The Wizard and the Prophet2

by Charles C. Mann

  Tomatoes are essentially little balls of flavored water. During my visit the weather was hot and dry—100-degree days, cloudless skies. Outside the farms the landscape was sere. It occurred to me to wonder where the water for the tomatoes came from. Peter asked if I had seen the movie Chinatown. That stuff about people killing for water in California? It’s all true.

  California produces more fruits, vegetables, and nuts than anywhere else in North America, and most of them are grown in the Central Valley. The valley runs for about 450 miles between the Coastal Mountains on the west and the Sierra Nevada on the east. Its floor is a trough of impermeable rock. Over the eons, the mountain ranges have eroded and filled the trough with bands of silt, gravel, sand, and clay several thousand feet deep. Water from melting snow in the heights runs into the deposits and is trapped there by the impermeable rock. Some of the water eventually spills out at the edge of the valley into streams. The rest is stored far underground. Early in the twentieth century, deep-well drills were invented. Suddenly farmers could draw from the ground as much water for irrigation as they wanted. Within a few decades they had sucked out so much water that many parts of the Central Valley were drained and some were sinking like foundering ships into the earth. Here and there the water table declined by more than three hundred feet.

  Farmers begged for help. The California state legislature responded in 1933 with the biggest infrastructure project since the Great Wall of China. In the next forty years the Central Valley Project captured and channeled two-thirds of the runoff in the state. It retooled two big river systems with a thousand miles of giant canals and aqueducts, more than twenty big dams and new reservoirs, and a score of huge pumping plants. Naturally, the state was not able to cover the bills. Two years after the Central Valley Project’s inception, Washington took over. That left California free in the 1960s to pursue an additional, overlapping State Water Project that was almost as large—twenty-one dams and more than seven hundred miles of canals that funnel water from the far north of the state down the west side of the Central Valley to within fifty miles of the Mexican border.

  Peter told me all of this as we drove through the valley in blazing heat. I asked what California did with all the millions upon millions of gallons of water that it shuffled around. He pointed outside. We were passing through a land of rice paddies. From one end of the horizon to the other were shallow rectangular pools with brilliant green strands of rice waving above. As I remember it, I could almost see the water steaming off the surface and flooding the sky.

  I was startled. They spent all that money to send all this water here from hundreds of miles away and then they just let it evaporate?

  He nodded.

  Is that crazy?

  Not if you’re a rice farmer, he said.

  The 170-Mile Sphere

  A trope in science fiction novels is the approach to Earth by first-time visitors from other stars. In their spaceships the aliens pass by the outer planets without much interest—ice giants like Neptune and Uranus and gas giants like Saturn and Jupiter are interstellar commonplaces. So are barren rocks like Mars and the asteroids. Then the visitors see Earth and are thunderstruck: it is sheathed in water.

  About three-quarters of our world’s surface is covered by water, either liquid or ice. Above it is yet more water in the form of clouds. There is lively scientific debate about where all the water came from and why it isn’t seen on other planets. 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

  Exactly how much of that sphere people already use is not readily ascertained, because it is difficult to measure water flows, and because it is difficult to define water use. One often-cited study from 1996 claimed that humankind already used almost a third of the world’s supply of renewable freshwater. For the year 2000, estimated the environmental historian J. R. McNeill, the figure was almost 40 percent. That year a respected Russian researcher, I. A. Shiklomanov, put out a lower number: 12 percent. Whatever the tally, it is a lot—the rest of the water, after all, has to nourish all the other millions of species as they provide our air, break down our wastes, and produce our food.

  In any case, global figures are almost beside the point, according to Peter Gleick, founder of the Pacific Institute, a water-research agency in Oakland, California. “If you think about how much water is available, the total amount is still more than what we use,” he told me. “The real problem is that water is incredibly short in the western United States and the Middle East and parts of Africa and China, whereas water in Canada and Norway is not scarce at all.” Brazil, which has one-sixth as many people as India, has more than four times as much water. The total supply is enough for both nations, but there is no way to distribute it from one to the other.

  Children learn in school that freshwater goes through the hydrologic cycle. The cycle begins when water evaporates from seas and lakes. As water vapor rises into the air, it cools and condenses to form clouds. The clouds produce rain and snow, which fall to the surface. There the water either evaporates back into the atmosphere, runs into rivers and streams and then to the sea, or penetrates into the land and becomes groundwater.

  River and surface water moves through the cycle quickly, in weeks or months; groundwater moves through it slowly, in years or decades. Either way, economists describe freshwater as a flow: a current with a value that is measured by time (gallons per day, for rivers). The sunlight streaming in a window, the electricity issuing from hydroelectric dams, the wheat growing in a field, the wind passing over the wheat—each in its own way is a flow. By contrast, resources like marble and gold and coal are stocks—they exist in a fixed amount. Turn on a tap and fill a bucket with water. The water gushing from the spigot is a flow; the water in the bucket is a stock.

