As a result of rapid urbanization in China, most major cities face serious problems with soil subsidence caused by forbidden water production and a large number of construction work. The study shows that almost half of these cities are moving at a pace exceeding 10 millimeters per year.
This process, especially active in coastal areas, threatens millions of residents due to possible flooding as a result of increasing sea level. The fight against soil subsidence has a long history in China, but the problem becomes especially relevant in the modern period because of the rapid rate of urban development.
Researchers, having analyzed 82 cities with a population of more than 2 million people, found that 45% of urban territories have moved more than 3 millimeters annually, which is a serious threat to 67 million inhabitants.
The causes of subsidence include the geological features and overweight of buildings, but the main factor, according to researchers, is the loss of groundwater. This process is not unique to China, as such problems are observed in other cities in the world, such as Houston, Mexico City and Delhi.
According to the authors of the study, one of the main threats to the future is possible floods arising from the combination of soil subsidence and increasing the level of sea caused by climate change.
