"The number of Americans who believe that global warming is a scientific fact has been dropping, and environmental groups and climate scientists who say the evidence for warming is clear are scratching their heads over this reversal and scrambling to find a new strategy.

Three years ago, former Vice President Al Gore won a Nobel Prize for publicizing the threat of climate change with his book and documentary film, An Inconvenient Truth. After that, scientists rejoiced, says Dan Lashof, director of the Climate Center at the Natural Resources Defense Council, an environmental group.

"We in the scientific community by and large said OK, the science debate is over, we are moving our efforts into what we are going to do about it. And that left the science debate in the public largely untended," he says. "That has been recognized as a strategic error."

They hadn't won. Climate skeptics worked to convince the public that the scientific argument for climate change was dodgy and exaggerated. The debate sometimes got hostile and personal, as it did in an exchange between climate skeptic Mark Morano and climate activist Joe Romm."

Christopher Joyce reports for NPR's Weekend Edition December 5, 2010. [2]