Many of the inhabitants of America's cities and towns may soon need a snorkel to get around, a new study has revealed.
By 2100, it is estimated that thousands of US cities and towns, including Boston, New York and Miami will be "locked in" by greenhouse gas emissions built up in the atmosphere.
The survey does not specify a date by which these cities, or parts of them, would actually fall under water. Instead, it specifies a "locked-in" date, by which time a future under water would be certain – a point of no return.
Even if all carbon emissions stopped immediately, it would take some time for the related global temperature rises to ease off. That means the fate of some cities is already sealed, the study in the Proceedings of the National Academy of Sciences says.
"Hundreds of American cities are already locked into watery futures and we are growing that group very rapidly," said Benjamin Strauss, a researcher at Climate Central, and author of the paper. "We are locking in hundreds more as we continue to emit carbon into the atmosphere."
The list of threatened communities spans Sacramento, California – which lies far from the sea but would be vulnerable to flooding in the San Joaquin delta – and Norfolk, Virginia. The latter town is home of America's largest navy base, whose miles of waterfront installations would be at risk of being locked in to future sea level rises by the 2040s. The Pentagon has already begun actively planning for a future under climate change, including relocating bases.
But the region at highest risk was Florida, which has dozens of towns which will be locked by century's end. The date of no-return for much of Miami would be 2041, the study found. Half of Palm Beach with its millionaires' estates along the sea front would be beyond saving by the 2060s. The point of no return for other cities such as Fort Lauderdale would come before that.
"Pretty much everywhere it seems you are going to be under water unless you build a massive system of dykes and levees," Strauss said.
