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Rising Sea Levels Cause Concern
The State Oceanic Administration alarmed for the first time the rising sea levels around China, urging the authorities to strengthen dykes and limit the extraction of ground water.
Excessive extraction of ground water in a number of seaside cities has considerably lowered local ground water levels and caused land to cave in, facilitating sea water invasion.
Dykes, mostly built using outdated engineering standards, have in the past three years become vulnerable as sea levels reach record levels, said the administration's 2000 bulletin on sea level, the first of its kind.
Affected by global weather, sea levels around China, as in other areas, have risen over the past 50 years. But those levels increased faster between 1998 and 2000, rising on average 2.5 millimeters a year.
The bulletin explains that severe floods in the Yangtze River basin in 1998 and 1999 forced sea levels in the Yellow Sea and the East China Sea to rise considerably.
The bulletin forecasts that sea levels are not expected to rise as quickly over the next three years, though the average level in 2003 is still estimated to be 31 millimeters higher than the standard world average between 1975 and 1986.
However, Chen Manchun, environment division director of the State Marine Information Center, said the authorities should not relax their efforts, because rising sea levels off certain areas, such as Shanghai and Hainan, might still be as high as 76 millimeters and 71 millimeters above the average world level between 1975 and 1986.
With sea levels set to continue their rise, China needs to try to stop the invasion of salt sea water by building higher dykes and extracting less ground water.
Since most Chinese seaside cities are less than four meters above sea level, with the lowest even less than one meter, Chen believes this problem will remain a threat long into the future.
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