Global warming will lead to the significant deterioration of
glaciers, frozen soil and snow in China which will have a serious
negative impact on the local ecological environment.
During the International Symposium on Climate Change, which ended
in Beijing on Wednesday, Prof. Ding Yihui, special advisor on
climatic change with the China Meteorological
Administration, said the alpine ecology was very sensitive to
climatic changes, as illustrated by the shrinkage of glaciers due
to rising temperatures.
According to scientific calculations, the total glacial area in
China's northwestern mountains has been reduced by approximately
7,000 square kilometers, or 24.7 percent, since the Minor Ice
Age.
In
1964, the glacial coverage along the Urumqi River valley in
westernmost
Xinjiang Uygur Autonomous Region stood at 48.2 square
kilometers. By 1992, however, the figure had fallen to 40.9 sq
km.
Taking into account what factors guided into glacier reduction
since the Minor Ice Age and the predictions of temperature and
precipitation changes for the coming summers, scientists have
estimated that the melting of west China's glaciers will proceed at
an even faster pace in the next 50 years.
Scientists predict that, by the year 2050, glacier coverage in the
country's western region will have been reduced by 16,184 cubic km,
or an additional 27.2 percent.
They also predict that glaciers in the Qaidam Basin of China's
northwestern Qinghai
Province and the Qinghai-Tibet Plateau will undergo intensive
melting during a 20-year period from 2030 to 2050. The melt water
from glaciers around the Tarim Basin is predicted to increase the
runoff volume from local rivers by about 25 percent before
2050.
Prof. Ding Yihui acknowledged that, although the massive thawing of
glaciers may increase river runoff, it is also likely to cause
floods.
Experts also warned that global warming will alter the spatial
distribution of frozen soil on the Qinghai-Tibet Plateau over the
next 50 years.
The rise in temperature will generate a more profound seasonal
thawing of frozen earth, giving rise to "thawing interlayers". In
addition, frozen topsoil will be reduced by 10 to 15 percent, and
the bottom limit of permafrost soil will be raised by 150 to 250
meters.
"Marshes will form on the thawed frozen ground. Meanwhile, large
amounts of carbon dioxide, methane and other greenhouse gases,
formerly sealed in the frozen soil, will also be released into the
air, which, in turn, will aggravate global warming," Ding Yihui
said.
Moreover, experts note that the designers of the Qinghai-Tibet
Railway, on the advice of meteorologists, have given full
consideration to the problem of the thawing of frozen earth because
of climatic warming on the plateau. The future security of the
railway will thus not be affected.
Designed to be built partially on the plateau's frozen ground, the
Qinghai-Tibet Railway, currently under construction, is expected to
play a significant role in China's western development
strategy.
Experts have also predicted that seasonal snows in China will be of
shorter duration due to warmer winters. By the year 2100, snow will
largely disappear even before March, which will reduce the water
level of rivers and intensify spring dry spells.
(Xinhua News Agency April 3, 2003)