A recent study reveals that approximately one-third of China’s urban population faces the threat of land subsidence, shedding light on a global trend with far-reaching implications. By 2120, the urban area below sea level in China could triple, potentially impacting between 55 to 128 million residents.
Researchers, including those from the University of East Anglia, UK, utilised satellite data to analyse 82 cities, including major metropolises like Shanghai and Beijing, which collectively house nearly 700 million people.
Their findings, published in the journal ‘Science’, unveil alarming statistics: 45 per cent of the urban land area studied is sinking, with 16 per cent experiencing a rapid subsidence rate of 10 millimetres per year.
Coastal cities at risk
Cities like Beijing and Tianjin emerged as notable hotspots of subsidence, exacerbating concerns for coastal areas. The research estimates that 270 million urban residents could be affected, with nearly 70 million facing rapid subsidence of 10 millimetres or more annually.
This phenomenon, predominantly driven by human activities in urban environments, not only amplifies climate change and sea-level rise but also disproportionately impacts coastal cities.
Combining subsidence with projected sea-level rise, the study forewarns of a potential tripling of China’s urban area below sea level by 2120, highlighting an urgent need for robust societal responses.
Shanghai, China’s largest city, has already subsided by up to 3 meters in the past century, underscoring the gravity of the situation. The researchers emphasise the importance of comprehensive models that consider all contributing factors, including human activities and climate change, in predicting subsidence.
Failure to account for land sinking in adaptation and resilience strategies could jeopardize lives and infrastructure in the coming decades. Hence, proactive measures are imperative to mitigate the catastrophic impacts of land subsidence on urban communities across China and beyond.