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Sea Level Rising Near Shanghai
A side effect of its breakneck pace of development, Shanghai is slowly sinking into the sea.
The relative sea level will rise 50-70 centimetres by 2050, said Huang Runde, a senior engineer of the Shanghai Bureau of Water Conservancy.
"The sea level is increasing because of global warming that melts the ice in polar areas,'' he said.
Water levels in the north Pacific Ocean rise even faster than average at 1.19 millimetres a year, according statistics from the Permanent Service for Mean Sea Level.
Another factor contributing to rising sea levels is the sinking of the city caused by excessive use of groundwater, he said.
Because Shanghai sits on the alluvial plain at the mouth of the Yangtze River, it is more sensitive to the movement of sea and land, said Huang.
"The city has been sinking at the speed of nearly 10 millimetres a year,'' said Zhang Xiangyu, director of the Shanghai Water Supply Administration Office.
Zhang said the exploitation of groundwater to support the huge population, underground construction of subways and basements below skyscrapers and overpasses has all led to ground sinkage.
In early 1980s, China began researching sea level changes and their environmental and economic impact.
A 1993 study conducted by the Chinese Academy of Science found the caving in bedrock below the city is also causing the sinkage, according to the Sheshan Astronomical Observatory.
Since it is hard to stop the rising sea level or sinking bedrock, the key to solving the problem is to stop the ground from sinking, Zhang said.
He said the city drafted laws on the annual drawing of groundwater.
Any water-consuming enterprise is officially required to pump double amount of water used back into the earth. And annually 16 million cubic metres of water are returned to the earth in this way.
The city is also considering building a 315 kilometre-long flood prevention wall to address these problems. Plans for a dam on the Huangpu River are also being evaluated.
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