On Thursday, President Donald Trump delivered on his campaign promise to withdraw from the Paris Agreement on climate change, a global deal more than two decades in the making.

With the move, Trump signaled that coastal properties around the globe were not his concern; we can expect bigger storms, higher tides, and more flooding without efforts to actively curb these effects of climate change.

It’s an ironic move, considering Trump’s prized Mar-a-Lago, located on a barrier island north of Miami off Florida’s coast. Southern Florida is one of the most vulnerable places to sea level rise because of the low elevations, concentration of population, and value of property developments. One recent study estimated that Miami will lose $2.5 billion annually in flood damages by 2050.

“The failure of the federal government to recognize global warming as a threat and to address global warming as the cause of sea level rise makes it more difficult for communities to plan for the impacts of sea level rise,” Stephen Tilbrook, a Fort Lauderdale environmental lawyer, tells Inverse. “We are today seeing that there’s a difference from just 10 years ago. There’s more flooding than there was 10 years ago. The king tides that we experience are more severe than they were 10 years ago. I would expect in another 10 years it will continue to get worse.”

mar-a-lago sea level rise projection map climate central
Mar-a-Lago, located between Woodbridge Road and Southern Boulevard, would be half-swamped by five feet of sea level rise.

In the short run, Trump may be able to afford to pony up for seawalls and drainage systems to keep his properties above water. But those costs will only rise, and they will go up faster the longer the president ignores climate change as a viable threat to American industry and livelihoods. And while rich coastal property owners will certainly suffer, it’s worth noting that around the world it is the poorest and most vulnerable populations that will feel the effects of global warming and sea level rise most deeply. Residents of a Native American community in Louisiana have already been forced from their homes.

Trump is a fan of coastal property, and many of his golf courses will also become more expensive to insure and maintain as sea levels creep up. His company actually cited global warming in an application to install a seawall at Trump International Golf Links & Hotel Ireland last year.

Although Miami is basically doomed, there’s good evidence to suggested that aggressive climate change action now will make a very real and potentially huge difference to the future costs of sea level rise. A study from last year found that unchecked greenhouse gas emissions could set off the irreversible collapse of ice sheets in Antarctica, resulting in 30 feet or more of sea level rise over coming centuries. Aggressive climate change action, on the other hand, limited long term sea level rise to almost nothing.

Just five feet of sea level rise would swamp half of Mar-a-Lago, and some estimates predict that could come before the end of the century if fossil fuel burning continues unchecked. Trump’s grandkids may well be in a position where they have to spend a fortune every year to maintain an enormous rampart around a beachless island, or abandon coastal dreams for good.

Photos via Climate Central, Regine Mahaux / Getty