Rising sea levels could put about 87,000 square kilometers of coastal area across the country under water by 2050, according to an official report.

The annual report on the country's change in sea level, released by the State Oceanic Administration on July 4, said that from 1980 to 2011 sea levels along China's coast increased an average of 2.7 millimeters every year, higher than the world's average.

Rapid economic development since 1990s has accelerated the pace of the rise in China, it said.

By 2050, sea levels in China will increase by 76 mm to 131 mm above the level in 2011, and the sinking land due to a diminishing water table and a growing number of skyscrapers is also increasing the area threatened by rising sea levels, according to the report.

The southwestern part of the Bohai Sea, the southern part of the Yellow Sea and the eastern part of Hainan province are the top three areas where sea levels increased most in the past three decades - about 100 mm, the report said.

The report forecast sea levels in Shandong, Jiangsu, Shanghai, Guangdong and Hainan will rise most dramatically in the coming several decades, with millions of coastal people threatened.

In 2011, marine disasters claimed 76 lives and caused direct economic losses of more than 6.2 billion yuan ($968 million) across the country, according to the administration.