It is a complete embarrassment and literally shameful that the country that first of all invented environmentalism and gave it to the world, and second of all did all the science originally around climate and global warming and presented that to the world, has been the country that has refused to participate in a constructive way to the solution.

When we work all over the planet, it's mostly poor and black and brown and young people, because that's mostly what the world [environmentalism] is.

Between [Speaker of the House] Paul Ryan, [Senate Majority Leader] Mitch McConnell, and Donald Trump's team, I don't see a lot of openings for making real progress.

To me the analogy [to climate change] is... doctors worry a lot about cholesterol. And if you go to the doctor, and the doctor says "oh, your life would be happier if you ate a different diet and exercised" people pay no attention.

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.

There's no huge mystery. If you dig up huge amounts of carbon, huge amounts of ancient biology, hundreds of millions of year's worth of ancient biology, and flush it into the atmosphere in a matter of decades, then it stands to reason that we're going to have enormous effects, and now we can see those effects all around us.

I try not to be either optimistic or pessimistic. I try not to think about outcomes on that scale. My job, it seems to me, is to wake up every morning and figure out how to cause as much trouble for the fossil fuel industry as I can.