Thanks to global warming, glaciers on the Tibetan Plateau are rapidly liquefying, possibly causing many of the region's water woes--especially flooding--in the past decades. The huge meltdown could cause serious ecological trouble in the future, including water shortages, Chinese experts say.

The Tibetan Plateau is the source of many major rivers in Asia.

It is estimated that the annual amount of water melting from the glaciers is equal to the total annual flow volume of the Yellow River.

One of the examples of the speedy meltdown phenomenon is the massive melting glacier on Meili Snow Mountain (Meilixueshan). The 6,740-meter-high mountain is located in the border area between Yunnan province and the Tibetan autonomous region at the southern end of the Tibetan Plateau.

Local Tibetan Buddhists worship the sacred mountain. About 300 Tibetans live in Miyon village, located on the mountain at 2,350 meters above sea level.

Climbing a steep 4-kilometer route from the village leads hikers to the tip of the glacier that stretches along a deep valley over 11.5 kilometers. The glacier looks brownish, covered in dirt and rocks.

The tip of the glacier is a wall of ice standing more than 5 meters tall. It has a hollowed-out appearance and looks like a spacious cavern. From the top of the ice wall, water drips. This drip eventually turn into a stream, which then flows into the Mekong river nearby. When chunks of ice crack apart from the glacier, booming sounds echo through the valley.

Jashi, a 43-year-old farmer who grew up in Miyon village, said: "Fifteen years ago, the tip of the glacier was about 200 meters closer to our village. The height of the ice wall at the end of the glacier was also double the current one. The melting makes it seem the glacier is running away from villagers."

The Chinese Academy of Sciences' Institute for Cold and Arid Regions Environment and Engineering Research is in charge of researching the glacier's meltdown.

According to the institute, which is based in Gansu province, the glacier near Miyon village stretches over the mountain slope from about 2,800 meters above sea level to 6,000 meters above sea level. The glacier's total size is now 12.55 square kilometers, and its average thickness is 30 meters.

Usually, glaciers expand as snow accumulates in winter and shrink when they melt in the summer. However, because this glacier is located on a sharp slope, it used to increase in size at a higher rate than other glaciers. For example, from 1959 to 1971, the glacier expanded more than 800 meters.

But the glacier started shrinking by about 20 to 30 meters a year in 1998.

According to the meteorological bureau of the Deqin county, where the Meili Snow Mountain is located, the average temperature in 2003 was 1 degree higher than the average of the previous 30 years. Since 1994, which saw a peak snowfall of 70 centimeters, the snow accumulation has been on the decline annually, with only 9 centimeters in 2004, the bureau said.

While the mountain has had less snowfall in the past few years, the amount of summer rainfall has been increasing. Because of this, the amount of water in the Mekong river is rapidly increasing.

"The abnormal climate has been the norm since 2000. The rise in temperature and the decrease in snowfall is accelerating the speed of the glacier melting," said an official with the meteorological bureau.

Chilen, 75, one of the leaders of Miyon village, said: "In Tibet, glaciers are considered to be part of sacred mountains. If the meltdown is caused by global warming, which results from the development of other regions, we, the Tibetans, cannot protect the glacier."

The Tibetan Plateau is on average more than 4,000 meters above sea level. The Yangtze River, Yellow River and other big rivers such as the Indus, Ganges and Mekong begin from sources on the plateau.

Researchers at the Chinese Academy of Sciences' Institute of Tibetan Plateau Research are monitoring 15 locations on the Chinese side of the plateau.

Yao Tandong, 51, director of the institute, said about 46,298 glaciers lie in and around the plateau in China, covering 59,406 square kilometers in total.

However, the coverage has shrunk by 7 percent over the past 40 years. On the other hand, the total amount of water melting from these glaciers has increased by 20 percent. As a result, water levels in most of the lakes nearby are rising, which is steadily expanding the sizes of those lakes.

In and around the Tibetan Plateau, 1,091 lakes measure more than 1 square kilometer. Of them, more than half were created from water that had melted from the glaciers.

In the central part of the Tibetan autonomous region, many pasture lands were submerged after the expansion of lakes in the 1990s. This kind of natural phenomenon has had ill effects on local people's lives. For example, an entire village community was forced to evacuate three times to different lands.

Despite all the rising water, some are concerned about future water shortages.

In Qinghai province, a glacier in the area provides water to the Yellow River. According to the Institute for Cold and Arid Regions Environment and Engineering Research, the glacier shrank by 17 percent from 1966 to 2000. The glacier's rapid shrinkage during that period is 10 times faster than that of the past 300 years, the institute said.

Partly because of that, underground water levels in the area around the glacier have sharply dropped. That has caused many of the nearby lakes to dry up and drastically decreased the quantity of water in the Yellow River.

He Yuanqing, 48, a researcher at the institute, pointed out that a future water shortage could be caused by the accelerated rate of melting. If the underground water supply sharply decreases, the area would feel a huge impact in the amounts of drinking and agricultural waters available.

In the Xinjiang Uyghur autonomous region, some oases have already disappeared.

"If global warming continues, water volume in large rivers will decrease by 10 to 20 percent in the next 50 to 100 years," He said.

Yao also said: "There is a possibility that 50 to 60 percent of the glaciers on the Tibetan Plateau will disappear in the next 100 years. As long as global warming continues, it is impossible (for us) to prevent the glaciers from melting.

"All we can do to slow the melting speed is to take measures against global warming."(IHT/Asahi: January 4,2006)

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