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 more usual right-wing variety. Casual readers may have thought this is a relatively recent obsession of his (3 articles and responses over the last month), however, Cockburn has significant form* and has a fairly long history of ill-informed commentary on the subject of global warming.
[Read more…] about Cockburn’s form
Climate Science
The weirdest millennium
Much research effort over the past years has gone into reconstructing the temperature history of the last millennium and beyond. The new IPCC report compiles a dozen reconstructions for the temperature of the Northern Hemisphere (including of course the original “hockey stick” reconstruction, despite opposite claims by the Wall Street Journal). Lack of data does not permit robust reconstructions for the Southern Hemisphere. Without exception, the reconstructions show that Northern Hemisphere temperatures are now higher than at any time during the past 1,000 years (Figure 1), confirming and strengthening the conclusions drawn in the previous IPCC report of 2001.
Fig. 1: Figure 6.10 (panel b) from the paleoclimate chapter of the current IPCC report (see there for details).
“Climate sceptics” do not like this and keep coming up with their own temperature histories. One of the weirdest has been circulated for years by German high-school teacher E.G. Beck (notorious for his equally weird CO2 curve). This history shows a medieval warm phase that is warmer than current climate by more than 1 ºC (see Figure 2). So how did Beck get this curve?
Why global climate models do not give a realistic description of the local climate
Global climate
Global climate statistics, such as the global mean temperature, provide good indicators as to how our global climate varies (e.g. see here). However, most people are not directly affected by global climate statistics. They care about the local climate; the temperature, rainfall and wind where they are. When you look at the impacts of a climate change or specific adaptations to a climate change, you often need to know how a global warming will affect the local climate.
Yet, whereas the global climate models (GCMs) tend to describe the global climate statistics reasonably well, they do not provide a representative description of the local climate. Regional climate models (RCMs) do a better job at representing climate on a smaller scale, but their spatial resolution is still fairly coarse compared to how the local climate may vary spatially in regions with complex terrain. This fact is not a general flaw of climate models, but just the climate models’ limitation. I will try to explain why this is below.
Glacier Mass Balance: equilibrium or disequilibrium response?
Guest Commentary from Mauri S. Pelto
I get asked at least once a day about the future prognosis for alpine glaciers and whether they have a future. I will focus here on North American glaciers whose mass balance measurements in the West from 1984-2005 indicate a declining trend. The trend suggests that all of the glaciers are out of balance and that some will disappear. The question is determining which glaciers are merely out of equilibrium and can retreat to a position of equilibrium, and which are in complete disequilibrium and will melt away? Let me explain.
[Read more…] about Glacier Mass Balance: equilibrium or disequilibrium response?
Start here
[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).
A bit of philosophy
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 Philosophy Stephen Gardiner, the conference was dedicated to the particular ethical and moral issues raised by the spectre of anthropogenic climate change. Since we aren’t philosophers by training, and since it would probably stray too far from RealClimate’s focus on science, we won’t comment in great detail. However, we thought it worth making our readers aware that there is a very interesting and growing literature on the subject. Based on their remarks at the conference, we heartily recommend checking out the papers and commentaries written by the various philosphers, scientists, and political theorists who attended. You can get abstracts of their talks on the conference web page. Below, we simply wish to note several issues raised at the conference that we found particularly interesting.
[Read more…] about A bit of philosophy
Hansen’s 1988 projections
At Jim Hansen’s now famous congressional testimony given in the hot summer of 1988, he showed GISS model projections of continued global warming assuming further increases in human produced greenhouse gases. This was one of the earliest transient climate model experiments and so rightly gets a fair bit of attention when the reliability of model projections are discussed. There have however been an awful lot of mis-statements over the years – some based on pure dishonesty, some based on simple confusion. Hansen himself (and, for full disclosure, my boss), revisited those simulations in a paper last year, where he showed a rather impressive match between the recently observed data and the model projections. But how impressive is this really? and what can be concluded from the subsequent years of observations?
[Read more…] about Hansen’s 1988 projections
Korelasyonlarla eğlenelim!
We are forever being bombarded with apparently incredible correlations of various solar indices and climate. A number of them came up in the excoriable TGGWS mockumentary last month where they were mysteriously ‘improved’ in a number of underhand ways. But even without those improvements (which variously involved changing the axes, drawing in non-existent data, taking out data that would contradict the point etc.), the as-published correlations were superficially quite impressive. Why then are we not impressed?
To give you an idea, I’m going to go through the motions of constructing a new theory of political change using techniques that have been pioneered by a small subset of solar-climate researchers (references will of course be given). And to make it even more relevant, I’m going to take as my starting point research that Richard Lindzen has highlighted on his office door for many years:
[Read more…] about Korelasyonlarla eğlenelim!
Bu Hafta
Ingilizce’den çeviren Figen Mekik/
Kaydedilmeye değer ufak tefek bazı konularımız var bu hafta.
