Bill Hamilton and I fought like cats. It was a very difficult association. Eventually, Bill, whose untimely death I mourn, said, "You've convinced me that the world does self-regulate. But that could not happen via [Darwinian] natural selection." Then he and my student, Timothy Lenton, published a paper together, "Spora and Gaia," exploring how these regulatory mechanisms might develop. Bill came to see the ideological battle between Gaia and the selfish gene as pointless. In a sensible world, we need them both.

You've said, "Natural selection favors the improvers." What exactly do you mean by that?

I mean that nature favors those organisms which leave the environment in better shape for their progeny to survive.

At the Gaia 2000 conference, someone asked, "What would happen if the Sahara Desert were replaced with vegetation?" The answer, in a nutshell, was more rainfall, cloud cover and cooler weather in Egypt and, especially, western Africa. Some rainfall might be drawn away from the Caribbean. Now, this was simply a thought experiment, but what if someone actually did try to forest the Sahara, or some other desert? There's lots of talk these days about massive tree plantings to offset global warming. Do you think that's a good idea?

Doesn't work. The French tried that sort of thing at the turn of the last century. Sadly, it's much easier to create a desert than a forest. There's evidence that portions of the Pakistan desert were forested in biblical times. It appears that much of the Australian outback was once forested, lost to the dreadful tradition of fire-drive hunting. Now it's desert as well. The tropical rain forests in the Amazon and Malaysia do not respond well to deforestation and are going to desert. This is because those rain forests make their own rain, rather than benefiting from the rainfall that would occur, say, from ocean breezes sweeping up a mountain range, as, for example, is the case with the Costa Rican rain forest.

Your doctorate is in medicine, training that has led you to regard the Earth's body as having "vital organs" -- key regions that, if debilitated, could imperil the health of the global ecosystem as a whole.

Yes. The tropical rain forests are a telling example. Once cut down, they rarely recover. Rainfall drops, deserts spread, the climate warms.

Perhaps genetic engineering will save the day. For example, genetic engineers now feel that rubisco, the enzyme primarily responsible for photosynthesis, could eventually be tinkered with to work 1,000 times as fast. Trees might sprout up in weeks, not years. Do you see that sort of thing as a boon to our future, or a threat?

I don't really know; you'd have to ask Lynn Margulis. I suspect any worries about genetic engineering may be unnecessary, from a Gaian perspective. Genetic mutations have always happened naturally, anyway. Of course there may be short-term problems, but as far Gaia goes, it's a minor event.

Of course, from the human perspective events might not be so minor. Are we, as a species, in danger of extinction?

Human beings are very tough and will survive -- have survived for at least a million years. Civilizations, though, are fragile. Thirty or so have come and gone in the past 5,000 years. And there's no reason to assume that ours is permanent. Indeed, there is little evidence that our individual intelligence has improved through recorded history.

Has the global environment improved or deteriorated over the past 30 years?

It has deteriorated considerably.

Then global warming is truly a problem?

Yes, its grim effects will become apparent later on in this century.

Do you oppose nuclear power?

No. If a power station were to be built down the road, I'd prefer a nuclear plant over an oil burner, and definitely over a coal burner. We simply have to lessen our consumption of fossil fuels. Take the automobile, that dreadful invention that we can't seem to do without -- too many people driving too many cars and burning too much fossil fuel.

E.O. Wilson has called for a spiritualization of the environmental movement. He says we need to invest some of the passion now reserved for traditional religion into caring for our environment.

I agree wholeheartedly. I am a great admirer of his. I especially like Wilson's characterization of human beings as unfortunate tribal carnivores that have acquired intelligence.

But Wilson is an atheist. So isn't he saying, in essence, "Here's what everyone else should believe?"

I'm a scientist, not a theologian. I don't know if there is a God or not. Religion requires certainty. Revere and respect Gaia. Have trust in Gaia. But not faith.

What is our duty to posterity?

To leave the right message behind so that our successors can correct the mistakes we've made.

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