Beijing’s in trouble. Examining satellite images and data collected by sensors, scientists from China, the UK, Germany and Spain have determined the city is sinking by up to four inches every year. Nor is this a new phenomenon – China’s capital has been sinking since 1935.
Beijing’s water struggles are likely responsible for the sinking. According to the scientists, the city is “one of the most water-stressed cities in the world” and mainly relies on underground aquifers for water. But because demand outstrips supply and too much water is being pumped out, the researchers believe the diminished groundwater levels are the main contributing factor in the subsidence issue; active faults and soil thickness are likely contributors as well.
The scientists concluded some areas in Beijing sank around 30 inches between 2003 and 2011, The trend appears to be the worst in Beijing’s Chaoyang district, where the Central Business District is located. There, the city might be sinking even faster than four inches every year.
Subsidence could damage buildings, trains, and infrastructure as different areas sink at different rates, and the government has made moves to address the problem. A recently completed project called the South-North Water Diversion will send water to Beijing and 367 Chaoyang water wells will be retired. The country’s State Council will try to prevent further subsidence through a plan to monitor areas where it’s occurring and to limit use of groundwater. It remains to be seen if such measures will help. The researchers do think subsidence could be halted, and in some areas even recovered if the city can restore its groundwater supplies and stops pumping.
Beijing is not the only city sinking. According to the researchers, “China has 45 cities and municipalities where disastrous land subsidence have occurred or is occurring.” This isn’t a new issue – studies back in 2012 drew attention to the dilemma – and Beijing is not alone. Bangkok, Jakarta, Mexico City, and areas in the San Joaquin Valley are among other places sinking.
Via the Los Angeles Times