You're an animal that needs to move across the landscape, you can't anymore, and that's another way we're just changing the surface of the Earth in very dramatic ways.

The Earth is big. There are huge natural forces that have worked over geological time. But it turns out, when you look carefully at the geological time, you can't find anything like us.

Humans will eventually become extinct. People treat that as a radical thing to say. But the fossil record shows us that everything eventually becomes extinct.

Several decades ago, a detachment of the American right cut itself loose from reason, and it has been drifting along happily ever since. If the birthers are more evidently kooky than the global-warming "skeptics" or the death-panellers or the supply-siders or the Swift Boat Veterans for Truth, they are, in their fundamental disregard for the facts, actually mainstream.

There are a lot of things that we could do to minimize what we're doing, but we're not getting back those frogs that I saw that no longer exist.

Increasingly developing countries are asking for aid to help deal with the consequences of climate change, which we don't want to give.

People sometimes say we need to be really almost on a wartime footing if you want to change. Our whole economy is based on burning fossil fuels, which is taking CO2 out of the ground and putting it up into the air.