The University of East Anglia’s official report about the leaked e-mails concluded that “opposing interpretations can be obtained from the same statement.” But even if we give those involved the benefit of the doubt — presuming that “trick” and “hide the decline” mean precisely what Mann’s defenders insist they mean — the episode still suggests something important: that Mann and his colleagues have processed their data in a way that makes global warming appear more severe than the evidence suggests on its own. There is little doubt that some of the information with which the group was working has proven to be inconvenient. Per some of the tree-ring results, temperatures have declined in the second half of the 20th century; per the instrumental record, however, temperatures have gone up. Thus have Mann and Co. seen fit to drop certain proxy data that imply such a decline, and to add in certain instrumental data that show an increase. Most egregiously, in the 2001 IPCC report — which unleashed the hockey stick on a shocked world — Mann and his co-authors simply removed the declining post-1960 proxy data collected by Keith Briffa (thus “hid[ing] the decline”) but left in his colleagues’ more convenient proxy findings, thereby making the proxy reconstructions appear more consistent and accurate than they really were.

—Charles C. W. Cooke, “The Climate Inquisitor”