In the past century the earth's human population has quadrupled, growing from 1.5 billion in 1900 to about 6 billion today. By 2050, it is estimated that the global population will reach 9 billion. In 1968, a young biologist named Paul Ehrlich wrote a best-selling book called The Population Bomb, which sparked an ongoing debate about the dangers of overpopulation. He argued that population growth was destroying the ecological systems necessary to sustain life. So just how worried should we be? Is population growth a problem or not? And if so, what should we do about it?
Peter Robinson: Today on Uncommon Knowledge, what if you threw a party and nine billion people turned up?
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Peter Robinson: Welcome to Uncommon Knowledge, I'm Peter Robinson. Our show today, how many people is too many people? Over the course of the 20th century, the population of the planet roughly quadrupled, growing from about 1.6 billion in 1900 to about 6 billion in 2000. Today the population is continuing to expand at about 80 million a year. That has some very concerned, Paul Ehrlich, for example. In 1968, Ehrlich, now a Professor of Population Studies at Stanford University, published a book entitled The Population Bomb.Ehrlich argued that the growing human population would eat up the resources of the planet. In a modified form, Ehrlich continues to make just that argument today. On the other hand, Nicholas Eberstadt a fellow at the American Enterprise Institute, says in effect, oh calm down, it's not at all obvious that large numbers of people is bad news. Is population growth a problem or is it not? If it is, what should we do about it? What can we do about it? Just how worried should we be?
Title: A Billion Here, A Billion There
Peter Robinson: A former director of the United Nations Population Fund, we need, "stabilization of the world population at the lowest possible level within the shortest period of time." Is that a goal to which the world should indeed address itself? Nick?
Nick Eberstadt: No, I don't think that it is a goal the world should address itself to. I think that it lends itself to anti-natal policies and even to coercive policies, and shall have an adverse effect upon human well being.
Peter Robinson: Paul?
Paul Ehrlich: Human population should be stabilized eventually at about 2 billion people--about a third of the present population size, but it has to be done in a way which avoids coercive policies and it's going to take a very long time.
Peter Robinson: You've just raised the first point, which is, how many people is too many people and what criteria do you use to say? Now Nick has written that simple demographic measures, such as rates of population growth, I quote you to yourself, "cannot by themselves unambiguously describe overpopulation." Explain that assertion.
Nick Eberstadt: Demographic indices by themselves can't describe overpopulation. If you look at places that are very crowded for example, the most crowded country in the world is Monaco and people don't think of that as an overpopulated place. When we're talking about overpopulation, I think what most people have in mind is squalid lives, bad health, crowded environments, hunger, but the name for that is poverty and the relationship between human poverty and human numbers is I think a lot more iffy.
Peter Robinson: And what about the sheer--the absolute number of people on the planet--6 billion--Paul just said 6 billion is too high, I'll ask him in a moment why, but what would your view be about that?
Nick Eberstadt: I don't know how many people the world can support and I'm not sure that anybody else does either. If you take a look at the human numbers now, we've got a higher global income level per capita than we've ever had before, despite the persistence of huge poverty in lots of places. If you take a look at natural resource use, it's much more intensive today than ever before. Human numbers and human affluence place tremendous resource demands on the earth, but if you take a look at things like prices of natural resources, they've been declining for a century.
Peter Robinson: So Paul, what are your criteria…
Paul Ehrlich: I agree completely with Nick that the simple demographic statistics don't tell you anything.
Peter Robinson: Okay.
Paul Ehrlich: I mean the statement that after all, there are so many people per square mile in Holland, but we don't consider Holland crowded, is correct. That's called the Netherlands Fallacy, because the issue is of course, as Nick has already indicated, that people in Holland don't live on the Netherlands. You couldn't populate the entire earth to that density or we'd be doomed. So the standard that biologists use and environmental scientists is very simple and that is you're overpopulated when you no longer can live on your interest, when you've got to live on your capital. And the three main forms of capital that we're getting rid of very, very rapidly at today's density and today's consumption patterns are deep rich agricultural soils, biodiversity, which is critical, and maybe the most short-term critical is our supplies of groundwater everywhere, which are being overdrafted. So, we are like the profligate child who has inherited a vast pile of resources, in this case from the planet, but every year we write a bigger check on it, but nobody bothers to look at what's happening to the balance, and that's the critical thing.
Peter Robinson: You don't then dispute the assertion that even as, over the last 40 years, the population has doubled, over the last 40 years per capita income, although unevenly distributed, per capita income has also increased, you would just say you can't keep it up.
