Climbing temperatures on the Qinghai-Tibet Plateau may pose a threat to the world's highest railway which is due to go into trial operation next year.

"By 2050, safe operation of the Qinghai-Tibet railway will be affected if temperatures keep rising steadily as observed over the past decades," a climatologist warned at a symposium in Beijing on climate change in the Sanjiangyuan region, an area cradling the Yangtze, Yellow and Lancang-Mekong rivers.

The plateau is seen by many climatologists as the "magnifier" of global climate change and the indicator of warming trends in China and East Asia due to its unique sensitivity to temperature changes.

Luo Yong, deputy director of the National Climate Centre, told the symposium on Tuesday that by 2050, winter and summer temperatures on the plateau may climb as much as 3.4 C.

Such warming, he said, could cause frozen ground to melt and threaten the railway. Since 1986, China has experienced 18 consecutive warm winters, Luo said.

And since the 1960s, frozen ground on both sides of the Qinghai-Tibet Highway has retreated 5 to 9 kilometers with its area of frozen soil decreasing 12 to 13 percent.

In the next five decades, temperatures in Qinghai Province, which sits on the Qinghai-Tibet Plateau, are predicted to rise 2.2 to 2.6 C, higher than neighboring areas.

Following the temperature climb, the plateau's area of frozen earth will probably shrink 30 to 40 percent in the subsequent 30 to 40 years, the symposium heard.

Such climate change will lead to the massive shrinking of glaciers, accelerated thawing of frozen earth and the early melting of spring snows, according to Luo.

Close attention needed

To cope with climate change on the plateau, particularly in the Sanjiangyuan region or the "source of three major rivers," Luo and experts urged authorities to pay close attention to the issue and its potential impact.

They also called on scientists to push forward research on protecting the region's ecosystems and look into its future sustainability.

Covering more than 360,000 square kilometers at an average altitude of more than 4,000 meters, the Qinghai-Tibet Plateau is home to rare wild animals such as the Tibetan antelope and black-necked crane and medicinal herbs such as the Tibetan snow lotus.

About half of the region belongs to China's largest nature reserve, but its environment and ecosystems have been worsening with rising global temperatures and increased human intrusion in past decades, according to the World Wide Fund for Nature.

Over-grazing and human activity have damaged the grasslands of the area, leading to serious soil erosion, a drop in soil fertility and worsening dersertification, experts said.

(China Daily June 23, 2005)