"Eliminating water shortages depends on a global attempt to raise water productivity similar to the effort launched a half-century ago to raise land productivity, an initiative that has nearly tripled the world grain yield per hectare." –Lester R. Brown, World Facing Huge New Challenge on Food Front in Plan B 3.0: Mobilizing to Save Civilization
Part 1. Assessing the Food Prospect: The Fast-Growing Water Deficit
While the soil deficit is growing slowly, the water deficit is growing rapidly. The world water deficit—historically recent, largely invisible, and growing fast—may be the most underestimated resource issue facing the world today. Because it typically takes the form of aquifer overpumping, the resulting fall in water tables is not visible. Unlike shrinking forests or invading sand dunes, falling water tables cannot be readily photographed. They are often discovered only when wells go dry.
In round numbers, 70 percent of all the water pumped from underground or diverted from rivers worldwide is used for irrigation, 20 percent is used by industry, and 10 percent goes to residences. But the demand for water in industry and for residential purposes is growing even faster than population, putting a squeeze on the amount available for agriculture. 19
In some 18 countries, population growth has reduced the fresh water supply per person to less than 1,000 cubic meters per year, the minimal amount needed to satisfy basic needs for drinking, hygiene, and food production. By 2050, U.N. population projections show that 39 countries, with 1.7 billion people, will be experiencing such water deprivation. 20
For most ecological deficits, we do not have a global estimate of their size. But for water we do. In her book Pillar of Sand, Sandra Postel, using data for India, China, the United States, North Africa, and Saudi Arabia, estimated the annual water deficit in terms of aquifer overpumping at over 160 billion tons per year. Using the rule of thumb of 1,000 tons of water to produce 1 ton of grain, this would be enough to produce 160 million tons of grain. With current world grain consumption of 300 kilograms per person, this would feed 533 million people. Stated otherwise, 533 million of us, out of the world population of 6.1 billion, are being fed with grain that is produced with the unsustainable use of water. 21
The world water deficit is concentrated in China, the Indian subcontinent, the Middle East, North Africa, and North America. This problem is historically recent, a product of the tripling of world water usage since 1950 and the spreading use of powerful diesel and electrically driven pumps. When the pumping of water from wells depended on human or animal power, the amount pumped was limited, but now with powerful mechanically driven pumps, aquifers can be depleted in a matter of years. 22
In a world where the demand for water continues its steady growth while the sustainable yield of aquifers is essentially fixed, the deficits grow larger year by year. The longer that governments delay in addressing this issue, the larger the annual deficit becomes, the faster water tables fall, and the more difficult it is to deal with. Scores of countries are now experiencing water deficits—from smaller ones like Iran or Yemen to the world’s most populous country, China. (See Table 1–4.) 23
Iran, a country of 70 million people, is facing an acute shortage of water. Under the agriculturally rich Chenaran Plain in northeastern Iran, the water table was recently falling by 2.8 meters a year. But the cumulative effect of a three-year drought and the new wells being drilled to supply the nearby city of Mashad, one of Iran’s largest, dropped the aquifer by an extraordinary 8 meters in 2001. Villages in eastern Iran are being abandoned as aquifers are depleted and wells go dry, generating a flow of water refugees. 24
In Yemen, which has a population of 17 million, World Bank data indicate that the water table under most of the country is falling by roughly 2 meters a year as water use far exceeds the sustainable yield of aquifers. World Bank official Christopher Ward observes that “groundwater is being mined at such a rate that parts of the rural economy could disappear within a generation.” In the basin where the capital, Sana’a, is located, the water table is reportedly falling at 6 meters (nearly 20 feet) per year. The Bank estimates that the aquifer will be depleted by the end of this decade. In the search for water, the Yemeni government has drilled test wells in the basin that are 2 kilometers (1.3 miles) deep—depths previously associated only with the oil industry. But they have failed to find water. Those living in Yemen’s capital may soon be forced to relocate within the country or to migrate abroad, adding to the swelling flow of water refugees. 25
