The largest numbers of people at risk are in Miami-Dade and Broward counties in Florida.
The homes of up to 13.1 million coast-dwelling Americans will be at risk by the end of this century due to rising seal levels, according to the study published in the journal Nature Climate Change.
The research combines population projections with sea-level rise projections. The largest numbers of people at risk are in Miami-Dade and Broward counties in Florida. These two areas would make up 25% of all people impacted nationally—or more than 3.5 million—if waters rise 6 feet, which is the most extreme scenario the study's authors anticipated.