“It’s a slow-motion emergency,” said Rob Moore, director of NRDC’s water and climate team. “But it’s happening right now. These last three hurricane seasons show us what it kind of looks like.”

A FEMA spokesman said the agency supports the  voluntary acquisition of flood-prone structures and provides the grant funding, but the prioritization of projects happen at the local level first and then by the state acting as the recipient. The agency believes each county floodplain manage and local official knows the needs of their communities best and are responsible for land usage and permitting.

About 6 million Floridians will need to move inland by century’s end to avoid inundation, according to Hauer, the demographer, in a 2016 paper. By then, about 80% of the nearby Keys, the archipelago that includes the tourist mecca of Key West, will be underwater. About 3.5 million people would be flooded in South Florida’s Miami-Dade and Broward, the two counties with America’s biggest exposed populations.

“Florida’s doing it at a really small scale,” said A.R. Siders, an assistant professor at the University of Delaware who studies climate adaptation. “Compared with the new housing units going up in South Florida, I don’t know if that would even cancel out.”

But Florida runs on tourism and real estate revenue, and managed retreat is a phrase that makes real estate listing agents nervous. But there’s another Florida housing bubble waiting to pop. The Union of Concerned Scientists warns of a coming housing crash — from Miami to San Mateo, California — on a scale worse than last decade’s foreclosure crisis, caused by climate change — from flooding to heat waves and wildfires.

Cities are only starting to grapple with where to resettle residents, and how to transport communities and hometown identities. And homes on higher ground will also demand higher prices, worsening an affordability crisis.

Fifteen years after Hurricane Katrina, Louisiana is trying to relocate the Native American settlement of about 100 people on the Isle de Jean Charles, a narrow island that lost 98% of its land over the past six decades to climate change. It’s working with a $48 million grant from HUD for buyouts and to help them start anew on a 500-acre sugar cane field 40 miles north that the government will populate with homes and businesses. Importantly, it will be 9 feet above sea level. All but three of about 40 households have signed on.

New Jersey has a $300 million fund for buyouts and has purchased hundreds of houses since Superstorm Sandy in 2012, though like Florida, even more homes have been built on the coast in the meantime. Harris County, Texas — which includes Houston, ravaged by a series of storms including 2017’s Harvey — has done more than 3,000 FEMA buyouts, more than any other county in the U.S., according to NRDC.

In Monroe County, Florida, where Rittel lives, the planning is just beginning. The county has applied for $5 million of the HUD money — the state maximum. Already, about 60 local homeowners have applied, so it will require triage. Senior citizens, families and residents in the riskiest flood zone would get priority, said Assistant County Administrator Christine Hurley.

Rittel isn’t sure how long she can hang on.