In China, water tables are falling virtually everywhere that the land is flat. Under the North China Plain, which produces at least one fourth of the country’s grain, the fall in the underground water table of 1.5 meters (5 feet) per year of the early 1990s has recently increased to 2–3 meters per year in some areas. In many parts of China, well drilling, either the deepening of wells or the drilling of new ones, has become a leading industry. 26
The big three grain producers—China, the United States, and India, which together account for nearly half of world output—depend on irrigation in varying degrees. In China, 70 percent of the grain produced comes from irrigated land. In India, the figure is 50 percent, and in the United States, 15 percent. In each country, water tables are falling in key agricultural areas. When farmers lose their irrigation water, whether from aquifer depletion or diversion to cities, and return to rainfed farming, they typically experience a drop in yields of one half or so. 27
Historically, water shortages were local, but in an increasingly integrated world economy, these shortages can cross national boundaries via the international grain trade. Water-scarce countries often satisfy the growing needs of cities and industry by diverting water from irrigation and importing grain to offset the resulting loss of production. Since 1 ton of grain equals 1,000 tons of water, importing grain is the most efficient way to import water. 28
Although it is often said that future wars in the Middle East are more likely to be fought over water than oil, the competition for water in the regions seems more likely to take place in world grain markets. This can be seen in Iran and Egypt, both of which now import more wheat than Japan, traditionally the world’s leading importer. Imports now supply 40 percent of the total consumption of grain—wheat, rice, and feedgrains—in both countries. Numerous other water-short countries in the Middle East also import much of their grain. Morocco imports half of its grain. For Algeria and Saudi Arabia, the figure is over 70 percent. Yemen imports nearly 80 percent of its grain, and Israel, more than 90 percent. 29
China regained grain self-sufficiency during the late 1990s in part by overpumping its aquifers, running up a huge water deficit. India is also essentially self-sufficient in grain, but it has achieved this by overpumping. Neighboring Pakistan, a country of 154 million people, is overpumping its aquifers for the same reason. Overpumping is by definition a short-term phenomenon. At some point, as aquifers are depleted, it will end. 30
Farmers who are overpumping underground water for irrigation are facing a double squeeze. Like the rest of the economy, they face cutbacks from aquifer depletion. But in addition, they face cutbacks as irrigation water is diverted to higher value uses in industry, where the value of output per ton of water used can be easily 50 times that in agriculture. Countries seeking to create jobs and raise living standards cannot afford to use scarce water for irrigation if it deprives industry of needed water. 31
Water deficits are already spurring heavy grain imports in numerous smaller countries, but it is unclear when they will do so in larger countries, such as India or China. Two things are obvious: the water deficits are growing larger in literally scores of countries, and they are doing so more or less simultaneously. National water shortages are not isolated events.
If countries like India, Pakistan, and China are already experiencing water deficits, what happens if their populations continue to grow as projected, demanding ever more water at a time when sharp cutbacks from aquifer depletion are imminent?
The risk is that growing water deficits in populous countries could push grain import needs above supplies in the handful of countries that export grain, triggering a rise in grain prices. It is one thing for small countries to turn to the world for much of their grain supply, but when a country like China, which consumes 390 million tons of grain per year, or India, which consumes 180 million tons, does so, it has the potential to overwhelm world grain markets, as noted earlier. If world grain prices were to double, as they did between 1972 and 1974, the ranks of those who are hungry and malnourished—estimated at 815 million—could expand dramatically as the urban poor are squeezed between low incomes and rising food prices. 32
Humanity is moving into uncharted territory in the water economy. With the demand for food climbing, and with the overpumping of aquifers now common in industrial and developing countries alike, the world is facing a convergence of aquifer depletions in scores of countries within the next several years. As this occurs, pumping will necessarily be reduced to the rate of recharge. Unfortunately, the world has no experience in responding to water deficits on the scale now unfolding.
