Genetic evidence suggests that at some point between fifty thousand to one hundred thousand years ago, our Homo sapiens ancestors possibly numbered as few as ten thousand. Then they began to wander out of Africa, following the species corridor north through present-day Israel and Palestine and branching into Europe, Asia, and beyond. Discovering more sustenance as they spread, they began to increase, but almost imperceptibly. As the Worldwatch Institute’s Robert Engelman notes in his book More, had they multiplied at modern growth rates (currently 1.1 percent annually worldwide, which means doubling every sixty-three years), within a few millennia, not just Earth but the entire solar system couldn’t have contained us.
The simple reason population remained low until recent human history was that people died about as fast as people were born. For tens of thousands of years, most of them likely didn’t see their first birthday. Birth rates might be high, but so were infant mortality rates. A woman would give birth to seven, and two might live.
Two people, one man and one woman who produce two children, essentially replace themselves.1 Any more than two, population grows. The fact that population grew so slowly until about two centuries ago means that the average number of children who lasted long enough to have children themselves was barely more than two. For every family with more than two who survived to adulthood, others had only one or none who made it—at any number below two, population contracts.
Occasionally, it contracted dramatically, such as during the Black Plague, which killed off an estimated one-fourth of humanity in the mid-fourteenth century. But even without unusual epidemics, the general pall of death that hung over every family didn’t began to dissolve until 1796. That year, British surgeon Edward Jenner discovered a vaccine for smallpox, a disease that used to knock back our numbers each year by the millions. Jenner’s cure was also the first vaccine for anything. It inspired nineteenth-century French chemist Louis Pasteur to develop others, against rabies and anthrax. Pasteur made two other key contributions to human survival. One was the familiar process our dairies still use. Pasteurization extended the shelf life of milk, which improved nutrition and reduced infections from pathogens such as salmonella and those causing scarlet fever, diphtheria, and tuberculosis.
Pasteur was also instrumental in convincing humanity that disease did not occur through some mysterious spontaneous generation, but was spread by germs. In the nineteenth century, hand soap became common for the first time, both in homes and in hospitals. Before, patients died as often from infections picked up from a surgeon’s unsterilized hands and scalpel as from the ailment he was trying to fix. One of the first uses of surgical disinfectant was in a maternity ward in Vienna, where doctors washing their hands in a chlorine solution lowered both infant and maternal mortality by a factor of ten—an innovation with a direct impact on the number of living humans.
In the twentieth century, medical advances kept coming, each saving—and extending—more human lives. After Cuban microbiologist Carlos Finlay pinpointed the carrier of the yellow fever virus, American doctors William Gorgas and Walter Reed implemented the world’s first massive mosquito control program, without which the Panama Canal would never have been completed. More vaccines for diphtheria, tetanus, and finally polio, and the crucial invention of antibiotics, all lowered mortality and increased longevity—which meant that more total people, young and old, were alive. In 1800, average life expectancy at birth for most humans was forty years. Today, in much of the world, it’s nearly double.
More people not dying early and living longer: Who could object to that? “The humane goals of lowering the death rate are very important to me,” admits Albert Bartlett cheerfully, “if it’s my death they’re lowering.”
No disagreement from anyone over forty, who might well not be alive without these medical victories. Probably nobody else will protest, either. So any discussion of an optimum population for the human race must assume optimal health care. The idea of lowering medical standards to limit our numbers is no more acceptable than thinning ourselves by selective culling.
That doesn’t dismiss, however, an ethical argument raised by the implications of further medical advances. If any of the current greatest challenges—say, finding cures for malaria or HIV—were successfully met, it would spur a significant uptick in humanity’s census. Malaria alone kills a child every thirty seconds. If children stop dying from it, they’ll survive to reproduce more children who also won’t die of malaria. As it would be unconscionable to oppose malaria eradication just to keep human numbers in check, the question becomes whether funders of malaria and HIV research have a moral obligation to also fund family planning—lest our numerical impact threaten the very ecological underpinnings of human life.
Thus far, there’s no vaccine against extinction.
The other reason that humanity ballooned so suddenly in the last century was an unprecedented increase of the food supply. To be able to nourish everyone on Earth sounds like another moral no-brainer. Yet this one’s a little trickier. It raises a paradox that, at first, seems as counterintuitive as the unexpected results of exponential doubling.
The growing number of people was crucial to the success of the labor-intensive European Industrial Revolution. But it also meant that Europe had to produce more food than ever before to feed them. A German chemist, Justus von Liebig, is credited with two contributions to that cause—one huge, the other monumental. The huge one was developing the world’s first infant formula. Whether his creation was, as he claimed, nutritionally equivalent to mother’s milk is still hotly contested. Nevertheless, it freed many mothers from the exhausting business of breast-feeding indefinitely, and it allowed their babies to survive early weaning. And since lactation releases hormones that tend to suppress ovulation, less breast-feeding resulted in even more pregnancies.
