For the more than 128 million people in the U.S. who live in counties that border the sea, water is never far away. Yet, it may be getting closer in ways not previously examined until now.
"It's not associated with a hurricane or a natural disaster. That maybe gets more attention," says Kelsea Best, an assistant professor at Ohio State University, focusing on civil, environmental and geodetic engineering and city and regional planning.
Best, along with researchers in New Zealand and at the University of Maryland, looked at how sea level rise might impact communities beyond just the flooding of structures.
"This idea that direct inundation, or direct flooding of people and properties, isn't really getting the whole story of how sea level rise is likely to impact communities," she said.
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According to NOAA, sea levels could rise by as much as a foot and a half along America's coasts in the next 30 years. However, new research shows the flooding risk is even greater for some communities than previously thought.
In a new study published in the journal Nature Climate Change, researchers looked at how sea level rise could disrupt roads and transportation corridors and lead communities to so-called "climate isolation."
"The study in Nature Climate Change showed that isolation could occur in some communities even decades before inundation," Best said. "So, that adds some urgency to the planning."
The researchers created an interactive map that allows anyone to look up their county and see for themselves how many people are at risk from flooding or isolation due to sea level rise in a given area.
For example, in Monroe County, which is home to the Florida Keys, about 22% of the population is at risk of direct flooding from sea level rise. But double that number — 44% — is at risk of isolation.
It's something we saw first-hand there two years ago.
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"By the year 2045, half of our roads, which is 150 miles, are going to be subject to inundation of some level or another," Monroe County Chief Resiliency Officer Rhonda Haag said in October 2021.
Low-lying communities there are already dealing with so-called "sunny day flooding," which occurs during high tides and can swamp streets.
"They call it 'nuisance flooding' also, because typically it's been known as a nuisance," Haag said. "But when it gets to that level of water and it's on for a tremendous period of time, it's no longer a nuisance. It's a real problem."
It's a problem because flooding like that is what researchers believe could lead to communities' climate isolation, as sea level rise impacts roads initially built decades ago.
"[It could] specifically disrupt people's ability to access essential services — places they might really need to get to, such as emergency services, like fire stations, hospitals, schools and education," Best said. "If a community is only thinking about inundation and thinks they have 50 years to address the problem, if you look at isolation, it really might be more like 20 years to address the problem."
It's a critical timeline now inching ever closer.
