Tibetan glaciers at risk, study warns
Climate change will melt half by 2090, causing floods
Half of the glaciers on the Tibetan Plateau will have melted by 2090, causing floods, droughts and other natural disasters that could have a global impact, according to a new national report.
The findings published last week by the China Geological Survey Bureau under the Ministry of Land and Natural Resources confirm an earlier UN Development Programme report that said most glaciers in Tibet would be gone in a century as a result of global warming, causing an ecological catastrophe affecting 300 million farmers in the country's arid north and west.
The four-year, 10 million yuan remote sensing project was the first of its kind to study changes over the past 30 years in Tibet's glaciers, deserts, lakes and wetlands.
Scientists have interpreted the world's rapidly diminishing glaciers as evidence of the impact of global warming, and the Tibet study found that in the past three decades, more than 10 per cent of the region's glaciers had melted away at an average rate of 131.4 sq km a year.
In the 1970s, Tibet's glaciers covered about 49,000 sq km, compared with about 44,000 sq km today.
Snow lines in most areas are also on the rise and have crept up several hundred metres in some places.
The study also found that fresh water supplies had increased in many areas, but the region's water reserves had decreased overall.
Tibet's wetlands are also in decline, shrinking by about 10 per cent from 30 years ago to 88,700 sq km. At the same time, the area of desert more than tripled.
Zhang Ruijiang , a scientist who participated in the study, said the estimates of a halving of the glaciers were conservative because they assumed there was no global rise in temperature.
Mr Zhang said the lakes in Tibet's heartland had doubled in the past 30 years, but the overloaded natural reservoirs had become an imminent threat. Once they collapsed, downstream areas within 1,000km - including parts of Nepal, India and Bangladesh - would be severely affected, he said.
He also said rising underground water levels had brought salt to the surface. 'Excessive logging, overgrazing and open-cut mining have destroyed Tibet's vegetation and environment, accelerating the pace of nature's revenge.'
The nation's leading glacier expert, Yao Tandong , director of the Chinese Academy of Sciences' Institute of Tibetan Plateau Research, said the consequences of Tibet's disappearing glaciers were very disturbing. Professor Yao said 'islands of green' in arid northwest areas would be the first to go because they were wholly dependent on ice-melt from the mountains.
Several of the world's biggest water systems, including the Yangtze, Yellow and Mekong rivers would be affected, and probably turn into seasonal rivers, because they originated in Tibet, he said.