Millions of Americans could lose their homes if planet-warming emissions continue unabated through 2100, pushing global sea levels up by more than 14 feet, 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.
"I would avoid buying property in South Florida in particular," Strauss told the Thomson Reuters Foundation.
Scientists fear ice sheets in Antarctica and other regions will melt as global temperatures increase, leading to major rises in sea levels.
Coastal California, New York and other cities on the US East Coast would also be hit hard by rising seas if carbon emissions are not cut drastically, he said.
To substantially blunt the threat, emissions reductions would have to be bigger than those pledged by the United States and more than 145 other countries as part of a new UN deal to tackle climate change, due to be agreed in December.
An independent, science-based analysis released this month by Climate Action Tracker said those plans, if implemented, would keep global warming to 2.7 degrees Celsius, higher than an internationally agreed limit of 2 degrees.
"Our actions today determine sea-level rise tomorrow," said Dr. Strauss, from the scientific group Climate Central, in a statement.
"We can act ... or we can delay and leave a legacy of irreversible rising seas that threaten to destroy some of our nation's most iconic cities."
The study did not look at the impacts of rising sea levels on cities in other countries.
To check if your city will be underwater by 2100, you can enter your ZIP in an interactive map the researchers created to hammer home the message in the United States, where some politicians and voters remain skeptical about human-induced climate change.
(Reporting By Chris Arsenault; Editing by Megan Rowling)