Following this month's elections in which conservative Republicans won control of the House of Representatives, Mann anticipates hostile hearings on the subject of climate change. He addressed science writers at the 48th annual New Horizons in Science meeting in New Haven, Connecticut, US earlier this month.

Mann described some of the multiple lines of evidence supporting the scientific consensus on climate. In the US, he said, almost alone among industrialized nations, there is political controversy on this point. He blamed "a well organized and orchestrated effort by the most powerful industry that has ever existed on the face of the Earth". He likened this campaign to the one conducted by the tobacco industry years ago, in which it sought to discredit solid scientific evidence that cigarette smoking caused cancer.

If climate change is an elaborate hoax, then the ice sheets must be in on it; the sea level must be in on it; and the polar bears are likely in on it, although they are big losers Michael Mann

Mann, a professor of meteorology and geoscience at Pennsylvania State University, US, is one of the scientists whose e-mails were hacked a year ago at the Climatic Research Unit of the University of East Anglia, UK. He said that "perhaps the greatest victory of the climate-change deniers" was the labeling of the episode as Climategate. "The irony is that Watergate was a crime," added Mann. "The crime here was the illegal theft of private correspondences, and arguably the moral crime was an intentional effort to distort the scientists' belief and what they think. And somehow, this got affixed with the 'gate' terminology."

"There was a campaign already in place the moment this broke to promote this story," Mann said. "This distracted the public at a critical juncture, just weeks before last December's Copenhagen summit on climate change."

Mann said his own career has not been affected. Although the hacked messages were "cherry-picked and taken out of context and distorted" to give the impression that scientists were hiding the true facts about climate, he noted that multiple investigations by peers had cleared them of any scientific misconduct.

Even so, Mann added, the Attorney General of the state of Virginia is seeking to gain access to e-mails that he wrote and received during his long service at the University of Virginia. It is not a question of access to data, Mann added, all of which are already freely available. The Attorney General, Kenneth Cuccinelli, would not know what to do with the data, anyway, he said.

"If climate change is an elaborate hoax, then the ice sheets must be in on it; the sea level must be in on it; and the polar bears are likely in on it, although they are big losers," Mann said, to general laughter. Asked how to deal with climate-change deniers, he said that both scientists and the media have important roles. Scientists are stepping up their informational efforts, he noted, citing a new initiative by the American Geophysical Union to respond directly to questions on climate science from reporters and others.

"Frankly," he added, "we are entirely reliant on the willingness of the mainstream media to serve in its role as a critical and independent arbiter, to not just report the two sides in the so-called debate, but to actually establish what is fact and what is fiction. The scientists will not be successful in their own efforts to combat this attack that will be coming, unless the media is serving its role."