Profiting from companies that are overloading the atmosphere with carbon and changing the atmosphere is wrong.

The most blatant examples are increased power and frequency in hurricanes and the increased depth and frequency of heat waves.

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.

In the States we've had by far the largest demonstrations in the last few years. The largest civil disobedience actions about anything in US history in the last 30 years have all been centred around the climate.

In the States, I think, the syllogism goes like this: 'free markets solve all problems. Free markets aren't solving global warming, QED global warming is not a problem'. It's not a very good syllogism but it's emotionally comforting if you're in that world.

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.

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.