The Wizard and the Prophet: Two Remarkable Scientists and Their Dueling Visions to Shape Tomorrow's World

by Charles C. Mann

Today the world has about 7.3 billion inhabitants. Most demographers believe that around 2050 the world’s population will reach 10 billion or a bit less. About this time, human numbers will probably begin to level off—as a species, we will be around “replacement level,” each couple having, on average, just enough children to replace themselves.

Over the years, as the conversations accumulated, it seemed to me that the responses to my questions fell into two broad categories, each associated (at least in my mind) with one of two people, Americans who lived in the twentieth century. Neither is well known to the public, yet one man has often been called the most important person born in that century and the other is the principal founder of the most significant cultural and intellectual movement of that time. Both recognized and tried to solve the fundamental question that will face my children’s generation: how to survive the next century without a wrenching global catastrophe.

The two people were barely acquainted—they met only once, so far as I know—and had little regard for each other’s work. But in their different ways, they were largely responsible for the creation of the basic intellectual blueprints that institutions around the world use today for understanding our environmental dilemmas. Unfortunately, their blueprints are mutually contradictory, for they had radically different answers to the question of survival. The two people were William Vogt and Norman Borlaug.

Vogt, born in 1902, laid out the basic ideas for the modern environmental movement. In particular, he founded what the Hampshire College demographer Betsy Hartmann has called “apocalyptic environmentalism”—the belief that unless humankind drastically reduces consumption its growing numbers and appetite will overwhelm the planet’s ecosystems. In best-selling books and powerful speeches, Vogt argued that affluence is not our greatest achievement but our biggest problem. Our prosperity is temporary, he said, because it is based on taking more from Earth than it can give. If we continue, the una...

Borlaug, born twelve years later, has become the emblem of what has been termed “techno-optimism” or “cornucopianism”—the view that science and technology, properly applied, can help us produce our way out of our predicament. Exemplifying this idea, Borlaug was the primary figure in the research that in the 1960s created the “Green Revolution,” the combination of high-yielding crop varieties and agronomic tech...

Both Borlaug and Vogt thought of themselves as environmentalists facing a planetary crisis. Both worked with others whose contributions, though vital, were overshadowed by theirs. But that is where the similarity ends.

I think of the adherents of these two perspectives as Wizards and Prophets—Wizards unveiling technological fixes, Prophets decrying the consequences of our heedlessness. Borlaug has become a model for the Wizards. Vogt was in many ways the founder of the Prophets.

Both men are dead now, but their disciples have continued the hostilities. Indeed, the dispute between Wizards and Prophets has, if anything, become more vehement. Wizards view the Prophets’ emphasis on cutting back as intellectually dishonest, indifferent to the poor, even racist (because most of the world’s hungry are non-Caucasian). Following Vogt, they say, is a path toward regression, narrowness, and global poverty. Prophets sneer that the Wizards’ faith in human resourcefulness is unthinking, scientifically ignorant, even driven by greed (because remaining within ecological limits will cut into corporate profits).

In theory, they could meet in the middle. One could cut back here à la Vogt and expand over there, Borlaug-style. Some people believe in doing just that. But the test of a categorization like this one is less whether it is perfect—it is not—than whether it is useful.

As a practical matter, the solutions (or putative solutions) to environmental problems have been dominated by one of these approaches or the other.

If a government persuades its citizenry to spend huge sums revamping offices, stores, and homes with the high-tech insulation and low-water-use plumbing urged by Prophets, the same citizenry will resist ponying up for Wizards’ new-design nuclear plants and monster desalination facilities. People who back Borlaug and embrace genetically modified, hyper-productive ...

Moreover, the ship is too large to turn quickly. If the Wizardly route is chosen, genetically modified crops cannot be bred and tested overnight. Similarly, carbon-sequestration techniques and nuclear plants cannot be deployed instantly. Prophet-style methods—planting huge numbers of trees to suck carbon dioxide from the air, for instance, or decoupling the world’s food supply from industrial agriculture—would take equall...

Most of all, the clash between Vogtians and Borlaugians is heated because it is less abo...

Prophets look at the world as finite, and people as constrained by their environment. Wizards see possibilities as inexhaustible, and humans as wily managers of the planet. One views growth and development as the lot and blessing of our species; others regard stability and preservation as our future and our goal. Wizards regard Earth as a toolbox, its contents freely available for use; Prophets think of the natural world as embodying an overarching order that should not casually be disturbed.

