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.

I don't like the idea of teaching religion in schools, and creation is not my thing, but that's a trivial point compared to saving the creation. I'd much rather have half of the people in the country be creationists and work really hard to save the creation than have everybody be evolutionists and be destroying the planet.

We ought to take good care of everybody we have on the planet, but we ought to regulate the rate at which people join us. The old saying is, "It's the top of the ninth inning, and humanity has been hitting nature hard, but you've always got to remember that nature bats last."

People have to decide, first of all, how they'd like to live, and how secure they want to be from disaster. After that, scientists can help determine what would be necessary to achieve that.

I don't think scientists can dictate from above what we should do, because it's not a matter of scientific decision. If you want to have everybody living like a Beverly Hills millionaire, then 2 billion people might be too many. If we want to have a battery-chicken kind of world, with everybody having an absolute minimum diet, you might be able to support 10 billion.

I'm sort of optimistic about what we could do, but I'm very pessimistic about what we will do. I can't tell you that Al Gore's 10-year plan is impossible. I'm old enough to remember the Second World War - if we had a World War II-type mobilization, we might accomplish Gore's plan. In 1940 we were making tens of thousands of automobiles, and in 1941 we were making tens of thousands of airplanes. We mobilized as a nation. If we get that kind of mobilization as a nation or globally, then we could solve a lot of these problems.

Most of the scientists I know think civilization is teetering on the brink of a global disaster. They just don't know when it's going to hit. I don't have the answer to that either. I'm scared as hell.