This is hardly Mann's first review. His work has been the subject of at least two major investigations by outside experts.
And last week, a message went around his department at the university, notifying everyone that a whistle-blower could make up to $12 million by uncovering fraudulent use of federal grants. One blogger gloated that the offer would lead to Mann's having "a very unhappy new year."
Though he has been accused of dodging the press, Mann, 44, agreed readily to an interview on a bitterly cold day last week. The campus was deserted, as almost everyone was away for winter break. Mann was affable and calm as he answered the assertions of his critics.
The hardest part for him, he said, is having his integrity questioned. Scientists, he said, are "not trained to deal with these kinds of attacks."
"My suspicion is, this has been orchestrated at a high level," he said of the hacking.
Behind his desk were a picture of his 4-year-old daughter and a plaque commemorating his contribution to the 2007 Nobel Peace Prize, shared by the Intergovernmental Panel on Climate Change. Mann was the lead author on the group's 2001 assessment report.
He became well-known in the 1990s for his use of tree rings, ice cores, and other clues to reconstruct Earth's climate in centuries past. That work led to a graph that came to be known as "the hockey stick" because it showed global temperatures taking a sharp upturn in the 20th century.
Mann points out that the hockey stick is not widely seen as a smoking gun implicating human activity in global warming. And it was not the giant graph used in Al Gore's An Inconvenient Truth. That was a graph of the carbon dioxide component of our atmosphere - which also is rising sharply.