These arguments have their roots in long-ago fights. Voltaire and Rousseau disputing whether natural law truly is a guide for humankind. Jefferson and Hamilton jousting over the ideal character of citizens. Robert Malthus scoffing at the claims of the radical philosophers William Godwin and Nicolas de Condorcet that science could overcome limits set by the physical world. T. H. Huxley, the famed defender of Darwin, and Bishop Samuel Wilberforce of Oxford, contending whether biological laws truly apply to creatures with souls. John Muir, champion of pristine wilderness, squaring off against Gifford Pinchot, evangelist for managing forests with teams of experts. The ecologist Paul Ehrlich and the economist Julian Simon betting whether ingenuity can outwit scarcity. To the philosopher-critic Lewis Mumford, all of these battles were part of a centuries-long struggle between two types of technology, “one authoritarian, the other democratic, the first system-centered, immensely powerful, but inherently unstable, the other man-centered, relatively weak, but resourceful and durable.” And all of them were about, at least in part, the relationship of our species to Nature—which is to say they were debates about the nature of our species.

Vogt was the first to put together, in modern form, the principal tenets of environmentalism, the twentieth century’s only successful, long-lasting ideology.

Sometimes I think of them as Plato’s four elements: earth, water, fire, and air. Earth represents agriculture, how we will feed the world. Water is drinking water, as vital as food. Fire is our energy supply. Air is climate change, a by-product, potentially catastrophic, of our hunger for energy.

Earth: If present trends continue, most agronomists believe, harvests will have to rise 50 percent or more by 2050. Different models with different assumptions make different projections, but all view the rise in demand as due both to the increase in human numbers and the increase in human affluence. With few exceptions, people who became wealthier have wanted to consume more meat. To grow more meat, farmers will need to grow more grain—much more. Wizards and Prophets have radically different ways of approaching these demands.

Water: Although most of Earth is covered by water, less than 1 percent of it is accessible freshwater. And the demand for that water is constantly increasing. The increase is a corollary of the rising demand for food—almost three-quarters of global water use goes to agriculture. Many water researchers believe that as many as 4.5 billion people could be short of water by as early as 2025. As...

Fire: Predicting how much energy tomorrow’s world will need depends on assumptions about, for instance, how many of the roughly 1.2 billion people who do not have electricity will actually get it, and how that electricity will be provided (solar power, nuclear power, natural gas, wind, coal). Still, the main thrust of every attempt to estimate future requirements that I am aware of is that the human enterprise will require...

Air: In this list, climate change is odd man out. The other three elements (food, freshwater, energy supply) reflect human needs, whereas climate change is an unwanted consequence of satisfying those needs. The first three are about providing benefits to humankind: food on the table, water from the tap, heat and air-conditioning in the home. With climate change, the benefit is invisible: avoiding problems in the future. Societies put their members through wrenching changes and then, with a bit of luck, nothing especially noteworthy occu...

The Wizard and the Prophet is a book about the way knowledgeable people might think about the choices to come, rather than what will happen in this or that scenario. It is a book about the future that makes no predictions.

Long afterward, it occurred to me that many of the Prophets’ dire forecasts had not come true. Famines had occurred in the 1970s, as The Population Bomb had predicted. India, Bangladesh, Cambodia, West and East Africa—in that decade all were wracked, horribly, by hunger. But the death tally was nowhere near the “hundreds of millions” predicted by Ehrlich.

Homo sapiens, she once told me, is an unusually successful species. And it is the fate of every successful species to wipe itself out—that is the way things work in biology. By “wipe itself out” Margulis didn’t necessarily mean extinction—just that something comprehensively bad would happen, wrecking the human enterprise. Borlaug and Vogt might have wanted to stop us from destroying ourselves, she would have said, but they were kidding themselves. Neither conservation nor technology has anything to do with biological reality.

The arrival of clothing was a sign that a mental shift had occurred. The human world was becoming a realm of complex, symbolic artifacts.

Like criminal gangs, fire ants thrive on chaos.

Until about 75,000 years ago—that is, for the majority of our existence on Earth—humankind was restricted to Africa, though we sent out occasional forays into the rest of the world, almost all unsuccessful, all limited in scope. Around 70,000 years ago, everything changed. People raced across the continents like so many imported fire ants. Human footprints appeared in Australia within as few as ten thousand years, perhaps within four or five thousand. Stay-at-home Homo sapiens 1.0, a wallflower that would never have interested Lynn Margulis, had been replaced by aggressively expansive Homo sapiens 2.0. Something happened, for better and worse, and we were born.

