Head CountFertilizer, fertility, and the clashes over population growth
by Elizabeth Kolbert October 21, 2013
Some experts worry that we have too many children; others that we have too few.
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Illustration by Nishant Choksi.
On May 12, 1907, toward the end of the annual meeting of the German Bunsen Society, which was held that year in Hamburg, a distinguished chemist named Walther Nernst insulted a not so distinguished junior colleague named Fritz Haber. The topic of the put-down—the synthesis of ammonia at very high temperatures—was, even by Bunsen Society standards, abstruse, but the gibe was strongly worded, so everyone at the meeting understood Nernst’s intent. Haber, who suffered from a variety of nervous ailments, was mortified. When he returned home to Karlsruhe, his skin broke out in hives. Before Nernst’s attack, he hadn’t been all that interested in synthesizing ammonia. The insult had the unintended consequence of stiffening his resolve. Haber threw himself full time into proving that ammonia could indeed be cooked up in the laboratory, using hydrogen and ordinary nitrogen gas. The result of this effort, which eventually became known as the Haber-Bosch process, had unintended consequences of its own, some of which proved to be world-altering.
Nitrogen is a tease. It’s crucial to life but exists mostly as N2, a form that living things can’t make use of. Early in the history of agriculture, people realized—without, obviously, understanding the chemistry behind this insight—that when usable nitrogen ran low fields turned barren. Eight thousand years ago, farmers in the Middle East were already planting legumes, whose roots harbor nitrogen-fixing bacteria, in rotation with cereal crops, such as wheat. Later, Cato the Elder recommended that Romans “save carefully goat, sheep, cattle, and all other dung.” Bird shit is an excellent source of nitrogen, and in the early nineteenth century, when Europeans learned that there were mountains of the stuff on remote islands off Peru, the discovery inspired a guano rush; by the eighteen-fifties, Britain was importing four hundred million pounds of bird poop a year, and the United States a hundred and seventy million pounds. In 1856, the U.S. Congress passed the Guano Islands Act, which authorized Americans to lay claim to any deserted guano islands they could find. (Through the act, the U.S. did not come into much nitrogen; it did, however, acquire a host of minor territories, including Midway Island.)
By Haber’s day, the appetite for crop-friendly nitrogen was so huge that scientists had turned their attention skyward. Nitrogen is the most common element in the earth’s atmosphere—nearly four times more plentiful than oxygen and more than eighty times more plentiful than argon—but almost all of it is floating around in the intractable form of N2. When the humiliated Haber showed how to bust up N2 to produce ammonia—NH3—he basically solved the problem. No more guano would be needed. Haber had, it was said, figured out how to turn air into bread.
The first industrial-scale factory to employ the new Haber-Bosch process opened almost exactly a century ago, near Ludwigshafen. It pumped out more than ten tons of ammonia a day; this was further processed into fertilizer and sold as quickly as it could be manufactured. When the First World War broke out, the plant was converted into a munitions factory; nitrogen, as it happens, is also critical for making explosives. Thanks to the Haber-Bosch process, the Germans were able to keep the bombs dropping even after their supplies of saltpeter had run low. (According to some historians, without the process the Second Reich would have collapsed as much as two years sooner.)
Since the end of the Second World War, nitrogen-based fertilizer production has increased at least twentyfold. Such are the quantities being churned out in factories from the U.S. to Uzbekistan that humans are now likely responsible for fixing more nitrogen than all terrestrial ecosystems combined. It’s been estimated that almost half of the world’s current population subsists on crops grown with the output of the Haber-Bosch process. These people—who may well include you and me—are eating bread made of air, and so, in a sense, are made of air as well.
In a 2007 best-seller, “The World Without Us,” Alan Weisman imagined a planet suddenly devoid of humans. His new book, “Countdown: Our Last, Best Hope for a Future on Earth?” (Little, Brown), represents a less radical thought experiment. Instead of eliminating people from the planet altogether, Weisman wants only to get rid of several billion of them. He argues that when Haber figured out how to make bread out of air, things took a turn for the worse. The circumventing of the nitrogen cycle allowed Homo sapiens to reproduce at an unprecedented pace. (E. O. Wilson has described the rate as “more bacterial than primate.”) Among the results of this explosive growth has been a buildup of greenhouse gases in the atmosphere, which now puts not only humans but also pretty much every other creature on earth at risk. Since it was the Haber-Bosch process that made the surge possible, the process also suggests a target for the abatement.
