Climate change linked to the contraction of wetlands at the source of the
country's two longest rivers, the Yangtze and the Yellow, has reduced the volume
of water flowing in them, scientists said.
Scientists from the institute
of mountain hazards and environment under the Chinese Academy of Sciences (CAS)
studied changes over the past 40 years to the wetlands on the cold Qinghai-Tibet
Plateau in west China where the two rivers have their source.
Analyzing
aerial photos and satellite remote-sensing figures, they found the wetlands on
the plateau have shrunk more than 10 percent over the past four decades. The
wetlands at the origin of the Yangtze have suffered the most, contracting by 29
percent.
In addition, about 17.5 percent of the small lakes at the source
of the Yangtze have dried up, the scientists said.
"The wetland plays a
key role in containing water and adjusting the water volume of the rivers," Wang
Xugen, a researcher with the institute, said.
"The shrinking of the
wetland on the plateau is closely connected with global warming," Wang said,
adding that - even though rainfall has increased in the region - the contraction
of the wetland has reduced the flow of the Yangtze and Yellow
rivers.
Figures from the World Wildlife Fund (WWF) weather station at the
head of the Yangtze showed annual rainfall at its source increased from 260 mm
during 1991-2000 to 323 mm in the period 2001-06.
"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," Li Shijie, a researcher with the
Nanjing institute of geography and limnology under the CAS, said.
Another
WWF study showed global warming has caused glaciers to shrink, frozen earth to
melt, grasslands to turn yellow and rivers to dry up.
The Qinghai-Tibet
Plateau used to boast 36,000 glaciers covering an area of 50,000 sq km. In the
past 100 years, the area has shrunk by 30 percent.
(China Daily
07/16/2007 page 3)
（英語點(diǎn)津 Linda 編輯）
About the broadcaster:
Matt Doran is an award-winning American newspaper journalist and an
undergraduate student at Albion College. He is currently a polisher for China
Daily Website and is on summer break from Beijing Foreign Studies University,
where he will resume his study of Chinese in the fall.
Matt Doran is an award-winning American newspaper journalist and an
undergraduate student at Albion College. He is currently a polisher for China
Daily Website and is on summer break from Beijing Foreign Studies University,
where he will resume his study of Chinese in the fall.
