Archives for 2010

The March 20th -26th cover story of The Economist, “Spin, science and climate change,” deftly bypasses the politics surrounding ‘climategate’, to tackle the more important issue: whether any of this has any bearing on climate change science and policy. This is a refreshing bit of journalism that everyone should read.
[Read more…] about The Economist does not disappoint

After weeks and months of press coverage seemingly Through the Looking Glass, Paul Krugman has sent us a breath of fresh air this morning in the New York Times Magazine, entitled “Building a Green Economy“. Krugman now joins fellow NYT columnist Tom Friedman as required reading in my Global Warming for English Majors class at the University of Chicago.

[Read more…] about Krugman weighs in

A new popular sport in some media these days is “climate scientist bashing”. Instead of dealing soberly with the climate problem they prefer to attack climate scientists, i.e. the bearers of bad news. The German magazine DER SPIEGEL has played this game last week under the suggestive heading “Die Wolkenschieber” – which literally translated can mean both “the cloud movers” and “the cloud traffickers” (available in English here ). The article continues on this level, alleging “sloppy work, falsifications and exaggerations”. By doing so DER SPIEGEL digs deeply into the old relic box of “climate skeptics” and freely helps itself on their websites instead of critically researching the issues at hand.
[Read more…] about Climate scientist bashing

by Rasmus & Jim

Who would think that Internet, ideas, disease, money, birds, and climate literacy have anything in common? Recent progress on complex systems and network theory suggests that they all can be described in terms of a ‘Levy flight‘. A recent and lengthy paper with the title ‘A study on interconnections between climate related ideas in complex networks’ (Ann. Trans. ICCPRS Soc. 52(3):1647-71; subscription required) by John McVenus argues that new ideas can be traced over the Internet just like dollar bills are traced at Wheresgeorge. Our take on this is that this study muddles things more than clarifying the facts – probably because McVenus tries to explain almost everything.

[Read more…] about Climate and network connections

The first (of three) inquiries on the CRU email affair has reported, and this thread is for discussions of the UK Parliamentary Select Committee report. The conclusions are not un-expected, but there is bound to something for everyone to chew on. Get gnawing!

p.s. there is a useful summary at DeSmogBlog.

In a recent post here at RealClimate, Simon Lewis wrote regarding a 2010 paper by Samanta et al. on the effect of single-year drought conditions on the Amazon. Samanta et al. claimed to have contradicted a 2007 paper by Scott Saleska et al., and to have thereby overturned some IPCC conclusions.

Here is Saleska’s commentary in full
——-
Guest Commentary by Scott Saleska, University of Arizona

The title of the Lewis post (“Up is Down, Brown is Green”) is perhaps even more true than the insightful commentary by my colleague Simon Lewis indicates! The Samanta et al paper says brown, but in fact their own data (when you dig it out of the supplement) shows green, consistent with (and indeed virtually indistinguishable from) our original findings published in Science (Saleska et al., 2007).

Samanta et al. misrepresents our work on many levels (one of which is to assert, falsely, that we did not filter out atmosphere-corrupted observations when in fact we did), and we intend, of course, to present an appropriate response in the peer reviewed literature, where the technical details of our differences may be evaluated by anyone who wishes. But for the moment we will, for the sake of argument, accept their analysis at face value and ask: even if Samanta et al. are 100% correct in their critique of our methods (which we of course dispute), what are the implications? Does the alternative to our method which Samanta et al. advocate, or the recent update in the MODIS satellite data (to version 5 from version 4), make any difference for the main conclusion of our paper? With due respect to our friends and colleagues at Boston University, the answer is no, it does not.

First: the actual relevant Samanta et al data (which comes from their Supplement, Table S3) is this:

Note that the green area in the drought region increases to its maximum (10.8% of the total area = 10.8/33.68 = 32% of the valid area) in 2005. In other words, the Samanta et al data contradict the Samanta et al text and title (which states that Amazon forests did not green up): not only do forests in the drought region green up, they green up alot, more than any other year since the MODIS satellite sensor was launched.

Second, how does this compare to Saleska et al. (2007), which Samanta et al claim to rebut? Here are the numbers (again, taken directly from Samanta et al, Table S3 and Saleska et al., 2007):

Fraction of valid pixels in the 2005 drought region that are “green” (> + 1 Standard deviation)
Saleska et al. (2007): 34% (p<0.000001) Samanta et al. (2010): 32% (p<0.004) The bottom line is that their observed 2005 result (32% greenness) is indistinguishable from ours (34%). I.e. Samanta et al effectively reproduce the results of Saleska et al. This summary response, of course, begs some very interesting questions about tropical forest function under climatic variability and change (indeed the most interesting questions of all!): what caused the anomalously disproportionate green-up in the drought region? And, even if satellite “green up” does in fact represent an increase in photosynthesis (as we think), could this in fact be a symptom of the trees compensating for the increased stress of the drought? The bottom line “carbon balance” of a tree depends on both photosynthetic uptake and respiratory losses, and it is almost certainly the case that those losses (which were not seen by the satellite) increased under the hotter and drier conditions of the drought as well. Thus, the most intriguing idea to me is that the short-term satellite-detected green-up, and the longer term increase in net carbon loss reported in the Phillips et al paper (discussed by Simon Lewis) are not in conflict at all. It might well be that they represent different parts of a coherent forest response to drought, in which the longer term losses are larger than the satellite-detected attempt to compensate for them by increasing photosynthesis, and in the end, increased tree mortality is the result. In conclusion I would like to reinforce Simon’s point about Samanta et al and the IPCC. More important than whatever they say about our one short paper, Samanta et al. truly and egregiously misrepresent the implications, of both their work and ours, when they claim that a single paper on short term vegetation response somehow rebuts the IPCC’s review of the large scientific literature on how Amazonia might respond to long-term shifts in the mean climate state. It is an illogical and misguided claim on many levels, one that is already and deservedly attracting the opprobrium of many of my colleagues, talented scientists who study Amazon forests and climate (see Scientists speak: Amazon “myths” are not debunked).

In sum:

— Samanta et al data show a drought region green up that is on average indistinguishable from Saleska et al (but they call it NO green up).
— Samanta et al data almost exactly reproduce Saleska et al’s most salient bottom-line result (but they say what we did was not reproducible).
— the Samanta et al paper, based on a three-month drought response, says not one word about long-term climate change scenarios reviewed in IPCC (but they advertise their analysis as “reject[ing] claims” put forward by the IPCC).

Another open thread. OT comments from the Amazon drying thread have been moved over. As usual, substantive comments only please and no abuse.