Rising seas pose danger to big cities

Sea levels rising at an 'alarming' rate because of climate change and depleting groundwater threaten coastal economies.

Two key cities, Shanghai and Tianjin, are among those facing the biggest threat, State Oceanic Administration (SOA) spokesperson Li Haiqing said, citing the agency's 2007 sea-level monitoring report. In the last 30 years, the financial hub of Shanghai has seen the sea level rise 115 mm, or the length of half a chopstick, the report says. Tianjin, a major port about two hours' drive from Beijing, has seen the level rise as much as 196 mm, about the length of a new pencil. In the past 30 years, the country's overall sea level has risen 90 mm with the average offshore surface temperature going up by 0.9C. In comparison, when the global sea level rose 1.7 mm every year between 1975 and 2007, the Chinese sea level rose 2.5 mm every year. In the next decade, the SOA forecasts, China's coastal sea level is likely to rise by 32 mm, or 3.2 mm every year. Global warming is the main reason for the rising sea levels, but surface subsidence is also to blame for the threat of floods in Shanghai and Tianjin, due to their 'indiscriminate exploitation of groundwater resources.

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