Sen. Ed Markey, D-Mass., in promoting his Green New Deal, warned Tuesday that President Trump’s Florida estate will be underwater within 15 years if the U.S. does not act to stop climate change.

“Within 15 years, Mar-a-Lago’s going to be underwater for over 100 days a year, it’s going to be Mar-a-Lagoon, not Mar-a-Lago,” Markey said in a discussion on the Green New Deal at the Council on Foreign Relations.

Markey, who has long focused on environmental issues, introduced a resolution on the Green New Deal in February along with Rep. Alexandria Ocasio-Cortez, D-N.Y. While the legislation failed a Senate test vote last month, the Green New Deal has spread into the Democratic mainstream -- and Markey’s resolution was co-signed by a number of top 2020 Democratic presidential hopefuls.

Feb. 8: Massachusetts Sen. Ed Markey speaks at The Institute of Politics at Harvard Kennedy School in Cambridge, Massachusetts. (Photo by Paul Marotta/Getty Images)

That push for a Green New Deal has been accompanied by increasingly apocalyptic language from Democratic lawmakers, who have seized on a U.N. report that concluded significant actions must be taken by 2030 to reduce climate change.

2020 hopeful Beto O’Rourke, after he unveiled a climate change initiative that would cost $5 trillion over 10 years to reach zero carbon emissions by 2050, said Monday that society has 10 years to “make the kind of bold change that we need.”

Ocasio-Cortez put it more bluntly in January: “Millennials and people, you know, Gen Z and all these folks that will come after us are looking up and we’re like: ‘The world is gonna end in 12 years if we don’t address climate change and your biggest issue is how are we gonna pay for it?'"

Republicans, including in the White House, have been skeptical about climate change and have opposed Democrats’ government-focused ideas to combat the threat. But Markey on Tuesday declared the question was not up for debate.

"It's no longer a debatable subject, regardless of how much money the Koch brothers throw at the phony science, no matter how much greenwashing the fossil fuel industry seeks to engage in,” he said. “That debate is over."