  The difference may seem academic, but it has repercussions. Every use of a stock reduces the supply of that stock. Take a ton of marble from a quarry, and the next day the quarry has less marble. Keep mining the marble, and eventually the stock runs low. When that happens, the cost of extraction goes up, and with it, typically, the price. People respond by searching for additional supplies (new marble quarries), finding substitutes (home builders use granite instead of marble for kitchen counters), or inventing cheaper methods of using the material (mass-manufacturing marble counters, for instance, thus reducing their cost). Problems have a tendency, however imperfect and slow, to self-correct.

  Flows are different. Some flows, like sunlight or wind, cannot be affected by human action. No matter how many solar panels I put on my roof to absorb sunlight, they will have no effect on what the sun does tomorrow. But other flows—“critical-zone resources,” in the jargon—can be exploited to exhaustion. Consider an archetypical critical-zone flow: the run of salmon swimming upstream to spawn. Drop a net across the watercourse and the fish will swim right into it. As long as the number of fish taken from the river every year doesn’t exceed the number of new young fish bor
n in the river that year, fishing can continue indefinitely—the supply won’t go down, no matter how many years people put in nets. But leave the net in too long one year and it will take every single salmon and there will be no more fishing after that. Catching the last fish is just as easy as catching the first—laying the net across the stream doesn’t get more costly as the supply diminishes. With critical-zone flows, things typically go fine until they suddenly don’t.

  Flows can be wrecked in ways that are uncommon for stocks. It is hard work to ruin an iron-ore deposit. But anyone who has ever seen a toxic chemical spill knows that a river can be contaminated in a careless instant. Interruptions of water flows can be particularly severe because water, unusually, has no substitute. If a salmon run stops, there are other salmon streams and other species of fish. Or people can go without. But everyone has to drink water every day. Coca-Cola or Chianti, apple juice or aquavit, all are just flavored water. Every month millions of householders look at their water bill. Not one of them says, “Oh, this is too much cost and bother—I guess I’ll stop drinking water this month.”

  Groundwater flows take longer to destroy than rivers but are just as vulnerable. Most important groundwater sources are aquifers: underground layers of permeable, water-holding rock. The bands of silt and sand in California’s Central Valley form an aquifer. Similar sediments comprise the Ogallala Aquifer, among the world’s biggest, which runs from South Dakota to Texas. Aquifers can also be made of porous, sponge-like stone like limestone and dolomite. Water seeps slowly into aquifers and moves through them with equal torpor. The flow through the northern part of the Ogallala Aquifer, to give one example, is on the order of fifty to a hundred feet a day. Drill a few wells and the current is unaffected; the water will pass through as before. But take more than the flow allows and bad things happen—the particles in the porous sand and silt, which had been held apart by water pressure, suddenly compact and become impermeable. The flow is interrupted and often cannot resume.

  Contamination is a still more potent worry. Farmers spray pesticides and herbicides on their crops; the residues dissolve in rainfall; the rainfall seeps into groundwater, carrying the chemicals; the chemicals turn up, toxic additives, in people’s wells. According to the European Environment Agency, nitrates, heavy metals, or harmful microorganisms contaminate groundwater in nearly every European country and former Soviet republic. Some of these will filter out of groundwater over time, but all too often the damage is permanent. When people pump too much water from coastal aquifers, saltwater can rush in. Thick with salt and minerals, seawater is denser than freshwater; once in an aquifer, there is no known way of flushing it out. Coastal aquifers are imperiled from Maine to Florida; on the Arabian coast; in the suburbs of Jakarta (metropolitan population, more than 10 million); throughout the Mediterranean; and in a host of other places.

  Journalists sometimes describe unsexy subjects as MEGO: My Eyes Glaze Over. Alas, water quality is the essence of MEGO. Nonetheless, the stakes—human and environmental—are high. Today, according to the International Water Management Institute, a Sri Lanka–based cousin to IRRI and CIMMYT, one person out of every three on the planet lacks reliable access to freshwater, whether because the water is unsafe, unaffordable, or unavailable. The problems are not restricted to poor nations. By 2025, the institute predicts, all of Africa and the Middle East, almost all of South and Central America and Asia, and much of North America will either be running out of water or unable to afford its cost. As many as 4.5 billion people could be short of water.

  Typically such reports focus on urban water supplies. The emphasis is understandable: most people live in metropolitan areas and water from their taps is what will make them sick if contaminated. But most freshwater is actually used by agriculture—almost 70 percent, according to the U.N. Food and Agricultural Organization. Just 12 percent goes to direct human consumption: drinking, cooking, washing, and so on. (Industry takes the rest.) For most of human history, agriculture’s overwhelming thirst didn’t matter; water was plentiful enough for all. But now populations have risen enough that the requirements of families and the requirements of agriculture are colliding.

