Two and a half years ago, a paper was published in Nature purporting to be a real prediction of how global temperatures would develop, based on a method for initialising the ocean state using temperature observations (Keenlyside et al, 2008) (K08). In the subsequent period, this paper has been highly cited, very often in a misleading way by contrarians (for instance, Lindzen misrepresents it on a regular basis). But what of the paper’s actual claims, how are they holding up?
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The new post-partisan world
Unforced variations 3
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 seen recently include discussions on the epistimology of climate modelling, Andy Dessler’s adventures in debate land and his new paper on water vapour trends, and a review of trends in the Columbia glacier. Have at it.
Addendum: Kevin McKinney has beaten us to the mention of this, but another recent article of importance is a thorough review of the state of knowledge of drought, past and future, by Dai. The article is open access here.
Cuccinelli goes fishing again
In keeping with our role as a site that tries to deal with the science of climate change rather than the politics, we have specifically refrained from commenting on various politically-motivated legal shenanigans relating to climate science. Some of them have involved us directly, but we didn’t (don’t) want to have RC become just a blog about us. However, the latest move by Ken Cuccinelli, the Attorney General of Virginia, against Mike Mann and UVa is so ridiculous it needs to be highlighted to the widest audience possible.
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Doing it yourselves
We’ve been a little preoccupied recently, but there are some recent developments in the field of do-it-yourself climate science that are worth noting.
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Monckton makes it up
Guest commentary by Barry R. Bickmore, Brigham Young University
If you look around the websites dedicated to debunking mainstream climate science, it is very common to find Lord Christopher Monckton, 3rd Viscount of Brenchley, cited profusely. Indeed, he has twice testified about climate change before committees of the U.S. Congress, even though he has no formal scientific training. But if he has no training, why has he become so influential among climate change contrarians? After examining a number of his claims, I have concluded that he is influential because he delivers “silver bullets,” i.e., clear, concise, and persuasive arguments. The trouble is his compelling arguments are often constructed using fabricated facts. In other words, he makes it up. (Click here to see a number of examples by John Abraham, here for a few by myself, and here for some by Tim Lambert).
Here I’m going to examine some graphs that Lord Monckton commonly uses to show that the IPCC has incorrectly predicted the recent evolution of global atmospheric CO2 concentration and mean temperature. A number of scientists have already pointed out that Monckton’s plots of “IPCC predictions” don’t correspond to anything the IPCC ever predicted. For example, see comments by Gavin Schmidt (Monckton’s response here,) John Nielsen-Gammon (Monckton’s response here,) and Lucia Liljegren. Monckton is still happily updating and using the same graphs of fabricated data, so why am I bothering to re-open the case?
My aim is to more thoroughly examine how Lord Monckton came up with the data on his graphs, compare it to what the IPCC actually has said, and show exactly where he went wrong, leaving no excuse for anyone to take him seriously about this issue.
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Expert Credibility in Climate Change – Responses to Comments
Guest commentary by William R. L. Anderegg, Jim Prall, Jacob Harold, Stephen H. Schneider
Note: Before Stephen Schneider’s untimely passing, he and his co-authors were working on a response to the conversation sparked by their recent paper in the Proceedings of the National Academy of Sciences on climate change expertise. One of Dr. Schneider’s final interviews also addresses and discusses many of the issues covered here.
We accept and rely upon the judgment and opinions of experts in many areas of our lives. We seek out lawyers with specific expertise relevant to the situation; we trust the pronouncement of well-trained airplane mechanics that the plane is fit to fly. Indeed, the more technical the subject area, the more we rely on experts. Very few of us have the technical ability or time to read all of the primary literature on each cancer treatment’s biology, outcome probabilities, side-effects, interactions with other treatments, and thus we follow the advice of oncologists. We trust the aggregate knowledge of experts – what do 97% of oncologists think about this cancer treatment – more than that of any single expert. And we recognize the importance of relevant expertise – the opinion of vocal cardiologists matters much less in picking a cancer treatment than does that of oncologists.
Our paper Expert Credibility in Climate Change is predicated on this idea. It presents a broad picture of the landscape of expertise in climate science as a way to synthesize expert opinion for the broader discourse. It is, of course, only a first contribution and, as such, we hope motivates discussion and future research. We encourage follow-up peer-reviewed research, as this is the mark of scientific progress. Nonetheless, some researchers have offered thoughtful critiques about our study and others have grossly mischaracterized the work. Thus, here we provide responses to salient comments raised.
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An icy retreat
) (
) 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 and again in early summer the question arises whether the most recent trend in sea-ice extent might lead to a new record minimum, with a sea-ice cover that will be smaller than that in the record summer of 2007.
However, before looking at the possible future evolution of Arctic sea ice in more detail, it might be a good idea to briefly re-capitulate some events of the previous winter, because some of those are quite relevant for the current state of the sea-ice cover. The winter 2009/2010 will be remembered by many people in Europe (and not only there) as particularly cold, with lots of snow and ice. Not least because of the sustained cold, some began to wonder if global warming indeed was real.
The Montford Delusion
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 details of the controversy over the “hockey stick,” then A. W. Montford’s book The Hockey Stick Illusion: Climategate and the Corruption of Science might persuade you that not only the hockey stick, but all of modern climate science, is a fraud perpetrated by a massive conspiracy of climate scientists and politicians, in order to guarantee an unending supply of research funding and political power. That idea gets planted early, in the 6th paragraph of chapter 1.
The chief focus is the original hockey stick, a reconstruction of past temperature for the northern hemisphere covering the last 600 years by Mike Mann, Ray Bradley, and Malcolm Hughes (1998, Nature, 392, 779, doi:10.1038/33859, available here), hereafter called “MBH98” (the reconstruction was later extended back to a thousand years by Mann et al, 1999, or “MBH99” ). The reconstruction was based on proxy data, most of which are not direct temperature measurements but may be indicative of temperature. To piece together past temperature, MBH98 estimated the relationships between the proxies and observed temperatures in the 20th century, checked the validity of the relationships using observed temperatures in the latter half of the 19th century, then used the relationships to estimate temperatures as far back as 1400. The reconstruction all the way back to the year 1400 used 22 proxy data series, although some of the 22 were combinations of larger numbers of proxy series by a method known as “principal components analysis” (hereafter called “PCA”–see here). For later centuries, even more proxy series were used. The result was that temperatures had risen rapidly in the 20th century compared to the preceding 5 centuries. The sharp “blade” of 20th-century rise compared to the flat “handle” of the 15-19th centuries was reminiscent of a “hockey stick” — giving rise to the name describing temperature history.
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Revisiting the Younger Dryas
Guest Commentary by Chris Colose
One of the most intriguing and well-studied climatic events in the past is the Younger Dryas (YD), a rather abrupt climate change between ~12.9 and 11.6 thousand years ago. As the world was slowly warming and ice was retreating from the last glaciation, the YD effectively halted the transition to today’s relatively warm, interglacial conditions in many parts of the world. This event is associated with cold and dry conditions increasing with latitude in the North, temperature and precipitation influences on tropical and boreal wetlands, Siberian-like winters in much of the North Atlantic, weakening of monsoon intensity, and southward displacement of tropical rainfall patterns. RealClimate has previously discussed the YD (here and here) however there have been a number of developments in recent years which deserve further attention, particularly with respect to the spatial characteristics and causes of the YD.
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