For example, as temperatures increase and rainfall lessens, the southern Mississippi River is experiencing drought, a problem for countless citizens who rely on river water. Since June 2023, thousands of Louisianans in Plaquemines Parish, downstream of New Orleans, have been forced to rely on bottled water, and the Big Easy may be next. This threat has prompted talk of a 12-mile pipeline to save the city’s water supply.

Such costly placeholder projects are being faced by many cities on the East Coast and West Coast, the very areas that have seen population booms in recent decades. Already the resort town of Hilton Head, South Carolina, has lost 10 of its 14 freshwater wells. The same thing is happening on the coast of Rhode Island.

Most at risk are Florida and California. Experts give their cities five to 10 years before their potable water is contaminated, too. Miami may not have that long, as its salt line is moving inland by 330 feet a year.