Justus von Liebig’s second, monumental discovery was that nitrogen, along with phosphorus and potassium, is one of the essential nutrients for plants. Although he is considered the inventor of fertilizer, he was not responsible for the artificial nitrogen fertilizer used today, an innovation that probably changed the course of human events more than any other in modern history, cars and computers included. That would come later. In von Liebig’s day, commercial nitrogen fertilizers came chiefly from the excrement of seabirds and bats. Particularly prized was guano from islands off the coast of Peru, where cormorants, pelicans, and gannets that fed on enormous schools of nutrient-rich anchovetas had deposited layers of white poop 150 feet thick. In the nineteenth century, galleons and steamships carried more than 20 million tons of it around Cape Horn to Europe.
Having neglected to patent his discoveries, von Liebig profited little from them. Later, chagrined at the riches accrued by Nestlé and other competitors, he did secure the rights to one last invention that arguably contributed to human nutrition: the beef bouillon cube.
The essential nutrient nitrogen is a gas so relatively inert that, unlike hydrogen, there’s plenty of it floating around in its free state. In fact, over three-fourths of the air we breathe is pure nitrogen. Nothing in our lungs chemically combines with it, so we harmlessly exhale it away. In all nature, only one family of enzymes can fix airborne nitrogen—that is, absorb and chemically convert it into a nongaseous form, such as the plant food ammonium. And just a few plants host bacteria bearing these enzymes, which, in return, get fed by nodules on their roots.
They are mainly legumes, such as lentils, beans, clover, soy, peas, alfalfa, gum acacia, and peanuts. Until synthetic fertilizer, such symbiotic plant-bacteria pairs were the main source of nitrogen in soil, limiting the amount of plant life the planet could produce. Virtually anything green that grew was benefiting from nitrogen that leguminous plants had fixed. For that reason, farmers traditionally would rotate legumes with grains, or grow them together (such as corn and beans in Latin America), or plow cover crops like nitrogen-rich clover into their fields to replenish them.
Justus von Liebig was now bringing extra nitrogen into the mix from halfway around the world, but since his fertilizers came from natural sources, they, too, were limited by the biological food chain. By the beginning of the twentieth century, the easy pickings on Peruvian islands were already exhausted, and new guano wasn’t being produced as fast as new human babies. The next nitrogen source to be exploited was saltpeter: sodium nitrate crystals that occur in abundance only in very dry environments such as Death Valley, California, and Chile’s Atacama Desert. Then, in 1913, agricultural technology broke through nature’s ceiling. Fritz Haber and Carl Bosch, who figured out how to grab nitrogen out of the air and feed it to plants in quantities far beyond what von Liebig had ever imagined, were also Germans. Each would be awarded a Nobel Prize for his separate contribution to what became known as the Haber-Bosch process, which has transformed the world like no other. And each would be undone by his German nationality.
Fritz Haber was born to a Prussian Hasidic Jewish merchant family in 1868. He studied chemistry under Robert Bunsen, whose eponymous burner considerably enhanced laboratory research. In 1905, while teaching at the University of Karlsruhe and researching thermodynamics, Haber discovered that by passing nitrogen and hydrogen over an iron catalyst at 1,000°C, he could produce small amounts of ammonia. Later, adding high pressure, he accomplished this at half the temperature.
After he published his findings, his process was acquired by the German dye manufacturer BASF. They assigned a young engineer, Carl Bosch, to scale Haber’s ammonia lab experiment up to industrial levels. Bosch spent four years designing double-chambered pipes that wouldn’t explode under pressure, a purified iron catalyst, and blast furnaces that could handle both high pressures and temperatures.
In 1913, BASF opened its first synthetic ammonia plant. Ammonia was the feedstock for ammonium sulfate—nitrogen fertilizer. The dye manufacturer was now in a completely new business: agro-industry. Within a few years their new artificial nutrient was already making history, as an Allied blockade cut Germany’s access to Chilean saltpeter during World War I. Not only could Germany now keep feeding itself, but ammonium sulfate could be converted into synthetic saltpeter, from which BASF was soon manufacturing gunpowder and explosives. Without the Haber-Bosch process, World War I would have been far shorter.
Fritz Haber’s discovery of how to synthesize fertilizer was so enormous that a Nobel Prize in chemistry should have been no surprise. But coming in 1918 just as the war ended, it was controversial. During the war, Haber achieved the rank of captain for first proposing, and then directing, Germany’s use of chemical weapons against enemy trenches. When his wife, also a chemist, learned he was responsible for chlorine and mustard gas attacks, she committed suicide. (Later, their chemist son would also take his life, for the same reason.)
