Two of China's great rivers are shrinking because of climate change, Chinese scientists report.

Bodies of water are shrinking all over the world. In this picture, a researcher is shown in what was once a pond on Cape Herschel on Ellesmere Island in Canada's High Arctic.
(M.S.V. Douglas)

The wetlands, lakes and glaciers that feed the Yangtze and Yellow rivers have shrunk over the past four decades, the Xinhua official news agency reported Sunday.

Scientists from the Institute of Mountain Hazards and Environment monitored the source of the two rivers in the Tibetan Plateau in western China, using aerial photos and remote sensing.

They found that:

• The wetlands that feed the Yangtze shrank by 29 per cent.
• Nearly one in five of the small lakes at the source of the Yangtze have dried up.
• The area of the glaciers on the Tibetan Plateau has shrunk by 30 per cent.

"The shrinking of the wetland on the plateau is closely connected with global warming," said Wang Xugen, a researcher with the institute.

Average annual rainfall measured at the head of the Yangtze has increased to 323 millimetres in 2001-2006 from 260 mm during from 1991-2000, the World Wildlife Fund weather station at the head of the river has reported.

"But the increased rainfall didn't lead to more water flow in the rivers because the evaporation was so fast as a result of global warming," said researcher Li Shijie of the Nanjing Institute of Geography and Limnology.

The Chinese report is the third this month about bodies of water shrinking because of global warming. The other reports said ponds in Canada's High Arctic and a lake in Chile had been affected by climate change.

The Yangtze is the third longest river in the world at 6,300 kilometres, and the Yellow is 5,400 kilometres, according to the Encyclopedia Britannica.

The longest river in Canada, the Mackenzie, is 4,240 kilometres.