Produced by: Tarun Mishra
A new study published in the journal Science has revealed that nearly half of China's major cities are experiencing sinking due to water extraction and the weight of urban infrastructure.
The research indicates that cities such as Beijing and Tianjin are facing a "moderate to severe" risk of subsidence, with 45% of China's urban land sinking at a rate faster than 3 millimetres per year.
In some cities, subsidence is occurring rapidly, with one in six cities experiencing sinking at a rate exceeding 10 millimetres per year. Notably, Beijing is sinking at a rate of 45 millimetres annually near its subways and highways.
The study attributes subsidence to various factors, including groundwater withdrawal and the increasing weight of buildings and infrastructure due to urban development.
Natural factors such as geological settings and bedrock depth influence the ground's capacity to support weight without sinking. Additionally, groundwater loss and urban development activities contribute to subsidence.
Subsidence jeopardizes the structural integrity of buildings and infrastructure, exacerbating flooding risks, especially in coastal cities where it amplifies the effects of sea-level rise.
Researchers emphasize the importance of long-term and sustained control of groundwater extraction to address city subsidence effectively.
The findings underscore the need for a national response in China and highlight the potential risks faced by other susceptible cities worldwide.
Experts caution that millions of people are at risk due to subsidence, emphasizing the urgency of addressing this issue to mitigate its adverse impacts on communities and infrastructure.