mass, changes in the anthropogenic portion of aerosols since 1750 have resulted in a globally averaged net radiative forcing of roughly -1.2 W/m2, in comparison to the overall average CO2 forcing of +1.66 W/m2.
[Read more…] about Aerosols: The Last Frontier?
Fraser Institute fires off a damp squib
New addition: Download an annotated pdf of the Fraser report. An interactive pdf file, to be read on the screen, is here, and a printable version is here. Suggestions for further commenting are welcome. Additions to the pdf have to be short, and tied to particular pieces of text or figures. And of course we will only incorporate comments that we deem to be scientifically sound and cogent.
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While most of the world’s climate scientists were following the IPCC fest last week, a few contrarians left out in the cold were trying to to organize their own party.
An unofficial, “Independent Summary for Policymakers” (ISPM) of the IPCC Fourth Assessment report has been delivered by the Fraser Institute. It’s a long, imposing-looking document, resembling, come to think of it, the formatting of the real Summary for Policymakers (SPM) document that was released on Friday after final negotiations of the IPCC in Paris last week. The Fraser Institute has assembled an awesome team of 10 authors, including such RC favorites as tilter-against-windmills-and-hockey-sticks Ross McKitrick, and other luminaries such as William Kininmonth, MSc, M.Admin — whose most recent paper is “Don’t be Gored into Going Along” in the Oct-Nov issue of Power Engineer. To be fair, he did publish a paper on weather forecasting, back in 1973. According to the press release, the London kickoff event will be graced by the presence of “noted environmentalist” David Bellamy. It’s true he’s “noted,” but what he’s noted for is his blatant fabrication of numbers purporting to show that the world’s glaciers are advancing rather retreating, as reported here.
The IPCC Fourth Assessment SPM
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) () We’ve had a policy of (mostly) not commenting on the various drafts, misquotes and mistaken readings of the Fourth Assessment report (“AR4” to those in the acronym loop) of the IPCC. Now that the summary for policy makers (or “SPM”) has actually been published though, we can discuss the substance of the report without having to worry that the details will change. This post will only be our first cut at talking about the whole report. We plan on going chapter by chapter, hopefully explaining the key issues and the remaining key uncertainties over the next few months. This report will be referenced repeatedly over the next few years, and so we can take the time to do a reasonable job explaining what’s in it and why.
Stern Science
) () () Halldór Björnsson, William Connolley and Gavin Schmidt
Late last year, the UK Treasury’s Stern Review of the Economics of Climate Change was released to rapturous reception from all sides of the UK political spectrum (i.e. left and right). Since then it has been subject to significant criticism and debate (for a good listing see Rabbett Run). Much of that discussion has revolved around the economic (and ethical) issues associated with ‘discounting’ (how you weight welfare in the future against welfare today) – particularly Nordhaus’s review. We are not qualified to address those issues, and so have not previously commented.
However, as exemplified by interviews on a recent Radio 4 program (including with our own William Connolley), some questions have involved the science that underlies the economics. We will try and address those.
How much CO2 emission is too much?
) () This week, representatives from around the world will gather in Nairobi, Kenya for the latest Conference of Parties (COP) meeting of the Framework Convention of Climate Change (FCCC) which brought us the Kyoto Protocol. The Kyoto Protocol expires in 2012, and the task facing the current delegates is to negotiate a further 5-year extension. This is a gradual, negotiated, no doubt frustrating process. By way of getting our bearings, a reader asks the question, what should the ultimate goal be? How much CO2 emissions cutting would it take to truly avoid “dangerous human interference in the climate system”? [Read more…] about How much CO2 emission is too much?
Tropical SSTs: Natural variations or Global warming?
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 (or tropical cyclone) data show any significant variations, what those variations are linked to, and whether our understanding of the physics of tropical storms is sufficient to explain those links.
Several recent studies such as Emanuel (2005 — previously discussed here) and Hoyos et al (2006 — previously discussed here) have emphasized the role of increasing tropical sea surface temperatures (SSTs) on recent increases in hurricane intensities, both globally and for the Atlantic. The publication this week of a comprehensive paper by Santer et al provides an opportunity to assess the key middle question – to what can we attribute the relevant changes in tropical SSTs? And in particular, what can we say about Atlantic SSTs where we have the best data? [Read more…] about Tropical SSTs: Natural variations or Global warming?