The results of the campaigns were ghastly. Millions of women were sterilized, often coercively, sometimes illegally, frequently in unsafe conditions, in Mexico, Bolivia, Peru, Indonesia, Bangladesh, and, especially, India. In the 1970s and 1980s the Indian government, then led by Indira Gandhi and her son Sanjay, embraced policies that in many states required sterilization for men and women to obtain water, electricity, ration cards, medical care, and pay raises. Teachers could expel students from school if their parents weren’t sterilized. More than 8 million men and women were sterilized in 1975 alone. (“At long last,” World Bank head Robert McNamara remarked, “India is moving to effectively address its population problem.”) All the while, the same programs were pushing birth control with equal vigor. In Egypt, Tunisia, Pakistan, South Korea, and Taiwan, health workers’ salaries were, in a system that invited abuse, dictated by the number of IUDs they inserted into women. In the Philippines, condoms and birth-control pills were literally pitched out of helicopters hovering over remote villages.

  Inspired by The Limits to Growth approach, Song Jian, a Chinese specialist in ballistic-missile control, formed a research team in 1978 to create, in effect, a Chinese version of the Limits model. Not one member of his team had experience in demography. This didn’t stop the group from using China’s defense-industry computers to churn out population projections. Swooping curves on graphs showed China’s population reaching 4 billion in 2080, an impossible burden. Borrowing methods from Dutch computer scientists, Song’s team calculated the desired trajectory for population as if it were aiming a missile. Out came the answer, as inexorable as fan-folded paper unfurling from a dot-matrix printer: the sole route that would allow China to stave off disaster would be for all Chinese couples to have but a single child, beginning immediately. Sneering at dissenting social scientists as useless hand-wavers, Song pushed for the one-child program that was adopted by the government in 1980. Tens of millions—possibly 100 million—of coerced abortions occurred, often in poor conditions that led to infection, sterility, and even death. Millions more women were forced to insert IUDs or be sterilized. (The anti-population campaigns have largely been abandoned.)

  Vogt was not responsible for these cruelties—he died before they began, and in any case was no longer in a position of influence. But his intellectual guilt is heavy. If his great success was stoking concern about the connection between population and environmental degradation, his great failure was believing that the connection was simple, clear, and pivotal. In The Population Bomb, Ehrlich, too, described the link as straightforward. He devoted the first section of his book, “The Problem,” to explaining the issues. After describing population growth, food shortfalls, and environmental problems, the section ends with a summation: “The causal chain of degradation is easily traced to its source. Too many cars, too many factories, too much detergent, too much pesticide, multiplying contrails, inadequate sewage plants, too little water, too much carbon dioxide—all can be traced easily to too many people” (emphasis in original). And then ends the chapter. The white space on the page testified to Ehrlich’s view that the relationship between population and environmental degradation was too obvious to be worth belaboring.

  So rapidly was The Population Bomb rushed into print that nobody noticed that the fuse-lit bomb on the cover was captioned “THE POPULATION BOMB KEEPS TICKING.” Credit 84

  Some parts of the case, to be sure, are obvious. A world with zero people in it clearly would have no worry about human impacts. Similarly, it is easy to credit that a population of 20 billion would have a huge effect on natural systems. But it’s not at all evident what happens between zero and twenty, or between zero and ten, where humanity has spent its entire existence. The reason is that people are not fungible—the impact of one person living one kind of life is completely different from that of another person living another kind of life.

  Looking back, Ehrlich told me, he wished he had “given more emphasis to consumption, and not just population”—an issue he rectified in later writings. Consider the opening scene of The Population Bomb. The first sentences describe a ride in an “ancient taxi” taken by Ehrlich and his family through “a crowded slum area” in Delhi.

  The streets seemed alive with people. People eating, people washing, people sleeping. People visiting, arguing, and screaming. People thrust their hands through the taxi window, begging. People defecating and urinating. People clinging to buses. People herding animals. People, people, people, people….[S]ince that night, I’ve known the feel of overpopulation.

