For anyone following the news this summer, it would be easy to think the planet is drowning.

Fourteen million Chinese have been driven from their homes by rivers surging over their banks. On the other side of the world, hurricanes and tropical storms last month poured rain over the Atlantic and Gulf coasts of the United States, forcing beach goers to flee inland.

Despite such destructive deluges, experts say that water scarcity, rather than flooding, is the more serious threat to humankind.

"Water that once sufficed to meet all needs now does not," says Robert Engelman, program director of Population Action International in Washington. "Population is growing, and water is not."

The world's population is expected to reach 8 billion in the first quarter of the next century. The supply of the vital liquid is roughly the same as it was 2,000 years ago -- and what there is is threatened by pollution.

Consider these examples, drawn from a new report by the Johns Hopkins University School of Public Health:

Despite periodic flooding in southern China, the Yellow (Hwang Ho) River, the country's second largest, normally is dry for 70 days a year. One-third of the wells around Beijing have dried up.

Africa's Lake Chad has shrunk in the past 30 years from nearly 10,000 square miles to just 800 square miles because of droughts and farmers tapping it to irrigate their croplands. The lake's once-thriving fishing industry has dwindled.

Even in the relatively water-rich United States, there is scarcity. Cities and farmers in the arid Southwest have siphoned so much water from the Colorado River that it rarely reaches the Gulf of California. In the rainy Southeast, Fort Myers, Fla., is planning to build a $33 million desalination plant to quench the thirst of its booming populace.

Dire prediction

Nearly half a billion people endure shortages now, mostly in Africa and the Middle East. But by 2025, Population Action International predicts that one in three people may live in countries without enough water.

Among the countries identified by the report as facing future water stresses are some unlikely ones: Belgium, the United Kingdom and Poland.

How can that be, when 70 percent of the Earth is covered with water?

Only 3 percent of all that water is fresh, and most of it is inaccessible -- locked in remote polar ice caps and glaciers or too deep underground to be pumped out affordably.

Even so, the planet has more than enough fresh water, even for billions more people. But as this summer's flooding in China illustrates, it is not distributed where and when it is needed most.

Two-thirds of the world's population lives in areas receiving only one-quarter of planet's rainfall, the Hopkins report notes. Tiny Iceland has more than 600,000 cubic meters of renewable fresh water per person, while Kuwait has only 75 cubic meters per resident.

And in much of the developing world, fresh water is supplied through seasonal rains, such as Asia's monsoons, that run off too rapidly to be useful. In India, for instance, 90 percent of the rains fall in one-fourth of the year, from June to September.

There is increasing competition for water for irrigation, for drinking and for industry. Globally, 69 percent of all water withdrawn from lakes and streams is used for agriculture, while industry takes 23 percent and households use about 8 percent.

In some developing countries, agriculture gets upward of 90 percent of available fresh water, leaving precious little for drinking, sanitation and other uses.

As countries such as China seek to develop industry, they practice what water expert Sandra Postel calls "the zero-sum game of water management" -- they supply water to new factories at the expense of farmers, threatening to reduce crop yields and raise food prices.

Even in the United States, with its relative abundance, competing demands for water supplies lead to court squabbles. The city of Baltimore, for instance, is threatening a lawsuit to gain unfettered access to the Susquehanna River for the region's drinking-water needs.

On the international scene, sabers rattle as desperate countries compete for water. Egypt has publicly warned Ethiopia and the Sudan not to interfere with the flow of the Blue Nile River.

"I wouldn't be surprised if we saw in the near future a real shooting war over water resources," says Don Hinrichsen, a consultant for the United Nations and chief author of the Hopkins report.

Water shortages will force developing countries to make some tough choices.

"You need water for everything, particularly for growing crops and raising livestock," Hinrichsen says. "They don't have it now, so where are they going to get it in the future when their populations are growing 2.5 and 3 percent a year?"

Birthrates are leveling off in many countries, but the world's population of nearly 6 billion is still growing by about 80 million people a year, and water use is outstripping population growth. While the number of humans has trebled in this century, water withdrawals have increased more than sixfold. Humans now use about 54 percent of all fresh water readily available in lakes, rivers and ground water, and that could increase to 70 percent or more by 2025.

Polluted rivers

Pollution -- especially from agriculture -- has degraded surface and ground water, rendering sources unfit for drinking and even for other industries. India's 14 major rivers are all polluted with untreated sewage and industrial wastes. More than three-fourths China's major rivers are so tainted and sediment-filled that fish cannot live in them.

The crisis poses health risks, as diseases like cholera, shigella and hepatitis can be spread by polluted water. The Hopkins report calls for a "Blue Revolution" in water management, mirroring the "Green Revolution" that transformed Third World agriculture in the 1960s.

Sea water can be converted to fresh water, but only oil-rich Persian Gulf nations and the United States may be able to afford to do it.

For most, the only way out of crisis will be to conserve existing supplies -- by using water more efficiently in farming and by cleaning polluted lakes and streams.

Making irrigation more efficient would help. No more than half of the water withdrawn to irrigate crops ever reaches them; the rest evaporates or runs off. Drip agriculture, which can reduce water use by as much as 60 percent, is practiced in arid parts of Australia, Israel, Mexico, South Africa and the United States. Urban waste water, referred to as "brown water," also can be reused by agriculture and industry.

While some have proposed U.N. action, Hinrichsen says that solutions are more local and regional than global.

Pub Date: 9/11/98