James Lawrence Powell

Abstract of my article in Bulletin of Science, Technology, and Society
The extent of the consensus among scientists on anthropogenic global warming (AGW) has the potential to influence public opinion and the attitude of political leaders and thus matters greatly to society. The history of science demonstrates that if we wish to judge the level of a scientific consensus and whether the consensus position is likely to be correct, the only reliable source is the peer-reviewed literature. During 2013 and 2014, only 4 of 69,406 authors of peer-reviewed articles on global warming, 0.0058% or 1 in 17,352, rejected AGW. Thus, the consensus on AGW among publishing scientists is above 99.99%, verging on unanimity. The U.S. House of Representatives holds 40 times as many global warming rejecters as are found among the authors of scientific articles. The peer-reviewed literature contains no convincing evidence against AGW.

My article is a direct, peer-reviewed refutation of the method and result of Cook et al. 2013, the source of the widespread and mistaken belief that the consensus on AGW among publishing scientists is “97%.” If that figure were true, on average 3 of 100 articles would reject AGW. Instead, to find a single rejecting article, one has to read thousands. (For my search and review methodology, see here. Environmental Research Letters, where Cook et al. published, also accepted my article: see here.)

Where did Cook et al. go wrong? They invented an incorrect and misleading definition of consensus; falsely assumed that publishing scientists routinely endorse the ruling paradigm of their discipline (see paragraph below); arbitrarily ruled out of the consensus 21,200 climate authors--two-thirds of their database; and declared a number of prominent climate scientists like James Hansen both in and out of the consensus. Their method rules out of the consensus every author on global warming in Environmental Research Letters in 2013-2104, including the Cook et al. authors themselves. When applied to widely accepted theories like evolution, meteorite impact, and plate tectonics, the Cook et al. method fails, requiring division of zero by zero. See here for details. For what Cook et al. did and did not measure, see here.

John Cook continues to defend the "97% consensus," even though his own words falsify the starting assumption on which it is based. On his website John writes, “That so many studies on climate change don't bother to endorse the consensus position is significant because scientists have largely moved from what's causing global warming onto discussing details of the problem.” And, "In the scientific field of climate studies – which is informed by many different disciplines – the consensus is demonstrated by the number of scientists who have stopped arguing about what is causing climate change – and that’s nearly all of them." But if "so many studies don't endorse the consensus," then endorsement is not a criterion of consensus. When a scientist admits that his starting assumption is false, does that not also falsify the result and require that he retract it?

This chart summarizes my results. Click to download. The slice represents the number of authors expanded ten-fold. Note that the five rejecting articles have only one citation. See here. But that citation is actually to correct a mistake in the original article, so none of the five have ever been cited positively. In their impact on science, it is as though the five rejecting articles had never been written.