“Before artificial nitrogen fertilizer became widely available, the world’s population was around 2 billion,” Weisman observes. “When we no longer have it—or if we ever decide to stop using it—that may be a number to which our own naturally gravitates.” The alternative to an orderly global “countdown” is, he warns, pretty dire. “Whether we accept it or not, this will likely be the century that determines what the optimal human population is for our planet,” he writes. “Either we decide to manage our own numbers, to avoid a collision of every line on civilization’s graph—or nature will do it for us.”
There is, of course, a long tradition in English of grim, though never quite realized, predictions of this sort. Thomas Malthus published “An Essay on the Principle of Population” in 1798, around the time humanity was reaching the one-billion mark (not that Malthus would have had any way of knowing this). It stated that people would inevitably produce more mouths to feed than food to feed them, since population “increases in a geometrical ratio” while “subsistence increases only in an arithmetical ratio.” Even a “slight acquaintance with numbers,” Malthus wrote, was enough to appreciate the “immensity” of the mismatch. War was one way the population and the food supply might be kept in line; another was “epidemics, pestilence, and plague.” If none of these proved sufficient, then “gigantic inevitable famine” would come to the rescue and “with one mighty blow” solve the problem.
A century later, in 1898, the number of people on the planet had nearly doubled when William Crookes, a chemist who’d recently become president of the British Association for the Advancement of Science, warned of an imminent crisis. According to Crookes, wheat production was levelling off, even as the number of wheat eaters continued to increase exponentially. “England and all civilized nations stand in deadly peril of not having enough to eat,” he declared. He gave the “civilized” world three decades.
By 1968, there were three billion people on the planet. That year, Paul Ehrlich published “The Population Bomb,” which announced that “the battle to feed all of humanity is over.” According to Ehrlich, a professor of biology at Stanford University, nothing could be done to avert disaster: “in the 1970’s the world will undergo famines—hundreds of millions of people are going to starve to death in spite of any crash programs embarked upon now.” In the most optimistic scenario Ehrlich could envision, after the “major die-back” had ended, those countries left with functioning governments—the United States, Russia, and Canada among them—would embark on a program of agricultural development that would allow what remained of humanity to survive. Ehrlich challenged his readers to come up with a plausible but more upbeat possibility. “I won’t accept one that starts, ‘In early 1972, the first monster space ships from a planet of the star Alpha Centauri arrive bearing CARE packages,’ ” he wrote. Since Ehrlich issued this challenge, the global population has once again more than doubled, to 7.2 billion.
According to one school of thought, what’s instructive about the Malthusian tradition is how consistently wrong its predictions have turned out to be. At any particular moment, it may look as if we’re at the end of our proverbial rope, but just at that moment we find new rope: synthetic fertilizers, the Green Revolution, genetically modified crops. If human numbers increase geometrically, so, too, it seems, does human ingenuity.
According to a second school of thought, Malthus et al. weren’t wrong, exactly; it’s just that their timing was off. Technologies like Haber-Bosch and genetic engineering mask but do not solve the underlying problem, which is that the earth’s resources are finite. By delaying the final reckoning, they guarantee that when the crash eventually comes it will be that much uglier.
The latest population projections from the United Nations were released in June. If they’re correct, by 2025 there will be eight billion people on the planet. By 2050, there will be nine and a half billion, and by 2100 there will be nearly eleven billion. This is an awful lot of mouths to feed. It’s also a lot of people for Weisman to turn, as it were, back into air.
When demographers peer into the future, the key figure that they look at is the total fertility rate, or T.F.R. The T.F.R. is designed to offer a snapshot of a process—childbearing—that occurs over many years. Roughly speaking, it represents the average number of children that the average woman will produce in her lifetime. Weisman’s goal of bringing down the world’s population to two billion within two or three generations requires a global T.F.R. of about one, which is to say a more or less universal one-child policy.
