When you're going through an emotional experience and you're focussed completely on what's happening, you can't even spare any attention that the camera's there.

Future generations may well have occasion to ask themselves, "What were our parents thinking? Why didn't they wake up when they had a chance?" We have to hear that question from them, now.

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.

The symbolism - and the substantive significance - of planting a tree has universal power in every culture and every society on Earth, and it is a way for individual men, women and children to participate in creating solutions for the environmental crisis.

Remember America, I gave you the Internet and I can take it away.

Science is warning us that if we do not quickly reduce the global warming pollution that is trapping so much of the heat our planet normally radiates back out of the atmosphere, we are in danger of creating a permanent 'carbon summer'.

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.