We know that if you have $20 million, it's better to buy a van Gough print than it is buy an executive jet, from the point of view of the environment. But when you start getting down, it's like the recycling question: What are things we can really afford to do, and how much pleasure do we get out of them? We haven't even started to have that discussion, and it's getting awfully late.

Anyone who opposes methods to control the birth rate, is automatically voting in favour having the death rate go up.

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.

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."

For example, I'm a great fan of pornography, but I don't see any reason not to restrict it so that people walking down the street who hate pornography don't have full color pictures outside of movie theaters. Let them be in a different district. I'm kidding about pornography, but you get the point.

In pushing other species to extinction, humanity is busy sawing off the limb on which it perches.

Your children should have it impressed upon them that their adult life-style will bear very little resemblance to yours and that they should now be acquiring knowledge, skills, values, and tastes that will sustain them in less materially affluent circumstances. On the other hand, the fresh insights and imaginations of your children may help you find a viable future while there's still time.