The sea level around Shanghai has risen 120 millimeters since 1977 - a level higher than the national average.

Action needs to be taken, an official of the State Oceanic Administration said yesterday.

Many scientists believe rising sea levels are caused by global warming but the city's continuous land subsidence exacerbates the problem.

"It's time we took action over rising sea levels," Chen Manchun, an SOA official who takes charge of recording sea levels, told Shanghai Daily yesterday.

He said the sea level around the country's coast had risen by 90 millimeters over the past 30 years and that Shanghai was 30 millimeters above the average.

He said sea levels were rising faster than at any time in history but due to the lack of statistics it is not known exactly how much sea levels rose prior to 1977.

At the same time, the city is sinking by about seven millimeters every year, partly due to the overuse of underground water and the rapid urban construction.

Chen said the rising sea level could cause sea water to flood into inland waters and, in the long run, lead to climate change which would affect farming and fishing.

He suggested the city government limit the construction of highrises to reduce the factors contributing to land subsidence. He also said the city government needed to raise its flood control walls on a regular basis.

Shanghai has more than 4,000 buildings over 18 stories and many more are under construction.

(Shanghai Daily December 4, 2007)