  The Ehrlichs took the cab ride in 1966. How many people lived in Delhi that year? A bit more than 2.8 million, according to United Nations figures. By comparison, the 1966 population of Paris was…about 8 million. One can spend considerable time searching through libraries for expressions of alarm about the way the Champs-Élysées “seemed alive with people” without success. Instead, Paris in 1966 was an emblem of elegance and sophistication. What was different in India? Why was Delhi overcrowded, if Paris wasn’t?

  Look at the numbers from the United Nations. In 1970 Delhi’s population was 3.5 million—an increase of 25 percent in the few years after Ehrlich’s taxi ride. Five years after that, in 1975, Delhi had 4.4 million people—another 25 percent gain. Amazingly, Delhi’s population was eleven times bigger in 2005 than it had been in 1950.

  What was the cause of the city’s extraordinary growth? I asked Sunita Narain, head of the Center for Science and Environment, a think tank in Delhi. “Not births,” she said instantly. Instead, she said, the overwhelming majority of the new people in Delhi then were migrants drawn from other parts of India by the hope of employment. Delhi had jobs because the government of India was trying to shift people away from small farms into industry, which it saw as the vehicle for national prosperity. Many of the new factories were located in and around Delhi, and people were moving there to improve their lives. Because there were more migrants than jobs, Delhi had become jam-packed and often unpleasant, exactly as Ehrlich had described. But the crowding that gave him, ever after, “the feel of overpopulation” had little to do with birth rates and natural resources and density of numbers and much to do with laws and institutions and government plans. “If you want to understand Delhi’s growth,” Narain said, “you should study economics and sociology, not ecology and population biology.”*5

  Few places better illustrate the complex relationship between population and environment than the lower Hudson River Valley, the area where Vogt got polio, went to college, and learned to love birds. To the west rise the Catskill Mountains, blue at sunset and blanketed by trees. Interstate 87 makes a black ribbon between the water and the mountains. In years past I spent some time driving back and forth on that road, and down long miles of its length the forest stretched out so far and so dark and so empty that I imagined I was looking at the America of 150 years past, before there were millions of people like me around. How wonderful, I thought, that so close to Manhattan is a huge piece of real estate that we never trashed.

  I was wrong. If I had traveled through the Hudson Valley in the closing decades of the nineteenth century, I would have passed through an utterly different landscape. I would have been surrounded by hardscrabble farms and pastures ringed by stone walls. It might have looked picturesque—guidebook writers of the day thought so. But I wouldn’t have seen many trees, because almost every scrap of land that wasn’t vertical had been clear-cut or burned.

  The forest was stripped to make way for agriculture and to supply New York’s army of charcoal burners (who needed lumber to make charcoal), tanners (who extracted tannin from bark), and salt makers (who used wood fuel to boil down seawater). Loggers played a role too: Albany, the northernmost deepwater port on the Hudson, was the biggest timber town in the nation and possibly the world. When the first Europeans came to New York, the rolling uplands were almost entirely covered by open forest; by the end of the nineteenth century less than a quarter of the state was wooded, and most of
what was left had been picked through, or was inaccessible, or was being kept by farmers as private fuel reserves. During the epoch that I, swooping along the tarmac in my minivan, was nostalgically picturing as a paradise, newspaper editorials were warning that deforestation would drive the valley toward ecological disaster.

  Since then the collapse of small farming on the East Coast has allowed millions of acres to return to nature. When New York State surveyed itself in 1875, the six counties that make up the lower Hudson Valley—Columbia, Dutchess, Greene, Orange, Putnam, and Ulster—contained 573,003 acres of timberland, covering about 21 percent of their total area. A hundred years later trees covered almost 1.8 million acres, more than three times as much.

