sábado, 29 de octubre de 2011

Climate Change - Tibetan plateau's glaciers melting rapidly

Glaciers in the Qinghai-Tibet plateau, the source of many rivers that sustain China and the Indian subcontinent, are melting “faster than ever,” according to a five-year study by Chinese researchers. 

Yaks and sheep graze on grasslands outside of Gonghe in the Qinghai-Tibet plateau. Melting glaciers and permafrost along the mountain ranges are leading to erosion of the plateau's grasslands and wetlands [Credit: AFP]

The study found that a large area of glaciers had melted across the 2,400-square-kilometre region. The researchers had focused their study on glaciers and wetlands near the headwaters of the Yangtze, Yellow and Lancang rivers. 

Around 5.3 per cent, or 70 sq.km., of the glaciers in the Yangtze river's headwaters had melted in the past three decades, according to Cheng Haining, senior engineer at the Qinghai province's Surveying and Mapping Bureau. 

Mr. Cheng told the official Xinhua news agency that data from three meteorological stations over the past 50 years showed a continued rise in the average temperature in the region, with last year touching a five-decade high. 

Seventy per cent of the glaciers in the headwaters of the Lancang had disappeared, while another group of 80 glaciers near the source of the Yellow river was shrinking, according to researchers. 

The study is the latest from Chinese researchers to document a rapid retreat of glaciers in Qinghai and in Tibet. While the government has in the past downplayed threats to Tibet's glaciers as being overly alarmist, scientists and some officials have begun to increasing warn of danger to the country's long-term water security because of the glacial melt. 

“The melting of the glaciers could lead to a water shortage and even a dry-up of rivers in the long run, and consequent ecological disasters like wetland retreat and desertification,” Xin Yuanhong, an engineer with the Qinghai Hydrography and Geology Study Center, told Xinhua. 


Another study last year, which conducted two-month-long environmental surveys on the Tibetan plateau, found higher water levels and surface areas for several lakes, attributed to rapid glacial melt. Besides global warming, greater exploitation of the Qinghai-Tibet plateau has been seen by Chinese researchers as being behind the increasing rate of melting of the region's glaciers. The official Chinese Academy of Sciences (CAS) has estimated that glaciers have decreased by seven per cent over the past four decades. 

Qin Dahe, a researcher at CAS and a former director of the China Meteorological Administration, warned last year that the melting of glaciers across the Tibetan plateau would bring floods in the short-term, as well as pose long-term dangers to the water security of China, India and the region. 

“In the long run, glaciers are vital lifelines for Asian rivers such as the Indus and the Ganges,” he said. “Once they vanish, water supplies in those regions will be in peril.”  

The Hindu 

Source: The Archaeology News Network

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