Trump’s 123-room Mar-a-Lago mansion and private club sit on a barrier island with the Atlantic Ocean to the east and Florida’s Intracoastal Waterway to the west. If the sea level climbs by 2 or 3 feet in this century — an amount that falls squarely within scientists’ predictions — that would push seawater onto the mansion’s western lawns. Nearby roads and bridges used to access the property would also be affected.

At some point this century, water is expected to completely cover many of the state’s barrier islands, especially during storms.

Trump’s beloved National Doral Miami golf course is inland, but it’s still at risk. As seas rise and Florida’s water table rises, state geologists predict that Florida’s porous limestone geology will allow water to easily percolate upward, flooding inland and coastal areas alike. If the course isn’t severely damaged by flooding, there will be more days when it’s too swamped for golfers.

The commander in chief’s sea-level headache doesn’t end in Florida. The Trump International Hotel & Tower in Waikiki Beach, Hawaii, is vulnerable too, as is his golf course in Ireland. The president also has business interests in properties near the ocean in Vancouver, Canada; Panama City, Panama; Uruguay and Mumbai, India, according to the Trump Organization website.

But the problem is especially fraught in Florida. Using the worst-case prediction of a 6-foot sea rise, real estate data provider Zillow estimates that 934,000 of the state’s homes, or nearly 12.6 percent, will be underwater by 2100. In Palm Beach, which includes Mar-a-Lago, about 51 percent of homes worth a total of $10.9 billion would be underwater, according to the data.

“We’re already in for a sea-level rise that will put all low-lying coastal areas out of business, and that’s using U.S. government projections,” said Harold Wanless, chairman of the University of Miami’s Department of Geological Science, who has been studying sea-level rise for decades. “At some point in the not-too-distant future, we’ll be leaving Miami … we’re all moving somewhere.”

So far, the threat of rising seas has not affected property values on Florida’s coast. Flood insurance rates are already high because of hurricane risks, but that hasn’t stopped the wealthy from investing in beachfront property.

Big changes will begin when the first bank denies a 30-year mortgage for a coastal property due to surging seas, leading to a “cascade” of other denials, Cason said.

Despite the scientific consensus that the climate is warming and sea levels rising, Trump has publicly called global warming a “hoax” perpetrated by the Chinese to gain an economic edge on the U.S.

Still, Trump has used the threat of climate change when it suited his business interests. He cited sea-level rise in a permit application to build a nearly 2-mile stone wall between the Trump International Golf Links and Hotel in Ireland and the Atlantic Ocean.

Local officials say they don’t have the luxury of ignoring the problem.

“Inaction is not an option for us in South Florida,” said Susanne Torriente, chief resilience officer for the City of Miami Beach. “The streets are flooding and days are getting warmer. It’s not a partisan issue for us. At a local level, we’re being much more practical.”