The Big Ratchet: How Humanity Thrives in the Face of Natural Crisis (16 page)

Qanats can move water only so far, and other inventions, such as dams and wells, are also only local solutions. But trade—the other, more hidden and surreptitious way to move water—involves much greater distances. The sun-powered sails that made the Columbian Exchange and guano part of the story of humanity’s domination of the planet also made possible the virtual trade in water. Moving water virtually, in products grown or raised with large amounts of water, spread the vital resource farther than was ever possible with Mesopotamia’s irrigation
canals or the ingenious qanats. Sugar, coffee, tea, oranges, rice, wheat, or any other crop that grows where water and sun are abundant could feed people in places with more meager endowments, so long as there was trade.

Trade of food, plants, animals, excrement, and virtual water—a practice nearly as old as agriculture itself—changed diets around the world. The mingling of ideas and the spread of knowledge accelerated humanity’s collective ability to resolve the conundrums of settled life. For European and North American farmers, Alexander von Humboldt’s discovery of the Incan solution came to the rescue of their soils. The guano and saltpeter trade allowed those societies to wriggle out of the problem of the day. People continued to flow into cities and towns. By the end of the nineteenth century, more than thirteen out of every hundred people in the world lived in urban areas, a statistic that had nearly
tripled during the preceding century. At the beginning of the century, Beijing was the world’s largest city, with over a million people. By midcentury, London topped the list, having
swelled to over 2 million people.

Europe’s boom in surplus food had ratcheted up the stakes for feeding the factory workers and other laborers who powered the industrial revolution. At the century’s end, as guano supplies were dwindling and saltpeter prices were escalating, the hatchet was poised to fall again. Once more, ingenuity’s task was to find even grander manipulations of the planetary machinery to keep soils fertile and people fed.

Pivots toward new ways to open the bottlenecks that constrained civilization from the beginning of settled life—nitrogen’s bottleneck from the air and phosphorus’s from below the ground—had already begun. The results of Sir Henry Gilbert’s and Sir John Lawes’s experiments had countered Justus von Liebig’s claims and proven that fixing nitrogen from the air was the lynchpin for a way out of the soil-fertility problem. But a solution to nitrogen alone would not keep soils fertile. A solution for depleting stores of phosphorus in the soils was needed
to plug the leak that could only be repaired naturally on a geologic time scale. Neither night-soil nor South American guano proved to be up to the task, even with the sun-powered sails to carry nutrients across the ocean. Again, the world’s expanding economy required new solutions to resolve the conundrums of settled life.

6: SMASH OPEN THE BOTTLENECKS

B
Y
1898,
A CENTURY HAD PASSED
since the Reverend Thomas Robert Malthus had delivered his dire warnings of starvation and calamity. In the meantime, London’s population had
swelled to nearly 5 million. A shortage of fertilizer was again looming on the horizon as the guano and saltpeter bonanza was coming to a close; meanwhile, growing numbers of factory workers and laborers in the cities were demanding more and more food from the countryside. Against this backdrop, the chemist Sir William Crookes delivered his presidential address to the British Association for the Advancement of Science.

“England and all civilized nations stand in deadly peril of not having enough to eat,” Crookes declared. “As mouths multiply, food resources dwindle. Land is a limited quantity, and the land that will grow wheat is absolutely dependent on difficult and capricious natural phenomena.” According to his calculations and extrapolations, land was too scarce to produce enough wheat to satisfy “the great Caucasian race,” which he claimed included “the peoples of Europe, United States,
British America, the white inhabitants of South Africa, Australia, parts of South America, and the white population of the European colonies.” He estimated that the number of bread-eaters was increasing “more than 6,000,000 per annum, necessitating annual additions to the bread supply nearly one-half greater than sufficed twenty-five years ago.” “What are our prospects of
obtaining this amount?” he asked.

Crookes’s motives in posing the question were not all benign—one could say they were chauvinistic, if not bordering on racist: “We are born wheat eaters. . . . Other races, vastly superior in numbers, but differing widely in material and intellectual progress, are eaters of Indian corn, rice, millet, and other grains; . . . the accumulated experience of civilized mankind has set wheat apart as
the fit and proper food.” But he was right on one point: the scarcity of nitrogen was becoming a problem. And this is what made Crookes’s fear for the future bread supply of what he called “civilized mankind.” The waste of city-dwellers was being squandered; nutrients were being flushed to the sea, rather than recycled to the field.

Crookes pointed in his speech to “a way out of the colossal dilemma”: “It is the chemist who must come to the rescue of the threatened communities. It is through the laboratory that starvation may ultimately be turned into plenty. . . . The fixation of atmospheric nitrogen, therefore, is one of the great discoveries, awaiting the
ingenuity of chemists.” Crookes’s notion stemmed from the heated intellectual pursuit earlier in the century about which nutrients in what forms could make crops grow. His “ingenuity of chemists” referred to an industrial solution for transforming nitrogen in the air into forms that plants could use, lifting the bottleneck imposed by nature. Soil microbes and lightning could not fix nitrogen fast enough to keep pace with population growth.