How could this be accomplished? Much of “Countdown” is spent trying to answer this question. Weisman’s method is to travel around the world asking people what they think about topics like family size, birth control, and impending environmental disaster. He spends a lot of time in China, which forcibly imposes a one-child limit. Weisman doesn’t exactly endorse this idea, nor does he exactly condemn it. He quotes a Chinese environmentalist named Ouyang Zhiyun, who says that most Chinese recognize the need for the policy. Without it, Ouyang observes, China’s population, now 1.3 billion, would be heading toward two billion and beyond. “Good-bye food and water,” Ouyang says.
Weisman seems to be happiest in Japan, because there they do it—or, really, don’t do it—voluntarily. (As a mother of one in a fancy Tokyo neighborhood puts it to him, “Frankly, Japanese people don’t have sex much anymore.”) Japan’s T.F.R. is 1.4. This is actually lower than China’s, which, despite official policy, is 1.5. Japan’s population peaked in 2006 and last year declined by nearly three hundred thousand. Life expectancy in the country is among the longest on earth, but, even if it continues to grow, the number of Japanese is expected to keep dropping at least through the middle of this century. In the mountainous Nara Prefecture, Weisman visits a town whose population has already shrunk by three-quarters. As the people have disappeared, those left behind—nearly half of them over the age of sixty-five—have found that animals are returning. Once heavily logged, the prefecture’s forests are growing back and being recolonized by bears, herons, macaques, and eagles. Weisman meets with a newcomer to the town, a thirty-three-year-old who is planning to take over an abandoned wasabi farm. The man has a girlfriend, and they are hoping to get married and to perhaps have one child.
There are lots of countries where the T.F.R. is approaching one, and even some where it’s dropped below that. Singapore’s T.F.R. is just .79. Taiwan’s is 1.1, and South Korea’s is 1.2. Most European countries have T.F.R.s under 1.5; these include Italy, Spain, Germany, and the Czech Republic. Even in some countries where the population is still increasing at a rapid clip, owing to what’s known as “demographic momentum,” fertility rates are way down: Iran’s T.F.R., for example, is 1.9 and Brazil’s 1.8.
But there are plenty of other countries—mostly in Africa—where the T.F.R. remains above five. Niger’s, the highest in the world, is seven. Mali’s, the second highest, is 6.25, and Somalia’s, the third, is 6.17. Such are the mathematics of fertility that, barring some sort of Malthusian crisis, these high-fertility countries will add a lot more people during the coming decades than the low-fertility nations will lose. They will also be home to an ever-increasing proportion of the world’s population. Nigeria, for example, currently has a hundred and seventy-four million people and a T.F.R. of 5.3. Within a few decades, it’s expected to overtake the U.S. as the world’s third most populous country. By the end of the century, it will have as many people as China. (By that point, India is expected to be the most populous nation on earth.)
Weisman travels to several countries with moderately to very high fertility rates. When he asks people in these countries what should be done to bring down the numbers, mostly the answer is “Nothing.” In Niger, in the village of Mailafia, he encounters a mother of eight who laments the lack of milk in her town. “All we want is food so we can produce children,” she exclaims. Also in Niger, in the city of Maradi, he meets an imam who tells him, “We know the future is alarming. But man cannot hold back doomsday.” In the Israeli city of Brei Brak, Weisman meets another mother of eight. She tells him she’s not the least bit concerned about the world’s burgeoning population, because “God made the problem, and He will solve it.” At a clinic in Karachi, Pakistan, he meets a technician who refuses to administer the contraceptive injection that one of the clinic’s patients has just been prescribed. “I don’t believe we should practice family planning,” the technician says. “Our community should increase in number.”
“Countdown” seems set up to take on the challenge posed by the Nigérien imam and the Israeli mom, yet it never quite gets around to doing so. Weisman ends more or less where he began, wondering whether it might be possible to persuade people to “embrace the idea of, so to speak, refraining from embracing as much,” so that, two or three generations from now, the population can reach an “optimum number.”
