It's our own throat that we are cutting in the end along with everyone else's. We need to be exercising precisely the kind of leadership that might allow us to nudge China and India, say, onto different energy trajectories, in order to improve our own chances of surviving this century.

All the signs of incipient activism and uprising, from Tahrir square to Zuccotti Park to [the recent] shutdown of the Internet to protest web censorship. People are getting smart and getting connected.

A world where one tenth of the population gets to be extremely wealthy, and six tenths very poor, is not, in the long run, a stable place.

If we all used clotheslines, we could save 30 million tons of coal a year, or shut down 15 nuclear power plants. And you don't have to wait to start. Yours could be up by this afternoon. To be specific, buy 50 feet of clothesline and a $3 bag of clothespins and become a solar energy pioneer.

I'm far less a leader than a writer.

We are altering the most basic forces of the planet's surface - the content of the sunlight, the temperature and aridity - and that brings out the most powerful questions about who is in charge. If you wanted to give a name to this theological problem, I think you could say that we are engaged in decreation.

If we were built, what were we built for? ... Why do we have this amazing collection of sinews, senses, and sensibilities? Were we really designed in order to recline on the couch, extending our wrists perpendicular to the floor so we can flick through the television's offerings? Were we really designed in order to shop some more so the economy can grow some more? Or were we designed to experience the great epiphanies that come from contact with each other and with the natural world?