High sea level triggers erosion

The sea level off the coast of Guangdong province reached the third-highest level on record last year, raising concerns about increased impact from typhoons, coastal erosion and salt tides.

The level was 105 millimeters higher than the average between 1975 and 1993, though it dipped by 10 mm year-on-year, according to a report on oceanic disasters last year released by Guangdong's Administration of Ocean and Fisheries.

The level rose by an average of 3.4 mm per year between 1980 and last year, higher than the 3 mm figure for the rest of the nation's coasts and above the national average.

The thermal expansion of the oceans and the melting of glaciers and polar ice sheets because of global warming have caused sea levels to rise around the world. Rising levels which caused seawater to flow into rivers - known as salt tides - aggravated coastal erosion, increased salt levels in the soil and storm tides, according to a report published by the State Oceanic Administration.

The increased sea level was one of the factors behind the increased impact of typhoons, coastal erosion and salt tides in Guangdong last year.

The province recorded the highest direct economic loss from oceanic disasters in the country last year, 6.04 billion yuan ($973.58 million), and three people were killed, said He Shaoqing, deputy director of the Guangdong administration. Typhoon Kalmaegi alone caused losses of 2.99 billion yuan.

More than 14,000 square meters, or 25 percent, of the shore area off the Jinsha Bay beach resort in Shenzhen was eroded between 2002 and 2013.

A basketball court built by the shore close to the Tuyang toll station on the Huizhou-Shenzhen highway disappeared as the sea eroded 280 meters of the coast between 2010 and last year. Fifteen salt tides hit Guangdong last year.

A major part of the Pearl River Delta in Guangdong lies less than 1 meter above sea level, and 13 percent is below sea level, according to Li Juan, a researcher at the SOA's South China Sea Marine Prediction Center.

The sea level off Guangdong is projected to rise by between 75 mm and 155 mm in the coming three decades, the SOA report says.

A report by the United Nations Intergovernmental Panel on Climate Change said: "By the end of this century, it is very likely that sea level will rise in more than about 95 percent of the ocean area. Sea level rise depends on the pathway of carbon dioxide emissions."

The SOA report says high concentrations of population and industries should be avoided in areas at risk from rising sea levels, flood protection should be upgraded and the use of underground water should be restricted.

It also calls for the conservation of wetlands, mangroves, delta areas and beaches and the building of dikes and floodgates to mitigate the impact of higher seas.

Zhai Jiajia contributed to this story.

Contact the writer at liwenfang@chinadaily.com.cn