"Michael Mann Faces Off With Foes on 'Hockey Stick' Tour"

"Hockey sticks and brawls aren't just for NHL playoff games. Climate scientist Michael Mann has the scars to prove it. But along the way he has picked up some fans as well."

"The "Hockey Stick" — the term given to a graph depicting the globe's average temperatures over the last millennium, looking like a flat shaft with a "blade" spiking upward at the end of the 20th Century — made Penn State's Mann and his colleagues into magnets for controversy among climate naysayers. Largely, they criticized the hockey stick's stark depiction, based for the most part on tree-ring data, of rising temperatures driven by global warming. The graph became famous after it appeared in a 2001 United Nations climate panel report.

Critics, most notably Canadian mining executive Steve McIntyre, argued that the type of statistics Mann used to collate past temperatures from tree rings inevitably introduced biases toward warming in the hockey stick reconstruction. But among scientists, a 2006 National Academy of Sciences report headed by Texas A&M's Gerald North that largely vindicated temperature reconstructions settled a lot of debate.

Along the way, Mann, author of the recently-released The Hockey Stick and The Climate Wars: Dispatches from the Front Lines, has faced Congressional hearings, university investigations and court cases, such as an ongoing fight with the American Tradition Institute, a climate science critic group pursuing his e-mail looking for signs of his bias. In the book, Mann recounts such episodes, including the four-month Penn State investigation in 2010, which found him, "cleared of any wrongdoing," in the infamous University of East Anglia case. In that episode e-mails lifted from British university's climate research center revealed that climate scientists basically don't like climate naysayers, don't like releasing their work to them, and quibble quite a bit with each other as well."

Dan Vergano reports for USA TODAY April 20, 2012.

Source: USA TODAY, 04/23/2012