Paul Ehrlich: Well, no--I'd also say is how much better would we have done if we hadn't had so much population growth in that period. In other words you can't bundle it all together. Yes, some measures globally like life expectancy and per capita income have gone up, but one of the issues is not only how long can you keep it up, but also would it have been better or worse if we'd of had more or fewer people.
Peter Robinson: Paul Ehrlich began warning about the dangers of population growth thirty-five years ago. If he was wrong then, couldn't he be wrong now?
Title: The Population Bomb Redux
Peter Robinson: 1968, you wrote in The Population Bomb, I quote, "The battle to feed humanity is over. In the course of the 1970's, the world will experience starvation of tragic proportions, hundreds of millions of people will starve to death." Right prediction but wrong timing? What were you thinking then that you're not thinking now?
Paul Ehrlich: Let me say one of the things that happened, in part because we raised the alarm back in those days, is that the world changed its way of handling famines and so on. And we did not suffer as many agriculturists expected, the levels of death that I predicted in that statement. On the other hand, about two hundred million people have died of starvation and hunger related disease since that statement was written, and when it was written, people said, no problem, we're going to be able to give wonderful lives and wonderful diets and everything to four or five billion people, no sweat. That hasn't happened either.
Peter Robinson: This notion of using up the planet, you have a wonderful phrase--actually I don't know whether it's a wonderful phrase, but lord knows it's a memorable phrase--that if we turn, and I'm quoting you, "the earth into a giant human feed lot, " we'll simply be using up our capital. This kind of thing is not sustainable. How then do you address the point that Nick made that prices of all kinds of natural resources are falling rather than climbing--price would indicate scarcity, right?
Paul Ehrlich: That's really easy. Any economist gives you the answer to that. Market prices don't include the externalities. And the issue is what are the scale of the externalities? And it's perfectly true what many economists will tell you, if you can internalize the externalities, neither Nick or I would have any worry at all about what happens with the population. Because if they were all internalized, we'd be getting exactly what we ought to be getting.
Peter Robinson: Right.
Paul Ehrlich: The problem is that prices can go down--that is, the market prices can go down while the social prices go up and you have to--the social costs go up--then you have to…
Peter Robinson: That is to say, the oil company has to pay for exploration, but not for pollution.
Paul Ehrlich: For pollution, right. Or for the wear on the infrastructure of the highways--I don't think you'll find an economist in the world who would say that gasoline is properly priced in the United States today with the majority of externalities internalized.
Peter Robinson: Okay, so you both agree on this notion of externalities.
Nick Eberstadt: We agree on the principle. It's a question of how we come down…
Peter Robinson: How would you size up the externalities?
Nick Eberstadt: I would say that in an increasingly global economy, with many, many more participants and many more people, if you will, voting with dollars than in the past, more closely linked, the chance that you are going to price things wrong consistently or increasingly for decades and decades, it's possible--I mean it is possible, but it just seems to me that it's increasingly unlikely.
Peter Robinson: Okay, so give me an example…
Paul Ehrlich: I'll give you an example where I think this is--I agree in part with that--but for example, if we had 145 million people in the United States today, which is the number--the largest number anybody has ever given a semi-sane reason for having alive at one time in the United States, we would be using less than half our petroleum. We'd have less than half our petroleum, we would not be importing any, George Bush would not be trying to invade Iraq to get some control over the second biggest pile of petroleum in the world…
Peter Robinson: Different show, Paul, different show.
Paul Ehrlich: Wait a minute. Wait a minute. But wait a minute, and what isn't included in the petroleum externalities are the actual costs of maintaining a military that can keep troops in Saudi Arabia, that can move whole battle groups into the Persian Gulf when needed, that is the sort of externality which is not being counted more and more in the price at the pump. And I don't know how you figure in the price…
Peter Robinson: But aren't you recapturing it in tax rates?
Paul Ehrlich: In tax rates?
Peter Robinson: It's something that an American has to pay.
Paul Ehrlich: An American has to pay, but it's not…
Peter Robinson: It's not directly enough linked to the price of that product.
Paul Ehrlich: That's right. The market price of gasoline is the issue as far as externalities are concerned, not that we don't have to pay for it or that other people don't have to pay for it, both in lives and in goods and money.
Peter Robinson: Next topic--assuming that we decide it's a good thing, let's look at some possible ways of reducing global birth rates.
