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
Greenhouse gases
This Week Bu Hafta
There are a few minor items this week worthy of mention:
1. The CO2 rise. Who dunnit?
Here at RealClimate, we have been (naively, apparently) operating under the assumption that climate change contrarians had long ago moved on from the untenable position that humans are not even responsible for the observed increase in CO2 concentrations over the past two centuries. The dubious paper by Ernst Beck we commented on the other day indicates that there is indeed still a rear guard attack being waged. As if to drive the point home further, pundit Alexander Cockburn, known generally for his progressive views, has perplexingly disputed the existence of any link between CO2 emissions and rising CO2 concentrations in the atmosphere in a screed he penned this week for the online journal “Counterpunch” (also printed in The Nation). It’s hard to know where to start, since his piece is so over the top and gets just about everything so thoroughly wrong, it’s almost comical. So we’ll just hit the low points: (a) Cockburn claims that there is zero empirical evidence that anthropogenic production of CO2 is making any measurable contribution to the world’s present warming trend, despite the fact that not even such strident climate change contrarians as Pat Michaels dispute that there is a measurable influence of anthropogenic greenhouse gases on global temperature. Plus there’s all the empirical evidence of course (see the new IPCC report). (b) Going further, Cockburn brazenly opines that ‘it is impossible to assert that the increase in atmospheric CO2 stems from human burning of fossil fuels’ despite the fact that there is an isotopic smoking gun for this connection. He then (c) fails to understand that water vapor is a feedback not a forcing, and citing ‘expert’ Dr. Martin Hertzberg, quite remarkably states that ‘It is the warming of the earth that is causing the increase of carbon dioxide and not the reverse.’ Never mind that isotopic evidence proves otherwise. Upon what evidence does he base this assertion?
Since no anti-global warming op-ed these days is complete without it, Cockburn (d) resorts to the usual misrepresentation of lag/lead relationships between CO2 and temperatures during glacial/interglacial cycles as if they disprove the causal relationship between greenhouse gas concentrations and surface temperatures (see our most recent debunking of this favorite contrarian talking point here). Oh dear.
2. The other (Glenn) Beck–Even Worse!
CNN gave their resident shock-jock Glenn Beck a forum for spreading more disinformation on global warming in an hour-long segment entitled Exposed: The Climate of Fear (see also this discussion by “Media Matters”). We could pick apart his (rather thin) arguments, which constitute the usual cocktail of long debunked contrarian talking points. Suffice it to say, however, that the moment a rhetorician invokes Hitler, Nazi Germany, and Eugenics, it is the moment they are no longer worthy of being listened to (cf Godwin’s Law of usenet debates). We don’t seem to be alone in our opinion here. Beck’s performance earned him the dubious title of “worst person in the world” from analyst Keith Olbermann.
However, there was one amusing moment: Beck asked Christopher ‘Incorrect’ Horner what the key thing to google was that would show that Al Gore was wrong. Horner suggested the lag between CO2 and temperature in the ice cores. Of course, if you do Google that, the first hit is the RealClimate debunking of the issue. Thanks!
3. Nature’s new blog
Nature has started a new blog called “Climate Feedback”, which says of itself ‘Climate Feedback is a blog hosted by Nature Reports: Climate Change to facilitate lively and informative discussion on the science and wider implications of global warming. The blog aims to be an informal forum for debate and commentary on climate science in our journals and others, in the news, and in the world at large.’
We wish it well, remembering their welcome for RealClimate, though early reviews based on the first few posts are decidedly mixed.
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.
Beck to the future
Guest commentary from Georg Hoffmann
Our understanding of the natural carbon cycle has greatly improved since the times of Svante Arrhenius (1859-1927) and Guy Stewart Callendar (1898-1964). We know what the atmospheric background value of CO2 currently is (it passed 380ppm last year, about 100ppm over the pre-industrial level), we know the seasonal/diurnal cycle in different environments, we have been able to put reasonable constraints on terrestrial and marine sources and sinks, and finally we know the impact of fuel combustion both globally and locally in heavily polluted areas.
[Read more…] about Beck to the future
The lag between temperature and CO2. (Gore’s got it right.)
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 comes up because it is one of the most popular claims made by the global warming deniers. It got a particularly high profile airing a couple of weeks ago, when congressman Joe Barton brought it up to try to discredit Al Gore’s congressional testimony. Barton said:
- In your movie, you display a timeline of temperature and compared to CO2 levels over a 600,000-year period as reconstructed from ice core samples. You indicate that this is conclusive proof of the link of increased CO2 emissions and global warming. A closer examination of these facts reveals something entirely different. I have an article from Science magazine which I will put into the record at the appropriate time that explains that historically, a rise in CO2 concentrations did not precede a rise in temperatures, but actually lagged temperature by 200 to 1,000 years. CO2 levels went up after the temperature rose. The temperature appears to drive CO2, not vice versa. On this point, Mr. Vice President, you’re not just off a little. You’re totally wrong.