Haber’s knack for developing agricultural chemistry that could be turned to darker purposes didn’t end there. A pesticide fumigant he created to use in grain storage, cyanide-based Zyklon A, was later refined by Nazi chemists into the more potent Zyklon B gas used in extermination camps. Although born Jewish, Haber was not a direct victim of his own invention. For converting to Lutheranism as a student and for his substantial military contribution, he was assured in 1933 that orders from the new Nazi government that cost a dozen Jews in his laboratory their jobs didn’t apply to him. When he quit in protest over their firing, he was shocked to find that his only choice was exile. A patriot who’d had no qualms about applying his genius to chemical warfare, outside of Germany he became a broken man. Within a year he died—en route to Palestine, where Zionist and future Israeli president Chaim Weizmann had invited him to head the research institute that today bears Weizmann’s name.
Carl Bosch, named director of I. G. Farben, the conglomerate that bought BASF, became one of the most powerful industrialists in Germany. His own Nobel Prize, in 1931, was for his high-pressure chemistry achievements, which also included inventing steam reformation of natural gas to produce hydrogen. Alarmed by the Third Reich, at one point he met with Hitler to try to discourage him from leading their country into another war. The Fürher wasn’t swayed, except to arrange for Bosch’s dismissal from I. G. Farben, which later produced Zyklon B. Despondent and alcoholic, Bosch died in 1940.
Between the two wars that their work helped to prolong so horribly, Haber and Bosch’s synthetic fertilizer process spread around the world, eventually revolutionizing agriculture. Creating artificial fertilizers requires high temperature and pressure, meaning intense energy inputs (now 1 percent of the world’s total). Because fertilizers also need natural gas for their hydrogen component, they are doubly dependent on fossil fuels. Our supply of artificial nitrogen, therefore, will last only as long as they do. But as long as we have it, artificial nitrogen practically doubles the amount of that plant nutrient that nature can provide, and nearly half of us could not be here without it.
Before artificial nitrogen fertilizer became widely available, the world’s population was around 2 billion. 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.
In August 1954, twenty-nine-year-old Bill Wasson was reassured that God existed. Raised in a devout, charitable Catholic family in Phoenix, Arizona, he’d never had cause to doubt—until, while preparing to be a missionary, the Benedictines expelled him during his final year of seminary. Emergency surgery to remove half of his thyroid, they ruled, had left him too weak for the priesthood.
Crushed, he’d returned home. His family convinced their sorely depressed son to enter graduate school. He earned a master’s degree in law and sociology, but remained underweight and moody. A Mexican vacation almost turned disastrous when he relapsed, until a Mexico City doctor determined that he’d been unwittingly overdosing himself with his daily thyroid medication. Suddenly Wasson felt better than he had in years. Grateful to have found a physician he trusted, he stayed and took a position teaching psychology and criminology at the University of the Americas.
Still, he mourned his lost dream to be a priest to the needy. He finally went to a psychoanalyst, who was also a Catholic priest. “You’re not crazy,” he told Wasson. Instead of psychotherapy, he prescribed a meeting with the new bishop of Cuernavaca, an hour south of Mexico City. In his first year, 1953, Bishop Sergio Méndez Arceo had already scandalized wealthy parishioners, and endeared himself to the poor, by adding street mariachis to the cathedral’s Sunday Mass. After two hours of grilling the gangly, fair-haired American, he told Wasson to get ready. “In four months, I’m ordaining you.”
He gave him Tepetates, the Cuernavaca marketplace church. Wasson loved it. He turned half his quarters into a free clinic and soup kitchen. When a thief who’d been pilfering the poor box turned out to be a homeless orphan, he refused to let the police jail him. “He’s not a criminal,” Wasson said. “He’s just hungry.”
Instead, he took the boy in. The next day came a knock on his door. It was the police, with eight more orphans from their lockup. “Since you think they’re just innocent waifs, you can have these, too.”
Wasson scrambled fast. By that night, he’d found a vacant beer warehouse they could all sleep in. The word soon got around: a gringo priest was taking in abandoned boys. Within a month, he had thirty. Within three months, eighty-three. He was amazed that there were so many out there. He wanted to find them all.
In 1954, Mexico’s population had just passed 25 million. Surging twice as fast as the planet’s population, it would more than quadruple in just the next half-century. Many of his boys, Wasson soon learned, had more than ten siblings. Some even had more than twenty, if they counted half-siblings in casas chicas—the families their fathers kept on the side. When women died—all too often from the exhaustion of raising so many, mainly by themselves—men frequently disappeared.
One night he returned to find the boys huddled around his radio, listening to reports of a hurricane in Veracruz. Orphaned children were reported wandering the flooded streets. “Padre, you have to go save them,” they insisted.
They were living on donated food, and on blankets on the floor. “We barely have enough beans and tortillas and blankets for ourselves—” he started to protest.
But they’d already decided. “We’ll share.”
