A third of China’s population is at risk from land subsidence, satellite data shows (representative)
New Delhi:
About a third of China’s urban population is estimated to be at risk from land subsidence, according to a new finding that researchers say is indicative of a global phenomenon.
China’s urban area below sea level could triple by 2120, potentially affecting 55 to 128 million residents.
Using satellite data, the research team studied 82 cities, including Shanghai and Beijing, with a combined population of almost 700 million people.
The team, made up of researchers from the University of East Anglia, Great Britain, found that 45 percent of the urban land area analyzed was sinking, with 16 percent sinking at a rate of 10 millimeters per year.
Hotspots included Beijing and the coastal city of Tianjin, they said.
The study estimated that 270 million city residents could be affected, with nearly 70 million people experiencing rapid subsidence of 10 millimeters per year or more. The findings have been published in the journal ‘Science’.
Land subsidence, mainly caused by human activities in cities, may also amplify climate change and sea level rise, mainly affecting coastal cities including Tianjin, the findings showed.
Subsidence is believed to be primarily caused by groundwater extraction, which lowers the water table along with the geology and weight of buildings.
Combining land subsidence with sea level rise in their analysis, the researchers found that the urban area below sea level in China could triple by 2120, potentially affecting 55 to 128 million residents. This could be catastrophic without a strong societal response, they said.
Shanghai, China’s largest city, was found to have sunk up to 3 meters over the past century.
The researchers said that while consistently measuring land sinking is important, models that predict land subsidence must consider all factors, including human activities and climate change.
Failure to factor land subsidence into adaptation and resilience plans now could potentially risk the destruction of lives and infrastructure in coming decades, they pointed out.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