Instead of natural ecosystems with their haphazard mix of species, farms are taut, disciplined communities dedicated to the maintenance of a single species: us. Before agriculture, the Middle West, Ukraine, and the lower Yangzi Valley had been sparsely populated domains of insects and grass; they became breadbaskets, as people scythed away suites of species that used soil and water we wanted to control and replaced them with maize, wheat, and rice. To Margulis’s bacteria, a petri dish is a uniform expanse of nutrients, all ready for the taking. For Homo sapiens, agriculture transformed the planet into something like a petri dish.

As in a time-lapse movie, we divided and multiplied across the newly opened land. It had taken Homo sapiens 2.0, aggressively modern humans, barely fifty thousand years to reach the farthest corners of the globe. Homo sapiens 2.0A—A for agriculture—took a tenth of that time to subdue the planet.

Today, almost half of all the crops consumed by humankind depend on nitrogen derived from synthetic fertilizer. Another way of putting this is to say that Haber and Bosch enabled our species to extract an additional 3 billion people’s worth of food from the same land.

In 2000, the chemist Paul Crutzen and the biologist Eugene Stoermer awarded a name to our time: the Anthropocene, the era in which Homo sapiens became a force operating on a planetary scale.

As any biologist would predict, this success led to an increase in human numbers—slow at first, then rapid, tracing Gause’s S-shaped curve. We began rising up the steepest part of the slope in the sixteenth or seventeenth century. If we follow Gause’s pattern, growth will continue at delirious speed until the second inflection point, when we have exhausted the global petri dish. After that, human life will be, briefly, a Hobbesian nightmare, the living overwhelmed by the dead. When the king falls, so do his minions; it is possible that in our desperation we might consume most of the world’s mammals and many of its plants. Sooner or later, in this scenario, Earth will again be a choir of microorganisms as it has been through most of its history.

Brown tree snakes in Guam, water hyacinth in African rivers, rabbits in Australia, Burmese pythons in Florida—all these successful species have overrun their environments, heedlessly wiping out other creatures. Not one has voluntarily turned back. When the zebra mussels in the Hudson River began to run out of food, they did not stop reproducing. When fire ants relentlessly expand their range, no inner voices warn them to consider the future. Why should we expect Homo sapiens to fence itself in?

We care more about the broken stoplight up the street now than social unrest next year in Chechnya, Cambodia, or the Congo. Rightly so, evolutionists say: Americans are far more likely to be killed at that stoplight today than in the Congo next year. Yet here we are asking governments to focus on potential planetary boundaries that may not be reached for decades or even centuries. Given the discount rate, nothing could be more understandable than a government’s failure to grapple with, say, climate change. From this perspective, is there any reason to imagine that Homo sapiens, unlike mussels, snakes, and moths, can exempt itself from the fate of all successful species? This is what Borlaug and Vogt were asking people to do in their very different ways.

Leopold’s career coincided with the rise of a new scientific discipline: ecology. In 1905, Leopold’s first year at Yale, the first ecology textbook was published. The author was Frederic Clements, whose ideas heavily influenced Leopold—and then, through Leopold, William Vogt and the global environmental movement.

El Salvador was for Vogt the sharpest example of the problem, a harbinger of what lay in store for much of the world. The poorest, most densely inhabited country in the Americas, it was, Vogt believed, “face to face with a crisis” that other places were just approaching. In El Salvador, he insisted, a growing population was colliding with “the progressively rapid destruction of its natural resources, especially its cultivable land.” The country’s people and its resources were like trains racing toward each other on the same track. “El Salvador should act—and act at once.” If it did not, he said, a future of poverty, political violence, and environmental ruin was inevitable.

It laid out the Prophet’s central tenet: humankind, though “apt to forget it, is a creature of the earth. ‘Dust thou art’ and ‘All flesh is grass’ were not said by scientists, but they are sound biology.”

In the late nineteenth century, Europeans and North Americans watched their societies acquire colonies all over the world. Conscripting Darwin and Malthus, many people in these places concluded that these triumphs reflected the white race’s innate superiority. All human groups had distinct, heritable physical and mental characters, they said. Some were better than others, and groups with better characters had won the struggle for existence. Racial superiority, these people claimed, was why Europe had colonized Asia and Africa, and not the other way around.

So ineradicable was the elitist mark on conservation that for decades afterward many on the left scoffed at ecological issues as right-wing distractions. As late as 1970, the radical Students for a Democratic Society protested the first Earth Day as Wall Street flimflam meant to divert public attention from class warfare and the Vietnam War; the left-wing journalist I. F. Stone called the nationwide marches a “snow job.”