Title: The Writing on the Wall
Peter Robinson: Al Gore gives us three in Earth and the Balance, his book, and there are three that are floating in popular culture, so let's take them one at a time. The first is to reduce birth rates--first way rather to reduce birth rates is as follows, I'm quoting Gore, "High literacy rates and education levels are important. Once women are empowered intellectually and socially, they make decisions about the number of children they wish to have" Education, especially for women--Nick?
Nick Eberstadt: Education especially for women is great because we should be in favor of education and we should be…
Peter Robinson: In and of itself, it is a good.
Nick Eberstadt: In and of itself.
Peter Robinson: But?
Nick Eberstadt: I'm less convinced that improving education and reducing illiteracy for women leads to an automatic or even a powerful general reduction in fertility rates. Simply by looking at the scatter plot out there today of what female illiteracy and total fertility rates in different societies look like. You have countries, there are countries, where similar rates of female illiteracy coexist with massively different fertility levels.
Peter Robinson: You've noted illiteracy rates are much higher in Mongolia than in Tanzania, but Tanzania has a higher fertility level.
Nick Eberstadt: So we learn from the World Bank.
Peter Robinson: Paul? Education?
Paul Ehrlich: I think first of all we both agree that education and improving women's literacy and getting them job opportunities is a good thing. But it's also certainly also correct that educating women and giving them a job opportunity is going to have different effects in different cultures. A famous study in India where people from two different cultures living exactly mixed in the same slum you get very different results with the same--on the other hand there's states like Kerala and Tamil Nadu in India and so on, where, for instance, Kerala has a lower birth rate, I believe a lower TFR than the United States. So, this is one of the things that I would say is let's do it and--well it can't hurt cause we agree that there's one important goal, just like I think we both agree charge more for gasoline even though we might have different conclusions about what we wanted it to accomplish, we both would agree that it's going to accomplish some good things.
Peter Robinson: Let's stick with Al Gore for a moment here. Second notion he presents, "low infant mortality rates give parents a sense of confidence that even with a small family, some of their children will grow to maturity." Better healthcare especially for infants.
Nick Eberstadt: Who can be against better healthcare for infants?
Peter Robinson: Another good, in and of itself.
Nick Eberstadt: Of course we want to have that, it's just the question about whether there is some sort of automatic or mechanistic connection between better survival for infants and lower fertility. As a general proposition, it makes sense to say if mortality levels are terribly high, people have to have large numbers of children simply to assure replacement. But again when you look at the devilish details today, infant mortality isn't that good a predictor of fertility levels.
Paul Ehrlich: I think he's right.
Peter Robinson: Okay, so…
Paul Ehrlich: I mean with Socrates I think was the last person that suggested not saving an infant that was lying face down in a puddle of water-who can be against that? But it is certainly not a quick fix…
Peter Robinson: Direct link.
Paul Ehrlich: …and of course it also has the complication if you're looking at the population growth situation, is that the better the health situation is, the more--after all, most of the low life expectancy of the more distant past, say more than 100 years ago--was not that people my age weren't going to live another five years, it was that people weren't going to live between zero and ten.
Peter Robinson: Right, okay. Al Gore number three--contraceptives, I quote him again, "nearly ubiquitous access to a variety of affordable birth control,"--he needed an editor apart from anything else--"nearly ubiquitous access to a variety of affordable birth control techniques gives parents the power to choose when and whether to have children." More and more affordable contraceptives.
Nick Eberstadt: Well, I think that Vice President Gore is correct that more and more affordable does give parents more purview over their choice of family size. The important point is that it is parental desired fertility that seems to be driving birthrates all around the world. And the amount that one can expect a new voluntary program to influence these rates is not so great.
Peter Robinson: Contraceptives permit parents to choose but they can't be relied on to choose the way you'd like them to choose.
Paul Ehrlich: Well, I think it's obviously a good to allow parents to have the number of children they want. That's one good out of that. The second good obviously would be if we used condoms is going to help with this very serious AIDS problem, which Nick has done a lot on. And the third thing is if everybody were using contraceptives, we'd be rid of the abortion problem. I don't like abortion, a lot of people don't like abortion. I think it's a necessary thing today, but if you could persuade everybody to use contraception, a very controversial issue could disappear.
Peter Robinson: But you don't see a direct link between proliferation of contraceptives and lower birth rates?
Paul Ehrlich: There's a lot of argument. I think both of us would probably agree that if everybody had access to free and effective contraception, birthrates would be lower. The issue is how much lower? Would it be significantly lower? There's an issue of really sound social science issue of how much unmet demand for contraceptions that are out there.
Peter Robinson: If none of the measures we've discussed so far is likely to be effective in reducing birthrates, what's left?
