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Ice age constraints on climate sensitivity

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There is a new paper on Science Express that examines the constraints on climate sensitivity from looking at the last glacial maximum (LGM), around 21,000 years ago (Schmittner et al, 2011) (SEA). The headline number (2.3ºC) is a little lower than IPCC’s “best estimate” of 3ºC global warming for a doubling of CO2, but within the likely range (2-4.5ºC) of the last IPCC report. However, there are reasons to think that the result may well be biased low, and stated with rather more confidence than is warranted given the limitations of the study.

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References

  1. A. Schmittner, N.M. Urban, J.D. Shakun, N.M. Mahowald, P.U. Clark, P.J. Bartlein, A.C. Mix, and A. Rosell-Melé, "Climate Sensitivity Estimated from Temperature Reconstructions of the Last Glacial Maximum", Science, vol. 334, pp. 1385-1388, 2011. http://dx.doi.org/10.1126/science.1203513

Two-year old turkey

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The blogosphere is abuzz with the appearance of a second tranche of the emails stolen from CRU just before thanksgiving in 2009. Our original commentary is still available of course (CRU Hack, CRU Hack: Context, etc.), and very little appears to be new in this batch. Indeed, even the out-of-context quotes aren’t that exciting, and are even less so in-context.

A couple of differences in this go around are worth noting: the hacker was much more careful to cover their tracks in the zip file they produced – all the file dates are artificially set to Jan 1 2011 for instance, and they didn’t bother to hack into the RealClimate server this time either. Hopefully they have left some trails that the police can trace a little more successfully than they’ve been able to thus far from the previous release.

But the timing of this release is strange. Presumably it is related to the upcoming Durban talks, but it really doesn’t look like there is anything worth derailing there at all. Indeed, this might even increase interest! A second release would have been far more effective a few weeks after the first – before the inquiries and while people still had genuine questions. Now, it just seems a little forced, and perhaps a symptom of the hacker’s frustration that nothing much has come of it all and that the media and conversation has moved on.

If anyone has any questions about anything they see that seems interesting, let us know in the comments and we’ll see if we can provide some context. We anticipate normal service will be resumed shortly.

The IPCC report on extreme climate and weather events

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The IPCC recently released the policy-maker’s summary (SREX-SPM) on extreme weather and climate events. The background for this report is a larger report that is due to be published in the near future, and one gets a taste of this in the ‘wordle‘ figure below. By the way, the phrase ‘ET’ in this context does not refer ‘extra-terrestrial’, and ‘AL’ is not a person, but these refer to the way of citing many scholars: ‘et al.‘

Fig. 1. The text analysis according to http://www.wordle.net/

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Scientific confusion

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“We have not succeeded in answering all our problems. The answers we have found only serve to raise a whole set of new questions. In some ways we feel we are as confused as ever, but we believe we are confused on a higher level and about more important things.”


I read this quote on a wall on Mark Cane’s office at LDEO (Columbia) many years ago and always wondered where it came from. He found it as an epigram in a book on ‘Stochastic Differential Equations‘ by Bernt Øksendal where it is sourced to a sign outside the mathematics reading room at Tromsø University. The actual source appears to be a 1951 report on an education workshop by Earl C. Kelley, a professor at Wayne University (sleuthing by QI).

Times Atlas map of Greenland to be corrected

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We were pleased to hear from the University of Arizona’s Jeff Kargel that the Times Atlas folks are now updating their atlas of Greenland. As we reported earlier, the first edition was completely in error, and led to some rather bizarre claims about the amount of ice loss in Greenland. Kargel reports that HarperCollins (publisher of the Times Atlas) has now fully retracted their error and has produced a new map of Greenland that will be made available as a large-format, 2-side map insert for the Atlas and will also be available free online. Meanwhile, Kargel and colleagues have produced their own updated small-scale map and have written a paper that includes both their new map and a description of the incident that led up to it. Kargel was instrumental in pushing the cryosphere community to send a strong message to the publishers that they needed to correct their mistake. (A pre-print of the paper, currently under review and under public discussion on Cryolist, is available here.)

Figure 1 in Kargel et al. (2011) generated by a collaboration of the Geological Survey of Denmark and Greenland (GEUS) and the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) with the Polar Geospatial Center Department of Geology and Geophysics, University of Minnesota. Contact: Michele Citterio (GEUS) for questions about the glacier outlines or Paul Morin (UMinn.) for questions about the MODIS base image mosaic.

