The scientific "truth" about climate change

Elizabeth Muller showed me a graph, showing temperatures recorded at 39,000 stations around the world averaged together. This is the temperature record.

"The thick, black line is carbon dioxide plus volcanoes," she said, "and everything else is the actual temperature record. And the amazing thing is how well the two fit right on top of each other."

In a New York Times editorial, the Mullers described themselves as converted global-warming skeptics - but they sure don't sound very converted.

"The number of hurricanes has not been going up. The number of tornadoes has not been going up," said Richard Muller.

And what about the droughts and the fires in the West? "Well, that's because we're building closer to the fire areas," he said. "The number of fires in the United States has actually been decreasing with time."

And what about polar bears? They're dying because of global warming, no?

"No," said Muller. "There's no good scientific evidence for that. There's a problem in that some people, whenever they see something they don't like, they attribute it to global warming - whether it's the death of the frogs, or the demise of the corals in the Pacific Ocean. But that's kind of cherry-picking, where they're simply saying, 'If it's bad, it must be global warming.'"