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.

I think it's going to be a tough century; I also think people are starting to rise up, and that a growth in human solidarity will help compensate for the loss of margin in the natural world that will make life harder.

When we think about global warming at all, the arguments tend to be ideological, theological and economic.

We have to figure out ways to scare and entice our leaders more effectively than the fossil fuel industry has managed to scare and entice them. They've got the big checkbooks. We've got to have the big crowd.

Here, there's more of a movement, it doesn't mean we're winning any more, but we're at least fighting.

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

There's no happy ending where we prevent climate change any more. Now the question is, is it going to be a miserable century or an impossible one, and what comes after that.