'When Rising Seas Hit Home': Hundreds of Towns Threatened by 2100

As an iceberg the size of Delaware broke away from an ice shelf in Antarctica Wednesday, scientists released findings that up to 668 U.S. communities could face chronic flooding from rising sea levels by the end of the century.

“We hope this analysis provides a wake-up call to coastal communities—and us as a nation—so we can see this coming and have time to prepare,”
—Erika Spanger-Siegfried, Union of Concerned Scientists

More than 90 U.S. communities are already grappling with “chronic inundation” from sea level rise caused by climate change—meaning they have crossed the threshold for when “flooding becomes unmanageable for people’s daily lives,” disrupting “people’s routines, livelihoods, homes, and communities.”

When Rising Seas Hit Home, the new report from the Union of Concerned Scientists, found that number could nearly double, to 170, over the next two decades.

Coastal sections of Lousiana and Maryland account for the majority of the communties that are currently experiencing heavy flooding, but UCS researchers predict these unmanageable floods will reach the Jersey Shore and Florida’s Gulf Coast by mid-century.

By 2100, they calculate 40 to 60 percent of all oceanfront communities on the East and Gulf Coasts, and a growing number of West Coast communities, will be inundated with chronic flooding. At-risk regions include major cities like Boston, Savannah, Fort Lauderdale, Newark, and four of New York City’s five boroughs.

“We hope this analysis provides a wake-up call to coastal communities—and us as a nation—so we can see this coming and have time to prepare,” said Erika Spanger-Siegfried, a UCS senior analyst and co-author of the report, the first study of its kind to examine potential flood risks for the entire coastline of the lower 48 states.

The UCS researchers also consider which cities may be spared from the worst of the flooding if the Paris Climate Agreement goals are met. Although Donald Trump withdrew from the climate agreement, many U.S. state and community leaders who have committed to upholding the Paris Climate Agreement.

“Meeting the long term goals of the Paris Agreement would offer coastal communities facing chronic flooding their best chance to limit the harms of sea level rise,” said Rachel Cleetus, UCS’s lead economist. 

Although “large-scale reductions in global warming emissions,” which are among the Paris agreement’s main goals, “may slow the rate at which sea level rise is accelerating and save many communities,” the report notes for many communities, it’s too little, too late.

“For hundreds of other cities and towns,” it says, “increased flooding is inevitable, and adaptation is now essential.”