Rapid retreat of Tibet’s glaciers alarms researchers

Researchers in China have documented what they describe as the rapid retreat of glaciers on the Tibetan Plateau, the source of many of the subcontinent’s rivers, and warned of the dangers to the water supply and livelihoods of millions in India, downstream of these rivers.Research teams from Greenpeace China and Green Earth Volunteers, a Beijing-based group, have in recent weeks documented receding snowlines and extensive flooding in the upper reaches of several Himalayan rivers, as a result of increased glacial melts. In some areas of the Tibetan Plateau, the researchers found that snowlines had risen by more than three kilometres since 2001.“This year, there has been massive flooding in Qinghai province [in northwest China],” said Li Yan, a campaigner at Greenpeace China, which recently conducted a study of glacial melts near the sources of the Yellow and Yangtze rivers. “Glacial retreat on the plateau has been very obvious, and there is direct evidence that the glaciers are retreating very rapidly.”

Conservationists attribute the increased pace of glacial retreat this past decade to rising temperatures and global warming. Government officials, in China and India, have in the past downplayed the reports as alarmist. But in recent months, even former officials and government agencies in China have begun to voice their concerns more forcefully about the fate of the Tibetan Plateau’s glaciers.“Due to global warming, glaciers on the Qinghai-Tibet Plateau are retreating extensively at a speed faster than in any other part of the world,” Qin Dahe, a former director of the China Meteorological Administration, said recently. “In the short term, this will cause lakes to expand and bring floods and mudflows. In the long run, glaciers are vital lifelines for Asian rivers such as the Indus and the Ganges. Once they vanish, water supplies in those regions will be in peril.”The Intergovernmental Panel on Climate Change estimates that Himalayan glaciers could disappear within three decades at current warming rates. A recent report by the Tibetan Plateau Climate Change Monitoring Service Program found that glaciers were receding by 131.4 sq.km every year, and snowlines were retreating 350 metres every year.

According to Mr. Qin, temperatures on the Tibetan Plateau were now rising four times faster than elsewhere in China. He warned of dire consequences, not just to China but across the subcontinent. “If vegetation cover on the plateau decreases, consequent absorption of solar radiation will change the intensity of summer monsoons in Asia,” he said. “This will bring drought to north India, and intensify floods in southern China and droughts in the north.”The Chinese Academy of Sciences (CAS) estimates that glaciers have decreased by 7 per cent in the last four decades. Yao Tandong, director of the Qinghai-Tibet Plateau Research Institute of CAS, said in a recent interview with China’s state-run Xinhua news agency that the warming on the plateau had been “abrupt and exceptional” and it was “warmer now than at any time during the past 2000 years.”Earlier this year, entire villages in Qinghai had to be relocated because of massive flooding on a never-before-seen scale, which researchers said was a result of increased glacial melts. A glacial lake that researchers had observed in 2005 burst earlier this year, causing extensive damage to communities downstream in the Qinghai province. The glaciers of the Tibetan Plateau in Qinghai feed the Yellow and Yangtze rivers, which are crucial to the livelihoods of millions in China.

The Hindu, November 2nd , 2009