I've got no advice. You guys know where you are and what will work. Just know that there are people all over the place working on this and that there's a great deal of solidarity around the world and we should try to build this big, sprawling movement that looks like the kind of energy system that we want - building lots of solar panels on lots of rooftops that are all interconnected.

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?"

I did very much like [Barack] Obama's attack on fossil fuel subsidies for fossil fuel companies. We asked for that in demonstrations and petitions, and now we'll try to push it forward.

With each month that passes, a solar panel gets 2 or 3 percent cheaper. So while we're holding the fossil fuel industry in check, the engineers in the renewable energy world are undercutting them from the other side.

We finally know where the red line for climate really is. After the rapid melt of arctic ice in the summer of 2007, our best scientists, led by NASA's Jim Hansen, went back to work and produced a series of papers showing that with more than 350 ppm (parts per million) of carbon dioxide in the atmosphere, we couldn't have a planet "similar to the one on which civilization developed and to which life on earth is adapted."

I think the best way is to keep stressing, that, as we build out a new energy system, one of the best things about it, if we do it right, will be that it will be more local, more democratic, more distributed, and, in the long run, much more economically sensible.

Climate change is a huge problem, an almost insoluble problem, for two reasons. One is the habits of the West in terms of consumption. The other is the incredible iniquity between poor countries and rich countries on this planet.