IPCC Lead Author Reports Flaws in Asserted 97-Percent Consensus

Published August 28, 2013

A recently published paper claiming 97 percent of peer-reviewed studies on climate change agree “humans are causing global warming” is riddled with errors and ends-driven measuring sticks, according to United Nations Intergovernmental Panel on Climate Change lead author Richard Tol. Tol reported his findings in an August 27 letter to University of Queensland (Australia) professor Peter Hoj.

Tol said the paper first caught his attention when he noticed several procedural errors.

“My attention was drawn to the fact that the headline conclusion had no confidence interval, that the main validity test was informal, and that the sample contained a very large number of irrelevant papers while simultaneously omitting many relevant papers,” Tol explained.

Tol then wrote to the main author of the paper, John Cook, seeking the underlying data forming the basis of the study. Cook, a blogger and global warming activist who works under Hoj at the University of Queensland, declined to send Cook all or even most of the data. Instead, Cook sent merely 13 percent of the requested data.

Even in the small percentage of data Cook submitted, Tol found many new problems.

“I found that that the consensus rate in the data differs from that reported in the paper,” Tol noted in his letter to Hoj. “Further research showed that, contrary to what is said in the paper, the main validity test in fact invalidates the data. And the sample of papers does not represent the literature. That is, the main finding of the paper is incorrect, invalid and unrepresentative.”

“Furthermore, the data showed patterns that cannot be explained by either the data gathering process as described in the paper or by chance,” Tol observed.

Tol noted the small number of people who rated the peer-reviewed studies and the lack of any identified means of assessing and correcting for reviewers’ bias.

Tol concluded his letter by asking Hoj to provide the requested data Cook declined to send to Tol.

“His foot-dragging, condoned by senior university officials, does not reflect well on the University of Queensland’s attitude towards replication and openness. His refusal to release all data may indicate that more could be wrong with the paper.”

Tol’s letter to Hoj can be found at science writer Joanne Nova’s website.