HarperCollins is to be commended for listening to the scientific community and producing a corrected map. Unfortunately, and despite recent events demonstrating that popular allegations against climate scientists are all wrong, HarperCollins still says on their web site that it’s all the scientists’ fault for not being clear (“The one thing that is very apparent is that there is no clarity in the scientific and cartographic community on this issue”,they write). Hmm. Our own view is that anyone flying over Greenland en route to Europe from North America would instantly have recognized a problem with the Times Atlas (assuming they knew their location of course). As Kargel and colleagues write in their paper:

“Distinguishing manifest, ignorable nonsense from falsehoods that might take root in the public mind is difficult, but the magnitude of and apparent authority behind this particular mistake seemed to warrant a rapid and firm response. The eventually constructive reaction of HarperCollins, which not only withdrew its mistaken claim but also produced a new map to be included in the Times Atlas as an insert, shows the value of such a response. No less than grotesque trivialization, grotesque exaggeration of the pace or consequences of climate change needs to be countered energetically.”

Nevertheless, they caution that “scientists cannot possibly challenge all of the innumerable misunderstandings and misrepresentations of their work in public discourse.”

Well said. Of course, many scientists can do more, and we encourage all of our colleagues to speak publically about their research and, as the international glaciological research community did in this case, to try to correct misconceptions. At the same time, hopefully, HarperCollins will catch on and recognize that being scientifically literate is not just scientists’ responsibility, but is everyone’s responsibility.

On record-breaking extremes

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It is a good tradition in science to gain insights and build intuition with the help of thought-experiments. Let’s perform a couple of thought-experiments that shed light on some basic properties of the statistics of record-breaking events, like unprecedented heat waves. I promise it won’t be complicated, but I can’t promise you won’t be surprised.
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Conference conversations

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Rasmus & Gavin

The reason why scientists like going to conferences (despite them often being held in stuffy hotel basements) is because of the conversations. People can be found who know what they are talking about, and discussions can be focused clearly on what is important, rather than what is trivial. The atmosphere at these conferences is a mix of excitement and expectations as well as pleasure at seeing old friends and colleagues.

The two of us just got back from the excellent ‘Open Science Conference‘ organised by the World Climate Research Programme (WCRP) in Denver Colorado. More than 1900 scientists participated from 86 different countries, and the speakers included the biggest names in climate research and many past and present IPCC authors.

Open Science Conference

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Keystone XL: Game over?

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Translations: (Deutsch) (Español) (English)

The impending Obama administration decision on the Keystone XL Pipeline, which would tap into the Athabasca Oil Sands production of Canada, has given rise to a vigorous grassroots opposition movement, leading to the arrests so far of over a thousand activists. At the very least, the protests have increased awareness of the implications of developing the oil sands deposits. Statements about the pipeline abound.

Jim Hansen has said that if the Athabasca Oil Sands are tapped, it’s “essentially game over” for any hope of achieving a stable climate. The same news article quotes Bill McKibben as saying that the pipeline represents “the fuse to biggest carbon bomb on the planet.” Others say the pipeline is no big deal, and that the brouhaha is sidetracking us from thinking about bigger climate issues. David Keith, energy and climate pundit at Calgary University, expresses that sentiment here, and Andy Revkin says “it’s a distraction from core issues and opportunities on energy and largely insignificant if your concern is averting a disruptive buildup of carbon dioxide in the atmosphere”. There’s something to be said in favor of each point of view, but on the whole, I think Bill McKibben has the better of the argument, with some important qualifications. Let’s do the arithmetic.

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MJO Conversations

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There is a (relatively) new blog from scientists involved in a big research program (DYNAMO) looking into the Madden-Julian Oscillation (MJO). Called Madden-Julian Conversations, it is run by Adam Sobel and Daehyun Kim (Columbia), Zhiming Kuang (Harvard) and Eric Maloney (Colorado State).



A schematic of the MJO from cmmap.org

The MJO can be seen in eastward propagating systems of rainfall and deep convection near the equator and influencing the Indian monsoon and El Niño dynamics. Each MJO cycle takes around 30-60 days, so these events can be seen in high frequency diagnostics of cloud cover, LW radiation, rainfall etc. The blog goes into a little more detail of what the MJO is (part i, and parts ii, iii, iv and v), (note that is sometimes referred to as the Intra-seasonal Oscillation or ISO), as well as descriptions of the DYNAMO program and what atmospheric scientists working in the field actually get up to.



(but note that apparently a helmet is not actually required for modelers to launch radiosondes).

This is exactly the kind of thing that should become more common – scientists actually showing the world directly what their research involves and the process that we follow to find stuff out. This will make a great backdrop to the rather dryer contributions to the technical literature that will come from this.