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Tibetan Glaciers Shrinking Rapidly: comprehensive survey reveals influence of prevailing winds

17.07.2012

The majority of glaciers on the Tibetan plateau - 100,000 square kilometers of glaciers that supply water to about 1.4 billion people in Asia - and in the surrounding region - are retreating rapidly, according to a study based on 30 years of satellite and field measurements. The research by Yao Tandong, a glaciologist at the Chinese Academy of Sciences’ Institute of Tibetan Research in Beijing and his colleagues, was published on 16 July, in Nature Climate Change. It “is the most comprehensive survey to date in the region”, says Tobias Bolch, a glaciologist in the University of Zurich, Switzerland. “The majority of the glaciers have been rapidly shrinking across the studied area in the past 30 years,” says Yao. And the rate of retreat has been accelerating. But embedded in this general trend, says Yao, is a large variation in different parts of the Third Pole. For instance, glaciers in the Himalayas are retreating faster on average than those in the Karakoram and the Pamir. To unravel the mechanisms underlying this variation, the researchers turned to climate records of the entire region. They found that changes in the glaciers, depend in large part on whether the ice is under the influence of the Indian monsoon or the westerlies, the prevailing winds from Europe. In places dominated by the westerlies, such as the Karakoram and the Pamir plateau, glaciers gain their mass mostly from winter snow, and so are less affected by warming because temperatures in winter are still below zero. In the eastern and central Himalayas, however, it snows mainly during monsoon season, and a slight increase in summer temperatures can affect glaciers drastically.

Photo (c) Anne Roberts / Flickr