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Retreating Mountain Glaciers Pose Freshwater Shortage

Climate's influence on Himalayan glaciers is still a looming concern for many scientists and governments, which worry about how warming will affect the region's water cycle



By NASA Godard Photo and Video, courtesy Flickr

Norway said yesterday it will spend $12 million to expand monitoring of Himalayan glaciers and help the region's communities adapt to climate change.

The Hindu Kush-Himalayas Climate Impact Adaptation Assessment Programme will run for five years, carried out by Norway's Centre for International Climate and Environmental Research, the U.N. Environment Programme and the Katmandu, Nepal-based International Centre for Integrated Mountain Development.

"The overarching theme is people plagued by either too much or too little water in these regions," said Bjorn Brede Hansen, deputy director-general of the Section for Environment and Sustainable Development within Norway's Ministry of Foreign Affairs. "This is really the framework for everything -- agriculture, livelihoods ... [the role of] women."

Himalayan glaciers are sometimes referred to as Earth's "third pole" because they supply fresh water to communities throughout Southeast Asia. Roughly 210 million people live in the region, and another 1.3 billion people who live downstream depend on rivers fed in part by glaciers and mountain snowpack.

The plight of Himalayan glaciers briefly dominated news headlines last year, after news broke that the Intergovernmental Panel on Climate Change erred by stating the region's ice could disappear by 2035, instead of 2350. But while the IPCC bungled its numbers, climate's influence on Himalayan glaciers is still a looming concern for many scientists and governments, which worry about how warming will affect the region's water cycle.

Yesterday, the U.N. Environment Programme said the majority of glaciers in the Hindu Kush-Himalayas and on the Tibetan Plateau are retreating, with some exceptions. Some glaciers in the Karakoram mountains, for example, recently advanced into areas that had been ice-free for a half-century. But in the northern Karakoram, in China, glaciers are receding. The thaw there is increasing the frequency of glacial lake outburst floods, or "glofs," caused by runoff that forms into lakes that burst suddenly and inundate nearby areas.

Major risks for nearby communities
"We need to get the numbers right on [Himalayan] glaciers," Madhav Karki, deputy director of general programs at the International Centre for Integrated Mountain Development, said yesterday at a news conference in Cancun, Mexico, at U.N. climate talks. "The fact is that glaciers are retreating. Some are advancing, but by and large, they are retreating, and we need to study them. And they are an important element in our future adaptation."

That point is underscored in a recent report by the U.S. Agency for International Development, which last month warned that even relatively slow shrinking of Himalayan glaciers presents major risks for nearby communities and those that depend on rivers fed by the alpine ice.

"Even small changes in glacier melt will result in large impacts downstream from High Asia," the USAID report cautioned.

But efforts to understand the interplay between the climate and the glaciers are hampered by a lack of data. Scientists have data about specific glaciers and are able to pick out some trends, but the information is too sparse to paint a clear picture of how fast glaciers are melting throughout the region -- sometimes, even within a single mountain range -- and how that compares to how they behaved in the past.

Part of the problem is reaching glaciers that sit at high altitudes. The most-studied Himalayan glaciers are largely the most accessible, often those at lower altitudes, the USAID report said.
High-altitude puzzles

That's crucial because glaciers at the highest altitudes, where temperatures are more likely to stay below freezing, are behaving differently than their counterparts at lower elevations. For glaciers that extend from low to high elevation, measurements taken at the low end -- the glacier's "snout" -- may not tell scientists much about how the same ice sheet is behaving higher up the mountain.

Scientists are also trying to figure out the role that aerosol particles -- including a component of soot known as black carbon -- play in influencing the behavior of Himalayan glaciers.

William Lau, who heads the atmospheric science laboratory at NASA's Goddard Space Flight Center, says his research suggests black carbon could rival greenhouse gases as a cause of warming in the Himalayas.

Particles of black carbon absorb heat from the sun, warming the atmosphere. When black carbon lands on white ice or snow, it reduces a glacier's ability to reflect sunlight -- adding another source of heat to the mix.

"Up to now, most people thought, 'OK, greenhouse warming is the reason these high mountain glaciers are moving faster,'" he said. "But another possibility is a contribution from the black carbon and other absorbing aerosols, including dust."

Still, he said, "we're not saying global warming is not important."

Reporters Lisa Friedman and Jean Chemnick contributed from Cancun, Mexico.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500

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