He came back with thirty more. Fortunately, people who’d learned what he was doing, and who kept telling him he couldn’t keep taking them all, also kept helping him find food and money when he ignored them. When he realized that several new boys from the ravaged Gulf Coast were worrying about brothers they’d left behind, he returned to find them. His family numbered nearly two hundred when the bishop’s secretary quit her job to help him, because the boys had sisters, too.
By 1975, Nuestros Pequeños Hermanos, Our Little Brothers and Sisters, population twelve hundred, was the biggest orphanage in the world. Mexico City was the biggest city in the world, and Mexico itself, population 60 million, was the planet’s fastest-growing country—so fast that the government that year defied the Catholic Church and began a national family-planning program. Mule-back riders were soon climbing mountains and descending canyons, their polystyrene saddlebags bearing condoms and birth control pills—and also polio and diphtheria-pertussis-tetanus vaccines. Women, it turned out, were willing to hike to a village clinic for pills to avoid pregnancy as long as their living children would be vaccinated against diseases that might otherwise kill them.
Within a decade, Mexico’s doubling rate slowed from every fifteen years to every twenty-four years. Had it not continued to lower, theoretically by the twenty-second century there might have been a billion Mexicans—a physical impossibility that long before would have overwhelmed both its environment and whatever fence its neighbor to the north might have built to keep them out. Today, Mexico’s average family is just 2.2 children: almost replacement rate. Even so, the sheer momentum of population growth means Mexico will keep growing in coming decades, as the ones already born add children of their own.
Father Bill Wasson already had more than he could feed. More than half the time he was off raising funds to keep them alive, clothed, and schooled. In the late 1970s, he moved his huge family south of Cuernavaca to a donated former sugarcane hacienda that Emiliano Zapata’s troops had sacked during the 1910 Mexican Revolution. The plan was to grow enough corn, beans, and vegetables to feed all the children. To assist came Dr. Edwin Wellhausen, recently retired from the International Maize and Wheat Improvement Center, known by its Spanish acronym, CIMMYT.2 Founded by the Rockefeller Foundation near the famous Teotihuacán pyramids northeast of Mexico City, CIMMYT is considered today the birthplace of the so-called Green Revolution. Its late director, Dr. Norman Borlaug, was awarded the Nobel Peace Prize for developing a disease-resistant, high-yield strain of dwarf wheat (dwarf, because normal wheat plants would fall over from the weight of the extra grains Borlaug’s genetically selected strains produced).
Edwin Wellhausen was CIMMYT’s corn-breeding specialist. He had developed a high-lysine amino acid corn variety that would significantly raise protein levels in the tortillas that the Nuestros Pequeños Hermanos children ate at every meal. A tall, thin, bespectacled man in a straw sombrero, Wellhausen arrived with a trailer truck loaded with hundreds of white sacks. Some contained donated seed. Others were ammonium nitrate and urea: nitrogen fertilizers. The rest were pesticides and fungicides: Green Revolution laboratory-bred hybrids, forced quickly through generations to emphasize certain desired traits, lacked resistance to various bugs that grains like corn, a native to Mexico, had acquired over thousands of years of evolution.
By now, Father Wasson had a sizable staff, including many of his grown children who were helping to raise and teach the next generation of Little Brothers and Sisters. The appearance of all these chemicals, several of them poisonous, provoked a discussion about potential threats to the children and to the soils of their donated hacienda. Another concern was cost. This truckload was a gift, but after a quarter-century, the orphanage had learned that an act of charity rarely keeps giving forever.
It was a short discussion. They had too many mouths to feed. They would worry about it later.
At one point during the twenty-five-mile drive from Mexico City to CIMMYT, the highway briefly passes through something startling: empty land. The bleak salt marsh is what remains of Lago Texcoco, the largest of five lakes that filled this high basin in central Mexico when Hernán Cortez’s Spanish troops first saw it. The Aztec capital, called Tenochtitlán, was on an island, connected to the shore by causeways. After the conquest, the Spaniards drained the lakes; eventually, the basin refilled and overflowed—with people. Today, 24 million live in one of the Earth’s greatest expanses of continuous concrete and asphalt, covering Mexico’s Distrito Federal and parts of five surrounding states. The sheer weight of the city atop its overpumped aquifer has sunk it so low that sewage canals no longer flow outward. Especially when it rains, Mexico City is in danger of drowning in its own wastes, requiring construction of the world’s longest sewer pipe: twenty-three feet across and thirty-seven miles long, tunneling nearly five hundred feet down to drain into a valley below.
