In 1968, Stanford University biologist Paul Ehrlich published The Population Bomb, a synthesis of scientific research and personal observations that offered a disturbing account of a world with too many people and too little food. The book was a national bestseller. Now 40 years later, Ehrlich, still at Stanford, and his wife, Anne, have come out with a new book, The Dominant Animal, in which they seek to explain how man's rapid rise to dominance has spawned a series of interlinked woes: soaring energy demand, agriculture crises, and, above all, environmental degradation. No longer, the Ehrlichs argue, can these issues be viewed as independent of one another, nor will a single response suffice as a remedy. U.S. News recently spoke with Paul Ehrlich. Excerpts:

Energy, food, and environment problems seem increasingly entangled. We can't talk about one without talking about the others. Where do we start?



We've got to dramatically revise the way people think about the world—and about our cultures. You can get all the way through Stanford University and still think your food comes from supermarkets. For example, people don't understand the involvement of the transport system in agriculture, or the oil connection. Obviously, there are huge problems with what's happening to people who live on two bucks a day and can't afford food, but agriculture is also our single most important activity and generates our biggest environmental threats. We can't go back to hunting and gathering. We've got to tackle the population issue, so ever more mouths don't need to be fed. There is also a consumption problem. I just spent four weeks in Africa, and there and all over the world people want to eat the way we do, which of course means more beef and pork and much more production to feed animals. The so-called new consumers in Asia have been cited as a big factor in the fuel and food crises today. Who are they?



People who have a little more money and education have, in China and India particularly, developed very rapidly the same consumptive attitudes as the average American and European. That's not necessarily bad: Who can deny them wanting the stuff we have when we haven't shown the slightest interest in reducing our own impact on the environment? In 1972, I cowrote an op-ed called "What if all the Chinese had wheels?" At that time, there were 500 million Chinese, and it looked like one day they might want cars. Now, we have 1.3 billion Chinese, and we know damn well they want cars; they're buying them and manufacturing them. Some estimates show the world population growing to about 9 billion people by 2050. Can the planet sustain that?



Probably not without disaster. If humanity put the effort in, we could end up with fewer people then. We have already seen a trend toward smaller families and actual shrinkage of population in Europe. It's not written that everybody has to have huge families. But in Africa, where the people are poor and have four, five, six kids, it will be tough. Even the optimistic scenario of population falling to 7.5 billion in 2100 takes us through roughly a doubling of energy use, and energy use is the best single measure we have of damage we do to our life-support systems. We don't have a clue if we can hold society together through that. What if these predictions are off—and population growth continues?



Population growth will end sooner or later. The big question is: Will it end by a huge die-off, or will it end because low birth rates spread in Europe, Japan, and a few other places to the rest of the world? The actual limits depend on consumption patterns and technologies available and how environmentally benign they are, and what kind of lifestyle people want to live. We can't all go back to being subsistence farmers. We must make decisions about technologies and lifestyle. If you're rich, you can by a Van Gogh or you can buy a private jet. Obviously, one of those consumption decisions has a very different impact on the environment than the other.

But how do you control consumption?



There are no consumption condoms. This problem is enormously complex. What I am convinced of is that it is human behavior we have to change. The discussion of key issues is limited to a tiny portion of a population. We need to set up a system to keep these issues on the front burner...They are all long-term issues. The politicians, of course, have very little interest in them because solutions don't give votes for the next election. You say that our energy supply is adequate. So what's the problem?



We're not running out of fossil fuels—we're running out of environment. We could go a long time if we could just burn up fossil fuels and dump the carbon dioxide in the atmosphere. We'd be in good shape at least for long enough to carefully consider our future. But when you see what's happening with the climate, you realize we can't do that. One of my colleagues went to Norway recently. She said it was horrendous to see global warming actually in action. Almost all the lakes they used to ice skate across in summer are gone. Everything is just melted. We don't have the time to continue what we're doing now and hope to change later. The same holds for the food supply?



Unless we are extremely lucky, climate change will continuously alter the distribution of precipitation all over the planet. It's not that we're just going to deal the cards once and some farms are going to be better off and others worse off. Changes in water management will be required over centuries, for instance, switching from rain-fed to irrigation and maybe back. It's going to be extraordinarily expensive and disruptive, especially when we have a problem of how to feed ever more people. Crude oil is at record prices. What's the first immediate step on energy?



You really need an overall energy policy. We have been reducing our energy research and development budget, not increasing it. The quickest energy solution is efficiency. Next is to stop population growth. If we'd stopped U.S. population growth in 1945 at half today's size, guess how much less fuel we would need to buy from the Middle East. Energy policy is a vast area we are not putting the right kind of thought into. The whole launch into biofuels was done without any ecological analysis of what the actual climate gains and losses would be or what the environmental impact would be. Can biofuels even be part of a real solution?



It's not necessarily an insane idea. What was insane was not to very carefully look at it and get some more lead time. There may be some place in a sensible world for use of biofuels. It's not crystal clear. You hear, well, we'll just do X and Y in wasteland. I work in a laboratory in a beautiful mountain valley in Colorado. All the land is classified as wasteland and could be used for biofuel production, which would just be destroying beauty and biodiversity. It's important to understand that when biodiversity is gone, we're gone, too. Brazil has a thriving biofuels industry based on converting sugar cane to fuel.



They are also cutting down big chunks of the Amazon. We don't know how much of the Amazon you can cut down before the whole thing goes, and what the effect on global climate will be. Besides the loss of biodiversity, the resulting climate change could basically destroy us, and we're probably not going to know in the near future until we've run the experiment and find out. Recently there's been chatter about revisiting nuclear power.



Nuclear power, whether you are in favor of it or against it, is not a silver bullet. It is another very complex issue. There may be a place in our energy mix for nuclear power. But it's not going to solve this complex of problems. What else might be in that mix?



We could easily increase efficiency on energy use in buildings and transportation. Let's build only coal-fired power plants that can sequester carbon dioxide, or shift away from coal to natural gas and then various solar technologies. There are lots of things we can do; no single one of them is going to solve the problem. You need action at the local level, at the state level, and the federal level, and the international level.

At the federal level, there is gridlock. How can we speed up progress?



Elect smart, informed people. I get the impression that Congress thinks if it promotes wind power, in two years we could be getting 75 percent of our energy from wind. Actually, we'd be lucky to be getting 10 percent in 30 years. There is a huge time delay in deploying new energy technologies. The only way to speed that up is basically to go to a WWII-type commitment. The Manhattan Project took three or four years, but we put gigantic amounts of effort into it. We need a Manhattan Project on energy and the environment, but we don't yet even know what direction to go. The presidential campaign, so far, hasn't offered much guidance.<



Essentially none of this is in the campaign. Sure, there are occasional statements on candidates' websites about climate. But what my colleagues and I are dealing with all the time and are scared witless about are not presidential campaign issues. It's sort of a wonderland. Whatever you think about gay rights and what starlet isn't wearing her panties today, those are not critical issues for most of our society. The international community is starting work on replacing the Kyoto Protocol, which was intended to decrease greenhouse gas emissions. The U.S. never ratified it, and other countries haven't upheld their pledges. Is there any reason to be optimistic this time?