Large swathes of deltas along China's shore are threatened by erosion as sea levels rise, oceanic authorities said.

"A total of 2,500 square kilometers of land at Laizhou Bay gave way to seawater last year, when the waterfront moved 45 kilometers inland at the furthest," said Wang Shicheng, an oceanic official in the eastern Shandong Province, on Friday.

A growing area of the low-lying shoreline of Laizhou Bay off the Bohai Sea has been seriously salinized, rendering it unsuitable for farm produce or fish breeding, said the Shandong Oceanic Administration deputy head.

According to the 2007 Sea Level Bulletin released by the State Oceanic Administration (SOA) earlier this month, the rise in sea levels along China's shores have gained speed in recent years, as climate change intensifies. Meanwhile, coastal areas in the country's north and south had more frequent abnormal temperature rises and oceanic disasters.

Wang said the water temperature of China's Bohai Sea and Yellow Sea rose by 1.1 degrees and 1.8 degrees Celsius, respectively, year-on-year in March, while the sea level for each surged by 0.102 meter and 0.148 meter.

"High tides generated by the strongest windstorm in 38 years rolled over 2 meters high on the coast. The tide flush-in induced direct economic losses of 2.1 billion yuan," said Wang, a prominent Chinese oceanographer. The damage was equivalent to about US$293.9 million.

China's total sea level rise in the past 30 years was 0.09 meter on average. Among all coastal areas, the northern city of Tianjin, which lies along the Bohai, saw the fastest speed of sea level rise, with a total increase of 0.196 meter. Shanghai, in the east, had a rise of 0.115 meter, according to the Bulletin.

The SOA has warned Tianjin its coastal embankment is not solid enough to withstand strong tides, a result of the continuous rise of the sea level.

Wang said the melting of polar glaciers due to global warming had been recognized as the direct cause of the rise in global sea levels.

"The sea level off Shandong will continue to rise by 0.029 meters in the next decade."

The administration expects that nationally, the sea level along China's coast would rise 0.032 meter on average in the next decade.

On the southern coast, many freshwater reservoirs have been contaminated by seawater, and large areas of fertile mangrove had disappeared due to shoreline erosion and offshore pollution.

According to a report on China's oceanic development released on Friday by the SOA, the country's coastal area suffering pollution has nearly doubled in the past decade to reach an excess of 160,000 square km.

The coastal areas have been plagued by a degradation of seawater quality, eutrophication and red tide, the report said. The deterioration of the coastal area eco-system has led to "frequent" poisonous incidents caused by aquatic products.

Despite efforts to restore the oceanic eco-system in recent years, the coastal areas are still suffering from serious desertification.

China has lost 73 percent of its mangrove forests, 80 percent of its coral reefs and 57 percent of its wetlands. All three have a major influence on the oceanic eco-system balance, SOA figures showed.

The report blamed excessive fishing, aggravated pollution in estuaries, and high incidence of oceanic disasters, such as red tide, for the sharp increase in the polluted coastal area.

The amount of fishing dropped for nine consecutive years since 1999, the report said, noting many coastal areas now had absolutely no fishing resources.

(Xinhua News Agency February 23, 2008)