  Back in 1875 these six counties had a collective population of 345,679. The U.S. Census says the figure for 2012 was 1.06 million. In other words, the number of people living there tripled in the same period that the local ecosystem climbed out of its sickbed and threw away its crutches. This wasn’t just some odd thing that happened in New York. As a whole, U.S. forests are bigger and healthier than they were in 1900, when the country had fewer than 100 million people. Many New England states have as many trees as they had in the days of Paul Revere. Nor was this growth restricted to North America: Europe’s forest resources increased by about 40 percent from 1970 to 2015, a time in which its population grew from 462 million to 743 million.

  “People pollute,” as Hugh Moore said. But more people ≠ more pollution. Eco-critics claim with some justification that the Hudson Valley recuperated because farmers abandoned it in order to wipe out the native grasslands of the Great Plains. But they can’t explain away all the other good news. Seals and dolphins return to the Thames. White-tailed deer, almost extinct in 1900, plague New England gardens. Air quality in formerly polluted Japan improves remarkably. Wild turkeys have a greater range than they did when they were first seen by European colonists. If all this occurred during the population boom, why the belief, voiced by Vogt, Osborn, Leopold, and so many who followed them, that overpopulation will lead to an eco-catastrophe?

  Years ago I had the chance to ask this question of Dennis Meadows, coleader of the research team that produced The Limits to Growth. “You can look at Lake Erie or Detroit and see it’s gotten better,” he said. “But to leap from that to the conclusion that there has been overall improvement is to look at one person getting rich and say that everybody is better off.” Then a professor emeritus at the University of New Hampshire, Meadows and his co-workers had updated Limits several times, each update as pessimistic or more so than the original book. “When a rich country becomes concerned about environmental problems,” Meadows told me, “then it can typically develop effective responses.” Lead additives in gasoline became a subject of U.S. worries, he pointed out. Washington forced petroleum companies to pay to phase out leaded gas and car companies to pay to change their engines and drivers to pay more at the pump. Money was flung at the problem, and lead levels diminished.

  I dutifully quoted Meadows to this effect in an article. Only a year after it was published did it occur to me that this argument might amount to saying that economic growth in fact allows societies to buy their way out of environmental problems—a Borlaugian stance. Curious, I again telephoned Meadows, who kindly took my call. Was affluence the answer, as Wizards said? No, he told me. He gave an example: the lush, beautiful evergreen forests in the mountains of Japan. Japan maintains them, he said, by importing all of its lumber from Southeast Asia, Australia, Brazil, and the U.S. West. Like the New Yorkers shifting agriculture to the Midwest, Japan was using its wealth to shift the ecological burden of deforestation. I asked if Japan couldn’t simply ban wood imports and build its homes with plastic and foam and the weird new high-tech materials one sees on Tokyo streets. The shift might be costly, I suggested, but Japan is prosperous. Couldn’t they buy their way out of this problem, too? No, Meadows said. When I asked why, he became exasperated with my stupidity. “Look, the basic facts are obvious,” he said. “You can’t keep growing forever on a finite planet—there are limits.” But the exact relations among economic growth, environmental destruction, and planetary limits no longer seemed so obvious to me.

  Compare a family in Delhi (2015 per-capita income: $3,180) to a family in, say, Copenhagen (2015 per-capita income: $47,750). Given their relative incomes, it seems safe to posit that the citizens of Copenhagen consume much more than the denizens of Delhi. But if people in Delhi burn coal to cook their food and heat their homes they may do more damage to the local and global environment than people in Copenhagen, who can get most of their power from the country’s plentiful wind-power stations (wind supplies almost half of Denmark’s electricity). In the fall of 2016 Delhi’s smog was so bad that schools were closed all over the city for days. The pollution was due to coal in the city and small farmers burning crop residues in the adjacent states of Punjab and Haryana. Meanwhile the Copenhagen government has announced plans to cut the city’s carbon dioxide emissions to zero by 2025.

