Dong warned the deterioration of the plateau may trigger more droughts and increase sandstorms that lash western and northern China. He reached his conclusions after analysing four decades of data from China's 681 weather stations.

Han Yongxiang of China's National Meteorological Bureau said average temperatures in Tibet had risen 0.9 centigrade since the 1980s, accelerating the melting of glaciers and frozen tundra across the plateau.

The Qinghai-Tibet plateau covers 2.5 million square km (0.96 million square miles) -- about a quarter of China's land surface -- at an average altitude of 4,000 metres (13,000 ft) above sea level.

Dust and sandstorms are a growing problem, particularly in North China, due to deforestation, drought and the environmental depredations of China's breakneck economic growth.

A strong sandstorm swept across one eighth of China's territory on April 16 and 17, dumping 330,000 tonnes of dust on Beijing and reaching as far as Korea and Japan.