World agriculture, already burdened with soil and water deficits, is facing a projected addition of 3 billion people and billions of low-income people who want to move up the food chain, consuming more livestock products. These soaring demands on an agricultural system that is already ecologically stressed are leading to some basic structural changes in the world food economy. 33
|Table 1-4. Selected Examples of Aquifer Depletion|
|Source: See endnote 23.|
19. Gleick, op cit. note 5, p. 64.
20. Population and water availability from Tom Gardner-Outlaw and Robert Engelman, Sustaining Water, Easing Scarcity: A Second Update (Washington, DC: Population Action International, 1997).
21. Sandra Postel, Pillar of Sand (New York: W.W. Norton & Company, 1999), p. 255; rule of thumb from FAO, Yield Response to Water (Rome: 1979); grain consumption from USDA, op. cit. note 12; population from United Nations, op. cit. note 2.
22. Water usage from Gleick, op. cit. note 5, p. 52; pumping from Postel, op. cit. note 21.
23. Table 1–4 from the following: China from Michael Ma, “Northern Cities Sinking as Water Table Falls,” South China Morning Post, 11 August 2001; United States from Postel, op. cit. note 21, p. 77, and from Bonnie Terrell and Phillip N. Johnson, “Economic Impact of the Depletion of the Ogallala Aquifer: A Case Study of the Southern High Plains of Texas,” presented at the American Agricultural Economics Association annual meeting in Nashville, TN, 8–11 August 1999; Pakistan, India, and Mexico in Tushaar Shah et al., The Global Groundwater Situation: Overview of Opportunities and Challenges (Colombo, Sri Lanka: International Water Management Institute, 2000); Postel, op. cit. note 21; Iran from Chenaran Agricultural Center, Ministry of Agriculture, according to Hamid Taravati, publisher, Iran, e-mail to author, 25 June 2002; Christoper Ward, “Yemen’s Water Crisis,” based on a lecture to the British Yemeni Society in September 2000, at <www.al-bab.com/bys/articles/ward 01.htm>, July 2001.
24. Taravati, op. cit. note 23.
25. Population from United Nations, op. cit. note 2; Yemen’s water situation from Ward, op. cit. note 23; Christopher Ward, The Political Economy of Irrigation Water Pricing in Yemen (Sana’a, Yemen: World Bank, November 1998); Marcus Moench, “Groundwater: Potential and Constraints,” in Ruth S. Meinzen-Dick and Mark W. Rosegrant, eds., Overcoming Water Scarcity and Quality Constraints (Washington, DC: International Food Policy Research Institute, October 2001).
26. Water table dropping 1.5 meters a year from James Kynge, “China Approves Controversial Plan to Shift Water to Drought-Hit Beijing,” Financial Times, 7 January 2000.
27. Grain production from USDA, op. cit. note 12; irrigation from FAO, FAOSTAT Statistics Database, op. cit. note 5, with irrigation data updated 10 July 2001.
28. Water to grain conversion from FAO, op. cit. note 21.
29. USDA, op. cit. note 12; USDA, World Agricultural Supply and Demand Estimate (Washington, DC: 12 June 2002).
30. Overpumping from Postel, op. cit. note 21; population from United Nations, op. cit. note 2.
31. Water value comparison based on ratio of 1,000 tons of water for 1 ton of grain from FAO, op. cit. note 21, on global wheat prices from IMF, International Financial Statistics (Washington, DC: various years), and on industrial water intensity in Mark W. Rosegrant, Claudia Ringler, and Roberta V. Gerpacio, “Water and Land Resources and Global Food Supply,” paper prepared for the 23rd International Conference of Agricultural Economists on Food Security, Diversification, and Resource Management: Refocusing the Role of Agriculture?, Sacramento, CA, 10–16 August 1997.
32. Grain consumption from USDA, op. cit. note 12; grain prices from IMF, op. cit. note 31; hunger and malnutrition from FAO, The State of Food Insecurity in the World 2001 (Rome: 2001), p. 2.
33. Population from United Nations, op. cit. note 2.
Copyright © 2002 Earth Policy Institute