President Donald Trump has called climate change a “hoax” and a very expensive “tax” on American businesses that make the United States less competitive. In June, he announced that it was in the best interest of the country to withdraw from the Paris climate accord drawing on several bogus arguments.

His administration has also axed several regulations issued by President Obama to limit greenhouse gas emissions and reduce the impacts of climate change. The latest to fall: a 2015 directive to federal agencies requiring them to account for sea-level rise and storms when making grants and building infrastructure.

The so-called federal flood risk management standard was still in the works, but the aim was to create design standards to guard against increased flood risks for new construction in flood-prone areas. Trump did away with it in his executive order on infrastructure on Tuesday.

Environmental groups say the standard would have helped mitigate the risk of costly and harmful damages from floods. Now, “taxpayer dollars will likely be wasted through investments in projects that could be washed away in the next storm,” said Rachel Cleetus, lead economist and climate policy manager at the Union of Concerned Scientists, in a statement. According to FEMA, floods led to $260 billion in damages between 1980 and 2013.

Of course, Trump himself is one such property owner who stands to lose a lot in future flood events. Mar-a-Lago is the crown jewel of his extensive real estate portfolio and his preferred location for carrying out many of his official presidential duties. But rising sea levels are causing more frequent and more damaging tidal floods on the Florida coast. And projections suggest that the risk to human lives and property from climate change-related flooding events in this region is only going to increase dramatically in the coming years.

The National and Oceanic Atmospheric Administration (NOAA) has put out a variety of different estimates of rising sea levels in Southern Florida. The more conservative finding suggests that they could jump anywhere from 3 feet by 2050 to 7 feet by 2100.

But in January, the agency put out new “extreme” sea level projections — its doomsday scenario, in other words. In this scenario, we’d see a 10- to 12-foot rise in sea level in the US by 2100, which would have dramatic consequences for places like Mar-a-Lago (see the photo above).

Of all US states, Florida faces the greatest risk from rising sea levels

So what would a 10-foot rise in sea levels mean for Florida? Here’s a satellite image of what that would look like. Large swaths of the state are submerged. Miami is entirely flooded, along with the rest of Southern Florida:

There is evidence that average sea levels are already steadily rising in Southern Florida. A 2016 paper found that in the past decade, the average rate of sea-level rise had tripled from 3 millimeters a year to 9 millimeters. And overall sea levels in Southern Florida had risen about 90 millimeters, or 3.5 inches, since 2006.

Of the 30 most populous US cities that would be negatively affected by extreme sea-level rise, Climate Central, a nonprofit climate science research group, found that 19 were located in Florida (circled in yellow in the chart below).

Sea-level rise is hard to predict, but it’s clear Mar-a-Lago is at risk of extreme flooding

Scientists don’t have a great understanding of how exactly rapidly sea levels will continue to rise or the precise impact on specific areas.

But new research that indicates parts of the Antarctic ice sheet may collapse in the next 100 years — and that has scientists scrambling to model more extreme scenarios. If the Antarctic ice sheet does melt, it could trigger a catastrophic 10-foot spike in sea levels and inundate major US cities like New York and Miami, displacing nearly 150 million people worldwide.

“It may be a lot less stable [in Antarctica] than we thought,” said Ben Strauss, a vice president at Climate Central. “But the truth is we are relatively early in our scientific understanding of how the great ice sheets will respond to warming.”

Last summer, the Guardian investigated Trump’s coastal properties to see how at risk each of them were to flooding from rising sea levels.

What they found was Mar-a-Lago was already in serious trouble.

The estate was at high risk for flooding during heavy rains and storms, with water already pooling on the premises in addition to nearby bridges and roads in Palm Beach. Plus, in the next 30 years, they estimated there will be 210 days a year where Mar-a-Lago will be flooded with at least a foot of water.

Keren Bolter, chief scientist for Coastal Risk Consulting and the firm that analyzed Trump’s properties, told the Guardian that tidal flooding in the next 30 years could partially submerge some of the club’s luxurious cottages and bungalows. And perhaps even eventually render Trump’s “Southern White House” uninhabitable.

For now, though, Trump remains stubbornly in denial of the threat. In June, he reportedly told the mayor of Tangier Island, Va., which is losing up to 16 feet of coastline a year, that there was no need to worry about sea-level rise.