on the topic has not benefited him financially—rather, it’s taken time away from more profitable business.
* Correction: An earlier version of this piece stated that the graph featured in the film showed temperature rise. It actually shows rise in CO2 levels. We regret the error.
McIntyre belongs to the school of skeptics known as “lukewarmers”—those who believe the planet is warming and humans are playing a role (see our Field Guide to Climate Change Skeptics), but don’t think this is as much of a problem as it has been made out to be.
“I’m not particularly comfortable with either side of the US debate,” McIntyre told me. “There are obviously competent and intelligent people that view it as a serious problem. That doesn’t mean that they’re right, but it’s not a hoax.” Nor does he oppose government regulations on principle, as do some of the free-market think tanks that regularly invite him to DC for speaking engagements. “I’m a Canadian,” says McIntyre. “I think governments can do things.”
McIntyre’s entrée into the climate debate came with a paper he coauthored with economist Ross McKitrick that critiqued an earlier version of Mann’s (PDF) hockey-stick graph. The paper was published in the November 2003 issue of Energy and Environment. It’s a publication known for providing a platform to skeptics—which is why, among the trove of hacked emails, there’s one from Mann urging colleagues to “dismiss this as [a] stunt, appearing in a so-called ‘journal’ which is already known to have defied standard practices of peer-review.” Mann predicted that “the usual suspects are going to try to peddle this crap.”
Sure enough, McIntyre and McKitrick were soon invited to Washington for a briefing (PDF) arranged by the George C. Marshall Institute and the Competitive Enterprise Institute (CEI), both free-market think tanks that have been heavily funded by ExxonMobil and other oil interests. They were also asked to meet with Sen. James Inhofe (R-Okla.), who has called climate change “the greatest hoax ever perpetrated on the American people.”
The targets of McIntyre’s audits were less enthralled. “I wouldn’t send him anything,” Mann emailed CRU head Phil Jones in February 2004. “I have no idea what he’s up to, but you can be sure it falls into the ‘no good’ category…There is no reason to give them any data, in my opinion, and I think we do so at our own peril!”
In February 2005, McIntyre and McKitrick published (PDF) another critique of the hockey-stick chart in the more-respected Geophysical Research Letters. They argued, essentially, that the chart underestimates the uncertainties about historical temperatures and relies on proxy data that they believe are “no more informative about the distant past than a table of random numbers.”
McIntyre isn’t alone in his skepticism about proxy data—in fact, it’s at the heart of the climate debate. Recorded temperature measurements only go back about 160 years, so scientists use data from tree rings, ice cores, and coral to reconstruct what the climate was like before that. For two millennia, those data sets align to show swings of about one degree Fahrenheit in either direction. But then, in the 1960s, some tree-ring data diverge (PDF) and suggest declining temperatures—even as actual temperatures show a dramatic rise. No one knows quite why this is; some researchers suggest the trees may actually be showing the stress from human activities. This divergence is one reason that many skeptics argue against using temperature reconstructions in climate change research.
McIntyre’s paper made headlines. A few days after publication, he was featured in a front-page piece in the Wall Street Journal that pitted (PDF) his hockey-stick critique against the whole of global warming science, saying he had “helped to reopen the debate.”*
Few scientists will ever get that kind of coverage for their life’s work, let alone for a single article on someone else’s research. But McIntyre’s critique came at a time when those seeking to block action on climate change were on the defensive—many had been pilloried for their 