The study, undertaken by researchers from Princeton and Rutgers universities, found that along all of the US coastline, the average risk of a 100-year flood will increase 40-fold by 2050.
The research found that if emissions are not curbed, San Francisco and Seattle would both get a 100-year flood every year by 2050, while San Diego would expect 10 such events annually and Key West in Florida would be hit 11 times a year. Some of the worst affected areas would be in Hawaii, with Mokuoloe island, situated off Oahu, forecast to be deluged by 130 floods a year that are currently considered to be 100-year events.
Michael Oppenheimer, a Princeton climate scientist and co-author of the paper, added that New York City is set to get a 100-year flood every 20 years by 2050 but this frequency would leap to a large flood every other month by 2100.
“Most coastal areas will experience relatively large increases in flooding events,” he said. “A 40-fold increase on average is gigantic – cities may not be able to defend themselves. They will have to spend a lot of money or there will be quite a lot of damage.
Rising sea levels could displace millions of Americans this century, with US coastal cities badly situated for the looming crisis. In 2013, the World Bank said that of the 10 cities around the globe most at risk of damage from sea-level rise, half are in the US – Miami, New York, New Orleans, Tampa and Boston.