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Supreme Court Amicus Curiae from scientists

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In the wake of the NY times editorial yesterday, we’ve been asked to provide a link to the Amicus Curiae (draft) written by David Battisti, Christopher Field, Inez Fung, James E. Hansen, John Harte, Eugenia Kalnay, Daniel Kirk-Davidoff, James C. Mcwilliams, Jonathan T. Overpeck, F. Sherwood Rowland, Joellen Russell, Scott R. Saleska, John M. Wallace and Steven C. Wofsy in the current Supreme Court case (Commonwealth of Massachusetts et al vs. US EPA et al). Some discussion of this statement is also available at Prometheus.

Update: The actual brief (of which the first link was a draft) is available here (see comments below).

Update 2: We also note that on the final brief, Mario Molina, Ed Sarachik, Bill Easterling, and Pam Matson were additional signers.

New Google search function

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It can be easy to find climate science information on the web, but that information ranges from the excellent to the atrocious – and it can often be hard to tell them apart without some prior expertise. Wouldn’t it be great if someone could vet the information beforehand so that you had some confidence that it wasn’t completely bogus? Well, you need wait no longer!

Some of you may have already noticed that we have updated our search facility to use a new service from Google Co-op which is being launched today. The idea is that the search is restricted to domains and pages that have passed some kind of quality control. RealClimate is one of the demo sites of the new technology and we have started off with a selection of sites (IPCC, goverment labs, research institutes etc. – as well as RealClimate itself of course!) that we know provide quality information about climate science. As we get used to this service, we will be adding sites and pages that we feel are up to the mark. Suggestions for sites that we might not yet have found or have overlooked, will of course be welcome.

Eventually, we hope to have a service that could be an essential resource for the interested public, journalists, and possibly even scientists, that would give a higher quality level of information than is possible now. Let us know if this ends up being useful to you and if you have any suggestions for improving the service.

Con Allègre, ma non troppo

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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 is one of the most decorated french geophysicists specializing in geochemistry and the use of paleomagnetism. Being a longtime friend of the former prime minister, Lionel Jospin, he even became Minister of Education and Research in the former Socialist government. He still plays an active role within the Socialist party and though he has never published anything directly related to anthropogenic climate change, one would assume that he has some understanding of the scientific matter. But this assumption would be wrong.

In the French weekly journal l’Express he exposed his “sceptical” views in an article entitled “The snows of Kilimanjaro”. In the short editorial, he somehow became lost when following Ernest Hemingway to East Africa. Allègre mentions two scientific examples to demonstrate that there is something fundamentally wrong in the IPCC statements on the reality of climate change. First, he commented on the disappearing glaciers of the Kilimanjaro, sometimes treated as the “Panda” of anthropogenic climate change. Citing a “Nature” study (which was in fact published in Science) by Pierre Sepulchre and colleagues from my laboratory, he claimed that this modelling study demonstrated that Kilimanjaro’s glaciers are controlled by tectonic activity. In fact, the article describes the impact of tectonics of the East African Highlands on Indian ocean moisture transport —- on a time scale of millions of years! This confuses glacier variability over the last ~100 years with rainfall trends extending back to the time of the early hominids (such as Lucy).

In fact, there are good reasons to believe that the situation on the Kilimanjaro is a bit more complicated than a simple “atmosphere gets warmer/ glaciers are melting” equation (for instance, see this previous post on tropical glacier retreat). Furthermore, the real link to climate change does not come from the retreat of one single tropical glacier, but from the fact that, to my knowledge, all studied tropical glaciers have retreated over the 20th century, and the retreat rates have generally increased in recent decades.

Allègre’s misunderstanding was immediately followed by another one. Citing a recent study on relatively stable Antarctic snowfall over the last 30 years (Monaghan et al, 2006, discussed here) , he highlighted what he thought was a clear contradiction to future climate simulations of global circulation models (melting of the Antarctic ice sheet). However, that’s not what they predict. All models predict a comparably stable Antarctic ice sheet for the 21th century in which comparably moderate temperature changes in Antarctica are compensated by slight increase in snowfall. The Monaghan et al study does not contradict these model scenarios.

The French climate research community was of course not very pleased about this short sequence of misrepresentations and personal attacks (“les Cassandres”) and corrected Allègre in an open letter published here on the website of the Institute Pierre Simon Laplace (which includes links to the ongoing back and forth, for those that speak French).

Curiously enough, twenty years ago Allègre wrote in “Clés pour la géologie”, (éd. Belin/France Culture):

“En brûlant des combustibles fossiles, l’homme a augmenté le taux de gaz carbonique dans l’atmosphère, ce qui fait, par exemple, que depuis un siècle la température moyenne du globe a augmenté d’un demi-degré.”

(Translation)
“By burning fossil fuels man enhanced the concentration of carbon dioxide in the atmosphere which has raised the global mean temperature by half a degree in the last century”.

But at that time he used this argument against the anti-nuclear energy movement. It might be that there is simply a bit too much politics in Allègre’s life…

The trouble with sunspots

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by Gavin Schmidt and Michael Mann

Solar forcing of climate is a subject that gets far more attention than any new observations or improved understanding would warrant. Two new articles appearing today attest to that. One is occasionally tempted to agree with Oscar Wilde when he said:

Why does not science, instead of troubling itself about sunspots, which nobody ever saw, or, if they did, ought not to speak about; why does not science busy itself with drainage and sanitary engineering?