Past the gray thorn scrub of the dry lake bed and some low hills composed entirely of automobile carcasses, urbanity resumes until the road reaches fields of wheat and maize surrounding the agricultural research center. A billboard near the entrance shows Norman Borlaug, who died in 2009 at ninety-five, in khaki shirt and pants, waist-high in dwarf wheat, notebook in hand. His many international awards are noted above the green and white CIMMYT logo, including the 1970 Nobel Peace Prize. Only five years earlier, Borlaug and his team had put the hybrids they’d developed in Mexico to the test in India and Pakistan. Both were nearing famine, despite massive grain imports from the United States. By 1970, harvests in both countries doubled and imminent disaster was averted. Green Revolution crops and breeding techniques began to spread around the world. In 2007, the United States awarded Borlaug its Congressional Gold Medal for having saved more lives than anyone in history.
He was also widely credited for having scuttled the dour predictions of Thomas Robert Malthus, a British economist and Anglican vicar. Malthus’s 1798 magnum opus, An Essay on the Principle of Population, warned that population growth would always outstrip food availability. This, Malthus concluded, doomed the masses to misery as their burgeoning numbers divided ever further what little pie was allotted to them. Many scientists, most notably Charles Darwin, were directly influenced by his work. Most economists, however, bridled at the suggestion that growth—especially, in Malthus’s time, growth of the labor force—was anything but wonderful. Malthus’s pronouncements seemed so inherently dismal, so contrary to the natural impulse to add more life to the world, that his scholarly essay became universally notorious. More than two centuries later, both its unsettling power and notoriety continue, and his name has entered the language, usually as a pejorative: Malthusian.
In 1968, Malthus’s ominous caveat was resurrected by a Stanford University ecologist, Paul Ehrlich, in a book titled The Population Bomb. By then, we had reached 3.5 billion—half of today’s count. Ehrlich, an entomologist who studied population dynamics in butterflies, had begun to lecture and write about human population following a trip to India with his wife and collaborator, Anne. Their book3 predicted widespread famines and accompanying disasters, beginning in the 1970s.
The year The Population Bomb appeared was also the same year that humans first got far enough away from Earth to turn around and take its picture. A photograph by Apollo 8 astronaut Bill Anders of the Earth rising over the moon’s horizon, so vividly alive compared to the surrounding black void, helped ignite a popular environmental movement that had been smoldering since Silent Spring, Rachel Carson’s seminal book on pesticides sixteen years earlier. The following year, the United Nations declared the first Earth Day. By 1970, Earth Day was a worldwide movement.
With the Ehrlich book, population joined pesticides and pollution as a headliner on the environmental agenda. The Population Bomb sold millions of copies. In the United States, Paul Ehrlich became a celebrity, appearing on The Tonight Show with Johnny Carson more than twenty times. Like Malthus’s name, his book’s title entered and remains in the popular vernacular in many languages—even after its most urgent argument apparently proved wrong. The famines that it predicted would leave hundreds of millions Asians dead within a decade never happened. The Ehrlichs had not foreseen Norman Borlaug’s astonishing Green Revolutionary boost to the world’s food supply.
In the decades that followed, Ehrlich’s and Borlaug’s names became routinely linked, usually by the former’s detractors. “Ehrlich was sure that ‘the battle to feed humanity is over.’ He insisted that India would be unable to provide sustenance for the two-hundred-million-person growth in its population by 1980,” wrote Duke University engineering professor Daniel Vallero in a 2007 textbook titled Biomedical Ethics for Engineers. “He was wrong—thanks to biotechnologists like Norman Borlaug.” This was a typical jeer: While the doomsayer Ehrlich prophesized starvation in India and Pakistan, Borlaug was bringing both countries to self-sufficiency in wheat production by the mid-1970s.
Through “technical optimism,” Vallero added, “engineers ‘mess up’ the Malthusian curve by finding ways to accomplish this (e.g., Borlaug spoiling Ehrlich’s predictions).” This was a typical conclusion: by enabling millions more to eat and live, Norman Borlaug had refuted Ehrlich and Malthus’s panic-mongering about overpopulation.
That conclusion, however, was not shared by Borlaug himself. His Nobel Peace Prize acceptance speech ended not in triumph, but with a warning:
… we are dealing with two opposing forces, the scientific power of food production and the biologic power of human reproduction. Man has made amazing progress recently in his potential mastery of these two contending powers. Science, invention, and technology have given him materials and methods for increasing his food supplies substantially and sometimes spectacularly… Man also has acquired the means to reduce the rate of human reproduction effectively and humanely. He is using his powers for increasing the rate and amount of food production. But he is not yet using adequately his potential for decreasing the rate of human reproduction…
There can be no permanent progress in the battle against hunger until the agencies that fight for increased food production and those that fight for population control unite in a common effort.
The Green Revolution, Borlaug often said, essentially bought the world another generation or so to resolve the population problem. For the rest of his life, he served on the boards of population organizations, even as he continued crop research to feed the multiplying millions his work had added to the global census.
