Highest icefields will not last 100 years, study finds

After the most detailed study ever undertaken of China's glaciers, which are said to account for 15 per cent of the planet's ice, researchers from the Academy of Science said that urgent measures were needed to prepare for the impact of climate change at high altitude.

Their study, the Glacier Inventory, was approved for publication last week after a quarter of a century of exploration in China and Tibet. It will heighten alarm at global warming.

Until now, most research on the subject has looked at the melting of the polar ice-caps. Evidence from the inventory suggests that the impact is as bad, if not worse, on the world's highest mountain ranges - many of which are in China.

Shrinking glaciers

In the past 24 years, the scientists have measured a 5.5 per cent shrinkage by volume in China's 46,298 glaciers, a loss equivalent to more than 3,000 sq km (1,158 sq miles) of ice; there has been a noticeable acceleration in recent years.

Among the most marked changes has been the 500metre retreat of the glacier at the source of the Yangtze on the Tibet-Qinghai plateau.

The huge volumes of water from the glacier's melted ice, estimated at 587bn cubic metres since the 1950s, are thought to have been a factor in flooding that has devastated many downstream areas in recent years.

Shrinkages were observed at almost every ice-field in the Karakorum range, including the Purugangri glaciers, which are said to be the world's third largest body of ice after the Arctic and Antarctica. According to Yao Tandong, who led the 50 scientists in the project, the decline of the Himalayan glaciers would be a disaster for the ecosystem of China and neighbouring states.

Warming temperatures

If the climate continued to change at the current pace, he predicted that two-thirds of China's glaciers would disappear by the end of the 2050s, and almost all would have melted by 2100.

"Within 20 to 30 years, we will see the collapse of many of the smaller glaciers," he said. "Within 60 years, we can predict a very significant reduction in the volume of high-altitude ice fields."

In the short term, he said, the water from the ice would fill reservoirs and lead to more flooding - as was already the case in Nepal and downstream areas of China.

Rising seas

In the future, he predicted, the end of the glaciers would deprive the mountain ecology of its main life source and hasten the desertification that threatens western China, particularly in Gansu and Xinjiang provinces.

Once the mountain ice was gone, rivers would start to dry up and ocean levels would rise, threatening coastal cities.

The inventory confirms earlier studies of Everest, which showed the world's tallest peak more than 1.3 meters shorter than in 1953, when it was first scaled by Edmund Hillary and Tenzing Norgay.

To ease the impact of the glacial melt, the scientists plan to advise China's government to build more reservoirs and hydro-electric dams to improve downstream flood control.

But they said that there were limits to what could be achieved.

"No one can reverse the changes to a glacier," said Shi Yafeng, head of China's environmental and engineering research institute for the cold and arid regions.

Jonathan Watts is The Guardian correspondent in Beijing.

Guardian Unlimited � Guardian Newspapers Limited 2004 . This article was first published by The Guardian, (Friday, 24th September 2004). All rights reserved. Reproduced with kind permission.

For more details of how you can help, click here.