Almost half of China's urban areas are sinking, and this increases the risk of flooding for millions of people. In Shanghai alone, some areas have sunk by up to three meters in the last century.
Scientists warn of the long-term effects of ground subsidence, especially in densely populated coastal regions. They predict that the combination of land subsidence and rising sea levels could cause around a quarter of the area below sea level to sink in the next hundred years. This would pose a significant flood risk to large populations. There is also direct damage to buildings, foundations, infrastructure, and sewage systems. The east coast of the USA is also at risk of increasing flooding, especially New York. In recent decades, subsidence-related disasters in China have caused hundreds of deaths.