Photo by Jakob Montrasio.
Kate Springer of TIME’s Ecocentric blog, has some eye-popping numbers in her latest post on land subsidence, which she says is affecting more than 50 cities in China. Across the country, 49,000 sq. mi. of land have dropped at least 8 in, and Shanghai is, unsurprisingly, leading China’s rapid descent into the ground, and has sunk more than 6 ft. since 1921.
A quick history of Shanghai’s land subsidence woes from Springer:
The problems began in the 19th century, when Shanghai transformed into a trading port and began attracting both immigrants and Chinese transplants. By 1900, the population had tripled to more than 1 million. People started consuming more groundwater than the overlying turf could handle, and the problem worsened dramatically. By the 1950s and ’60s, the area started sinking 4 in. per year. Since then, the city has descended more than 16 in., despite government bans on wells and efforts to pump water back into underground reservoirs. Every day, Shanghai is redirecting 60,000 tons of water through 121 wells, China Daily reported.
Shanghai may have had this problem before the 1950s, but it didn’t start emerging in other cities until the early ’80s. Now more than 50 cities across the country face sinking problems, according to a report by the China Geology Survey. Three regions in particular have “serious land-subsidence problems,” including the Yangtze River delta area, the Fenhe River-Weihe River basin and the North China Plain. According to CCTV, Cangzhou, a city in north China’s Hebei province, has descended nearly 7 ft. In 2009, the city had to demolish a three-story building housing a branch of the city’s People’s Hospital because the first level sank so low that it fell underground.
Predictions by environmentalists have the waters surrounding Shanghai rising 9 to 27 in. by 2050 — yiiiiikes — due to the melting glaciers in the North and South poles, and that’s not good news for us:
“If you look at Shanghai during high tide, you can see the water level is higher than the streets but separated by the wall,” [Jiang Li, a professor of civil engineering at Baltimore’s Morgan State University] says. “This is a situation where if you have a major disaster like a hurricane, tsunami or tropical storm, it can cause serious damage.” He is especially worried about severe flooding in the coastal areas, where the majority of Chinese migrants have settled. The only way to really solve the problem is to reduce — or better yet, stop — groundwater pumping. Another option is to decrease the density of buildings, which would mean fewer heavy skyscrapers, perhaps an unrealistic solution for China’s rapidly growing cities.