Why are major cities in China sinking 'rapidly'?
Source: Middle East Insurance Review | Jun 2024
By 2120, around a quarter of China’s coastal land could be below the sea-level, according to a research paper published in the scientific journal Science.
The new study published in April 2024 says the northern city of Tianjin, home to more than 15m people, has been identified as one of the worst-hit. Last year, 3,000 residents were evacuated after a sudden geological disaster in the city.
The study reveals that one in ten residents of China’s coastal cities could be living below sea level within a century, because of land subsidence and climate change. Also, around 16% of the mapped area of China’s major cities is sinking “rapidly” — faster than 10mm every year. An even greater area, roughly 45%, is sinking at a “moderate” rate, a downward trajectory greater than 3mm annually.
The situation could see one-quarter of China’s coastal lands slip below sea level within a few decades, posing “serious threats” to the hundreds of millions of people who live on the coast.
South China Normal University faculty and leader of the research team Ao Zurui said with China’s urban population already more than 900m people, “even a small portion of subsiding land in China could therefore translate into a substantial threat to urban life.”
Researchers attribute several reasons for the land subsidence, the chief one being the rapid rate of urban development. The huge amounts of groundwater needed to support urban population alongside the weight of the buildings, use of transport systems and infrastructure are contributing to the sinking.
Previous studies have also pointed out excess groundwater extraction as a main cause of land subsidence across the world. M