On Global Warming:
Ms. Bumiller: Mr. President, why did your administration change its position on what causes global warming?

THE PRESIDENT: I don't think we did.

Ms. Bumiller: According to —

THE PRESIDENT: I don't think so, Elisabeth.

Ms. Bumiller: You said that it's almost certainly carbon monoxide — which you hadn't said in the past, carbon dioxide.

THE PRESIDENT: I think that was my position during the campaign, if I'm not mistaken.

Ms. Bumiller: It changed —

MR. McCLELLAN: You're talking about the National Academy of Science report?

Ms. Bumiller: Yes, yes.

MR. McCLELLAN: We've always talked about how that would - we'd be guided by their science on the issue, and that's why the President has done a lot in terms of climate change, advancing the science of climate change, and also doing more research —

THE PRESIDENT: Let me get back with you on that, because I think you might — I don't know why you said what you just said.

Ms. Bumiller: Well, we had a story in the paper this morning saying that you issued a report saying —

THE PRESIDENT: Oh, okay, well, that's got to be true.