The crisis is a concrete threatening reality today. It stands to get catastrophically worse unless we take action before the accumulation [of] this global warming pollution reaches such toxic levels that the problem becomes bigger than we can solve.

The presidency is more than a popularity contest.

When you have the facts on your side, argue the facts. When you have the law on your side, argue the law. When you have neither, holler.

A lot of people go straight from denial to despair without pausing in the middle and doing something about it.

Hey, you know what, I've gotta go on that 'Letterman' show. That show is so lame.

All I'm doing, all I have done for 40 years, is spend time with the best scientific experts, gain their confidence, and take advantage of their patience in explaining things to me over and over again in progressively simpler language that I can understand, so that I can read it back to them and get their sign off, where they say, "Yep, that's it, Al. You've got it." When I understand it, I know I can explain it to other people. When the scientists' predictions end up being true, I see that as an opportunity to say to people, "Listen carefully to what they're saying now."

The interior of the earth is extremely hot – several million degrees.