“When I started this job, people kept asking me, ‘Why do we have so much flooding now?’ and I said, ‘Well, there’s just one problem: The whole city’s four feet too low—that’s all!’” But as Miami Beach city engineer Bruce Mowry, the person responsible for maintaining and improving the island’s public infrastructure, steered his car through the Flamingo Park neighborhood this past January, his typically cheery mood dimmed. “You know, I drive around a lot, looking at all these streets and trees and homes and thinking about what’s coming,” Mowry said. “If we get the four feet of rise that’s predicted, all of this area will be two-and-a-half feet underwater.”

“This whole beautiful landscape’s going to change,” he said.

Miami Beach consists of a long, low barrier island accompanied by a scattering of manmade islets. It’s one of the lowest-lying municipalities in the country, and its residents are leading the way into the world’s wetter future. Along the island’s low western side bordering Biscayne Bay, people have come to dread full-moon high tides, when salt water seeps into storm-drain outlets and the porous limestone that provides the island’s foundation, forcing water up and out into the streets and sidewalks and threatening buildings and infrastructure.

And Miami Beach is just one small part of a region that’s in big trouble. If sea levels rise as projected, no major U.S. metropolitan area stands to rack up bigger losses than Miami-Dade County. Almost 60 percent of the county is less than six feet above sea level. Even before swelling of the seas is factored in, Miami has the greatest total value of assets exposed to flooding of any city in the world: more than $400 billion. Once you account for future sea-level rise and continued economic growth, Miami’s exposed property will far outstrip that of any other urban area, reaching almost $3.5 trillion by the 2070s.

The sea level around the South Florida coast has already risen nine inches over the past century. Among experts, the optimists expect it to edge up another three to seven inches in the next 15 years and nine inches to two feet in the next 45 years. More pessimistic (some say increasingly realistic) predictions say the rise will be much faster. Even the very gradual rise of recent decades will make extensive infrastructure reengineering necessary—Mowry’s job. However, according to a report published by the Florida Department of Transportation, it will become difficult, expensive, and maybe impossible for these efforts to keep up with the accelerated sea-level rise that is actually expected.