BEIJING, July 16: Climate change is shrinking wetlands at the source of China's two greatest rivers and has already led to reduced water flows that could have an impact across Asia, state media reported on Monday.

The contraction of the wetlands, which serve a vital role regulating the flow of the Yangtze and Yellow rivers, comes as China is already struggling to meet the increased water needs of a fast-expanding economy.

Wetlands on the Qinghai-Tibet plateau have shrunk more than 10 per cent in the past 40 years, with those at the Yangtze's origin contracting an alarming 29 percent, the China Daily newspaper said, citing a recent study.

About 17.5 per cent of the small lakes at the Yangtze's source also have dried up, said the study by the Chinese Academy of Sciences.

“The wetland plays a key role in containing water and adjusting the water volume of the rivers,” said Wang Xugen, a researcher with the academy.

“The shrinking of the wetlands on the plateau is closely connected with global warming,” he added.

The report is the latest worrying indication of global warming-induced change in the region, a source of concern to scientists because the massive plateau is considered a sensitive barometer of the world's climatic health.

It is also the source of several of Asia's other big rivers besides the Yangtze and Yellow, including the Ganges, Brahmaputra, Indus, and Mekong. About three billion people live along or near the waterways.

A Chinese study released earlier this year found that glaciers on the Tibetan plateau have been melting at an average rate of 131.4 square kilometres per year over the past 30 years.The survey said that even if global warming did not worsen, the icefields would shrink by half by 2090.

Scientists say a depletion of the water reserves stored in glaciers and wetlands on the plateau could have a severe impact on regional water supplies.

The UNDP has said that in China alone 300 million farmers in the country's western regions already face worsening water shortages from lower volumes flowing from the reduced glaciers.

The academy's Wang added that even though rainfall in the region was increasing due to climate change, water flows in the Yangtze had not increased due to faster evaporation caused by higher temperatures.

Last week, state press quoted another study as saying massive glaciers in northwestern China's Xinjiang region have also shrunk by 20 per cent while snow lines have receded by about 60 metres since 1964.—AFP