Will Humans Run Out of Fertilizer?

It helped people spread and multiply. Now critics worry it's destroying the planet. An Object Lesson.

A farmer spreads fertilizer at a rice paddy in Vietnam. (Nguyen Huy Kham / Reuters)

Editor’s note: This article originally failed to disclose that the author is an analyst and spokesperson for Fueling U.S. Forward, an organization that advocates for the use of domestic oil and natural gas. We've updated the article to reflect that affiliation and regret the error.

“Nobody adores fertilizer,” the writer Shellen Lubin once mused. Lubin isn’t entirely correct. Bill Gates, for example, has admitted to being “a little obsessed with fertilizer.” Yes, fertilizer. The stuff you sprinkle, spray, and spread over plants to help them grow. Not the “all natural” kind that originates in the guts of farm animals, but human-made fertilizer derived from natural gas, a fossil fuel.

Most people don’t think about fertilizer, but few innovations are as central to modern life. In the 20th century, human-made fertilizer helped avert catastrophe on a massive scale. With population growth outstripping the food supply, experts predicted millions of people would starve. Fertilizer helped farmers grow more food on less land and feed a growing population, proving the experts wrong.

“Two out of every five people on Earth today owe their lives to the higher crop outputs that fertilizer has made possible,” Gates writes in his paean to the stuff. That is equivalent to the populations of China, India, and the United States, combined. According to The Fertilizer Institute, an industry trade association, “Without fertilizer, modern farming would cease to exist.”

Some claim fertilizer is a dangerous “fixation” that wrecks the environment. And yet, global population is expected to near 10 billion people by 2050—that’s 2 billion more mouths to feed—so humans will likely need a lot more. Can humankind innovate its way out of a potential disaster?

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People have used human and animal waste to help crops grow for thousands of years. Manure is rich in nitrogen, phosphorus, and potassium, critical nutrients for strong crops. Yet this “natural” fertilizer has inherent limitations, and eventually a problem arose. The population started growing faster than the food supply needed to support it. That meant one of two things had to happen: Either fewer people or more food. But more food requires more fertilizer, and on this front nature let humanity down. In 1798, Thomas Malthus summarized the dilemma: “The power of population is indefinitely greater than the power in the Earth to produce subsistence for man.”

In some sense, Malthus was right. The Earth, by itself, does not produce enough useable resources to support rapid population growth. It provides plenty of raw materials, but raw materials are different than useable resources. Oil, for instance, was an essentially useless raw material until people figured out how to convert it into useable energy—kerosene for lamps, then gasoline for vehicles.

But Malthus failed to appreciate the people’s ability to make the Earth more productive than nature alone would allow. Enter Carl Bosch and Fritz Haber. In 1908, these two German scientists discovered how to mass-produce nitrogen fertilizer using natural gas, replacing animal manure as the primary method of delivering nutrients to crops. This discovery, known as the Haber-Bosch process, applied human ingenuity to convert natural gas, a raw material, into a useable resource, nitrogen fertilizer.

“It’s hard to think of many things in our life that are more underappreciated than the advent of synthetic fertilizer,” Jayson Lusk, an agricultural economist at Oklahoma State University and the author of Unnaturally Delicious, told me. “Wealth and opportunity, freedom from famine, and the ability to go through life without having to worry about where our next meal comes from, we can credit to the discovery of nitrogen fertilizer.”

Still, human-made fertilizer didn’t “take off” until after World War II, according to the Canadian environmental scientist Vaclav Smil. Global fertilizer production rose 220 percent between 1920 and 1940 but exploded by 3,000 percent from 1940 to today. In the mid-20th century, many experts maintained the Malthusian view that population growth would outpace food production and millions of people would starve to death. In his 1968 book, The Population Bomb, for example, the American biologist Paul Ehrlich lamented: “The battle to feed all of humanity is over.”

Another American biologist, Norman Borlaug, had other ideas. Farmers needed to dramatically increase crop yields to meet rising food demand. But fertilizer was a double-edged sword: It helped grow crops, but sometimes the crops would grow too large and tip over, ruining the harvest. In response, Borlaug developed a shorter, more compact wheat plant that wouldn’t fall.

“When high fertilizer levels were applied to these new ‘semidwarf’ plants, the results were nothing short of astonishing,” explained The New York Times in its 2009 obituary of Borlaug. “This strange principle of increasing yields by shrinking plants was the central insight of the Green Revolution, and its impact was enormous.”

How enormous? Since 1950, global grain production per person has increased by 27 percent, while the amount of land dedicated to grain production per person has declined by 56 percent, according to the USDA. In other words, we produced more food, on less land, and fed more people—particularly in the developing world. “Borlaug is responsible for the fact that throughout the postwar era, except in sub-Saharan Africa, global food production has expanded faster than the human population, averting the mass starvations that were widely predicted,” Gregg Easterbrook wrote in 1997 for The Atlantic.

For his work combining humanmade fertilizer with genetic crossbreeding, Borlaug won a Nobel Peace Prize and became known as “the man who saved a billion lives.”

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Despite its benefits, fertilizer is mired in controversy. Critics point to soil erosion, nitrogen runoff, and carbon-dioxide emissions. Grist, for instance, published a series of reports titled “The N2 Dilemma: Is America Fertilizing Disaster?” Ammonium nitrate, a key component of fertilizer, is also used to make explosives. It is no small irony that Fritz Haber, one of the scientists who won a Nobel for developing human-made fertilizer, is also known as “the father of chemical warfare.”

There is also a more fundamental criticism of fertilizer. It is rooted in the belief that people are not part of nature, but a blight on it. The more people on the Earth, the more the Earth suffers.

“Borlaug’s mission—to cause the environment to produce significantly more food—has come to be seen, at least by some securely affluent commentators, as perhaps better left undone,” wrote Easterbrook. “More food sustains human population growth, which they see as antithetical to the natural world.”

While critics like Ehrlich see projected population growth as another impending catastrophe, it doesn’t have to be. The history of fertilizer shows what the economist Julian Simon, an arch rival of Ehrlich, has described as the “master resource” (energy) and the “ultimate resource” (people) working in tandem to improve the human condition—and beat the odds.

“Energy is the master resource, because energy enables us to convert one material into another,” Simon writes. “The ultimate resource is people—skilled, spirited, and hopeful people who will exert their wills and imaginations for their own benefit, and so, inevitably, for the benefit of us all.”

Haber and Bosch used natural gas to produce human-made fertilizer. Borlaug figured out how to combine human-made fertilizer with genetically modified crops to massively increase agricultural productivity. Today, scientists are developing “precision agriculture” techniques to further increase crop yields while using fertilizer more efficiently.

Pessimists like Malthus and Ehrlich consider people a self-destructive drain on nature, but as Lusk, the Oklahoma State University agricultural economist sees it, “they underestimated the ability of humans to adapt and innovate and make productive use of the resources we have available.”

This article appears courtesy of Object Lessons.