For decades, scientists have warned that Shanghai, one of the world’s largest and most densely populated coastal megacities, has been slowly sinking because of how humans have used the land beneath it. The problem is not new. As per reports, historical records show that parts of Shanghai have dropped more than 2 metres over the past century because of excessive groundwater pumping and the city’s soft, compressible soil. That sinking makes the city more likely to flood, have sea levels rise, and have its infrastructure damaged.
But even with all of this sinking, Shanghai hasn't suddenly fallen apart or disappeared. Engineers and officials have found ways to slow down how quickly the ground sinks. They have started doing things like pumping less groundwater, moving water extraction to deeper aquifers, and recharging aquifers with treated surface water instead of letting the land get drier as they remove water. These actions have been like an invisible support under the city, pushing back against subsidence and slowing it down.