Steven Philip Kramer is a professor at the National Defense University, in Washington, D.C., specializing in the branch of military decision-making known as grand strategy. Like Weisman, he’s worried about demographics. The problem that concerns Kramer, however, is not too many children; it’s too few. In “The Other Population Crisis: What Governments Can Do About Falling Birth Rates” (Johns Hopkins), Kramer argues that countries like Singapore and Italy, where the fertility rate has dropped below replacement levels, are in deep trouble. As their populations age and ultimately shrink, low-fertility countries will have fewer and fewer workers supporting more and more retirees. This will strain their social-welfare systems. To compound the problem, young people, Kramer says, tend “to be in the vanguard of technological innovation,” so aging countries may suffer from a sort of app gap.
Kramer visits several nations that have tried to lift their birth rates, with varying degrees of success. (Boosting fertility is, Kramer maintains, even harder than reducing it, as “you can sterilize people so they can’t procreate, but even the Nazis could not force people to breed.”) France gets high marks. The country has a variety of “pronatalist” policies, including direct grants to families with two or more children, generous tax deductions for dependents, and four months of paid maternity leave financed through the national health-insurance system. These programs appear to be at least somewhat successful, as the country’s fertility rate, which fell to a low of 1.74 in 2002, has since rebounded, to 2.08.
To Kramer, as to Weisman, Japan stands out, though as far as Kramer is concerned the country is a basket case. Its policies are notable only for their “inadequacy.” Child-care slots are limited, and tax deductions for couples with kids are too low to make a difference. Also like Weisman, Kramer is struck by the national prudishness. He cites a recent study by the Japan Family Planning Association indicating that “36% of males 16-19 had no interest in sex or even despised it, that 59% of female respondents said they were uninterested or averse to sex, and that 40.8% of married people said they had not had sex in the past month!”
In the United States, the fertility rate is currently estimated at 2.06. This figure puts the U.S. ahead of all European nations except France, and right about at replacement level. Nevertheless, according to Jonathan Last, a senior writer at The Weekly Standard, the country is facing doom by depopulation. At the start of “What to Expect When No One’s Expecting: America’s Coming Demographic Disaster” (Encounter), he breaks the number down by race, income, and education. Black women have what Last terms a “healthy” fertility rate of 1.96. Hispanic women are “doing most of the heavy lifting,” with a rate of 2.35. White women, by contrast, are slackers. Their rate is 1.79, which makes them about as productive or, if you prefer, unproductive as the Dutch and the Norwegians. Poor women generally have more kids than middle-class women, while women who drop out of high school have more than those who graduate, and way more than those who earn advanced degrees. All this adds up, Last writes, to a “kind of reverse Darwinism where the traditional markers of success make one less likely to reproduce.”
Last has aimed his book at the same sort of readers who subscribe to The Weekly Standard. He describes himself as an “anti-abortion nut job,” lampoons the “feminist-industrial complex,” and laments a decline in marriage rates among the “lower classes.” Those who find Last’s politics less than congenial are likely to be less than convinced by his arguments. Among the problems he attributes to low fertility rates is that they tend to make countries reluctant to fight wars. Among the solutions he advocates is cutting back on higher education, thereby reducing its depressing influence on American fertility.
It may seem that one world can’t have two population problems: either the glass is too empty or it’s too full. But the crises Weisman and Kramer are worried about can ultimately be traced to the same cause. In most of Europe and also in the U.S., social-welfare systems were put in place at a time of rapid, Haber-Bosch-fuelled population growth. The programs were structured around the assumption that there would always be more young people paying for benefits than there would be old people receiving them. (As Last points out, Social Security operates on much the same principles as a Ponzi scheme.) Thus the systems depend on endless population growth, but endless population growth is probably not possible and certainly not desirable. This double bind is distressing to contemplate, but, as Malthus advised his unhappy readers, “The most baleful mischiefs may be expected from the unmanly conduct of not daring to face truth because it is unpleasing.” ♦http://www.newyorker.com/arts/critics/books/2013/10/21/131021crbo_books_kolbert