The world’s biggest cities are sinking. Is yours one of them?

Scientific American · Sanidhya Sharma · 2026-10-30 18:47 UTC

Global cities are subsiding by up to several inches a year, an exhaustive new survey shows

Major cities across the world—including hotspots such as New Orleans, Mexico City, Jakarta and Rome—are sinking by up to several inches every year.

Those are the findings of an exhaustive new survey published in Nature Cities, in which researchers used satellite radar to track 465 urban areas of more than a million people from 2014 to 2023. The results, displayed in an interactive map, shows that sinking isn’t just “a local curiosity” for a small handful of cities, but “a global urban problem,” says study coauthor Guoquan Wang, a geophysicist at the University of Houston.

Satellites can measure the land’s gradual sinking, called subsidence, by taking radar images of the same area over time to determine the shift in the radar signal’s travel—even a change of mere millimeters (twenty-fifths of an inch) of ground can result in a signal taking slightly longer to return than the past. The new work, which examined small chunks of land—just a few houses wide—all over the world, is “the most comprehensive and systematic exploration of subsidence in urban cities,” says Roland Bürgmann, a geophysicist at the University of California, Berkeley, who was not involved in the study.

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