Parched and cracked soil is prevalent throughout the Minqin Oasis, Gansu province, China, making the growing of crops and plants increasingly difficult. Sean Gallagher

Analysis by Lester R. Brown* WASHINGTON, Jul 20, 2011 (IPS) – Many countries are facing dangerous water shortages. As world demand for food has soared, millions of farmers have drilled too many irrigation wells in efforts to expand their harvests. As a result, water tables are falling and wells are going dry in some 20 countries containing half the world’s people. The overpumping of aquifers for irrigation temporarily inflates food production, creating a food production bubble that bursts when the aquifer is depleted. The shrinkage of irrigation water supplies in the big three grain- producing countries – the United States, India, and China – is of particular concern. Thus far, these countries have managed to avoid falling harvests at the national level, but continued overexploitation of aquifers could soon catch up with them. In most of the leading U.S. irrigation states, the irrigated area has peaked and begun to decline. In California, historically the irrigation leader, a combination of aquifer depletion and the diversion of irrigation water to fast-growing cities has reduced irrigated area from nearly nine million acres in 1997 to an estimated 7.5 million acres in 2010. (One acre equals 0.4 hectares.) In Texas, the irrigated area peaked in 1978 at seven million acres, falling to some five million acres as the Ogallala aquifer underlying much of the Texas panhandle was depleted. Other states with shrinking irrigated area include Arizona, Colorado, and Florida. All three states are suffering from both aquifer depletion and the diversion of irrigation water to urban centers. And now that the states that were rapidly expanding their irrigated area, such as Nebraska and Arkansas, are starting to level off, the prospects for any national growth in irrigated area have faded. With water tables falling as aquifers are depleted under the Great Plains and California’s Central Valley, and with fast-growing cities in the Southwest taking more and more irrigation water, the U.S. irrigated area has likely peaked. India is facing a much more difficult situation. A World Bank study reported in 2005 that the grain supply for 175 million Indians was produced by overpumping water. Water tables are falling in several states, including Punjab and Haryana, two surplus grain producers that supply most of the wheat and much of the rice used in India’s massive food distribution programme for low-income consumers. Up-to-date and reliable information is not always easy to get. But it is clear that overpumping is extensive, water tables are falling, wells are going dry, and farmers who can afford to are drilling ever deeper wells in what has been described as “a race to the bottom”. Based on studies by independent researchers, there is ample reason to think that decades of overpumping in key states are leading to aquifer depletion on a scale that is reducing the irrigation water supply. India’s water-based food bubble may be about to burst. In China, the principal concern is the northern half of the country, where rainfall is low and water tables are falling everywhere. This includes the highly productive North China Plain, which stretches from just north of Shanghai to well north of Beijing and which produces half of the country’s wheat and a third of its corn. Overpumping there suggests that some 130 million Chinese are being fed with grain produced with the unsustainable use of water. Furthermore, China’s water-short cities and rapidly growing industrial sector are taking an ever-greater share of the available surface and underground water resources. In many situations, growth in urban and industrial demand for water can be satisfied only by diverting water from farmers. Although new dams being built in the mountainous southwest may offset at least some of the losses elsewhere, it is possible that the irrigated area has peaked in China – and therefore in all three of the leading grain-producing countries. […] *Adapted from World on the Edge, by Lester R. Brown, founder and president of the Earth Policy Institute. Full book available online at www.earth-policy.org/books/wote.

Growing Water Deficit Threatening Grain Harvests