It was huge mistake to avoid working with the rest of the world because (a) we're the largest source of the problem: 4% of us who are in the U.S. produce 25% of the world's carbon dioxide.

To me, it's more important to take the 60-70% of people who really understand that there's a problem [of climate change] and get some percentage of them active than to try and stamp out the last embers of pre-scientific thought.

I just keep trying to explain what's going on with our planet - and now, to explain what's going on with our politics, which explains why we're not doing anything about the former.

We've built a new Earth. It's not as nice as the old one; it's the greatest mistake humans have ever made, one that we will pay for literally forever.

Those of us in the west have figured out a lot of ways to damage the lives of poor people in this country and around the world over the years.

We don't know exactly where all the tipping points are in the physical world for inescapable damage, but we're clearly reaching close to some of them.

The real negotiation is between humans on the one hand and chemistry and physics on the other. And chemistry and physics, unfortunately, don't bargain.