Rising seas have long been a threat to coastal cities. New research suggests that cities—particularly in Asia—are sinking as well, compounding the risks of frequent and severe flooding.
In Karachi, land is sinking five times as fast as the sea level is rising, according to the study published this month in Geophysical Research Letters. Manila and Chittagong, Bangladesh’s second-largest city, are sinking at 10 times the rate of the rising waters.
In China’s Tianjin, a coastal city about 150 kilometers southeast of Beijing, the ground is giving way at 20 times that speed.
In those four cities alone, the phenomenon could affect roughly 59 million residents.