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

by Charles C. Mann

By measuring the solar energy falling onto a plant and its associated growth, scientists had roughly calculated how much of that energy the plant actually used. Not very much, was the answer. Photosynthesis, Weaver said, “has an over-all efficiency surely less than 0.00025%”—one-quarter of one-thousandth of one percent! The inefficiency was mind-boggling.

Liebig’s Law of the Minimum: plants need many nutrients, but their growth rate is limited by the one least present in the soil. In most cases, that nutrient is nitrogen. At first blush, the notion of nitrogen being a limit seems odd; there is more nitrogen in the world than carbon, oxygen, phosphorus, and sulfur combined. Unfortunately, more than 99 percent of that nitrogen is nitrogen gas. Nitrogen gas—N2 in chemical notation—consists of two nitrogen atoms bound together so tightly that plants cannot split them apart for use. Instead, plants are able to absorb nitrogen only when it is in chemical combinations—“fixed,” as scientists say—that are easier to break up.

The world’s biggest nitrate deposits are in the high desert of northern Chile. Although it almost never rains there, the area is constantly bathed in a fine spray from the Pacific Ocean. The spray is very thin—less than an inch per year—but it contains the nutrients from the Humboldt Current that feed the anchovetas that feed the cormorants. Other nutrients fall from the sky as dust or well up from groundwater. With next to no rainfall to wash away the residue, the deposits build up over time. The result: a layer of naturally deposited fertilizer four hundred miles long, twelve miles wide, and up to nine feet deep. It was eagerly exploited. Nitrates from Chile became a principal ingredient in packaged fertilizers—and, alas, bombs. By the beginning of the twentieth century, as Vaclav Smil of the University of Manitoba has written in his history of nitrogen use, almost half the nitrates shipped to the United States were used to make explosives. In 1898 the British chemist William Crookes rang an alarm: the nitrogen would run out. Crookes was the new president of the British Association for the Advancement of Science, the group that had commissioned Liebig’s report. In his inaugural address, Crookes focused, quite literally, on Europe’s daily bread. The “bread-eaters of the world,” as he called them, were increasing by more than 6 million a year. To feed these new bread eaters, farmers either would have to expand into unused land or produce more from their existing land by fe...

Five years later Haber received a Nobel Prize for synthesizing ammonia; Bosch and his main assistant received a Nobel in 1931, for developing “chemical high pressure methods.” Ammonia synthesis remained so costly that artificial fertilizers did not truly become common until the 1930s. Nonetheless, the Nobels were richly deserved; the Haber-Bosch process, as it is called, was arguably the most consequential technological development of the twentieth century, and one of the more important human discoveries of any time. The Haber-Bosch process has literally changed the land and sky, reshaped the oceans, and powerfully affected the fortunes of humanity. The German physicist Max von Laue put it neatly: Haber and Bosch made it possible to “win bread from air.”

Today the Haber-Bosch process is responsible for almost all of the world’s synthetic fertilizer. A little more than 1 percent of the world’s industrial energy is devoted to it, as the futurist Ramez Naam has noted. Remarkable fact: “That 1 percent,” Naam says, “roughly doubles the amount of food the world can grow.” Between 1960 and 2000 global synthetic fertilizer use rose by about 800 percent. About half of that production was devoted to just three crops: wheat, rice, and maize. One way to look at this figure is to say that the accomplishment of Borlaug and his associates was to create strains of wheat, rice, and maize that could use what Haber and Bosch had provided.

“The basis of all Nature’s farming,” he said, was the Law of Return: “the faithful return to the soil of all available vegetable, animal, and human wastes.” When bacteria, bugs, and birds die, their bodies return to the soil and provide nutrition for other life. The same occurs for their wastes. Humans, too, must return the residues of their existence to the earth. Civilizations fall because societies forget this simple rule. We depend on plants, plants depend on soil, soil depends on us. The Law of Return embodies an insight: everything affects everything else.

Photosynthesis is hard to describe without sounding like a hand-waving mystic. By blending water from below with sunlight and carbon dioxide from above, photosynthesis links Earth to the sky. The crops in every farmer’s field are air and sunlight in cold storage. So are the trees around the field and the algae in nearby ponds. Every dot of green on the landscape is a ceaselessly active photosynthetic factory. If this furious microscopic churning stopped, Oliver Morton, the science writer, has remarked, “so would everything else that you care about.” The planet would survive. But it would no longer be green.

In the United States, for example, the proportion of the workforce employed in agriculture went from 21.5 percent in 1930 to 1.9 percent in 2000. Meanwhile, the number of farms fell by almost two-thirds. The average size of the surviving farms increased to match; their owners increasingly focused on exports to the world market.

