According to a study of national satellite data released on Friday ( Apr 19 ), nearly half of China’s major cities are experiencing “moderate to severe” levels of subsidence, which puts millions of people at risk of flooding especially as sea levels rise.
The study’s authors found that 44 % of China’s urban land was sinking more than 3mm annually, with 16 % falling even at more than 10mm, a result of declining water tables and the built environment’s sheer weight.
Even a small portion of China’s decreasing area could result in a significant risk to metropolitan life, according to the team of researchers led by Ao Zurui of the South China Normal University, given that the city’s population is already over 900 million individuals.
China already spends more than 7 on sinking. 5 billion yuan ( US$ 1. 04 billion ) in annual costs, and within the next decade, nearly a quarter of southern land could actually be lower than water amounts, putting hundreds of millions of people at an even greater danger of flood.
Robert Nicholls, a researcher at the University of East Anglia’s Tyndall Centre for Climate Change, said,” It actually makes it clear that this is a national issue and not just one or two sites.” And it serves as a portrait of what is going on in the rest of the world. “
The northeastern city of Tianjin, home to more than 15 million individuals, was identified as one of the worst-hit. 3,000 people were evacuated last year following a” sudden geographical disaster” that researchers attributed to the construction of geothermal reservoirs as well as water loss.