URUMQI/bole, Feb. 3, 2012 -- Xinjiang Uygur autonomous region has always been arid, a challenge to sustainable development. But water is getting scarcer.

In the past five decades, 243 lakes in China have disappeared and 62 of them - the most of any region - were in Xinjiang, according to a report on the country's water quality, water quantity and biological resources.

Xinjiang is left with 114 lakes of at least 1 square kilometer and a combined surface area of about 6,400 sq km - 7.7 percent of the total in China, said Wu Jinglu, researcher at Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, where the report was issued in December.

"Some of them could be seen a few years ago, but now they are all dried up," Wu said.

The lakes that have disappeared primarily were in southern Xinjiang. For example, Lop Nur Lake, which once covered 660 sq km, vanished in 1972. Taitema Lake, with a surface area of about 88 sq km, dried up around 1974.

Lakes in northern Xinjiang have also disappeared at a drastic pace. Aydingkol Lake, which covered 100 sq km in 1950, vanished in 1987 and now holds water only briefly after big rainstorms. The area of Manas Lake shrank to nothing in 1974 from 550 sq km in 1959.

Local ecologist Hai Ying told China Daily that no natural lakes remain in southern Xinjiang and only three - Aibi, Wulungu and Ailike - in northern Xinjiang. Others, including Kanas, Sayram and Tianchi, are well situated in the upper and middle reaches of rivers and do not face the deadly result.

"The vanishing of those lakes is a response to global climate change. In the latter half of the past century, the annual temperature of Northwest China increased by 0.6 C to 0.8 C," Wu said. "In the same period, the precipitation in Xinjiang saw an obvious decrease. The climate change, together with unreasonable exploration and development by human beings, resulted in shrinking or dried lakes."

Wu said the institute's research group continues to study how the decreasing number of lakes will affect Xinjiang's development, and vice versa.

"How to balance between ecological protection and economic development has been talked about too much," Hai said. "But people always care more about economic development. Only when we solve development problems will ecology become our concern. But then it will be too late."