At one end of Norman Borlaug’s spacious former office in the two-story CIMMYT headquarters building, Hans-Joachim Braun perches on the edge of a hardwood conference table, hunting for a PowerPoint slide on a Dell laptop. He sets it in front of Matthew Reynolds. “In the next fifty years,” the screen reads, “we will need to produce as much food as has been consumed over our entire human history.”
Reynolds nods. No argument.
Along with this office, Braun has inherited Borlaug’s title, director of CIMMYT’s Global Wheat Program. His CIMMYT colleague Reynolds heads an international consortium of geneticists, biochemists, crop breeders, and plant physiologists like himself, racing to improve wheat yields faster than expanding populations can eat them. Borlaug’s semidwarf wheat was a jump of quantum proportions, increasing harvests up to sixfold. Since then, however, gains have slowed dramatically, below 1 percent annually. Meanwhile, world population is still growing faster than that, and not peaking anytime soon: In seven of the new century’s first ten years, more wheat was consumed than produced. To keep up, they figure that somehow they must increase yields 1.6 percent annually by 2020.
How can they possibly do that? Clearing more forests isn’t an option, if only because when trees go, so does water. Braun is still fuming over a recent meeting at the United Nations. “We talk about global warming, we talk about all the problems, but the underlying, biggest problem—population growth—wasn’t mentioned once.” With his gray-bearded chin, he gestures at the laptop.
Not that the problems are unrelated. Like most crops, wheat is temperature-sensitive. For every degree Celsius that temperature rises, agricultural scientists calculate, wheat yields drop 10 percent in the Earth’s hotter midriff. Many agronomists (and economists) had speculated hopefully that global warming might actually help yields in cooler regions, but during recent European and Russian heat waves, losses spiked beyond 30 percent. The only thing that indisputably grew with added heat was the population of crop-devouring insects.
Temperature is rising, Braun and Reynolds agree, because more people are burning fuel and eating food made from it. The number of people is rising because there’s more food available. The Green Revolution’s two biggest success stories are in danger of choking on their good fortune: Before 2025, India will surpass China as the world’s most populous nation. Pakistan is now one the fastest-growing countries on Earth, its numbers tripling since 1970, to 187 million. Unable to generate jobs to keep up, especially for millions of frustrated young men, it’s also among the world’s most unstable places—and happens to be a nuclear power.
But not just more people: paradoxically, enhanced food production has resulted in a planet with more hungry people than ever before—around a billion. Thanks to agro-technology, the percentage of malnourished humans has dropped, but in creepy echoes of Malthus, the sheer number that survives to reproduce stays ahead of the pace that food reaches their tables.
“Though I have no doubt yields will keep going up, whether they can go up enough to feed the population monster is another matter,” Norman Borlaug said in 1997. “Unless progress with agricultural yields remains very strong, the next century will experience sheer human misery that, on a numerical scale, will exceed the worst of everything that has come before.”
Unless his successors can do something, fast, both the numbers and the percentage of the world’s hungry will rise, along with their tempers. But there aren’t many tricks left to try. “Reaching the moon was an engineering problem,” says Braun. “To produce the food we need in the next forty years is much more complicated. It will require more investments to solve than what was invested in the Apollo program. And we don’t see enough of them.”
Especially, they worry, there’s not enough research funding for wheat, which, they argue, with more protein than rice or maize, is the most important food crop. The reason is that, unlike corn, wheat is self-pollinating, so farmers can use their own grain to replant. “There’s five times as much invested in maize,” Reynolds says, “because farmers have to buy maize seed every year. Wheat, they keep the same seed. So it’s not related to food security; it’s related to making money.” His fist hits the table. “If we were taking food security seriously, those numbers would come closer together, wouldn’t they?”
It exasperates him to think of agriculture’s driving incentive being not to feed, but to profit. Reynolds rises and stalks to the window. Both these men have made their careers here, working alongside Dr. Borlaug, authoring papers with him. A Nobel Peace laureate, and yet money to continue his work on the veritable staff of life that launched human civilization, and on which it still depends, is so damned scarce. Gazing out at the brown December fields, Reynolds pulls his fleece vest tighter. Beyond the test rows of hybrid corn, each with a sign explaining its complex crossbred lineage, a dozen Mexican graduate students in blue CIMMYT caps are assessing a conservation agriculture experiment to produce more food with the least damage.
What’s being conserved is fertility, and possibly the atmosphere: this is CIMMYT’s version of the recent trend in no-till farming. Usually, farmers burn organic detritus after harvest or feed it to their animals, then plow and harrow to eliminate weeds, mix in fertilizer, and loosen the soil for seeding. Whether by hoe, draft animal, or tractor, this takes time—often, a week or more—and energy. It also destroys soil structure created by worms, insects, and bacteria.
