Nearly half of China's major cities are 'sink'
Apr 19, 2024
Beijing [China], April 19: Nearly half of China's major cities, with a population of 270 million, are gradually sinking and coastal areas face the risk of flooding and rising sea levels.
The warning was given in a study published in the journal Science on April 19. According to research conducted based on nationwide satellite data, nearly half of China 's major cities are experiencing moderate to severe subsidence, posing a risk of flooding as sea levels rise. .
According to Reuters, the study authors found that 45% of land in urban areas in China (home to 270 million people) is sinking faster than 3 millimeters per year, of which 16% of the area (where home to 67 million people) has a decline rate of more than 10 mm/year.
The cause of this situation is not only due to the reduced amount of groundwater but also due to the weight of the constructed structures. Researcher Ao Zurui at South China Normal University, leader of the research team, said that with China's urban population exceeding 900 million people, a small portion of the land area sinking also poses a great threat to life. live in urban areas.
The city of Tianjin with more than 15 million people near Beijing was identified as one of the worst affected places. Last year, 3,000 residents here were evacuated after an unusual geological disaster that investigators attributed to water depletion as well as the construction of geothermal wells.
Subsidence is already costing China more than 7.5 billion yuan ($1.04 billion) a year, and within the next 100 years, nearly a quarter of coastal land could sink below sea level . seawater, putting hundreds of millions of people at greater risk of flooding.
Many old coal mining areas are also affected by over-exploitation, forcing authorities to often pump concrete into sinkholes to reinforce them.
According to Reuters, urban subsidence is not a problem unique to China. A study published in February found that about 6.3 million square kilometers of land globally is at risk. Among the worst affected countries is Indonesia, with much of the capital Jakarta already below sea level. Of the 44 major coastal cities suffering from this subsidence, 30 are in Asia, according to a 2022 study in Singapore.
Source: Thanh Nien Newspaper
