I think fracking for gas will reduce the incentive to turn to renewables, and I think it will do a lot of other damage across the countryside.

Without a movement pressing for change, there's little hope. We've got to work the political system to make this happen fast. The physics and chemistry are daunting. The resources on the other side are very large.

It's off the charts - and if you don't believe the scientists, ask the insurance industry, the people we pay to analyze risk in our society.

I don't spend a huge amount of time fixated on climate denial because I don't think that their objections, though sometimes couched in science, are based in science. I think they're based in ideology. And I don't think there's anything you can do.

A voluntary simplification of life-styles is not beyond our abilities, but it is probably outside our desires.

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

When we work all over the planet, it's mostly poor and black and brown and young people, because that's mostly what the world [environmentalism] is.