Wetlands near Shanghai. Climate change is shrinking wetlands on China's huge Qinghai-Tibet plateau that are vital to regulating the flow of the country's giant rivers, state media reported Monday. [AFP]

The contraction of the wetlands has already led to reduced flows of the Yangtze and Yellow rivers, the China Daily newspaper said, citing a recent study.

Wetlands on the plateau have shrunk more than 10 percent overall in the past 40 years, with wetlands at the Yangtze's origin contracting an alarming 29 percent, said the report by scientists from the Chinese Academy of Sciences.

About 17.5 percent of the small lakes at the Yangtze's source also have dried up, it said.

"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," Wang said.

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

The report is the latest sobering indication of climatic change on the plateau, a source of several of Asia's biggest rivers, which scientists say could have a severe impact on the sustainability of water supplies in the region.

Recent studies have found rising temperatures and alarming rates of glacial retreat.

Last week, state press quoted another study as saying massive glaciers in northwestern China's Xinjiang region have shrunk by 20 percent while snow lines have receded by about 60 metres (200 feet) since 1964.