It's as if we think the laws of physics are subject to debate and amendment and political contributions can sway the laws of physics.

Anyone who deals with the climate crisis has an internal dialogue between hope and despair, because the challenge is so huge and the danger is so great and the stakes are so high. But I have always resolved that in favour of hope, and actually I'm more hopeful now than I was a decade ago when the solutions were visible on the horizon, but you had to seek reassurance that the technology experts that they're coming, they'll be here.

Civil disobedience has an honourable history, and when the urgency and moral clarity cross a certain threshold, then I think that civil disobedience is quite understandable, and it has a role to play.

The signs that the world is spinning out of kilter are increasingly difficult to misinterpret. The question is how to convince enough people to join a critical mass of urgent opinion, in the U.S. and the rest of the world.

The interior of the earth is extremely hot – several million degrees.

I never like the question about letter grades, but I think Trump is failing. I think that every day there's another set of tweets and another set of controversies, and nothing seems to be getting done that's any good. And there seems to be kind of a policy paralysis in Washington. Even the appointments he's supposed to make as a new president, so I focus most of all on climate, and so my opinion of his time as president is certainly influenced by my opinion of the job he's done on climate. He's tried to move the country in the wrong direction.

I am a passionate advocate of getting special interest money out of politics.