Population Outrunning Water Supply as World Hits 6 Billion

POPULATIONS OUTRUNNING WATER SUPPLY AS WORLD HITS 6 BILLION

As world population approaches 6 billion on October 12, water tables are falling on every continent, major rivers are drained dry before they reach the sea and millions of people lack enough water to satisfy basic needs.

Water tables are now falling in China, India, and the United States, which together produce half the world's food. Historically, irrigated farming has been plagued with waterlogging, salting, and silting, but now, with the advent of powerful diesel and electrically powered pumps, it is also threatened by aquifer depletion.

In China, water tables are falling almost everywhere that the land is flat. Under the North China Plain, the country's breadbasket, water tables are falling by 1.5 meters, or roughly 5 feet, per year. Where wells have gone dry, farmers have been forced either to drill deeper, if they can afford it, or to abandon irrigated agriculture, converting back to lower-yield rainfed farming.

In India, a country whose population hit 1 billion on August 15, the pumping of underground water is now estimated to be double the rate of aquifer recharge from rainfall. The International Water Management Institute, the world's premier water research group, estimates that India's grain harvest could be reduced by up to one fourth as a result of aquifer depletion. In a country adding 18 million people per year, this is not good news.

Third in a series of reports on global population issues leading up to the Day of 6 Billion, October 12, 1999.

In the southern Great Plains of the United States, depletion of the Ogallala aquifer has already led to irrigation cutbacks. Texas, Oklahoma, Kansas, and Colorado have been losing irrigated land over the last two decades. Texas, for example, has lost irrigated land at roughly one percent per year since 1980.

Rivers running dry provide an even more visible manifestation of water shortages as growing populations take more water. The Yellow River, the cradle of Chinese civilization, first ran dry in 1972. Since 1985, it has run dry for part of each year. In 1997, it failed to reach the sea during 226 days, or roughly 7 months of the year.

During the dry season, the Ganges River has little water left when it reaches the Bay of Bengal. India, with more than a billion people taking the lion's share of the water, is leaving too little for the farmers of Bangladesh during the dry season.

In central Asia, the Amu Darya, one of two rivers that once fed the Aral Sea, is now drained dry by farmers in Turkmenistan and Uzbekistan. As the Sea has shrunk to scarcely half its original size, the rising salt concentration has destroyed all fish, eliminating a rich fishery that once landed 100 million pounds of fish per year.

Similarly, the Colorado, the major river in the southwestern United States, rarely ever makes it to the Gulf of California. The fishery at its mouth that once supported several thousand Cocopa Indians has now disappeared. Today the Nile, like many other major rivers, has little water left when it reaches the sea. Even though virtually all the water in the river is now claimed, the population of the three principal basin countries-Egypt, the Sudan, and Ethiopia, where most of the water originates-is projected to increase from 153 million today to 343 million in 2050, generating intense competition for water.

Hydrologists estimate that when the amount of fresh water per person in a country drops below 1,700 cubic meters per year the country is facing water stress. In her new book, Pillar of Sand: Can the Irrigation Miracle Last, Worldwatch senior fellow Sandra Postel reports that the number of people living in countries experiencing water stress will increase from 467 million in 1995 to over 3 billion by 2025 as population continues to grow. In effect, these people will not have enough water to produce food and satisfy residential and other needs.

Postel estimates the current world water deficit ˚ the excess of water pumping over recharge from rainfall ˚ at 160 billion tons per year. Since it takes 1,000 tons of water to produce 1 ton of grain, this water deficit is equal to 160 million tons of grain, a quantity only slightly less than annual world grain exports of 200 million tons.

Ironically, the excessive grain supplies that have depressed world grain prices in 1999 are partly the result of overpumping. If falling water tables were stabilized by a cutback in pumping, the resulting decline in grain production would likely drive prices off the top of the chart.

As water becomes scarce, the competition for water between cities and countryside intensifies. In this competition, farmers almost always lose. In North Africa and the Middle East, the region ranging from Morocco in the west to Iran in the east, virtually every country is experiencing water shortages. As cities grow, countries take water from agriculture to satisfy expanding urban water needs. The countries then import grain to offset the water losses.

Given that importing one ton of grain is equal to importing 1,000 tons of water, this is the most efficient way for water-short countries to import water. Last year the water required to produce the grain and other farm products imported into this region was roughly equal to the annual flow of the Nile River. With more and more countries looking to the world market for food, spreading water scarcity may soon translate into world food scarcity.

It is often said that the competition for water among countries may take the form of military conflict. But it now seems more likely that the competition for water will take place in world grain markets. It is the countries that are financially strongest, not those that are militarily the strongest, that are likely to win in this competition.

If the world could move from the U.N. medium population projection of nearly 9 billion in 2050 to the low projection of less than 7 billion, water stresses would be greatly alleviated, making the water problem much more manageable. If the world stays on the current population trajectory, a growing share of humanity may simply lack the water needed for a decent life.

LESTER R. BROWNis president and BRIAN HALWEIL is staff researcher at Worldwatch Institute, a Washington, D.C.-based research organization.