Title: Big Mother Is Watching
Peter Robinson: Nick has written, "Advocates of population programs must make a fateful choice. They must opt for voluntarism,"--you already like that you've said--"in which case the population targets however will remain meaningless or they must embrace coercive measures, there is no third way." Explain yourself to Dr. Ehrlich, who's already said we have three times too many people on the planet.
Nick Eberstadt: Well, voluntary family planning programs will help parents achieve their own desired family size if they're successful. And if their own desired family size is way above replacement as currently seems to be the case in some parts of the world anyhow, a perfectly effective family planning program that's perfectly voluntary will be complicit in rapid population growth.
Paul Ehrlich: Somebody once said that family planning can mean planning to breed like rabbits. But I'm not sure the dichotomy is the one that he makes. In other words, my position would be in between the two and that is saying, first of all, do the things we both agree on and then try and find things that will change socially the conditions so that people will desire to have fewer children. That is for example, helping small farmers in Africa and helping supply water to people where now children are considered to be extremely valuable because they spend their day trekking the six miles that it takes to drag back the water and so on. There are lots of things you can do to change people's view of how many children they want. I think when governments get into it, you get the sort of thing we have in China, namely a program which is more coercive than it ever would have had to be and probably not the ideal program even if they're going to be coercive. So, what I'd like to do is prevent us from getting to any coercive measures…
Peter Robinson: You just said something very interesting there. So in China we have a one child policy…
Paul Ehrlich: Sort of.
Peter Robinson: Sort of. I understand that it's not actually enforced evenly, but nevertheless in at least--the principle is one child per family. We know that there are some forced abortions, some forced sterilizations, we also have some data that suggests that certain--that sometimes you can pay off an official to get him to turn a blind eye to a second child and so forth. Nevertheless, that's their stated policy. But you suggest they didn't need to go that route. What else could they have done?
Paul Ehrlich: Well, if they'd started 15 or 20 years ago or even today say, for example, doing things that would even slow down the time of marriage, the age of marriage more, that might have been a much more effective way to get the same--the trouble is, when things get so bad the politicians recognize them, you get the kind of solutions that have not been thoughtfully looked at by demographers, ecologists, sociologists, and so on. You know, what are you going to do with all these--with a preference for boy children? The problem may stabilize around that in some sense eventually.
Peter Robinson: Is what we see here with Nick and Paul not just two different conclusions about the data, but also two different ways of looking at human beings?
Title: Are You a People Person?
Pete r Robinson: Nick stresses that even as, in the 20th century, the population increases sharply, human beings represent a resource in themselves and per capita wealth and production increases even more sharply. So in some sense, the more minds, the merrier. Whereas Paul tends to see people as consumers whose numbers have to be very carefully watched like, well you said, breeding like rabbits. That's the metaphor that comes to mind--seeing people as animals rather than agents of--all right, so I've drawn--I've been very crass about that, but is there sort of philosophical difference here between…
Paul Ehrlich: I don't think so.
Peter Robinson: You don't buy it at all.
Paul Ehrlich: I think we both value people highly. My problem is, and I think it's the same of all ecologists of my stripe, is I spend my time looking at a world where fisheries are now in collapse, where we're having horrible environmental problems with trying to replace them with…
Peter Robinson: Farmed fish.
Paul Ehrlich: With farmed fish, where I'm watching the forest disappear and the land, you know, ten percent of the land surface has already been made nonproductive. I would like to see--my view is this--I would be happy to say that we should have more population growth when we're taking proper care by Nick's standard--do it. Proper care of the six billion people we have now. In other words, I don't want to hear arguments for why we are so able to go on to nine, ten, or twenty, until we've said okay, why don't we just run the experiment of taking care of the people we've got.
Nick Eberstadt: I think that it is true that valuing human life highly you can come to very different perspectives on the way to proceed and the problem at hand. I would suggest, I may not be right, but I would suggest that part of what one hears in this discussion and in others, is the difference in specializations. I think that people who come through the biological sciences are more mindful of constraints, more mindful of physical constraints on the planet and various populations in the planet than people who come from an economics background. People who come from an economics background are constantly trained to think about substitutions, and alterations, and innovations, and ways that human agency can circumvent constraints. So I think you see…
Paul Ehrlich: I think that's fair.
Peter Robinson: Then let me ask you a different question. Are you both in favor, broadly speaking, of modernity? That is to say, education, literacy, the spread of highly developed economies, productive economies, and you're willing to take your chances that that's the first place to push, so to speak, and hopeful that that might give you the birthrate result that you'd like. But you're both in favor of markets and education and modern life?