Except in this case it’s Nature rather than Science who are troubling themselves…

A new review paper by Foukal et al does a reasonable job summarising the mainstream opinion on the issue. In particular, they outline quite clearly why some ideas related to long term solar variability (such as solar disk radius changes, or the difference between cycling and non-cycling stars) have recently fallen out of favor. Indeed, they assert that there is little evidence for any solar variability in irradiance that is not related to the shielding/enhancements of sunspots and faculae – which implies only a modest decrease in solar flux at the Maunder Minimum for instance. We could quibble with their use of paleo-reconstructions, their climate modeling approach, and the rather cursory treatment of the substantial body of work relating to amplyfying mechanisms due to UV/ozone links, but we’ve gone over this ground before and we refer readers to those earlier discussions.

Slightly more novel is the description in the News section of a new experiment at CERN that is attempting to test the cosmic-ray/cloud hypothesis by building a large cloud chamber mimicing the atmosphere and firing high energy particles at it. There’s nothing intrinsically wrong with the idea, but given the $11 million to spend on climate change research, we would have tended to favour projects that, unlike this one, have at least some empirical support within the observations….

Tropical SSTs: Natural variations or Global warming?

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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?

Why greenhouse gases heat the ocean

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Guest commentary by Peter Minnett (RSMAS)

Observations of ocean temperatures have revealed that the ocean heat content has been increasing significantly over recent decades (Willis et al, 2004; Levitus et al, 2005; Lyman et al, 2006). This is something that has been predicted by climate models (and confirmed notably by Hansen et al, 2005), and has therefore been described as a ‘smoking gun’ for human-caused greenhouse gases.

However, some have insisted that there is a paradox here – how can a forcing driven by longwave absorption and emission impact the ocean below since the infrared radiation does not penetrate more than a few micrometers into the ocean? Resolution of this conundrum is to be found in the recognition that the skin layer temperature gradient not only exists as a result of the ocean-atmosphere temperature difference, but also helps to control the ocean-atmosphere heat flux. (The ‘skin layer‘ is the very thin – up to 1 mm – layer at the top of ocean that is in direct contact with the atmosphere). Reducing the size of the temperature gradient through the skin layer reduces the flux. Thus, if the absorption of the infrared emission from atmospheric greenhouse gases reduces the gradient through the skin layer, the flow of heat from the ocean beneath will be reduced, leaving more of the heat introduced into the bulk of the upper oceanic layer by the absorption of sunlight to remain there to increase water temperature. Experimental evidence for this mechanism can be seen in at-sea measurements of the ocean skin and bulk temperatures. [Read more…] about Why greenhouse gases heat the ocean

Followup to the ‘Hockeystick’ Hearings

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The House Energy and Commerce committee held two hearings on the “Hockey Stick” and associated “Wegman Report” in July. We commented on the first of the two hearings previously. The hearings, while ostensibly concerning the studies of Mann and coworkers, were actually most remarkable for the (near) unanimity of the participating scientists on critical key points, such as the importance of confronting the issue of climate change, and the apparent acceptance of those points by the majority of congresspersons present.

The committee subsequently provided followup opportunities to participants to clarify issues that were discussed at the hearings. Mike Mann (Penn State Professor and RealClimate blogger) participated in the second (July 27 2006) of the two hearings, “Questions Surrounding the ‘Hockey Stick’ Temperature Studies: Implications for Climate Change Assessments”. He has posted his responses to five follow-up questions, along with supporting documents. Among the more interesting of these documents are a letter and a series of email requests from emeritus Stanford Physics Professor David Ritson who has identified significant apparent problems with the calculations contained in the Wegman report, but curiously has been unable to obtain any clarification from Dr. Wegman or his co-authors in response to his inquiries. We hope that Dr. Wegman and his co-authors will soon display a willingness to practice the principle of ‘openness’ that they so recommend in their report….

Update: There is an interesting discussion of the Wegman and North reports by Gerald North (talking at TAMU) available through Andrew Dessler’s site….

Fact, Fiction, and Friction in the Hurricane Debate

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Michael Mann and Gavin Schmidt

Judith Curry and colleagues have an interesting (and possibly provocative) article, “Mixing Politics and Science in Testing the Hypothesis That Greenhouse Warming Is Causing a Global Increase in Hurricane Intensity” in the latest issue of the Bulletin of the American Meteorological Society (BAMS). The article provides a solid review of the recent developments in the science focusing on potential climate change impacts on tropical cyclones. However, the article is more novel in its approach than the typical scientific review article. For instance, it attempts to deal with the issue of how one should test hypotheses that reflect a complex causal chain of individual hypotheses. This is of course relevant to investigations of climate change influences on tropical cyclone activity, where one is attempting to connect a phenomenon (climate change) that is global in spatial scale and multidecadal in timescale, to a phenomena that is intrinsically “mesoscale” (that is, spans at most hundreds of kilometers) in space and lasts only a few days.

More unusually, the article also takes an introspective look at the role of scientists in communicating societally-relevant science to the public, and provides a critical review of how the science dealing with climate change impacts on tropical cyclones and hurricanes has been reported in the media, and how that reporting has occasionally deepened the polarisation on the issue. In doing so, the article revisits some of the “false objectivity” problems we have talked about before (see here and here). They also assess fairly the quality of the arguments that have been made in response to the Emanuel (2005) and Webster et al (2005) papers in the hope of focussing discussion on the more valid points, rather than some of the more fallacious arguments. The article is unapologetic in advancing their particular point of view, and while we generally share it, we imagine that some readers may disagree. We hope, as we suspect the authors do as well, that it will in any case generate a productive discussion.

Climate Feedbacks

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Guest Commentary by Brian Soden (RSMAS, Miami)

Current model estimates of the climate sensitivity, defined as the equilibrated change in global-mean surface temperature resulting from a doubling of CO2, range from 2.6 to 4.1 K, consistent with observational constraints (see previous article). This range in climate sensitivity is attributable to differences in the strength of ‘radiative feedbacks’ between models and is one of the reasons why projections of future climate change are less certain than policy makers would like. [Read more…] about Climate Feedbacks