Not plowing, however, keeps the soil and its biological activity intact; by leaving crop residues in place, they become a nutrient sponge that holds water. Theoretically, no-till farming also keeps carbon dioxide bound in the earth.
In thirty-two CIMMYT no-till test plots, the students measure moisture, crop growth, weeds, earthworms, added benefits of rotation with legumes, and greenhouse gas emissions. Disappointingly, carbon retention isn’t proving significant, although there’s clearly a savings on tractor fuel. Weed control is another problem; without tillage, they’re needing more herbicide. But as in nature, the system is extremely productive: wheat rows sowed with tools they’ve developed to punch seeds through the previous harvest’s litter are twice as lush as the clean, conventionally plowed control rows. It’s not organic cultivation, however; the tools—some hand-operated, some mechanized—also inject nitrogen fertilizer into the soil. No-till helps, but not enough, by their reckoning: With so many people to feed, and with half the world’s calories coming from grains, CIMMYT can’t see how to avoid global chaos without continuing to force-feed crops with chemicals.
The one bit of magic that might make a difference, the one for which Matthew Reynolds’s worldwide consortium needs money, would be to supercharge the way plants turn air and sunlight into biomass in the first place: photosynthesis. Some increases may simply emerge from imaginative physics: Reynolds has a Chinese mathematician studying how light bounces around in a wheat field. “In a forest canopy,” he explains, “light reaching leaves at the bottom is completely different from what a leaf in full sunlight receives. They also get different amounts of nitrogen. A field is a microcosm of that canopy—if we understand it better, we can improve the efficiency of photosynthesis just through better light and nitrogen distribution.”
But there’s only so far that can go. Borlaug’s improved wheat already captures 90 percent of the solar energy it receives. The only thing left is to tinker with RuBisCO—the enzyme that actually turns atmospheric carbon dioxide into cellulose, lignin, and sugars. RuBisCO,4 in essence, is the basis of all plant and animal life. To ratchet up its carbon-fixing capacity would require genetic modification.
In the mechanics of photosynthesis, wheat and rice are known as C3 plants—which means that the initial building-block hydrocarbon molecules they make from the CO2 they inhale have three carbon atoms. Corn and sorghum, which evolved later, are C4 plants. At a CIMMYT sister institution, the International Rice Research Institute (IRRI) in the Philippines, plant geneticists are trying to rearrange the cell structure in rice leaves to kick it up from C3 to C4, which could raise its photosynthetic efficiency by up to 50 percent. If they’re successful, CIMMYT hopes that the same ploy will work with wheat. But IRRI scientists expect it will take at least twenty years to produce commercially viable C4 rice. They also have another goal: as well as increase yields, they want to hot-rod rice with enough energy to fix its own airborne nitrogen, to lower or eliminate its dependency on synthetic fertilizer’s costly fossil-fuel feedstock. Adapting any technology IRRI produces to wheat could take even longer, which doesn’t help the immediate problem of feeding more Pakistanis before food wars erupt.
A British researcher Reynolds knows recently increased biomass growth by 40 percent in a tobacco plant by manipulating a single bacterial enzyme. Learning whether this might work for wheat will also require precious time and funding. Everything does: even introducing a new variety just by crossbreeding plants takes ten to twelve years. To successfully insert genes into wheat would take twice as long and cost between $25 to $100 million—all before facing a gauntlet of international regulation and consumer fears of genetically modified plants.
The floor-to-ceiling white metal shelves of the Wellhausen-Anderson Genetic Resources Center, CIMMYT’s gene bank of wheat and corn germplasm, contain the largest collection of maize landraces in the world: about twenty-eight thousand, mostly from Latin America, where corn originated. Landraces are varieties that farmers themselves have bred and selected over thousands of years. All trace back to a grassy weed called teosinte, corn’s wild Mexican progenitor, which is also here. The yellow, white, blue, and red maize varieties are stored in plastic jugs. The wheat collection, about a hundred forty thousand modern cultivars and ancient landraces from all over the world, is hermetically sealed in aluminum pouches packed inside long cardboard boxes. Everything is bar-coded and kept at 0°C, and duplicated in a long-term collection a floor below at –18°C.
An identical set is housed at the National Center for Genetic Resources Preservation at Fort Collins, Colorado, and yet another goes to the Svalbard Global Seed Vault in a cavern deep in the Norwegian permafrost: the so-called doomsday repository for the Earth’s botanical diversity, should seed banks elsewhere be lost to disaster or war, or their source varieties succumb to climate change. The purpose of this gene bank is to dole out genetic material, five grams at a time, to breeders developing new strains. But it is also a hedge against emergencies, such as when stem rust, a dreaded wheat fungus, broke out in Uganda in 1999, and CIMMYT air-freighted hundreds of kilos of resistant seed to East Africa.