  The emissions difference does not necessarily mean that Delhi families cause more environmental damage than Copenhagen families. Danes eat so much meat and drive so many automobiles that in 2014 the Worldwide Fund for Nature claimed that Denmark had the fourth-biggest “ecological footprint” in the world. The main cause was the huge amounts of animal feed grown to support the Danish pork industry. To feed its meat habit, Denmark used more farmland per capita than anywhere else.

  Which is more eco-friendly, Delhi or Copenhagen? The answer depends more on the weights assigned to air pollution and land use than the absolute level of economic growth or consumption. I can spend a million dollars paving over a magnificent redwood forest and that will appear in the statistics of gross domestic product as a million dollars of economic activity. But I can also spend that money buying front-row opera seats for poor schoolchildren and that, too, will appear in the gross domestic product as a million dollars of economic activity. The two activities contribute identically to the statistics, but their environmental impact is strikingly different. Presumably I could buy many million dollars’ worth of opera tickets before coming close to the environmental impact of paving the forest—that is, I could increase GDP and have the net environmental impact shrink. How many people? is an important question, but it is less important than What are those people doing?

  None of this is to deny that environmental problems are real. Overfishing, deforestation, soil degradation, contaminated groundwater, declining populations of mammals and birds, and, most alarming, the possibility of very rapid climate change—all of these are important. But the contribution of population growth to them is indirect, and the relationship to economic growth is equivocal. Focusing on them as a root cause, as Vogt did, is a distraction. It was a waste of two decades, and doubly unfortunate because the fight over population sometimes shrouded the more important part of Vogt’s message, the part about limits. He denounced social scientists as fools, but he should have listened to them. And that, alas, applies to Borlaug, too.

  * * *

  *1 In April 1948 the Pan American Union was reconstituted as the Organization of American States, its current name. Because the new charter did not come into effect until 1951, I refer to the group here as the Pan American Union.

  *2 The IUPN became the International Union for the Conservation of Nature and Natural Resources (IUCN) in 1956. Today it has a membership of 1,200 governmental and private organizations and coordinates the work of 10,000 or more pro-bono scientists. Although IUCN has global reach, it is not well known in the United States, because the U.S. Fish and Wildlife Service performs many of the functions undertaken by IUCN elsewhere.

  *3 Huxley’s belief that society should be run by scientific experts was similar to the ideas of M. King Hubbert and Technocracy. But Huxley was influenced less by Technocracy than by the putatively scientific Five-Year Plans of Stalin’s Soviet Union. In effect, Huxley wanted to introduce Stalinist planning but without the brutali
ty of Stalinism itself.

  *4 It might have been useful if he had. As Vogt had feared, PPFA and Pincus didn’t have enough resources to test the pill properly, and women were initially prescribed dangerously high dosages. Moreover, the drug—as Vogt predicted—was too costly for women in poor places.

  *5 For much of the last half of the twentieth century, Delhi was the second-fastest-growing city in the world. The fastest-growing was Tokyo. Tokyo was and is extremely crowded, but it is also clean, safe, and prosperous—a legacy, in part, of effective urban governance. The vicissitudes of Japanese history and culture have much more to do with whether Tokyo is “overpopulated” than the rate at which Japanese babies are coming into existence.

  [ NINE ]

  The Wizard

  Multiples

  The world is various but the view from the laboratory bench is ever similar. Scientists speak different tongues and live in different places and worship different gods, but at any one time the array of available problems and techniques is limited and apparent to all. In consequence, discovery is a crowded business. “The pattern of independent multiple discoveries in science is in principle the dominant pattern,” wrote the sociologist Robert K. Merton, in a passage well known to historians of science. Look hard at individual cases, Merton argued, and you will find that “all scientific discoveries are in principle multiples.” Men and women emerge from the obscurity of the laboratory waving a flag in triumph and discover somebody ahead and somebody behind, each with the same flag. Almost always, even the most original scientists have doppelgängers—intellectual near twins who would have accomplished the same work, if circumstances had been slightly different. However different in temperament and circumstance, they were scrabbling along the same path.