Overpopulation and the Green Revolution

The Green Revolution saved many from starvation, but its father, Norman Borlaug, knew it was only half the answer. The other? Slowing population growth.

Man in wheat field rust resistance counts

Norman Borlaug, in 1964, scoring wheat plants for rust resistance.

Photo by Flickr/CIMMYT

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In August 1954, 29-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 Mendez 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 30. Within three months, 83. 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 20, 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 30 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 200 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 1,200, 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 15 years to every 24 years. Had it not continued to lower, theoretically by the 22nd 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 (for Centro Internacional de Mejoramiento de Maiz y Trigo). Founded by the Rockefeller Foundation near the famous Teotihuacan 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 a corn-breeding specialist for CIMMYT. 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 25-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 Cortés’ Spanish troops first saw it. The Aztec capital, called Tenochtitlan, 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: 23 feet across and 37 miles long, tunneling nearly 500 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 95, 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’ 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’ time, growth of the labor force—was anything but wonderful. Malthus’ 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’ 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. Though Anne Ehrlich was not credited as coauthor of The Population Bomb due to a publisher’s decision, their book 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 16 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 20 times. Like Malthus’ 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 of 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 200-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’ 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:

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.

Alan Weisman is the author of several books, including The World Without Us, an international bestseller translated into 34 languages. Excerpted from his latest book Countdown (Little, Brown), which vividly details the burgeoning effects of our cumulative presence on the planet, and reveals how we can regain balance.