Some want Gore to cool the hype

Hollywood has a thing for Al Gore and his three-alarm film on global warming, "An Inconvenient Truth," which won an Academy Award for best documentary. So do many environmentalists, who praise him as a visionary, and many scientists, who laud him for raising public awareness of climate change.

But part of his scientific audience is uneasy. In talks, articles and blog entries that have appeared since his film and accompanying book came out last year, these scientists argue that some of Gore's central points are exaggerated or erroneous. They are alarmed, some say, at what they call his alarmism.

"I don't want to pick on Al Gore," Don J. Easterbrook, an emeritus professor of geology at Western Washington University, told hundreds of experts at the annual meeting of the Geological Society of America. "But there are a lot of inaccuracies in the statements we are seeing, and we have to temper that with real data."

Gore, in an e-mail exchange about the critics, said his work made "the most important and salient points" about climate change, if not "some nuances and distinctions" scientists might want. "The degree of scientific consensus on global warming has never been stronger," he said, adding, "I am trying to communicate the essence of it in the lay language that I understand."

Although Gore is not a scientist, he does rely heavily on the authority of science in "An Inconvenient Truth," which is why scientists are sensitive to its details and claims.

Criticisms of Gore have come not only from conservative groups and prominent skeptics of catastrophic warming, but also from rank-and-file scientists like Easterbrook, who told his peers that he had no political ax to grind. A few see natural variation as more central to global warming than heat-trapping gases. Many appear to occupy a middle ground in the climate debate, seeing human activity as a serious threat but challenging what they call the extremism of both skeptics and zealots.

Kevin Vranes, a climatologist at the Center for Science and Technology Policy Research at the University of Colorado, said he sensed a growing backlash against exaggeration. While praising Gore for "getting the message out," Vranes questioned whether his presentations were "overselling our certainty about knowing the future."

Typically, the concern is not over the existence of climate change, or the idea that the human production of heat-trapping gases is partly or largely to blame for the globe's recent warming. The question is whether Gore has gone beyond the scientific evidence.