Nick Eberstadt: Yeah, I guess I'd say that education, eradication of illiteracy, reduction of mortality and promotion of health, what else is part of the modernity project?
Peter Robinson: Well, I think Paul would include contraceptives.
Nick Eberstadt: Yeah, adequate--access to available effective contraceptive techniques. All of these are part…
Peter Robinson: And markets?
Nick Eberstadt: None of this will work without markets. None of this will work without markets.
Paul Ehrlich: The Soviet Union, among others, proved that you can't really run a complex society without markets. That doesn't mean I think it's a mistake to believe that no controls are needed on markets of various…
Nick Eberstadt: But the Netherlands Fallacy presupposes markets.
Paul Ehrlich: Yes, right. No, exactly.
Peter Robinson: So Paul, so things are going in the right direction?
Paul Ehrlich: No, not necessarily, we're going in the right direction, but in my view, going back to what Nick said, we aren't putting enough attention into constraining, changing the playing field, and so on, so that for example…
Peter Robinson: So I make you emperor of the world for a day, give me a…
Paul Ehrlich: Well, the first thing I would do is put three or four bucks--gradually put three or four bucks worth of taxes on every gallon of gasoline in the United States--to give you a very explicit example. But at the same time, I would pay down the FICA tax, with the huge revenues from that, so you don't drive poor people out of the economy. I mean, to put something…
Peter Robinson: We're all opposed to regressive taxation. So, as a kind of pressure point, one thing you would do is look over the economy and say, where are externalities not being captured? You and Ken Arrow and Milton Friedman and Nick Eberstadt could all sit down together, trained biologists and trained economists and sort it out and do some real good.
Paul Ehrlich: I think most of us would agree that tax policy is one of the lever points on this issue.
Peter Robinson: You'd agree with that?
Nick Eberstadt: Absolutely.
Peter Robinson: Last, predictions--the long-term trend in global population.
Title: Up, Up and Away
Peter Robinson: We have six billion now, forty years ago we had about three billion, at the beginning of the century we had under two billion. So the trajectory is up, up, up, up, up. Twenty years from now, what will it be? Now, I'm not exactly asking you to look into a crystal ball, but the answer you give will say something about your views on this. What will world population be in twenty years say?
Nick Eberstadt: Barring catastrophe, we would expect at least another billion people, maybe more. The interesting question is what happens over a longer period…
Peter Robinson: All right.
Nick Eberstadt: …fifty or a hundred years.
Peter Robinson: All right.
Nick Eberstadt: It's perfectly conceivable to hypothesize about a world a hundred years from now where population is declining, maybe higher than it is today, but will have been declining under non-catastrophic conditions just because part of the modernity project that you referred to seems to be a preference for smaller family size, for sub-replacement fertility, at least in a lot of places in the world today.
Peter Robinson: You say barring catastrophe.
Nick Eberstadt: Barring catastrophe.
Peter Robinson: You don't see the growth in population in and of itself suggesting catastrophe?
Nick Eberstadt: Not to me.
Peter Robinson: Paul, you call it.
Paul Ehrlich: I think the potential is higher than he thinks it is, but there's no way for us to settle that argument. I'm really worried about, among other things, the chances of global epidemics, and we have one bad example already, and I'm very concerned about some of the technical things that have happened in agriculture, which actually in the course of avoiding, what I predicated, we have exposed ourselves to various chances. On the other hand there's not much…
Peter Robinson: Give me an example of that so I know what you mean.
Paul Ehrlich: Oh, because we are--for example, we are dependent in huge areas planted in the same strains of the major crops. And we don't put enough attention to agriculture and agricultural research to help us avoid that. Agriculture is sort of a poor child in the system. And the other thing is what you feel about the precautionary principle and that's--but I think his numbers are basically correct. If we avoid catastrophe, that's what's going to happen. But the issue is, what are the odds of catastrophe, how much should we pay to take out insurance. It's not a scientific answer. In other words, suppose there is a ten percent chance through global warming that we'll have an utter catastrophe and a ten percent chance we'll get away with it entirely. And that's about what the IPCC, the Intergovernmental Panel on Climate Change thinks. The issue for society is what do you pay for insurance to cover that ten percent risk, and that's not an answer that either one of us can give; society has got to decide.
Nick Eberstadt: No. But I agree with that perspective for trying to come to an answer on that question.
Peter Robinson: All right, fine. Nicholas Eberstadt, Paul Ehrlich, thank you very much. I'm Peter Robinson, for Uncommon Knowledge, thanks for joining us.