What isn’t in doubt is that water—H2O—is one of the most common molecules on Earth, perhaps the most common. Which makes the idea of water scarcity seem odd. How could people run short of something so abundant? The reason is that 97.5 percent of the world’s water is saltwater—undrinkable, corrosive, even toxic. More than two-thirds of the remainder is locked into polar ice caps and glaciers, the great majority of it in Antarctica. The rest—all of the planet’s lakes, rivers, swamps, and groundwater—is less than 1 percent of the total. That is the theoretically available freshwater supply. Put together, it would form a sphere about 170 miles in diameter. In fact, though, this is a wild overestimate, because more than nine-tenths of that water is groundwater, and most groundwater is unusable or inaccessible. Although water is common, the total global supply (large sphere) is less than one might imagine. Smaller still is the total supply of freshwater (medium sphere), and most of that is locked up in glacial ice or buried too far underground to reach. The total supply of available, usable freshwater—all the water for the world of 10 billion—is shown in the tiny sphere. Credit 46

The irrigation systems were built up more slowly than Lowdermilk thought, not reaching their apex until about the birth of Christ. By then erosion was already epidemic. Societies throughout the Fertile Crescent had cut down forests to build cities and, especially, feed the forges that made bronze and iron. Without tree cover, the hills could not retain water; floods destroyed canals downstream. The same biblical peoples who had created the great city of Babylon set in motion its destruction. Islam and goats had little impact. And the failure to restore the land was due not to nomadic peoples but to the wholly sedentary Ottoman Empire, based in faraway Istanbul, which ruled the area from the fifteenth century until the end of the First World War.

Rapid urbanization is a hallmark of our age. In 1950 fewer than one out of three of the world’s people lived in cities. By 2050, according to United Nations projections, the figure will be almost two out of three. Meanwhile the world’s population will have more than tripled. In 1950, 750 million people lived in urban areas; by 2050, demographers project, 6.3 billion will—more than eight times as many.

When plants die today, fungi decompose them, releasing their trapped solar energy. In the Carboniferous, most fungi apparently had not yet evolved the ability to break down lignin, the tough compound that gives plant stems their strength and bulk. Buried in almost oxygen-free sludge, attacked only slowly or not at all by fungi, the lepidodendrons, horsetails, and giant ferns decayed at an infinitesimal rate, creating layers of peat. Over the eons, crushed and heated by the slow churning of the earth, the peat became coal. All the while, in a parallel process, the earth was crushing and heating ocean-floor layers of dead plankton, algae, and other marine organisms to form the sticky gumbo of oil, gas, and other compounds known collectively as petroleum.

In June 1866 a high school mathematics teacher in Tours, in central France, attached a toy steam engine to a small metal container full of water. Working with a mechanic friend, the teacher placed the device in front of a curved mirror. Shaped like a shallow trough, the mirror focused the sun’s rays on the container. After an hour, the water began to boil. Steam gushed out, driving the steam engine—“a success that surpassed my expectations,” the teacher crowed. It was the first true example of solar power: converting energy from the sun into mechanical force that could accomplish useful tasks. Today the math teacher is a historical footnote, but it seems likely that tomorrow he will have a place in the main text. His name was Augustin-Bernard Mouchot.

In an 1882 demonstration in Paris, Mouchot’s assistant used his solar engine to drive a printing press.

But the last and greatest descendant of Mouchot and Ericsson was an uncompromising Portuguese priest, Manuel António Gomes, known as Father Himalaya for his extreme height. Born into a poor family in 1868, Father Himalaya went into the priesthood mainly for the paycheck. A polymath who taught himself chemistry, biology, and optics, he invented an explosive, himalayite, said to be safer and more powerful than dynamite, and the first rotary steam engine. He was critical of other solar pioneers, because their mirrors did not track the sun with sufficient precision: their inexact alignments meant that the central boiler cast a shadow on the mirror. By contrast, Father Himalaya’s first solar engine, which avoided both problems, generated temperatures hot enough to melt iron. Indeed, its very effectiveness was a problem. His second prototype, incorrectly operated by an assistant, melted itself down before a delighted mob. Undaunted, Father Himalaya decided to build a new machine that would track the sun automatically, without needing unreliable human operators. The Pyrheliophoro was unveiled at the 1904 World’s Fair in St. Louis. Shaped like a sail, its reflector consisted of 6,117 hand-sized mirrors attached to a steel frame forty-two feet high. The Pyrheliophoro focused light so intensely that an awed New York Times reporter noted that the reflected heat killed birds forty feet above it. It could produce temperatures up to 7000°F, then the highest ever seen on Earth.

The two researchers, Calvin Fuller and Gerald Pearson, were members of the team that transformed the transistor, invented at Bell in 1947, from a finicky laboratory prototype into the mass-produced foundation of the computer industry. At the center of this work was silicon, common and inexpensive, a principal constituent of beach sand. Silicon forms crystals, each atom linked to four neighbors in a pattern identical to that formed by carbon atoms in diamonds. As students learn in high school chemistry, the atoms bond to each other by sharing their outer electrons. Silicon crystals can be adulterated—“doped,” in the jargon—by replacing a few of the silicon atoms with atoms of boron, arsenic, phosphorus, or other elements. If the added “dopant” atoms have more shareable electrons than the silicon atoms they replaced, the crystal as a whole ends up with extra electrons. Because electrons have a negative charge, the crystal becomes negatively charged. Similarly, if the dopant atoms have fewer shareable electrons, the doped crystal has, in effect, some electron-sized “holes”—it is positively charged. Like the electrons in the crystal, the “holes” are shared, meaning that their locations can move about somewhat in the way that physical electrons can move about. Fuller and Pearson placed a thin layer of the first type of doped silicon (extra electrons) atop a layer of the second type (extra holes). The two Bell researchers attached the little assembly to a circuit—a loop of wire,...

