Thursday, April 07, 2005

Disappearing Lakes, Shrinking Seas

West Africa’s Lake Chad has shrunk to a mere 5 percent of its former size. Central Asia’s Aral Sea is shrinking, gradually turning into desert. In Israel, the receding shores of Lake Tiberias—also known as the Sea of Galilee—sometimes allow mere mortals to walk where the water once was. Thousands of lakes in China have disappeared entirely. The diversion of river water in India and Pakistan that allowed for a doubling of irrigated area over the last four decades has depleted many lakes. All told, more than half of the world’s 5 million lakes are endangered.

The world's water problem is even more frightening than the immanent peaking of oil production--but somehow the water crisis has not gotten the attention that oil has. There is no Association for the Study of Water Depletion.

Over the last half-century world water use has tripled, growing even faster than the population. Irrigation accounts for two thirds of all global water use. Over the last half century the "green revolution" has expanded farming lands into marginal areas, some of which are now using as much as 120 percent of yearly water supply.

The result is plainly visible for anyone who cares to look. Tha Aral Seas has lost four fifths of its volume, receding as much as 250 kilometers, leaving behind a salty desert. The U.N. estimates that every day 200,000 tons of salt and sand are blown from the uncovered seabed and dumped on nearby farmland, destroying the land's ability to support agriculture.

In Africa, Lake Chad has shrunk by 95 percent over the last 35 years. China's Hebei province has lost 969 of 1,052 lates. China's Qinhai province once had 4,077 lakes, but over the last 20 years more than half have disappeared. Mono Lake, North America's oldest, has lost 40 percent of its volume as more and more water has been diverted to Los Angeles. Mexico’s largest lake, Chapala, is the primary source of water for Guadalajara’s growing population of 5 million. This lake’s long-term decline began in the 1970s, corresponding with increased agricultural development in the Río Lerma watershed. Since then, the lake has lost more than 80 percent of its water.

Peak Oil people talk of a "die off" once oil production goes into permanent decline. How much more dangerous it the disappearance of so many sources of fresh water?


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