Millions of people in the United States could be forced to abandon their homes if planet-warming emissions continue unabated through 2100, pushing global sea levels up by more than 14 feet (4.2 meters), researchers said.

In the United States, between 20 and 31 million people are living on land that would be submerged by rising oceans without aggressive cuts to greenhouse gas emissions, according to a study published on Monday in the Proceedings of the National Academy of Sciences.

That scenario could occur if global average temperatures rise by 3.3 degrees Celsius (5.9 degrees Fahrenheit) from pre-industrial levels by the end of the century, said the study’s lead author, Benjamin Strauss.

Scientists fear ice sheets in Antarctica and other regions will melt as global temperatures increase, leading to major rises in sea levels.

“I would avoid buying property in South Florida in particular,” Strauss told the Thomson Reuters Foundation.