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A new study lists the cities that are expected to be affected by higher sea levels

Almost 200 places may not be livable in the next 15 or 20 years, it says

CNN  — 

For the past several years, scientists have been trying to get people to wake up to the dangers that lie ahead in rising seas due to climate change. A comprehensive list now names hundreds of US cities, large and small, that may not make it through the next 20, 50 or 80 years due to sea level rise.

Featuring places like New York, Boston, San Francisco and Miami, the list paints a grim picture of what our nation could look like if sea level predictions are accurate.

The left panel shows current high tide and the extended reach of extreme tides, which defines a chronic inundation, or limited-use zone. The right panel shows how sea level rise later in the century has expanded the reach of not just extreme tides but also more typical tides such that some land is permanently inundated and a greater portion of the community is chronically flooded.

If you live along the coast, your city could be one of them – meaning you could be part of the last generation to call it home.

“This research hones in on exactly how sea level rise is hitting us first. The number of people experiencing chronic floods will grow much more quickly than sea level itself,” Benjamin Strauss, vice president for Sea Level and Climate Impacts at Climate Central said in reaction to this study.

Is your city on the list?

The Union of Concerned Scientists released a study Wednesday listing the cities that will be inundated with water in the years to come, with inundation defined as a “non-wetland area is flooded at least 26 times per year or the equivalent of a flood every other week.”

weather Projected 21st-Century Sea Level Rise

The study isn’t a doomsday scenario, as the parameters are pretty conservative.

To put it in perspective, Miami – which already floods on a regular basis and has spent millions of dollars on mitigation – hasn’t even reached the 10% threshold of inundation. According to the study it deems as “chronically inundated” any coastal community that experiences this frequency of flooding over 10 percent or more of its land area, excluding wetlands and areas protected by levees.”

According to the study, the intermediate scenario (yellow), about 30 cities with populations over 100,000 faces chronic inundation by 2100. In the high scenario (pink), that number rises to more than 50 and includes Boston, Miami, Oakland, and four of the five boroughs of New York City.

“Between 165 and 180 chronically inundated communities in just the next 15 to 20 years; between 270 and 360 in roughly 40 years, depending on the pace of sea level rise; and 490 by end of century with a moderate sea level rise scenario,” co-author and senior climate analyst for UCS, Erika Spanger-Seigfried said. “With a higher sea level rise scenario, that number rises to about 670; that’s about half of all of the oceanfront communities in the lower 48.”

Ninety communities are considered “inundated today,” mostly in Louisiana and Maryland, where seas are rising and the land is sinking.

“This study highlights something it’s really important for people to understand. Sea level rise means sharp growth in coastal flooding. In fact, most coastal floods today are already driven by human-caused sea level rise,” Strauss said.

The cities expected to be inundated by 2035 aren’t too surprising; they include places along the Jersey Shore and in parts of North Carolina, south Louisiana and neighboring areas that have been known as vulnerable for years.

By 2060, the list grows to hundreds of coastal communities, large and small: cities like Galveston, Texas; Sanibel Island, Florida; Hilton Head, South Carolina; Ocean City, Maryland; and many cities along the Jersey Shore.

Hurricane Sandy caused widespread flooding and devastation along the southern shore of Long Island, in 2012 (top). By 2100 in the high scenario, a similar flood extent occurs every other week on average (bottom).

By the end of the century, the list says, more than 50 cities with populations of more than 100,000 could be affected. Cities like Boston; Fort Lauderdale, Florida; and four of the five boroughs of New York will be considered inundated. Although the West Coast seems to be spared the brunt of inundation over the next few decades, even places like San Francisco and Los Angeles will be on the list by 2100.

Is it too late to protect these coastal cities?

Residents of roughly 500 cities across the US will be faced with the same choices by the end of the century: whether to mitigate or to abandon their homes.

“In hundreds of coastal American cities and towns, decades before sea-level rise permanently puts land underwater, chronic, disruptive high tide flooding arrives and makes it impossible to carry on business as usual in impacted areas,” Spanger-Siegfried said.

Many times, the cost to keep the water out is too high and provides only a temporary fix. The study suggests the urgency for cities to make decisions soon – to help spare towns of the incredible loss of infrastructure, history and way of life down the road.

President Donald Trump’s promise to withdrawal from the Paris agreement has alarmed the science community, which has a goal to hold the planet’s warming to a minimum. This study also suggests the importance of the Paris Climate Agreement.

“Holding warming between 1.5 and 2 degrees Celsius by the end of the century could spare between roughly 200 and 380 US coastal communities, including nearly 50 major cities from chronic flooding,” the study states.

According to Spanger-Siegfried, “we want to help people and communities see this chronic inundation problem coming. We want to give them a sense of the time they have before carrying on business as usual becomes impossible, and outline some things they can do to respond – both to prepare for the threat and to curtail it.”

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    She says communities and individuals can’t solve this problem alone. She thinks the “federal government should be on notice that it’s got a ballooning, national sea level rise problem – one that requires stronger federal policies and more resources to deal with it, as well as a renewed seriousness about addressing climate change and hopefully slowing the pace of sea level rise.”

    Strauss said, “Most coastal floods today are already tipped over the balance by sea level rise. This important research shows that things could get much worse, and soon, for lots of people.”