Green Blog: On the Fate of Asia's Great Rivers

A new report from the National Research Council, a scientific arm of the United States government, brings some sobriety to the oft-heated discussion about melting Himalayan glaciers.

Interest in the glaciers intensified in 2010 when the Intergovernmental Panel on Climate Change, the United Nations body that publishes periodic summaries of climate science, acknowledged an error in its 2007 report. One paragraph had said in reference to the Himalayan glaciers that ?the likelihood of them disappearing by the year 2035 and perhaps sooner is very high.? After New Scientist magazine questioned this claim in 2010, the I.P.C.C. said the paragraph was based on poor information.

The new report, published on Wednesday, concludes that glaciers in the eastern and central regions of the Himalayas and the Tibetan Plateau are indeed melting, at accelerating rates, while those in the western part of the region are in better shape. However, over at least the next few decades, melting glaciers are not likely to be the main factor influencing water availability at lower elevations, the panel concluded.

A statement accompanying the report said that ?shifts in the location, intensity and variability of both rain and snow will likely have a greater impact on regional water supplies than glacier retreat will.? My colleague Vikas Bajaj, for instance, recently outlined the effect that shifts in the annual monsoon are having on Indian agriculture. He followed up on that report by answering questions and laying out possible solutions to India?s water problems.

The question of future water supply in this region is of profound importance. The Himalayan glaciers are the headwaters of many of the big river systems in Asia ? the Ganges, the Mekong and the Yantze rivers, for instance ? and those rivers in turn are a major component of a hydrologic system that supplies drinking and irrigation water. The rivers are thus vital to the welfare of about 1.5 billion people, or more than 20 percent of the world?s population.

While discounting fears of a near-term crisis precipitated by glacial melt, the National Research Council report also warned of potential long-term risks associated with the climatic warming of the region.

?Many basins in the region are ?water-stressed? due to both social changes and environmental factors, and this stress is projected to intensify? with growing populations, the summary statement said. ?Climate change could exacerbate this stress in the future.?

Source: http://green.blogs.nytimes.com/2012/09/12/on-the-fate-of-asias-great-rivers/?partner=rss&emc=rss

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