Understandably, Mr. McIntyre doesn't agree with dismissals of his work, and the criticism he has received has made him increasingly critical of the peer-reviewed process that has vindicated the hockey-stick graph. "Peer-reviewed scientists have denied the point of [our]research," he complains. Many of his recent attacks on climate change have focused on the argument that seemingly independent studies validated by peer review are actually the work of a small group of insiders who control the peer-review process and rubber-stamp each other's scholarship.
Online writing has other advantages over the peer-reviewed system, some bloggers believe. If blogging is a speedy new medium, peer review is a classic example of a slow and deliberative old medium.
"There are 10 peer-reviewed articles I could draw out of the Climate Audit posts," Mr. McIntyre says, "but I've got this very large audience. I've got to keep feeding the blog."
As much as climate change, the issue of peer review separates Mr. McIntyre from his critics. "There is a very fundamental distinction between the way science actually moves forward, which isn't on blogs," Prof. Mann notes. "It's through the traditional process of doing the hard work necessary to get your work published in legitimate peer-reviewed scholarly journals and then it's out there for others to either improve upon, to refute, to address. That's the self-correcting process. Frankly, that process has been subverted by those who … make sometimes outlandish claims in the completely un-peer-reviewed environment of the Internet."
Still, the scientists concede that the work of some of these online bloggers has led to some necessary corrections - including sloppy misrepresentations of data such as the recent "Glaciergate" brouhaha (over unreliable estimates of when Himalayan glaciers would eventually melt), which Mr. Mooney says the researchers "ought to be ashamed of."
Gavin Schmidt, of the National Aeronautics and Space Administration's Goddard Institute for Space Studies cites a mistake that Mr. McIntyre found in an analysis of global temperatures, which "we fixed in a day and thanked him for his attention. That got blown out of all proportion and was made to look like we did it on purpose ... something McIntyre did nothing to prevent. So you take something that is constructive and turn it into a huge piece of misinformation."
One little-known irony of the debate is that for all the harsh words, many scientists have a grudging respect for Mr. McIntyre's intelligence. "He could be a scientific superstar," Mr. Schmidt says. "He's a smart person. He could be adding to the sum total of human knowledge, but in effect he adds to the reduction of the sum total of human knowledge."
As the world looks toward Mexico, where further climate change negotiations are scheduled in July, how much impact have the bloggers had on the political debate? Polling data on the issue is inconclusive and the full impact of Climategate has yet to be felt, but there are some telling signs. Last month, a poll from researchers at Yale and George Mason universities revealed that 50 per cent of Americans are "somewhat" or "very" worried about global warming, down from 63 per cent in 2008.
Jeet Heer is a Toronto-based freelance writer.