Over the coming years, CIMMYT intends to genetically classify its entire germplasm collection. Along with historic strains, it holds seeds that Norman Borlaug archived during all the steps that led to his Green Revolution varieties, believing that eventually biotechnology would allow them to see exactly what they did to improve wheat over the last few decades. They’ll begin with several thousand lines whose useful traits—high yield; resistance to disease or drought—have already been identified. Taking seeds from each, they’ll grow at least one plant apiece in a greenhouse, then send fresh leaves to a genotyping service, to extract DNA and produce genetic sequences for every line.
Their hope is that decoding this vast genetic heritage will reveal how, whether through transgenics or more ingenious hybrids, to keep increasing global yields without putting any more of the planet’s land under cultivation. That is a widely shared ecological urgency, but at CIMMYT it’s also a point of pride. The oft-repeated rejoinder here to environmental outrage over the Green Revolution’s fossil fuel gluttony, its river-fouling fertilizers, its drug dependence on poisons, and its monocultural menace to biodiversity is that without improved crop varieties, billions more acres of the world’s forests and grasslands would have been plowed to keep everybody fed.
It’s a claim that recognizes that a world losing its trees and other native flora is a world on the brink, yet one that neglects CIMMYT’s own responsibility for the surfeit of hungry humans whose existence threatens them. Saving more lives than anyone in history also means there are more lives, period—which then beget even more. CIMMYT’s dilemma is a microcosm of the world’s: how to keep growing even more, in a space that does not grow.
Each new success only squeezes things tighter, and heightens the demand for still more. Even the elegant mathematics of genetic sequencing can’t square a vicious circle.
More than thirty years have passed since Nuestros Pequeños Hermanos turned their donated hacienda in the Mexican state of Morelos into a home and a Green Revolution farm to feed orphan children. Father William Wasson has passed on as well, in 2006, at age eighty-two—but not before founding more branches of their family in Honduras, Haiti, the Dominican Republic, Guatemala, El Salvador, Nicaragua, Bolivia, and Peru. Many of the fifteen thousand children he raised now help run these new homes.
The original home in Mexico is still the biggest, but its population has dropped from a high of twelve hundred to around eight hundred. This change reflects Mexico’s own demographic shift, from a country doubling every twenty years when Wasson took in his first homeless boy in 1954, to its current annual growth of less than 1 percent. If that pace continues, Mexico will double again in seventy-one years, but the rate of increase, now barely above replacement, is still falling. As planificación familiar became established in Mexico, women chose to have fewer babies, and their daughters have had fewer still. Most Mexicans now live in cities, where they don’t need extra hands to tend flocks or fetch firewood. Most Mexican women want or need to work, and can’t be tied down to eight kids at home.
Even though they mostly stop at two, their grandmothers didn’t, and the rural villages surrounding the orphanage’s hacienda are now overlapping towns. The hacienda’s former sugarcane cribs are now dormitories, and a primary and secondary school have been added. Across the lawn from where children play volleyball is a life-sized bronze of three figures by sculptor Carlos Ayala, who grew up here: a seated Father Bill, talking with a boy and girl.
Behind the dormitories are the fields. Next to a galvanized steel silo, five girls shuck ears atop a mound of white corn. In the silo are a few bags of nitrogen fertilizer, the gift of a German donor. Sheep graze around fish ponds and a tilapia hatchery. There are pig pens and a chicken house. In a newly donated greenhouse, a dozen children are sowing two varieties of winter tomatoes. A drip-irrigated vegetable patch produces beets, watermelon, cabbage, lettuce, chili peppers, cauliflower, and carrots; a different child is in charge of planting and weeding each furrow.
Luis Moreno, the veterinarian in charge of the farm, inspects an ear of corn. He’s grateful that the yield this year from the eight hectares they still have planted of the original forty was decent. Still, the twelve-ton harvest will provide for just one hundred days of tortillas. It’s a good thing that the population is dropping, because when he arrived three years earlier, he was shocked at the condition of the soil. Decades of intensive chemicals had left fields “looking like they’d been napalmed.” In some places, not even weeds grew. It reminded him of reading about the Oklahoma dust bowl in the 1930s. He could barely believe the neighbors and older children who told him how much corn used to grow here.
He’s switched to no-till cultivation, and smaller plots. The owner of a nearby fertilizer plant, who underwent a sort of agro-religious conversion, now sells them organic nutrients titrated with beneficial bacteria and fungi, which Luis is applying in a fifty-fifty mix with synthetic nitrogen. In the greenhouse and truck garden, they’re trying to go all organic.
“Someday I hope we’re completely natural. Manure is slower, but it’s long-term. Chemical fertilizer is gone in twenty days, and leaves everything saline.” Slowly, by spreading animal and corn wastes, they’re letting the rest of the land recover. Birds and earthworms are returning.
He looks at the girls, filling plastic pails with white corn kernels. “We don’t want more dust bowl children.”