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.

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.

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.

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.

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.

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.