ANNA AURILIO (U.S. Public Interest Research Group federal legislative director): Well, Neil, the top climate scientists say something's really happening. We've got cherry blossoms in January. As Larry [Cosgrove] pointed out, the polar bears are drowning, the ice that they depend on is melting. And again, the good news is, the things --
CAVUTO: But how do you know -- wait, wait, how do you know that wasn't occurring 150 years ago? Reliable statistics we have now go back only about 100 years, right?
AURILIO: Well, no, I mean, if we go back to the great explorers of the Earth, they were always looking for a Northwest Passage through the Arctic Sea ice. This goes back hundreds of years. This year, for the first time --
CAVUTO: But you don't have accurate --
AURILIO: -- people were actually able to find it.
CAVUTO: But you don't have accurate measurements of what the Earth's temperature was even more than a century ago, right?
AURILIO: Actually, the International Panel on Climate Change, which is the world's top climate scientists, say that the Earth's temperature and the carbon buildup in the atmosphere, more importantly, is higher than it's been in 20,000 years. And they know that from all the --
CAVUTO: Do you buy that Larry? Is it the highest it's been in 20,000 years?
COSGROVE: And again, I have to disagree, Anna, simply because the data, as Neil pointed out, is not reliable beyond about 100 years.
And I'll take it one step further. Let's go further back to when the Norse settled Greenland. Now, think about that. It's very tough to settle an ice, rock-bound community, but they were doing farming in Greenland many, many hundreds of years ago. Why? Because the climate had warmed sufficiently to allow that.
My bottom line is this: Yes, carbon emissions may be hurting the atmosphere. It may be inducing --
CAVUTO: OK.
COSGROVE: -- some global warming, but is it doing it all? I don't think so. I think there's a natural cycle.
CAVUTO: All right. Larry and Anna, I want to get you both back here. You both argue your points very well. Thank you.
Aurilio's statement that “the International Panel on Climate Change, which is the world's top climate scientists, say that the Earth's temperature and the carbon buildup in the atmosphere, more importantly, is higher than it's been in 20,000 years” may be a reference to the IPCC's latest report on climate change. The report's “Summary for Policymakers” states: