With more than 8 million people, New York City is the most populated city in the United States. It’s also sinking about 1 to 2 millimeters (0.03 to 0.08 inches) per year, on average. People living in subsiding cities like this may see higher sea-level rise — rates up to four times faster — than more stable regions.

“If now the water is going up and your land is going down, then your houses will be flooded,” said Matt Wei, a geophysicist at the University of Rhode Island. “That’s the issue.”