1. CO2 yükselmesi. Faili kim?
Biz de sitemizde safça zannediyorduk ki iklim değişimine karşı çıkanlar en azından “insanların son ikiyüz yıldır görülen CO2 artışına hiç bir katkısı yoktur” gibi, savunulması güç tezleri çoktan geride bıraktılar. Ernst Beck’in bizim de daha önce üstünde durduğumuz bilimsel değeri şüpheli makalesi, daha hala bu saçma bu fikirlerin savunulduğunu gösteriyor. Dahası, ünlü alim Alexander Cockburn, ki ilerici düşünceleriyle tanınır, “Counterpunch” adlı site için uzun ve bıktıran bir eleştiri yazmış (The Nation’da da yayınlanmış) ve çok şaşırtıcı bir şekilde demiş ki CO2 emisyonuyla, havakürede görülen CO2 artışı arasında hiç bir bağlantı yoktur. Lafa nasıl başlayacağımızı kestirmek zor çünkü yazısı neredeyse komik olacak kadar saçma ve hemen hemen her konuda hatalı. Onun için sadece bir iki noktaya değinelim: (a) Cockburn diyor ki dünyamızın yaşadığı ısınma eğilimine insanların ürettiği CO2’nin katkısı olduğunu gösteren hiç bir delil yok. Bu çok tuhaf bir görüş çünkü en amansız karşı çıkıcılardan Pat Michaels bile insanların ürettiği sera gazlarının dünyanın ısınmasına ölçülebilir bir katkısı olduğunu kabul ediyor. Artı, bir sürü de deneysel veri var tabii (yeni Uluslarası Iklim Değişimi Görevgücü’nün raporuna bakın). (b) Daha da ileri giderek, izotoplarla kesin olarak ispat edilmesine rağmen, Cockburn hiç utanmadan ileri sürüyor ki ”atmosferdeki CO2 artışının insanların fosil yakıt kullanmasına bağlanması imkansızdır”. Ayrica, (c) anlamamakta inat ettiği bir başka konu da su buharı bir zorlama değil geribeslemedir. Ve hatta “uzman” Dr. Martin Hertzberg’e atıf yaparak ”dünyanın ısınması CO2’yi artırıyor ve tersi doğru değildir” fikrini öne sürüyor. Izotop verilerinin tam tersini ispat ediyor olmasını tamamen göz ardı ederek, hem de. Kendi görüşlerini hangi delillerle destekliyor acaba?
Ve küresel ısınmaya inanmayan yorum yazılarından hiç eksik olmayan bir diğer husus da (d) buzul ve buzul arası dönemlerde CO2-ısı arasındaki öncü-gecikmeci ilişkinin yanlış ifade edilmesi; sanki CO2 ve ısı arasındaki sebep-sonuç ilişkisi tamamen yanlışmış gibi (bunu en son burada tartıştık). Eyvah!
2. Diğer (Glenn) Beck —Daha kötüsü!
CNN, sansasyonel havadiscisi Glenn Beck’e bir saatlik, < a href=”http://www.cnn.com/CNN/Programs/beck.climateoffear/”>Açığa Çıktı: Korku Iklimi adlı (Media Matters’deki bu tartışmaya da bir göz atın) bir program vererek küresel ısınma hakkında yanlış bilgiler yaymasına olanak sağladı. Beck’in savunduğu çok zayıf iddiaları tek tek ele alabiliriz, ama çoğu zaten sıklıkla herkesin öne sürüp de rezil olduğu aynı iddialar. Onun için şunu demekle yetinelim: herhangi bir retoretisyen Hitler, Nazi Almanyası ve ırk islahı gibi fikirleri ortaya attı mı, dinlenebilirliğini yitiriyor (mesela Godwin’in kanunu gibi). Bu fikrimizde de yanlız değiliz galiba. Beck’in programı ona, Keith Olbermann tarafından < a href=”http://www.msnbc.msn.com/id/18438559/“>“dünyanın en kötü insanı” namını kazandırdı.
Ancak bizi güldüren bir an oldu. Beck, Christopher “Yanlış” Horner’a sordu: Al Gore’un hatalı olduğunu göstermek için neyi Google’lamalıyım? Horner da buzul karotlarındaki CO2 ve ısı arasındaki gecikeyi dedi. Tabii hakikaten bunu Google ederseniz, ilk çıkan RealClimate’ın bu konuyu püskürtmesi oluyor. Teşekkürler!
3. Nature dergisinin yeni blog’u.
Nature dergisi “Iklim Geribeslemesi” (Climate Feedback) adlı yeni bir blog başlatmış. Tarifi şöyle: Iklim Geribeslemesi Nature Reports: Climate Change’un ev sahipliğini yapacağı yeni bir blog. Amacı, küresel ısınma gerçeğinin ve geniş çaplı anlamlının canlı ve bilimsel olarak tartışmasını kolaylaştırmaktır. Blogumuz, resmi olmayan bir forumda, iklim bilimleri hakkında dergilerimizde, haberlerde ve dünyada yayınlanan bilgilerin tartışılmasını sağlayacaktır.
Onlara başarılar diliyoruz, çünkü onlar da bize dilemişlerdi, ama ilk yorumları biraz karışıktı.
Sulandırılmış Çorba ve Sulandırılmış bir Hikâye
A firm called planktos.com is getting a lot of airplay for their bid to create a carbon offset product based on fertilizing the ocean. In certain parts of the ocean, surface waters already contain most of the ingredients for a plankton bloom; all they lack is trace amounts of iron. For each 1 atom of iron added in such a place, phytoplankton take up 50,000 atoms of carbon. What could be better?
[Read more…] about Sulandırılmış Çorba ve Sulandırılmış bir Hikâye