What makes us different? We're the creature that can decide not to do something that we are capable of doing.

Everything that the administration has done has been counterproductive.

I don't spend a huge amount of time fixated on climate denial because I don't think that their objections, though sometimes couched in science, are based in science. I think they're based in ideology. And I don't think there's anything you can do.

Delhi is locked in a complete choking smog at the moment - they've had to close schools in one of the world's biggest cities. They have their own reasons for needing to get off fossil fuels fast.

There is an urgent need to stop subsidizing the fossil fuel industry, dramatically reduce wasted energy, and significantly shift our power supplies from oil, coal, and natural gas to wind, solar, geothermal, and other renewable energy sources.

My goal was to have as many of the primary sources as I could made available for people to look at and understand. Climate change is probably the most important thing that's ever happened, and yet people's understanding of it and its history remains a little fuzzy.

The fact that Washington has been a complete logjam for anything for the last six years has got to change because we need to have federal policy that really allows us to move quickly and nimbly.