It’s a scorching midsummer day, and the sawgrass is still under a pale blue sky. Waist-deep in water and sinking slowly into the muck, I fend off mosquitos as a man from South Florida’s Water Management District mixes a bag of salt into a hot tub-sized bucket on the side of the road. Thirty feet away in the marsh, another city official wearing waders and a bug hat stands on a narrow steel walkway, dangling the end of a long hose over a plexiglass chamber.
The experiment seems innocuous enough. Seawater is being added to a freshwater wetland, and scientists are observing what happens. The grim subtext is that this same experiment is about to play out in real life and on an enormous scale, from here in the southern Everglades, to Miami forty miles east, to the Florida Keys due south. If scientists are correct, much of South Florida will be underwater by the end of the century.