ties to industry (PDF) and right-wing think tanks, and public opinion was turning toward action on climate change. At this pivotal moment, reopening the debate was just what the skeptics, and their industry backers, needed. McIntyre and McKitrick were flown to Washington for another briefing with the Marshall Institute and CEI (PDF).
Congressional conservatives swung into action. Rep. “Smokey” Joe Barton (R-Texas), then the chairman of the House Energy and Commerce Committee, launched a formal inquiry into the work of Mann and other climate scientists in June 2005. As part of the inquiry, Barton—who believes acting on global warming is “absolute nonsense” and said in a hearing that “when it’s hot, we find shade“—enlisted George Mason University statistician Edward Wegman to produce a report on the hockey stick. (In doing so, Barton eschewed (PDF) the more traditional route of requesting (PDF) a report from the National Research Council, a branch of the National Academy of Sciences.)
The Hockey Game
600 years of temperature data can’t be wrong. Or can it?
MICHAEL MANN’S hockey-stick graph shows average temperatures over the past 1,000 years based on “proxy data” reconstructions from tree rings, ice cores, sediment, coral, and some instrumental data. The last 600 years of Mann’s proxy data are shown below in blue. Actual temperatures, starting in the 1850s, are shown in red. (The darker trend lines are based on 40-year averages.) Both sets of data show a sharp temperature spike after the Industrial Revolution and a slight dip in the 1960s followed by a continued rise in recorded temperatures. Other climatologists have done their own studies of historic climate variations, and there is much debate over the fact that some of those studies—specifically those focusing on certain sets of tree-ring data—suggest that modern temperatures are continuing to decline.
In a slideshow meant to highlight GMU’s investigations for Congress (PDF), a Wegman staffer noted that Barton’s office warned Wegman’s group to expect criticism and told them to have “thick skins.” Barton’s staff also provided the group with reams of reading material—particularly troubling, considering that none of the statisticians, she said, had “any real expertise in paleoclimate reconstruction.” Wegman’s group also consulted McIntyre in its evaluation of Mann’s study, but it never reached out to Mann.
When it was released in July 2006, the Wegman report (PDF) essentially agreed with McIntyre, citing statistical problems with the hockey stick and accusing climate scientists of uncritically reinforcing each other’s work. Years later, Barton and other skeptics still tout the document as proof that the hockey stick is broken (even though GMU is currently investigating allegations that Wegman may have lifted portions of the report from a previously published book).
Meanwhile, about five months after Barton commissioned Wegman for the report, the House Committee on Science asked (PDF) the National Academy of Sciences to prepare a formal report on the hockey stick. The review concluded (PDF) that while some uncertainties “have been underestimated,” there was nevertheless “an array of evidence” supporting the main conclusion of Mann’s work.
* Clarification: The original Wall Street Journal article referred to a report by researcher Hans von Storch, not McIntyre’s specifically: “Reports such as [von Storch’s] helped to reopen the debate, even to outsiders.”
The fights over the hockey stick eventually faded from the headlines, but the data war raged on. McIntyre turned his attention to pursuing the data that climate scientists had drawn from to conclude that the planet is drastically warming. He was particularly interested in East Anglia’s Climatic Research Unit, keepers of one of the most complete sets of temperature records in the world. He asked the unit for raw data, but was rebuffed. “If they ever hear there is a Freedom of Information Act (FOIA) now in the UK, I think I’ll delete the file rather than send to anyone,” CRU head Phil Jones wrote to Mann in February 2005. He