Of course, those who’ve been paying attention will recognize that Gore is not wrong at all. This subject has been very well addressed in numerous places. Indeed, guest contributor Jeff Severinghaus addressed this in one of our very first RealClimate posts, way back in 2004. Still, the question does keep coming up, and Jeff recently received a letter asking about this. His exchange with the letter writer is reproduced in full at the end of this post. Below is my own take on the subject.
[Read more…] about The lag between temperature and CO2. (Gore’s got it right.)
Learning from a simple model
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 can just write down the answer. This is the staple of most textbooks on the subject, but there are questions that arise in discussions here that don’t ever get addressed in most textbooks. Yet simple models can be useful there too.
I’ll try and cover a few ‘greenhouse’ issues that come up in multiple contexts in the climate debate. Why does ‘radiative forcing’ work as method for comparing different physical impacts on the climate, and why you can’t calculate climate sensitivity just by looking at the surface energy budget. There will be mathematics, but hopefully it won’t be too painful.
[Read more…] about Learning from a simple model
Save the World! Earn $25 million! Dünya’yı Kurtar! 25 Milyon Dolar Kazan! Sauvez la planète ! Gagnez 25 millions de dollars !
Guest commentary from Juliane Fry, UC Berkeley
On February 9, The Virgin Group chairman Sir Richard Branson announced a $25 million prize for anyone who can demonstrate “a commercially viable design which results in the removal of anthropogenic, atmospheric greenhouse gases so as to contribute materially to the stability of Earth’s climate.” At the press conference announcing this “Virgin Earth Challenge”, Branson was joined by Al Gore, and the panel of judges for the competition includes additional climate change celebrities: James Hansen, James Lovelock, Tim Flannery, and Sir Crispin Tickell.
The goal of the competition is to find a method that will remove at least 1 billion tons of carbon per year from the atmosphere. It will be very interesting to see what ideas come to the fore to scrub CO2 from the atmosphere. $25m should encourage some creativity! (and of course, once working should bring in a significant amount of carbon offset money). A ruckus was caused last year when discussion of injecting SO2 into the stratosphere to form reflective sulfate aerosols to mask global warming made scientists feel they needed to state their position on this controversial, poorly understood proposal. During the discussion, a New York Times feature (described here ) discussed various “geo-engineering” alternatives to exert a cooling effect to mask global warming. At least in this case, we are not seeking to add something new and uncertain to the atmosphere, but rather, remove something that we added.
Comentário convidado de Juliane Fry, UC Berkeley (tradução de F. M. Ramos e I. B. T. Lima)
No dia 9 de fevereiro, o presidente do Grupo Virgin, Sir Richard Branson, anunciou um prêmio de US$ 25 milhões para quem demonstrar “a viabilidade comercial de algum projeto para retirada da atmosfera de gases de efeito estufa de origem antropogênica, para contribuir materialmente para a estabilidade do clima da Terra”. Na coletiva de imprensa que lançou o desafio, batizado de “Virgin Earth Challenge“, Branson estava acompanhado de Al Gore, e o corpo de jurados da competição incluía outras celebridades das mudanças climáticas como James Hansen, James Lovelock, Tim Flannery, e Sir Crispin Tickell.
O objetivo da competição é encontrar um método que seja capaz de remover pelo menos 1 bilhão de toneladas de carbono por ano da atmosfera. Será muito interessante observar que idéias surgirão para varrer CO2 da atmosfera. US$ 25M devem suscitar alguma criatividade! (e naturalmente, uma vez implementado, proporcionar muito dinheiro na forma créditos de compensação de carbono). No ano passado, o barulho causado pela proposta de injeção de SO2 na estratosfera para formar uma camada refletiva de aerossóis de sulfato, de modo a neutralizar o aquecimento global, forçou muitos cientistas a tomar uma posição clara a respeito desta proposta controvertida e pouco compreendida. Durante os debates, uma matéria do New York Times (descrita aqui) discutiu várias alternativas de “geo-engenharia” para criar um mecanismo de resfriamento de mascarasse o aquecimento global. Pelo menos neste caso, não estamos procurando adicionar algo novo e incerto na atmosfera, mas ao contrário, retirar algo que foi adicionado.
