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.

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

Neanderthals were pretty smart, and if we actively killed them off, then probably we did so in the same way that humans kill each other.

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.

No matter what Donald Trump says, it's clear that global warming is rapidly changing conditions on our planet.

You've got to do everything, everything's got to be pointing in the same direction and you've got to really turn this whole economic engine from one that's based on fossil fuels to one that isn't.

One of the reasons that people, many people, many environmentalists are critical of President [Barack] Obama's policies towards global warming is on the one hand he says the right things and he says he's committed to trying to reduce our current emissions.