Paul Ehrlich on Overpopulation

Paul Ehrlich, University of Stanford professor and biologist, and author of “The Population Bomb”. Photo ©2012 Isaac Hernández

We are now 7,000 million people on Earth, according to the UN. Paul Ehrlich, University of Stanford professor and biologist, is perhaps most famous for writing an apocalyptic book about the consequences of human overpopulation. When he wrote “The Population Bomb” in 1968, the world’s population was at 3,500 million, half of today. His dire predictions did not come true because of advances in technology, but he still believes that we are living from the natural capital, instead of living from its interest, which is not sustainable.

QUESTION: Do you feel vindicated that overpopulation is a hot issue again, after thirty years of putting up with criticism?

ANSWER: Yeah, I think people are finally realizing how serious the population situation is, and I think that’s good. But I think that there’s still there a very strong taboo against covering it in the media here and elsewhere.

Q: Why do you think it’s such a taboo subject?

A: We all like children. And therefore the idea of somehow limiting the number of children we have does not receive much support. It’s a very personal decision. It’s getting to be more common for people to decide not more than one or at most two children. But in too many places people still see, and often accurately, that from their own personal point of view, is relatively economically viable for them to have more children; it may even be necessary. One of the challenges facing humanity is to close the rich/poor gap so that poor people don’t have to have children to support them in their old age, to help with their farm work, and that sort of thing.

Q: What do you think the ideal population for the planet would be?

A: It depends. The optimal population for the kinds of technology that we have today is a question of what lifestyle do we want to lead. If every person wants to lead the kind of lifestyle that a person in the United States does, then probably the total number would have to be below a billion, or around a billion. If you wanted to live more or less as many people do today, say as in México or so, then you could probably support three or four billion.

The most recent study I know of figures that you might be able to permanently support one and half or two billion people. But we of course are at seven, and rocketing towards nine or ten. So we don’t really need a big argument about what the ideal population size is, because every scientist who’s looked at is has come to the conclusion that it’s got to be fewer than we have today.

Q: A ten-year-old kid said to ask you: “What will the world be like in fifty years?”

A: It depends on whether or not the United States government gets serious about dealing with environmental issues, in particular, climate change. He could look forward to a very nice world, or he could look forward to a world that would be very different from today, and not in desirable ways. It’s entirely possible that if we don’t do something about the way we’re handling international affairs and the environment that we could have a nuclear war that would make any kind of life similar to what we have today in the United States impossible. So it really depends on us. And it depends on his parents, and probably his grandparents, too, and his own generation too, on whether they start taking the environment seriously. Nowhere in the world is anything really significant being done about the wrecking of our climate system, our general life support systems, the other plants and animals that we depend upon entirely for our lives, including our food. So unless we change our way, I’m afraid I can’t give him a cheery outlook. But I can say that if we did decide to do something about it, there are lots of things we could do, and he could live an even better life than his parents have led.

Q: Philosopher John Zerzan says that the only solution is to live primitive lives and that we will get there whether we like it or not.

A: I agree that that’s a very likely conclusion to our current course, but I wouldn’t call it a solution. I would say the solution would be to think really hard about how much consumption each person needs, and what the advantages are, of having so many people living at one time. The course we’re on now, we’re likely to have a population collapse sometime easily within the next half century to century. If you want to have the maximum number of people that can live, say, in this century, then you can destroy the life support systems, you can have maybe eight or nine billion people in this century, and then you could go to a few hundred thousand, and then go back to a hunting and gathering existence, which is not what I would favor.

Q: You also defend the notion that scientists should not only observe, but also be activists.

A: Everyone should at least put some of their time into taking action. As you can see now with the Wall Street gatherings in New York, and so on, people are getting fed up, and maybe they will start changing our political system. In the United States today it’s really sad that we have several people running for president who are basically morons. We have people who have no education, with very small brains, who say that the entire scientific community is wrong when they say, “there’s danger from population” and from changing the climate, and from putting toxic substances into the environment, and from not paying enough attention to how we grow our food. It’s a very dangerous time in particular in the United States because our government is broken. It’s ran by idiots; and it’s too bad.

Q: Do you feel like that the problem is that we’re too shortsighted, beginning with our economic system?

A: That’s right; the bottom-line rules, and also there’s this idea that the economy can grow forever. A very famous economist said that if you believe in the perpetual growth of the economy, you’re either insane or an economist. As long as the media are captured by the rich corporations, as long as the Supreme Court is insisting on transferring more and more power to the corporations and the very richest people in the country, we’re going to stay, in the United States, anyway, on the track we’re on, and unfortunately the United States tends to pull the rest of the world along with it.

