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As a true public service, Richard Tol has taken on the task of deconstructing (and thereby demolishing) the spurious Cook claim of a 97% consensus on AGW. This is sound work.
The 97% Cook Consensus – when will Environ Res Letters retract it?
Richard Tol has an excellent summary of the state of the 97% claim by John Cook et al, published in The Australian today.
It becomes exhausting to just list the errors.
Richard Tol‘s blog: Occasional thoughts on all sorts.
“Global warming consensus claim doesn’t stand up”
An edited version appeared in the Australian on March 24, 2015
Consensus has no place in science. Academics agree on lots of things, but that does not make them true. Even so, agreement that climate change is real and human-caused does not tell us anything about how the risks of climate change weigh against the risks of climate policy. But in our age of pseudo-Enlightenment, having 97% of researchers on your side is a powerful rhetoric for marginalizing political opponents. . . .
The Cook paper is remarkable for its quality, though. Cook and colleagues studied some 12,000 papers, but did not check whether their sample is representative for the scientific literature. It isn’t. Their conclusions are about the papers they happened to look at, rather than about the literature. Attempts to replicate their sample failed: A number of papers that should have been analysed were not, for no apparent reason.
The sample was padded with irrelevant papers. An article about TV coverage on global warming was taken as evidence for global warming. In fact, about three-quarters of the papers counted as endorsements had nothing to say about the subject matter.
Cook enlisted a small group of environmental activists to rate the claims made by the selected papers. Cook claims that the ratings were done independently, but the raters freely discussed their work. There are systematic differences between the raters. Reading the same abstracts, the raters reached remarkably different conclusions – and some raters all too often erred in the same direction. Cook’s hand-picked raters disagreed what a paper was about 33% of the time. In 63% of cases, they disagreed about the message of a paper with the authors of that paper.
Keep reading →
The 97% Cook Consensus – when will Environ Res Letters retract it?
Richard Tol has an excellent summary of the state of the 97% claim by John Cook et al, published in The Australian today.
It becomes exhausting to just list the errors.
Don’t ask how bad a paper has to be to get retracted. Ask how bad it has to be to get published.
As Tol explains, the Cook et al paper used an unrepresentative sample, can’t be replicated, and leaves out many useful papers. The study was done by biased observers who disagreed with each other a third of the time, and disagree with the authors of those papers nearly two-thirds of the time. About 75% of the papers in the study were irrelevant in the first place, with nothing to say about the subject matter. Technically, we could call them “padding”. Cook himself has admitted data quality is low. He refused to release all his data, and even threatened legal action to hide it. (The university claimed it would breach a confidentiality agreement. But in reality, there was no agreement to breach.) As it happens, the data ended up being public anyhow. Tol refers to an “alleged hacker” but, my understanding is that no hack took place, and the “secret” data, that shouldn’t have been a secret, was left on an unguarded server. The word is “incompetence”, and the phrase is “on every level”. . . . .
Richard Tol‘s blog: Occasional thoughts on all sorts.
“Global warming consensus claim doesn’t stand up”
An edited version appeared in the Australian on March 24, 2015
Consensus has no place in science. Academics agree on lots of things, but that does not make them true. Even so, agreement that climate change is real and human-caused does not tell us anything about how the risks of climate change weigh against the risks of climate policy. But in our age of pseudo-Enlightenment, having 97% of researchers on your side is a powerful rhetoric for marginalizing political opponents. . . .
The Cook paper is remarkable for its quality, though. Cook and colleagues studied some 12,000 papers, but did not check whether their sample is representative for the scientific literature. It isn’t. Their conclusions are about the papers they happened to look at, rather than about the literature. Attempts to replicate their sample failed: A number of papers that should have been analysed were not, for no apparent reason.
The sample was padded with irrelevant papers. An article about TV coverage on global warming was taken as evidence for global warming. In fact, about three-quarters of the papers counted as endorsements had nothing to say about the subject matter.
Cook enlisted a small group of environmental activists to rate the claims made by the selected papers. Cook claims that the ratings were done independently, but the raters freely discussed their work. There are systematic differences between the raters. Reading the same abstracts, the raters reached remarkably different conclusions – and some raters all too often erred in the same direction. Cook’s hand-picked raters disagreed what a paper was about 33% of the time. In 63% of cases, they disagreed about the message of a paper with the authors of that paper.
Keep reading →
