Especially in recent years, the more and more we understand what we are doing, the more we have the science to tell us what we're doing, the fact that we continue to do it without taking steps to address it strikes me as, among many other things, irreverent in an extreme.

If we had about 100 years, that sort of slow cultural conversion would be exactly the thing to do. But physics is calling the tune here. We've got to respond to a timetable that physics has set for us.

I did very much like [Barack] Obama's attack on fossil fuel subsidies for fossil fuel companies. We asked for that in demonstrations and petitions, and now we'll try to push it forward.

Climate change is a huge problem, an almost insoluble problem.

If it's wrong to wreck the planet, it's wrong to profit from the wreckage.

Do I think that people should in the best of all possible worlds have to go to jail for wanting the US government to pay attention to the warnings of scientists about climate change? Not really. I mean, in a rational world, if all the scientists said, "The worst thing that ever happened is about to happen and here's what you should do to stop it," you would expect any rational system to say, "Oh, sure, OK, let's do something about it." But that's not the world we live in. In the world we live in, you do need people willing to stand up, fight, march and sometimes go to jail.

I'm not sure I'm a very good source of advice since we're kind of making this up as we go along.