A 97 Percent Footnote

Pointing out the fraudulence and superficiality of the climatistas “97 percent!” campfire slogan is a tedious business, but someone has to do it. (My most complete analysis of it is here.)

The distinguished climate economist Richard Tol has been all over the original Cook paper, and has a fresh takedown up on his website right now. If you’re not familiar with Tol, he is one of the pre-eminent economists in the field of the economics of climate change. His work was cited several dozen times in the infamous and later admittedly politicized “Stern Review” in the UK that purported to find huge near-term costs of climate change. Tol not only repudiated the way his work had been used in the Stern Review; he said if a graduate student had turned in the Stern Review as a class paper, he would have flunked the student. Most other serious economists laughed at the Stern Review’s economics, which is one reason it quickly sank like a stone. Tol is not, incidentally, a skeptic of human-caused climate change. He just has economic scruples, and calls BS when he sees it.

Anyway, here are few highlights from Tol’s latest broadside about the shoddiness of the Cook “97 Percent” paper:

Some have claimed that Cook et al. found a consensus on the dangers of climate change (Kammen, 2013) or on the need for climate policy (Davey, 2013). They investigated neither. Even some of the authors of the paper misrepresent its findings (Nuccitelli, 2014, Friedman, 2014, Henderson, 2014).

Cook et al. took a sample of the academic literature and rated its contents. The raters were recruited through a partisan website (Cook et al., 2013) and frequently communicated with each other (Duarte, 2014). Their sample is not representative of the literature (Tol, 2014a). The sample was padded with large numbers of irrelevant papers (Tol, 2014a). For example, a paper on photovoltaics in Kenya (Acker and Kammen, 1996) was taken as evidence that climate change is caused by humans as was a paper on the coverage of climate change on US TV (Boykoff, 2008). Three-quarters of the “endorsing” abstracts offer no evidence either way (Tol, 2014a). Their attempt to validate the data failed (Tol, 2014a). An attempt to replicate part of the data failed too (Legates et al., 2013). The data show inexplicable patterns (Tol, 2014a) while the consensus rate suffers from confirmation bias (Cook et al., 2014a, Tol, 2014b).

The problems do not stop there. It appears – no survey protocol was released – that the research team (1) gathered data (19 February to 15 April 2014), (2) studied the results, (3) gathered more data (11 May to 1 June 2012), (4) studied the results again, (5) changed the classification system, and (6) gathered more data and reinterpreted the rest. The results from step (1) and (3) are different (raw sample chi-sq(df=6)=255, p<0.001; matched sample chi-sq(df=6)=393, p<0.001). The results from step (3) and (6) are different too: The dissensus rate changes by one-half (Tol, 2014a). . .

In sum, one of the most visible climate papers of recent years is not sound. Whereas previous critique could be interpreted as a lack of competence (Tol, 2014a), the later data release suggests that Cook et al., perhaps inadvertently, worked towards a given answer. This reflects badly on the authors, referees, editors and publisher. It also weakens the activists and politicians who cite Cook et al. in support of their position.

In light of how bad the Cook paper is, it is a travesty that NASA continues to trumpet it on its website.


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