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.

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.

Too many cars, too many factories, too much detergent, too much pesticides, multiplying contrails, inadequate sewage treatment plants, too little water, too much carbon dioxide - all can be traced easily to too many people.

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.

You take the huge income that comes with a big gas tax, and you use it to pay off regressive taxes like the FICA [Federal Insurance Contributions Act] tax. You can help the poor in other ways besides giving them cheap gas. You want to send the message that people want to be as efficient as possible using gasoline until we can transition away from that need entirely.

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?

Here's the scientific community saying, fundamentally, "If we don't change our ways, we're screwed." And they got no attention at all. Even though the Union of Concerned Scientists put out this statement which was signed by more than half of all the Nobel laureates in science and another 1,500 distinguished scientists.