My first policy move would be to try to get a conversation going in the US about what people stand for and what we really want. Do we want to keep adding people to the world and to our country until we move to a battery-chicken kind of existence and then collapse? Or do we want to think hard about what really is valuable to us, and figure out how many people we can supply that to sustainably?

People have not made the connection that the more of us there are, the more greenhouse gases go into the atmosphere. The Chinese have. They, unlike us, have a population policy. The right wingers just don't understand that the country they're in is probably the most overpopulated in the world, the one doing most of the destruction, and the one with horrendously bad leadership.

The main thing is, and of course this is a pedant talking, we should start our education on these issues in kindergarten. Instead of saying, "See Spot run," we ought to say, "See the plant grow in the sun." We ought to explain what runs the weather in the third or fourth grade to start out with.

It turns out the population issue is an easier thing to deal with than the consumption issue. Some obvious extremes in consumption we can deal with. The standard cure for a stuttering economy is to go out and buy an SUV and three more refrigerators. That's obviously not the way to go.

After The Bomb we developed a fairly good system for moving food around and have avoided the kind of massive famines that attract the media. Although of course we've had a fair number of them, particularly in Africa, since The Bomb was written. But we have had a steady level of attrition of malnutrition and malnutrition-related disease. Probably something on the order of 5 to 10 million people starve to death each year, but they're spread out; they're not dramatic news events.

Woman should have the choice whether to have an abortion or not, but I like what Bill Clinton said: It ought to be safe and rare. You don't want to offend people with it. You try and do as much as you can to let people be different, but also to try and protect them from things that they think are bad. And it's worth all of us giving a little.

I kind of like carbon taxes because we already know how to apply them. We already have apparatus in place. When we talk about these other solutions - like a billion tons of iron filings in the ocean or putting sunshades between us and the sun - they're huge. We have no idea if they will work. We have no idea what their nasty consequences might be. And it's unlikely we can do them anyway.