Enlightenment Now: The Case for Reason, Science, Humanism, and Progress

Machines also solve an inherent problem with food. As any zucchini gardener in August knows, a lot becomes available all at once, and then it quickly rots or gets eaten by vermin. Railroads, canals, trucks, granaries, and refrigeration evened out the peaks and troughs in the supply and matched it with demand, coordinated by the information carried in prices. But the truly gargantuan boost would come from chemistry. The N in SPONCH, the acronym taught to schoolchildren for the chemical elements that make up the bulk of our bodies, stands for nitrogen, a major ingredient of protein, DNA, chlorophyll, and the energy carrier ATP. Nitrogen atoms are plentiful in the air but bound in pairs (hence the chemical formula N2), which are hard to split apart so that plants can use them. In 1909 Carl Bosch perfected a process invented by Fritz Haber which used methane and steam to pull nitrogen out of the air and turn it into fertilizer on an industrial scale, replacing the massive quantities of bird poop that had previously been needed to return nitrogen to depleted soils. Those two chemists top the list of the 20th-century scientists who saved the greatest number of lives in history, with 2.7 billion.¹⁸

So forget arithmetic ratios: over the past century, grain yields per hectare have swooped upward while real prices have plunged. The savings are mind-boggling. If the food grown today had to be grown with pre-nitrogen-farming techniques, an area the size of Russia would go under the plow.¹⁹ In the United States in 1901, an hour’s wages could buy around three quarts of milk; a century later, the same wages would buy sixteen quarts. The amount of every other foodstuff that can be bought with an hour of labor has multiplied as well: from a pound of butter to five pounds, a dozen eggs to twelve dozen, two pounds of pork chops to five pounds, and nine pounds of flour to forty-nine pounds.²⁰

In the 1950s and ’60s, another giga-lifesaver, Norman Borlaug, outsmarted evolution to foment the Green Revolution in the developing world.²¹ Plants in nature invest a lot of energy and nutrients in woody stalks that raise their leaves and blossoms above the shade of neighboring weeds and of each other. Like fans at a rock concert, everyone stands up, but no one gets a better view. That’s the way evolution works: it myopically selects for individual advantage, not the greater good of the species, let alone the good of some other species. From a farmer’s perspective, not only do tall wheat plants waste energy in inedible stalks, but when they are enriched with fertilizer they collapse under the weight of the heavy seedhead. Borlaug took evolution into his own hands, crossing thousands of strains of wheat and then selecting the offspring with dwarfed stalks, high yields, resistance to rust, and an insensitivity to day length. After several years of this “mind-warpingly tedious work,” Borlaug evolved strains of wheat (and then corn and rice) with many times the yield of their ancestors. By combining these strains with modern techniques of irrigation, fertilization, and crop management, Borlaug turned Mexico and then India, Pakistan, and other famine-prone countries into grain exporters almost overnight. The Green Revolution continues—it has been called “Africa’s best-kept secret”—driven by improvements in sorghum, millet, cassava, and tubers.²²

Thanks to the Green Revolution, the world needs less than a third of the land it used to need to produce a given amount of food.²³ Another way of stating the bounty is that between 1961 and 2009 the amount of land used to grow food increased by 12 percent, but the amount of food that was grown increased by 300 percent.²⁴ In addition to beating back hunger, the ability to grow more food from less land has been, on the whole, good for the planet. Despite their bucolic charm, farms are biological deserts which sprawl over the landscape at the expense of forests and grasslands. Now that farms have receded in some parts of the world, temperate forests have been bouncing back, a phenomenon we will return to in chapter 10.²⁵ If agricultural efficiency had remained the same over the past fifty years while the world grew the same amount of food, an area the size of the United States, Canada, and China combined would have had to be cleared and plowed.²⁶ The environmental scientist Jesse Ausubel has estimated that the world has reached Peak Farmland: we may never again need as much as we use today.²⁷