Oil companies are radical because they're willing to alter the chemical composition of the atmosphere.

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?

The consumer culture in general has washed over our civilization. For the last 50 years, if you've had a credit card and some access to money, you don't really need neighbors around you. And as a result, they dwindled. The average American has half as many close friends as they did in 1950. Three quarters of Americans don't know their next-door neighbor. They may know their name, but they have no real relationship with them. That's an utterly new place for human beings to find themselves in - I mean, we're a socially evolved primate.

The end of nature sours all my material pleasures. The prospect of living in a genetically engineered world sickens me. And yet it is toward such a world that our belief in endless material advancement hurries us. As long as that desire drives us, here is no way to set limits.

Scientists are telling us that 350 parts per million [of carbon] in the atmosphere is the upper limit. We're at 387 parts per million now, and we're up in that zone where the risk of going past irrevocable tipping points is elevated. It's no different than going to a doctor and learning your cholesterol is too high, and you're at risk for a heart attack. You have to work to lower your cholesterol and hope to get there before the heart attack comes.

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.

It was huge mistake to avoid working with the rest of the world because (a) we're the largest source of the problem: 4% of us who are in the U.S. produce 25% of the world's carbon dioxide.