There are many places where we need to fight important battles to make sure that customers have access to solar.

We also have to engage - and I think this is important - in national politics because there is no way to address questions of this scale in the short time that we have to address them without engaging in real political change.

At the moment, the 4 percent of us in this country produce a quarter of the world's carbon dioxide - once you look at maps of rising sea levels and spreading mosquitoes, you realize that we've probably never figured out a way to hate our neighbors around the world much more effectively.

To me, it's more important to take the 60-70% of people who really understand that there's a problem [of climate change] and get some percentage of them active than to try and stamp out the last embers of pre-scientific thought.

In 50 years, no one will care about the fiscal cliff or the Euro crisis. They'll just ask, "So the Arctic melted, and then what did you do?"

Very few people on earth ever get to say: 'I am doing, right now, the most important thing I could possibly be doing.' If you'll join this fight that's what you'll get to say

We spend probably more of our time than we should, just because it's close to home, worrying about the West. But it's equally important to figure out how we're going to free up the resources to let the developing world leapfrog the fossil fuel age. That's at least as mathematically important, and at least as morally crucial.