  The water problems of cities and agriculture are both difficult, but the latter are possibly more consequential, probably more expensive, and certainly more intractable. Domestic water services involve smaller amounts of water. And because people are concentrated in cities, the infrastructure is less expensive on a per-capita basis. By contrast, farms need more water and spread it over bigger areas. Urban water is delivered to homes and businesses where the surplus and waste can be collected for reuse and treatment. Farm water goes into fields; because any excess sinks into the ground or evaporates into the sky, it is not easy to gather for reuse.

  Agricultural losses are costly to prevent. Most irrigation is deployed through canals. They lose water because it seeps through the bottom, evaporates during transmission, and spills out at junctions; a rule of thumb is that almost two-thirds of the water is lost, and often much more. (The figures are imprecise, because some of the “lost” water flows usefully into neighboring fields or percolates back into rivers.) Reducing such losses for the Central Valley Project would involve relining and roofing over more than a thousand miles of large canal—and would do nothing for the losses in fields. Farmers could not possibly pay for the measure; costs would be passed to others, either through taxes or higher food prices.

  If global affluence continues to rise, more people will want dishwashers, washing machines, and other water-using appliances. Meanwhile, the same rising prosperity indicates (as I have discussed) that food production will have to increase, possibly even double. Unavoidably, more food means more water to grow crops, especially if people eat more meat. In the world of 10 billion, water experts project, the demand for water could be 50 percent higher than it is now. Where will it all come from? New supplies will not be easy to find. Few lakes and rivers are unexploited, and aquifers are being depleted. Equally difficult would be stretching existing water supplies by reducing waste and encouraging thrifty use. Adding to the pressure, climate change is shrinking glaciers and drying streams.

  As with food, the disciples of Borlaug tend to react in one way to these worries; those of Vogt, in another. These have been called the paths of hard and soft water, and the choice between them will resonate in the lives of generations to come. The debate between hard and soft is occurring in many places, but can be seen with especial clarity in the Middle East and California. With its rapidly growing population and febrile political tensions, the former bids fair to have the world’s most severe water problem. If the latter were a separate nation, it would have one of the world’s ten biggest economies. Its water problem may be the biggest in scale.

  Fertile Crescent

  The battered Buick drove down the new Mussolini Highway through Libya and Tunisia to Egypt. At the wheel was Walter Clay Lowdermilk, associate chief of the U.S. Soil Conservation Service. Accompanying him were his wife, Inez, a Methodist missionary and social activist; his son, fifteen, and daughter, eleven; a teenaged niece, brought as a babysitter; a personal assistant; and an unruly dog, bought at an Algerian market to keep the children company. Amazingly, this was the full roster of an official U.S. scientific expedition.

  The Lowdermilks arrived in Cairo in January 1939, intending to cross the Sinai Peninsula to Palestine, then ruled by Great Britain. The family was advised not to follow this plan. For three years Palestinians had been in revolt against the British authorities. Although London had bloodily suppressed the insurgency, no travelers had crossed the Sinai for six months. Desert villages had been destroyed; nomadic people, hunted by both sides, were robbing survivors. Some had concealed homemade mines—improvised explosive devices—beneath rocks in the road. Lowdermilk decided to go anyway. His family would be safe, he explained, because the Buick could go faster than the men on camels who would be chasing it. And they would keep a lookout for mines—detouring around rocks on the
road, for instance, rather than moving them. Soldiers at the guard post of Beersheba in Palestine were astonished to see the Buick coming in from the desert. We are here, Lowdermilk informed them, to see the Holy Land.*1

  Walter Lowdermilk had made a great career from failing to look before he leaped. As a boy he left his family in Arizona and worked his way through high school in Missouri. A friend there told him about a new scholarship program named after the British tycoon Cecil Rhodes that paid for foreign students to attend Oxford. In an instant Lowdermilk decided the Rhodes scholarship was his future. He quit studying science and devoted himself to the required Latin and Greek. He won the Rhodes and went to Oxford, where he abandoned classics to study forestry. On his return to Arizona he took a job with the Forest Service, becoming friends with Aldo Leopold. Just before Lowdermilk left for Oxford he had met a young woman at church, Inez Marks, a pastor’s daughter. She became a missionary and social reformer in China, building schools for girls and campaigning against foot-binding. When Inez returned briefly to the United States, Lowdermilk drove to California and saw her for the first time in eleven years. Forty-eight hours later, he proposed marriage. Inez was returning to China; Walter quit the Forest Service to join her. He learned Chinese and took a two-thousand-mile solo trip up the Yellow River. Along the way inspiration filled him and he understood the path of history and the rise and fall of civilizations.