The fight around climate change, which I've spent my life on, is somewhat more difficult than gay marriages because no one makes trillions of dollars a year being a bigot, and that's how much the fossil-fuel industry pulls in pumping carbon into the air. But the principle is the same, I think.

We have built a greenhouse, a human greenhouse, where once there bloomed a sweet and wild garden.

It's much to the credit of the rest of the world that they have gone ahead and tried to do the Kyoto accords on their own. It makes it unbelievably difficult to do that, for a variety of economic and regulatory reasons, without the participation of the biggest energy user in the world.

All the things that we've done as a species have had a limited scope. We're talking about melting the ice caps, raising the level of the seas dramatically, changing the distribution of every other species on Earth, perhaps wiping out one-third or half of them. The changes at work are geologic in scale. The level of change required to deal with it is enormous, too. It will require change in every country. It will require a degree of global cooperation that we haven't seen before.

So far the earth has warmed about a degree Fahrenheit globally averaged. That doesn't seem like an enormous amount but it's unlike what we would have expected twenty years ago.

There is nothing that will discombobulate and degrade [more] the lives of people near the margin on this planet. You don't have to look much past New Orleans to see that. Who took the hit? Some of the poorest people in the U.S.

... the constant flow of images undercuts the sense that there's actually something wrong with the world. How can there really be a shortage of whooping cranes when you've seen a thousand images of them - seen ten times more images than there are actually whooping cranes left in the wild?