If seas rise six feet by 2100, 13 million people could migrate to higher ground, including 2.5 million fleeing South Florida alone, according to a Harvard researcher.

"Climate gentrification" could ensue as wealthy people claim high ground, displacing poorer residents. Jesse M. Keenan, a researcher at Harvard's Graduate School of Design, looked at home prices and elevation in Miami-Dade County since 1971 and suggested "early signaling" of this pattern, CBS News reports.

People will likely migrate from high-exposure to low-exposure properties, Keenan told CBS. Living in high-exposure are as, like the beach, could get so expensive due to insurance that only rich people can afford it. Even if governments invest in seawalls and pumps, properties nearest those fortifications would be in highest demand, and likely go to the rich.

So far, gentrification in South Florida has been the old-fashioned kind, driven by population trends, not climate. But developer Tony Cho has said that high ground was one factor in choosing Little Haiti as the site of his planned innovation district. The project's website touts "Magic City’s elevation and infill location." Cho, however, has said that he was careful to buy dilapidated warehouses, not residential properties, so as not to displace people.

Architects have predicted that Little Havana is ripe for developers seeking higher ground. Even in Liberty City, which sits 10 feet above sea level, activists and researchers are monitoring as climate gentrification creeps in.

Miami Chief Resilience Officer Jane Gilbert told PRI that her team is currently focused on fortifying against 2 to 3 feet of sea level rise by 2060.

“We feel that we can probably manage that without significant migration away from our coast,” Gilbert said.

A research paper published in the journal Nature in April emphasized that coastal cities are not the only ones that need to prepare for climate change. So, too, do inland areas like Austin and Orlando that will absorb a fleeing populace.

The expected population trends "could stress some landlocked areas unprepared for these migrations, while revitalizing others," the author, Matthew Hauser, wrote. "[Sea-level rise] is currently framed as a coastal hazard, but the migratory effects could ripple far inland."