Every second, the sun bathes Earth with 172,500 terawatts of energy. (A terawatt—a trillion watts—is the biggest energy unit in common use.) About a third of this prodigious flow is promptly reflected into space, mainly by clouds. The leftover—roughly 113,000 terawatts, depending on cloud cover—is available for capture. All human enterprises together now use a bit less than 18 terawatts.

About 85 percent of the world’s carbon dioxide emissions come from fossil fuels, and about 80 percent of those come from just two sources: coal (46 percent) in its various forms, including anthracite and lignite; and petroleum (33 percent) in its various forms, including oil, gasoline, and propane. Coal and petroleum are used differently. Most petroleum is consumed by individuals and small businesses as they heat their homes and offices and drive their cars. By contrast, coal is mainly burned by heavy industry: coal produces the great majority of the world’s steel and cement and 40 percent of its electricity.

Coal provides about two-thirds of China’s energy, but almost all of it is used by big industries. Coal provides less than a fifth of U.S. energy, but again almost all of it is for industry. In both places petroleum consumption is on a smaller, more individual scale.

The world has 1.3 billion vehicles and perhaps 1.5 billion households. Cutting emissions from these cars and homes means changing the daily lives of billions of people, a mind-boggling thought. Reducing global coal emissions, by contrast, means dealing with 3,300 big coal-fired power plants and several thousand big coal-driven steel and cement factories.*10 The task is huge, but it is at least imaginable—and it targets almost half of the world’s emissions at a stroke.

Covering 170 square miles, Jharia is India’s main reservoir of coking coal, the hard coal used to make steel. It has been on fire, calamitously, since 1916; entire villages have disappeared into the smoking ground. Undermined railroad lines have fallen into the earth, followed by farms and streams. When I visited the region, toxic fumes shimmered in the air. Issuing from cracks in the earth, they wreathed the ruined buildings and black, leafless trees. In the evening, patches of smoldering red were visible, scattered like watching eyes across the charred landscape: Mordor without the Orcs.

In a long study published in 2015, Jacobson, Delucchi, and eight other researchers laid out a path for taking the United States entirely to wind, water, and solar power by 2050.

Three years before Tyndall, a U.S. scientist published a two-page paper that described how different gases absorb solar energy. The scientist was Eunice Foote, a suffragist from upstate New York. Little is known about Foote; she published just one other article, on a different subject, and no further trace of her work has been found. Foote’s research was similar to but less comprehensive than Tyndall’s work. No evidence exists that Tyndall knew of it.

About radiocarbon dating: Earth is constantly bathed by a rain of high-energy subatomic particles from outer space. When these “cosmic rays” slam into a nitrogen atom, the violent collision can change the nitrogen into a mildly radioactive form of carbon: carbon-14 (14C), as scientists call it. By happenstance, 14C disintegrates into a form of nitrogen at almost exactly the same rate that it is created by cosmic rays. As a result, a small, steady percentage of the carbon in the air, sea, and land consists of 14C. Plants take in 14C through photosynthesis. When animals eat plants, they take it in, too. In consequence, every living cell has a steady, small level of 14C—they are all slightly radioactive. When organisms die, they stop absorbing 14C. Because the 14C in their cells continues to disintegrate, their bodies’ 14C level falls in a predictable way that researchers can use to estimate when the creatures were alive. Suess realized that carbon dioxide from burning petroleum would have almost no 14C because the organisms that had created it had died millions of years ago. It would thus be possible to detect if fossil fuels were pumping this 14C-less carbon dioxide into the environment—the overall 14C level would be a hair lower than it would be otherwise.

As it turned out, both Muir’s rapture over wild beauty and Pinchot’s thoughts of stewardship had a dark side: most of these “untouched” American landscapes in fact were inhabited by indigenous peoples.

Yellowstone and Yosemite were turned into parks by expelling people who had been there for centuries. As the journalist Mark Dowie has documented, similar dispossessions in the name of Nature have taken place ever since. All too often, the results have been dreadful, both morally, because they involve tearing people from their homes, and practically, because these areas were molded in the shapes of their first inhabitants. The peoples of the U.S. West, for example, burned undergrowth frequently, to discourage insects and encourage the tender new growth that attracted animals. Eliminating fire in the name of forest protection has created a buildup of flammable material that in turn has led to devastating wildfires.

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.

No European in 1800 could have imagined that in 2000 Europe would have no legal slavery, women would be able to vote, and same-sex couples would be able to marry. No one could have guessed that a continent that had been tearing itself apart for centuries would be largely free of armed conflict, even amid terrible economic times. No one could have guessed that Europe would have vanquished famine.