At TIME’s Ecocentric blog, Kate Springer discusses the problem of subsidence which, according to a recent government report, affects more than fifty cities and around 50,000 square miles of land across China. The issue is strongly tied to the country’s chronic water shortages, with over-extraction of groundwater accounting for almost 70% of subsidence. But in Shanghai, the sheer weight of buildings makes matters even worse.
Though some critics argue the Chinese government has been too slow to act, research, public concern and some hefty bills ($35 billion in Shanghai alone in the last 40 years), has sparked some momentum. Recently, the state council approved China’s Land Subsidence Prevention Project, a countrywide initiative to prevent land subsidence. Likewise, Beijing, which has descended more than a foot in the past decade, has also made an effort to reduce underground water extraction, with plans to close 800 water extraction wells in 2012, according to the Beijing Water Authority. By 2014, the city hopes to halt underground water extraction in urban areas altogether as part of the North-South Water Diversion Project. The project expects to bring 3 billion cubic feet of water supply to Beijing from the Yangtze River. This would not only satisfy one-third of the city’s total water demand, but would also cut the extraction of underground water in half.
But Li, who worked at the Chinese Academy of Science for 15 years, says such programs will not be enough. “It’s hard to quantify how much this might help, but the question is, is that a problem solved? The answer is no. The problem lies in the early issue with urbanization,” he says. Scientists expect the regulations to help curb the consumption of underground water supplies, but there a few things the government has less control over, such as global warming. As the land degradation and excessive guzzling of ground water continues, environmentalists predict waters surrounding Shanghai to rise 9 to 27 inches by 2050 as a result of melting ice caps.
