I thought if the climate was heating that CO2 was the only forcing, and it would be late in the century before we had trouble. Now that we know about the other half of the forcing, it's obvious that the trouble is coming much sooner.

With taxes, if they aren't working right, we can change them with a stroke of the pen. It's basically a market-type mechanism. People make their own choices. You run the taxes, and you get the results.

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.

There's no question at all that the population explosion will come to an end. The two basic choices are it'll come to an end because we control our reproduction, and in many areas we have started to do so, or we'll end up with a high death rate. You have to take a personal moral stand on this.

If we were redesigning around people instead of around automobiles, which I think the market is more or less going to do, although too slowly, than I'd be a lot cheerier.

To err is human, but to really foul things up you need a computer.

Chinese are already more on board than we are. China is the only country that actually discussed in formal government documents how important it is to control the size of your populations if you’re going to limit emissions.