Most important, Vogt and his friends—like Stoddard, like East, like Hitler—viewed people as biological units, ruled by the same laws as bacteria and fruit flies. (“Nature is inexorable,” wrote Stoddard. “No living being stands above her law; and protozoan or demigod, if they transgress, alike must die.”)

In the second of Road’s main innovations, Vogt summed up the relationship between humanity and this global environment with a single concept: carrying capacity. It is hard to overstate the importance of this. There are two ideas at the base of today’s globe-spanning environmental movement. One is that Homo sapiens, like every other species, is bound by biological laws. The second is that one of these laws is that no species can long exceed the environment’s carrying capacity.

To prevent “non-linear, abrupt environmental change,” they said, humankind must not transgress nine global limits. That is, people must not 1. use too much fresh water; 2. put too much nitrogen and phosphorus from fertilizer into the land; 3. overly deplete the protective ozone in the stratosphere; 4. change the acidity of the oceans too much; 5. use too much land for agriculture; 6. wipe out species too fast; 7. dump too many chemicals into ecosystems; 8. send too much soot into the air; and 9. put too much carbon dioxide into the atmosphere.

Something must be done, he thought. Those famished people were ready to tear apart the world, and who could blame them? Here began, or so he said afterward, the work that would make him the original Wizard. Everything commenced with the terrible fathomless hunger he saw explode in the street.

Much worse was the poverty. Borlaug had been poor all his life but always well fed and decently clad. In the Bajío he first encountered destitution on a geographic scale. Women walked for miles to carry water from contaminated wells. Men scratched at the earth with wooden hoes and slashed at weeds with sickles as ancient as time. Plumbing was a distant dream. Children died from diseases that were treatable nuisances in richer places. Again and again, he encountered people who had been so badly abused by authority that they clung to beliefs Borlaug found irrational. If Borlaug offered to procure steel plows and hoes, they told him that metal siphoned “heat” from the soil. If he asked about fertilizer, they told him it was a government plot against the farmer. Each conversation was like being thrust into a wildland of confusion and despair.

Borlaug could take the wheat package to any part of the globe. The seeds and fertilizers and water practices would have to be adjusted to local conditions, much as pharmaceutical companies packaged their universal antibiotics into shots or pills or liquids or nasal sprays according to local preferences. But the idea was that the guts of the package would work anywhere.

Borlaug, too, remained little known, even after he won the Nobel Peace Prize in 1970. But he and the Green Revolution had become exemplary to a certain sort of scientist, journalist, and environmentalist. The Borlaug package has become an emblem of the view that the road through humankind’s environmental difficulties lies through the groves of scientifically guided productivity. “Ours is the first civilization based on science and technology,” Borlaug said that day in 1968. “In order to assure continued progress we scientists…must recognize and meet the changing needs and demands of our fellow men.” The future of the world depends on science, he said, and on politicians guided by scientists. This vision of a scientific elite was like Vogt’s vision, in its way, except that Borlaug was possessed by the hope of more, rather than a call for less.

To the end of his life, he kept his head down and worked ferociously hard. He always believed that hard rational work would lead him to the goal in the end. It was impossible for him to understand that there were people who didn’t want to go there.

Weaver could say something about the sun, though. In principle, the sun pours onto Earth enough energy—vastly more than enough—to provide all humanity with the necessary 128,000 calories a day. “If solar energy could be utilized with full efficiency, the United States alone could sustain, energy-wise, a population over 40 times the present total population of the planet.” The global population then being about 2 billion, Weaver was suggesting that in terms of energy the theoretical carrying capacity of the United States was about 80 billion people.

The limit of 80 billion would never be reached, because nobody would want to live in such a jam-packed country. But thinking in these terms was clarifying, Weaver thought. It showed that viewing the human dilemma in terms of an ecological carrying capacity was a mistake. The planet’s actual, physical carrying capacity was so large—scores of billions of people—as to be irrelevant. The true problem was not that humankind risked surpassing natural limits, but that our species didn’t know how to tap more than a fraction of the energy provided by nature.

Harnessing these energy sources would require new technology. But once people learned how to make “direct use” of the sun (or nuclear power), all human needs for heat, air-conditioning, transportation, electricity, steel, cement, and everything else would be satisfied for eons to come. In this respect, Weaver thought, Vogt was flat-out wrong.