Misafir yazar Juliane Fry, California Üniversitesi, Berkeley (Ingilizce’den çeviren: Figen Mekik)
9 Şubat gunu, The Virgin Group’un (Bakir Grup) başkanı, Sir Richard Branson 25 milyon dolar ödüllü bir yarışma açıklamasında bulundu. Yarışmanın amacı dünya’nın küresel iklimini dengeleyebilecek yeni bir tasarım üretmek. Insanlar tarafından atmosferdeki yoğunluğu artırılan sera gazlarını eksiltebilen ve bunu en ucuz şekliyle başarabilen tasarımcıya 25 milyon dolar ödül verilecek. Bu Bakir Dünya Yarışmasının açıklandığı basın toplantısına, Branson’a Al Gore eşlik ettiği gibi, yarışmada hakemlik yapacak panelde yer alan diğer iklim meşhurları da katıldılar: James Hansen, James Lovelock, Tim Flannery ve Sir Crispin Tickell.
Yarışmanın amacı yılda en az 1 milyar ton karbonu atmosferden çekebilen bir yöntem geliştirmek. Atmosferdeki fazla karbon dioksidi yok etmek için ne çeşit fikirlerin ortaya atılacağını görmek çok ilginç olacak. Eh, 25 milyon dolar biraz yaratıcılığı teşvik eder herhalde (ve tabii ki, bu yeni yöntemler uygulandığında kâr da artar). Geçen sene küresel ısınmayı maskelemek amacıyla stratosfere SO2 aktarılarak yaratılacak parlak sülfat taneciklerinin (aerosol) iklimi soğutma etkisi tartışıldığında bir hayli gürültü koptu. Bilimciler çok tartışmaya sebep olan ve pek iyi anlaşılamayan bu konu hakkındaki tutumlarını açıkça beyan etmek istediler. Bu tartışma dahilinde New York Times’da çıkan bir yazı (tarifi burada) küresel ısınmanın etkilerini azaltmayı amaçlayan başka jeo-teknik çözümler önerdi. En azından bu sefer, bu 25 milyon dolarlık yarışmayla atmosfere yeni ve etkisi henüz tam kestirilemeyen bir şey eklemeyen bir çözüm aranıyor.
Juliane Fry, UC Berkeley, Traduit par Etienne Pesnelle
Le 9 février dernier, Richard Branson, président du groupe Virgin, a annoncé qu’il offrait 25 millions de dollars à quiconque pourra présenter « une invention commercialement viable qui permette de retirer de l’atmosphère les gaz à effet de serre d’origine anthropique, de façon à contribuer sensiblement à la stabilisation du climat de la Terre ». A la conférence de presse où il annonçait son « « Défi Virgin pour la Terre » », Branson a été rejoint par Al Gore, et le comité des juges de ce concours comprend d’autres célébrités du réchauffement climatique : James Hansen, James Lovelock, Tim Flannery, et Sir Crispin Tickell.
L’objectif du concours est de trouver une méthode qui pourra retirer de l’atmosphère au moins un milliard de tonnes de carbone par an. Il va être très intéressant de voir quelles idées de nettoyage de l’atmosphère vont émerger. 25 millions de dollars devraient encourager la créativité ! (et bien sûr, quand ça fonctionnera, ça devrait rapporter une somme significative en crédits de compensations d’émissions de carbone). Il y eut du grabuge l’année dernière, quand le débat à propos de l’injection de SO2 dans la stratosphère, visant à produire des sulfates en aérosol réfléchissant la lumière solaire qui contreraient le réchauffement climatique, a donné l’impression aux scientifiques qu’ils avaient besoin d’exposer leur position sur cette proposition mal comprise et controversée.
Durant ce débat, un article de fond du *New York Times* (décrit ici) a commenté les différentes options de « géo-ingénierie » ayant un effet refroidisseur contrant le réchauffement climatique. Au moins cette fois-ci, on ne cherche pas à ajouter quelque chose de nouveau et d’incertain à l’atmosphère, mais bien à en retirer ce qu’on y a ajouté.
The sky IS falling Le ciel nous tombe vraiment sur la tête
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 is causing various ionspheric layers to ‘fall’. This was highlighted a few years back by Jarvis et al (1998) and in New Scientist in 1999 (and I apologise for stealing their headline!).
The changes in the figure are related to the cooling seen in the lower stratospheric MSU-4 records (UAH or RSS), but the changes there (~ 15-20 km) are predominantly due to ozone depletion. The higher up one goes, the more important the CO2 related cooling is. It’s interesting to note that significant solar forcing would have exactly the opposite effect (it would cause a warming) – yet another reason to doubt that solar forcing is a significant factor in recent decades.
Update: The best explanation for the cooling trends can be found on ESPERE (alternative site), in particular, figure 3 (alt. version).