A few decades earlier, at an 1840 meeting of the British Association for the Advancement of Science in Glasgow, Justus von Liebig had proclaimed a
civilization-changing theory. The “humus theory” that had
previously prevailed purported that plants lived off extracts derived from organic matter, such as manure, and that a plant’s internal vital force generated other critical constituents. Liebig’s opposing “mineral theory” countered that plants could get their nutrients as readily from salts and rocks as from farmyard manure and night-soil. Liebig’s popular 1840 book on the applications of chemistry to agriculture had commanded the attention of farmers and the
growing fertilizer industry. The implication of the theory for humanity’s quest to produce food was profound: there might be a synthesized means to replenish soil fertility. The point was not lost on Crookes several decades later.

Apparently, Liebig had drawn his conclusions more from the experiments of other great minds than from his own original work, a habit not much appreciated by
some of his colleagues. One colleague wrote that Liebig had made mistakes, because he had based his conclusions “not in his laboratory, but at his writing desk, since no mention is made of any experiments that he has conducted nor of the
facts that he has gathered.” Another later reflected that “Liebig was more a promulgator and defender of truths that had already been announced than a
discoverer of new knowledge.”

The “mineral theory” breakthrough harks back at least to the now-obscure work of German agronomist Carl Sprengel in the 1820s. He had found mineral salts in humus and concluded that these salts, when dissolved in water and taken up by roots, were the true nutrients for plants. In the decades that followed, the theory inspired many experiments by many scientists who compared the yields of wheat, barley, oats, and other crops when fertilized with different kinds of ash, minerals from crushed rock, and organic manures. By the century’s end, the mineral theory was firmly established as a basis to produce chemical fertilizers on a commercial scale.

This discovery promised to usher in a new era of agriculture. No longer would humanity’s food supply be tethered to manure, guano, or
human waste. Here was a titanic pivot that could change the course of civilization. But, as Crookes noted, one twist was left: how to mimic bacteria’s process to bust apart the stubborn bond between two nitrogen atoms and capture synthesized fixed nitrogen in sacks of fertilizer. If human ingenuity could crack that puzzle, one conundrum of settled life would be solved. Declining soil fertility from lack of fixed nitrogen would never again plague humanity, at least for those who could get their hands on the synthesized source.

Food from Air

German chemist Fritz Haber finally answered Crookes’s call to solve the problem of fixing nitrogen from the air, but the achievement was hardly the result of just one man’s work. Haber’s solution, like Liebig’s mineral theory and all breakthroughs, built on knowledge accumulated in many minds in many places. By the end of the eighteenth century, inventors and scientists had established that electric sparks passed through air could fix nitrogen, though the method was more a curiosity than a means to an industrial process. In the nineteenth and into the early twentieth century, many seekers of solutions to the nitrogen problem had filed patents to break apart the stubborn bond with sparks and complicated chemical processes. Crookes himself had demonstrated that with high enough temperatures, hydrogen and nitrogen from the air could form ammonia. The key ingredients for all these solutions were lots of energy and a high temperature. Another solution was to trap the nitrogen in gas from burned coal, in essence recapturing the fixed nitrogen locked in plants hundreds of thousands of years ago. None of the methods were commercially viable or could satisfy the demands of the day from farmers to fertilize their fields.

In the early twentieth century, Haber found a way to do the job, after several attempts. The process could fix nitrogen at a lower temperature
than the other solutions, though very high temperatures and pressures were
still critical ingredients. The key was to pass nitrogen gas over metal filings to serve as a catalyst. Haber took out a patent on the process in 1908.

It’s one thing to demonstrate a chemical reaction in a laboratory. It’s quite another to produce ammonia from nitrogen gas in large enough quantities for commercial production. The German chemical company BASF bought Haber’s patent to add to the other methods it was working on to synthesize ammonia. The company assigned Carl Bosch to the task of figuring out how to make the process work in a factory. He devised the machinery to extract hydrogen from methane gas, mix it with nitrogen gas, and pass it over the iron catalyst multiple times to extract ammonia—and industrial fertilizer factories were born. The result was piles of solid, fixed nitrogen, in the form of ammonia-containing granules that could be packaged in sacks and sold to farmers. Haber received the Nobel Prize in Chemistry in 1918 for his achievement, and Bosch shared the prize in 1931 with his
colleague Friedrich Bergius.

Despite the fact that Haber and Bosch were only accomplishing what
Rhizobium
or
Azotobacter
bacteria do every day, their process for producing fertilizer rested on a major industrial apparatus. They could not have invented this process without the large-scale operations that came into being with the industrial revolution. They also needed ready sources of inexpensive energy to provide the high temperatures and pressures the process required. Without the coal that miners had started to dig from deep in the Earth, the twentieth-century solution to the soil-fertility problem would not have been possible. Energy from fossil fuels replaced the energy from lightning and the microbes’ metabolism in the planet’s nitrogen-cycling machinery. The far-ranging significance of the pivot from human muscle and animal brawn to fossil fuels as a prime source of energy caught the attention of American poet Ralph
Waldo Emerson: “Coal lay in ledges under the ground . . . until a laborer with pickax and windlass brings it to the surface. We may call it black diamonds. Every basket is
power and civilization.” Written in 1860, decades before the black diamonds paved the way for a resolution to the nitrogen bottleneck, these words were more prescient than Emerson likely thought.