This is the conclusion of a study led by an international group of researchers and published in the journal Science. Land subsidence was assessed using satellite data collected across 82 major Chinese cities between 2015 and 2022.

“Of the examined urban lands, 45% are subsiding faster than 3 millimetres per year, and 16% are subsiding faster than 10 millimetres per year, affecting 29 and 7% of the urban population, respectively,” the researchers’ paper explains.

The study authors note two main causes of this alarming subsidence: the pumping of groundwater and the weight of buildings.

Combined with rising sea levels, this subsidence is likely to lead to major flooding, putting millions of people at risk.

In particular, the study estimates that by 2120, 22% to 26% of China’s coastal land will have a relative elevation below sea level.

“Our results underscore the necessity of enhancing protective measures to mitigate potential damages from subsidence,” the researchers warn.

China is not the only region of the world threatened by rising waters and the weight of its skyscrapers.

A study published in May 2023 reported that New York City is also particularly prone to land subsidence, estimated at an average of one to two millimetres per year.

The issue is all the more crucial because the Big Apple, which is home to more than eight million people, is also in danger of disappearing due to rising water levels as well as an increase in hurricanes and storms.