Traduit par Etienne Pesnelle
Dans le numéro de cette semaine de Science, un article opportun de mise en perspective traite des problèmes du changement de l’atmosphère supérieure. Ladite atmosphère “supérieure” consiste en la stratosphère jusqu’à l’ionosphère (~20 à 300 km). Laštovicka et al soulignent que la tendance au refroidissement est exactement telle que prédite par la tendance à la hausse des gaz à effet de serre, et que l’accroissement de densité que cela implique est en train de provoquer la “chute” de différentes couches de la ionosphère. Cela a été mis en exergue il y a quelques années par Jarvis et al. (1998) et dans New Scientist en 1999 (et je m’excuse de leur avoir volé le titre de leur article!).
Les changements dans le graphique sont liés au refroidissement constaté dans les enregistrements MSU-4 de la basse stratosphère (que ce soit ceux provenant des bases de données UAH ou RSS), mais les changements à ces altitudes (~ 15-20 km) sont principalement dûs à la raréfaction de l’ozone. Plus on monte, plus le refroidissement dû au CO2 est important. Il est intéressant de noter qu’un forçage solaire significatif aurait exactement l’effet inverse (il provoquerait un réchauffement) – encore une autre raison de douter que le forçage solaire est un facteur significatif [du réchauffement climatique] des dernières décennies.
Mise à jour : la meilleure explication des tendances au refroidissement peut être trouvée sur ESPERE, en particulier la figure 3.
Avery and Singer: Unstoppable hot air
Last week I attended a talk by Dennis Avery, author with Fred Singer of Unstoppable Global Warming Every 1500 Years (there is a summary here). The talk (and tasty lunch) was sponsored by the Heartland Institute, and was apparently enthusiastically received by its audience. Still whoozy from a bit of contention during the question period, a perplexed member of the audience told me privately that he thought a Point/CounterPoint discussion might be useful (he didn’t know I wrote for realclimate; it was just a hypothetical thought). But here’s my attempt to accommodate. [Read more…] about Avery and Singer: Unstoppable hot air
Cuckoo Science La Science Coucou
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 scientific to the layperson (they have equations! references to 19th Century physicists!), but like cuckoo eggs in a nest, they are only designed to look real enough to fool onlookers and crowd out the real science. A cursory glance from anyone knowledgeable is usually enough to see that concepts are being mangled, logic is being thrown to the winds, and completely unjustified conclusions are being drawn – but the tricks being used are sometimes a little subtle.
Two pieces that have recently drawn some attention fit this mold exactly. One by Christopher Monckton (a viscount, no less, with obviously too much time on his hands) which comes complete with supplementary ‘calculations’ using his own ‘M’ model of climate, and one on JunkScience.com (‘What Watt is what’). Junk Science is a front end for Steve Milloy, long time tobacco, drug and oil industry lobbyist, and who has been a reliable source for these ‘cuckoo science’ pieces for years. Curiously enough, both pieces use some of the same sleight-of-hand to fool the unwary (coincidence?).
But never fear, RealClimate is here! [Read more…] about Cuckoo Science
Revealed: Secrets of Abrupt Climate Shifts
This story is the dream of every science writer. It features some of the most dramatic and rapid climate shifts in Earth’s history, as well as tenacious scientists braving the hostile ice and snows of Greenland and Antarctica for years on end to bring home that most precious material: kilometre-long cores of ancient ice, dating back over a hundred thousand years. Back in their labs, these women and men spend many months of seclusion on high-precision measurements, finding ingenious ways to unravel the secrets of abrupt climate change. Quite a bit has already been written on the ice core feat (including Richard Alley’s commendable inside story “The Two Mile Time Machine”), and no doubt much more will be.
It was the early, pioneering ice coring efforts in Greenland in the 1980s and 90s that first revealed the abrupt climate shifts called “Dansgaard-Oeschger events” (or simply DO events), which have fascinated and vexed climatologists ever since. Temperatures in Greenland jumped up by more than 10 ºC within a few decades at the beginning of DO events, typically remaining warm for several centuries after. This happened over twenty times during the last great Ice Age, between about 100,000 and 10,000 years before present.
The latest results of the EPICA team (the European Project for Ice Coring in Antarctica) are published in Nature today (see also the News & Views by RealClimate member Eric Steig). Their data from the other pole, from the Antarctic ice sheet, bring us an important step closer to nailing down the mechanism of the mysterious abrupt climate jumps in Greenland and their reverberations around the world, which can be identified in places as diverse as Chinese caves, Caribbean seafloor sediments and many others. So what are the new data telling us?
[Read more…] about Revealed: Secrets of Abrupt Climate Shifts