Q: What could cause a shift to a long-term vision?

A: If the people keep insisting that we shift to a long-term system, then it could. One of the advantages that we have is a very smart president, who’s crippled by first of all a lot of dumb advisers, and by the opposition of a party that borders on insanity, the Moron Party, the Republicans. It’s sad, because I used to be a Republican. But like many others, I’ve quit, since they’ve gone totally crazy.

Q: Do you think that the future will bring a voluntary compromise of having one child only? Or enforced, like how they do it in China?

A: I think we’ll see more of that, but it’s sad. We should have long ago found other ways to restrict reproduction. If it was ideal what you would want is to have in almost every country an average of 1.5 children. And that might be some people who are superb parents having three children, and a lot of people who don’t care that much having none.  The basic thing is, from a political point of view, the best slogan is “stop at two”. We need a reproductive rate, a completed family size, around one and a half children per family, to reasonably start lowering the size of the world population to a sustainable level, to a level where our children, grandchildren and great-grandchildren and all can lead decent lives, rather than worse lives than we’re living.

Q: How would you convey the importance of “stopping at two”?

A: It’s really important, if you love children, not to think about how many children you want, but about how many children can you have that would have a wonderful life.

Q: Did you ever speak about neutering human beings forcefully?

A: I said that we might come to that, but I never did think that was the ideal solution. I always thought that would be socially too difficult. I actually was surprised by the success that the Chinese had with limiting childbirths, but of course they’re more socially oriented than the more individualistic United States. We’ve always just recommended that you make contraception and backup abortion available to everybody who is sexually active, and that you find social policies to encourage people to stop at two. Gentle pressure… and it’s worked, for instance, in Europe, where the total fertility rates tend to be under two, virtually everywhere.

Q: You say in the book you co-wrote with your wife Anne Ehrlich, “The Dominant Animal,” that it doesn’t matter, for example, that in Spain, supposedly a Catholic country, population stays low even though the Pope is against contraception. Do you think it’s the same in Latin America?

A: I think not as much as in Europe, but it’s moving in that direction. When the Pope came out against the pill, a lot of women in Latin America asked their priests where could they get this pill that the Pope was against.

Q: You’ve studied evolution, with fruit flies evolving to be resistant to DDT in a couple of weeks. Human beings would take hundreds of years to evolve the same way.

A: The whole toxic situation is truly worrying. There are signs of the sex ratio shifting, so that in some sub-arctic villages there are twice as many girl babies being born as boy babies, and the usual ratio is about 107 boys to about 100 girls. There are changes in the age that puberty comes. And we know that many of the chemicals that we’re releasing into the environment, more and more, as our population grows and consumption grows, are both poisons and/or hormone mimics. We put into a lot of our plastic bottles a compound called Bisphenol A, which was developed as a female sex hormone. And it leaks out, in plastic bottles that you use to feed both male and female babies. It’s nuts! The whole toxic situation could be a time bomb… and it could be worse than climate change, because once that stuff is out there, there’s no way to get it back. Same thing with plastics; the oceans are becoming a solution, a mixture of tiny bits of plastic in the water that affect tiny organisms. We’ve coated the ocean with plastics, and have no way of knowing how that would be.

Q: Maybe this is how we’ll lower our population.

A: That’s not the method I’d recommend for controlling our population!

Q: Can you end with an optimistic message?

A: The optimistic message is this: there are many things we can do about the dilemmas we face. Including limiting our population, being fair in consumption, so that we redistribute resources properly; dealing with things we have to do to change our energy system to reduce the problems of climate change, dealing with toxic substances, all of these things, protecting our fisheries, protecting biodiversity, all of these things can be done if we have the proper political will, which means organizing the people of the world to get themselves really secure, instead of following the same old ways. There’s nothing pessimistic about what we could do. What I’m afraid is pessimistic is what we’re continuing to do. We have to change our ways. We can do that in ways in which everybody’s lives would be much better, and much more secure.


One Reply to “Paul Ehrlich on Overpopulation”

  1. Ladies and Gentlemen,

    Scientists warn of a rapid collapse of the Earth’s ecosystem.
    The ecological balance is under threat: climate change, population growth and environmental degradation could lead even in this century an irreversible collapse of the global ecosystem.


    The cardinal reason is the sudden development of human population that threatens to devour all our resources.

    Since 21 August there is therefore a petition at for the introduction of global birth-controls, also in HINDI!

    If you want to support this or publish it on your website, here is the link:

    Please continue to spread the link or the petition as possible to all interested people, organisations etc.

    Thank you and best regards
    Achim Wolf, Germany

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