Surviving a warmer world: Global forecast is 'mostly dry'

Climate change is already being blamed for altered rainfall patterns and shrinking glaciers that provide water for drinking and agriculture. Part 1 of an occasional series.

from the April 5, 2007 edition

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Ironically, global warming may provide a catalyst by forcing countries to work together to solve their mutual problem, he suggests. "All parties see it as a common threat – which it is," Mr. Unver says. "So it could provide the basis for common solutions to water management."

High glaciers retreating fast

Hundreds of millions of people around the world draw their water from major river systems whose sources are mountain glaciers and seasonal snowpack. From the Andes and Himalayas to the Alps, scientists are gathering data that tell a sobering tale of rapidly retreating tongues of ice.

The World Glacier Monitoring Service tracks 27 glaciers in nine mountain ranges around the world. The service's data show that these glaciers have been steadily losing mass since 1980.

This comes as no surprise to Lonnie Thompson. Since 1983 he has studied ice cores from mountain glaciers and ice caps in the Andes, Himalayas, and from Mt. Kilimanjaro in Tanzania. Last July, the Ohio State University professor and his colleagues published a paper suggesting that the current warming at high elevations is unprecedented in the last 2,000 years; in some areas, warming and the pace of glacial retreat is unprecedented for the past 5,200 years.

For example, the Qori Kalis glacier, the largest outlet for the Quelccaya ice cap in Peru, retreated 10 times faster during the 1990s than it did from 1963 to 1978, Dr. Thompson says. "The changes are overwhelming."

If global warming has shifted climate conditions closer to those that existed prior to 5,200 years ago, high-altitude glaciers may be under wholesale retreat and may disappear altogether "in the near future," Thompson says.

Already, some cities relying on these natural water towers are struggling to adapt. But these efforts are at their early stages, according to Walter Vergara, a civil engineer with the World Bank. In Quito, Ecuador, for example, the city of 2 million relies on water from the fast-retreating Antizana glacier. Quito has laid out pipeline and reservoir projects to expand its water supplies to keep pace with the city's growth through 2040. But the plans haven't factored in global warming, Mr. Vergara says.

Quito is now trying to anticipate the glacier's retreat and changing patterns of precipitation. This means extending water pipelines farther up the mountain and around the back of the glacier to tap its eastern, Amazon Basin side. The changes will add $100 million to the $300 million project, Vergara estimates.

Managing water supplies in a warmer, more variable climate "is a challenge developing countries face right now," notes Casey Brown, a climate scientist at Columbia University. "If they can meet this challenge, they'll be in much better shape to meet [the] other challenges [that] climate change brings."

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Click to enlarge SOURCE: IPCC REPORT FEBRUARY 2007/RICH CLABAUGH – STAFF