Pennsylvania State University climate scientist Michael Mann has filed a lawsuit against The National Review and The Competitive Enterprise Institute for articles that compared him to convicted child molester Jerry Sandusky.

Mann's lawsuit concerns two blog posts. The first appeared July 13 on openmarket.org, the blog of the Competitive Enterprise Institute (CEI), a nonprofit that promotes free enterprise and limited government. In the post, author Rand Simberg wrote that Mann manipulated data in creating his famous "hockey-stick graph," which shows global temperatures rising sharply with increased carbon-dioxide output by humans.

"Mann could be said to be the Jerry Sandusky of climate science," Simberg wrote, referring to the Penn State football coach now imprisoned for child sex abuse, "except that instead of molesting children, he has molested and tortured data."

Nine investigations of Mann's work, including one by the Environmental Protection Agency and another by the National Science Foundation, have found no evidence of academic fraud.

The CEI removed the references to Sandusky in the original blog post several days after publication, but not before the "The Corner," the blog of the National Review Online, picked up the quote in full and repeated the accusations. Mann and his lawyers filed suit against both organizations on Monday (Oct. 22) in the Superior Court of the District of Columbia.

To win the suit, Mann's lawyers will have to show that the statements made by the CEI and National Review were harmful, false and made with the malicious intent to injure Mann. They'll also have to show that the organizations should have known the statements were false but published them anyway. [How Climate Science Became Politicized]

"We do not believe he will succeed," said Sam Kazman, the general council attorney for CEI. "Mr. Mann is a very prominent person in a highly controversial issue involving both science and politics, and I would have thought by now he'd be accustomed to rhetoric that can be quite heated." (Mann is typically referred to as a "Dr." since he has a doctoral degree.)

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On his website, Mark Steyn, the author of the National Review blog post, wrote, "I'll have more to say about this when I stop laughing."

Mann said he was motivated to file the suit by years of similar accusations.

"There is a larger context for this latest development, namely the onslaught of dishonest and libelous attacks that climate scientists have endured for years by dishonest front groups seeking to discredit the case for concern over climate change," Mann wrote in an email to LiveScience.

Climate-change belief has become increasingly polarized in the last decade. According to long-running surveys by Yale University researchers, in 2003 only 7 percent of Americans called climate change a "hoax" or a "scam." By 2010, 23 percent were using those terms to describe climate change, indicating an increasing perception of intentional wrongdoing by scientists.

Some of the politicization dates back to the polarizing Clinton era, said Anthony Leiserowitz, the director of the Yale Project on Climate Change Communication. After Al Gore took on the role of environmental advocate with his 2006 documentary "An Inconvenient Truth," Leiserowitz said, those on the other end of the political spectrum began to link Gore and Democrats not only to climate-change policy, but also to climate-change belief.

"They loathe Al Gore," Leiserowitz told LiveScience in August. "Sometimes I joke that Al Gore could hold a press conference tomorrow to say that science has determined that the Earth is round and people out there would say, 'Well, no it isn't.'"

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