Sea levels around China's coasts are expected to continue rising in the next three to 10 years, creating grave challenges for coastal dwellers.

"They have to watch out for worsened torrential tides and the invasion of sea water," said Chen Manchun, a leading expert with the National Marine Data and Information Service in north China's Tianjin, Sunday.

Compared with the well-accepted benchmark level, which is the national average from the year 2000, the sea level around China will likely rise by 10 millimetres by the year 2006 and 28 millimetres by 2013, says the 2003 Bulletin on Sea Levels issued by the State Oceanic Administration on Saturday.

The rise has slowly but steadily continued in the past half century in China. Waters rose an average of 2.5 millimetres per year, slightly more than the world's average for the same period, said Chen.

According to the bulletin, by last year, the sea level around China's coasts had risen 60 millimetres more than the world average between 1975 and 1986. The worldwide average is the international benchmark to calculate changes in ocean levels.

According to the bulletin, the main culprit behind the rising tides is global warming. "The rising sea levels have become a common headache of many countries," said Chen.

As far as China is concerned, most regions reported higher than average temperatures last year, said Yao Xuexiang, vice-director of the Central Meteorological Observer in Beijing.

Although there may not be much that can be done to offset the rising sea levels in the short run, Chen said local governments can fend against a worsened invasion of sea water by stopping excessive extraction of underground water.

The invasion of sea water results in soil salinization and malfunction of urban sewage discharge systems.

(China Daily February 2, 2004)