If [a student's] college’s endowment portfolio has fossil-fuel stock, then their educations are being subsidized by investments that guarantee they won’t have much of a planet on which to make use of their degree.

Where people aren't as deeply reliant on fossil fuel as in the United States, it's far easier for them to imagine change on this scale. When you go to Europe, they're much more ready. They use half the amount of energy per capita that we use. They can imagine using less than that. They see the benefits. They're ready to go.

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.

[Kids] will grow up into a world that's difficult and wonderful, and they'll make the best of it they can, and hopefully help turn it in the best possible direction.

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 it's going to be a tough century; I also think people are starting to rise up, and that a growth in human solidarity will help compensate for the loss of margin in the natural world that will make life harder.