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

Scientists with access to data from Navy submarines traversing underneath the North polar ice cap have warned that there is now a 75 percent chance that within five years the entire ice cap will completely disappear during the summer months.

I'm not trying to top anything. I'm trying to be useful, to play a positive role, to serve the public interest.

I have faith in the United States and our ability to make good decisions based on the facts.

Where solar energy is concerned - and wind energy and battery storage and electric vehicles and efficiency technologies - that is what we are now seeing. So, yes, I'm very optimistic, but anyone who works on the climate crisis has an internal struggle between hope and despair. I won't deny that, but hope has always prevailed in my outlook.

And just as the false assumption that we are not connected to the earth has led to the ecological crisis, so to the equally false assumption that we arenot connected to each other that has led to our social crisis.