Where United States’ Climate Migrants Will Go As Sea Level Rises

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Above photo: This image was created by Nickolay Lamm, from StorageFront.com. Lamm, a researcher and artist, was inspired by the New York Times’ “What Could Disappear” interactive and collaborated with Remik Ziemlinksi from Climate Central. From Climate Action Business Association.

13 million U.S. coastal residents are expected to be displaced by 2100 due to sea-level rise.

Researchers are starting to predict where they’ll go.

When Hurricanes Katrina and Rita swept through Louisiana in 2005, cities like Houston, Dallas, and Baton Rouge took in hundreds of thousands of displaced residents—many of whom eventually stayed in those cities a year later. Where evacuees have moved since hasn’t been closely tracked, but data from those initial relocations are helping researchers predict how sea level rise might drive migration patterns in the future.

Climate experts expect some 13 million coastal residents in the U.S. to be displaced by the end of this century. A new PLOS One study gives some indication of where climate migrants might go.

“A lot of cities not at risk of sea of level rise will experience the effect of it,” says Bistra Dilkina, a computer scientist at the University of Southern California, who led the study. “This will require an adjustment in terms of the [increased] demand on the cities’ infrastructure.”

Dilkina and her team used migration data from the Internal Revenue Service to analyze how people moved across the U.S. between 2004 and 2014. Movement from seven Katrina and Rita-affected counties to unaffected counties between 2005 and 2006 was categorized as climate-driven migration. Researchers then combined that analysis with National Oceanic and Atmospheric Administration (NOAA) projections on the effects of sea level rise on coastal counties, and trained a machine-learning model to predict where coastal populations will move when forced to leave their homes—and how that, in turn, affects the migration of non-coastal residents.

Blue indicates counties where flooding will displace residents if sea levels rise by six feet by 2100. Counties in shades of pink and red will see higher-than-average migration, with the darker shades representing larger population increases. (PLOS One)

In the worst-case scenario, in which sea levels rise by six feet by 2100, the resulting map shows portions of almost all counties on the East and West Coasts, and along the Gulf of Mexico, under water. It also shows that cities closest to the flood-prone areas, and that aren’t typically attractive destinations for newcomers, could see a higher-than-average influx of migrants. In Florida, for example, that means people may increasingly move to the shrinking core of the peninsula as the coastlines disappear into the ocean. Demographer Mathew Hauer, whose climate migration research was a building block for Dikina’s, explained in Audubon Magazine that people tend to move to familiar places nearby, where they might already have friends, family, or some other support network. People may also flock to major urban centers like Dallas and Houston, which the model predicts will absorb the most migrants, and drive up the pace of urbanization.

In the short to medium term, cities on the receiving end will likely face a housing crunch, according to Jesse Keenan, a climate adaptation expert at Harvard University who was not involved in the study. He points to the 2018 wildfire that displaced some 50,000 residents in and around the city of Paradise, California. “It’s increased the property values of neighboring towns,” he says. One such town is Chico, which became the top refuge destination and turned into a boomtown almost overnight. By the end of that year, home sales doubled and housing prices jumped 21 percent, compared to December 2017.

In the long term, “that’s going to lead to displacement, housing pressure, and probably even to homelessness among people who are being indirectly forced out by the people moving in,” Keenan says—a phenomenon he calls “climate gentrification.”

Those with the means to move will likely relocate to another big city away from the coast, in search of comparable or better economic opportunities, according to the latest study. Many may end up moving to the suburbs in the Midwest, where the model shows a larger-than-average influx of migrants compared to historic trends.

Dilkina is careful to describe the study as only an “approximation” of how sea level change might drive migration patterns, not a precise picture of where people will actually move. “There’s still a lot of need for understanding different drivers and externalities,” she says, adding that her team will be presenting their results at various meetings and conferences with other academics who may want to collaborate. “We are setting up a model to be improved as we go.”

For one thing, sea level rise is just one effect of climate change. Heat waves will drive people north—and could make make cities like Duluth and Buffalo “climate havens.” Urban flooding will reshuffle populations within a city. And extreme storms will move people in yet other ways. Meanwhile, as in Paradise, “forest fires are going to have dramatic effects on the West Coast, including the Pacific Northwest,” says Keenan. “All of those things are changing land economics, housing economics, and public finance.”

Whether researchers can paint a precise picture of future migration patterns will require better—and more explicit—metrics for measuring how and why people move, and a better understanding of social behavior overall, says Keenan. Currently, migration data is both delayed and indirectly collected via proxies like Federal Emergency Management (FEMA) assistance applications and address changes submitted to the IRS and the post office.

Precision aside, though, Keenan thinks the value of this kind of study lies in the messaging. The map presents a “minimal threshold of the amount of people that would potentially be on the move,” he says. Socioeconomic factors—where companies create employment opportunities, who has the means to move, and how racial discrimination keeps people out, for example—will also play a role in dictating how many people move, and to where.

  • voza0db

    Move inland to higher ground!

  • didactic1

    Mountain Momma West Virginia.

  • didactic1

    West Va and Western PA and W NY need people. Farm. Or die.

  • voza0db

    I guess the sooner the sea level rises the better!

  • didactic1

    Species survival won’t happen with a population of IT specialists and consumers who think food is grown in plastic frozen bags.

  • voza0db

    Those will be the first to disappear when the cities support infrastructures collapse…

  • jwreitter

    “Go North young man” because, in addition to searise, it will also be getting a lot hotter in the South. People are already moving out of sweltering, polluted Southern areas that are seeing the brunt of heatwaves, storms and floods. Western areas are seeing more droughts and wildfires which will create more migration to the interior river valleys, mountains and cities. But the general direction will eventually have to be to the cooler Northern states and even to pristine areas and cities in Canada. I will not be around in 2100. Where will you be?

  • mwildfire

    Now wait just a cotton pickin moment! I live in WV, and do subsistence farming, and must point out that the prospects for serious farm expansion here are limited because 95% of any property is steep wooded hillsides, which because they are steep, need to remain wooded. Farming happens in narrow, semi-flat strips along creeks (subject to flooding) and on ridges. Western Pa and NY don’t have this problem, but northern WV and SW Pa are being seriously trashed by the gas industry, with plans to build a giant petrochemical complex along the Ohio River.

  • mwildfire

    Do we need people? Well I think WV is the only state that keeps losing population–personally I think we need more of what we have the least of, immigrants from south of the border. We could really use a boost in our genetic and cultural diversity, and a lot of those people know how to farm. Personally, I think what we don’t need is immigrants from big east coast cities who look down on hillbillies and as someone else said, are great with IT or marketing or something, and, as my daughter said when she went to Amherst, “These boys don’t even know how how to change their oil–some don’t even know how to check their oil!”

  • didactic1

    Let em sort it out. 18 cent style.

  • didactic1

    Orchards.

  • Barbara Mullin

    Looks like the end of Delaware in 2100 in this map.

  • mwildfire

    I suspect this map is wildly inaccurate because it only takes one or two factors into account. When Katrina happened, sea level rise had scarcely begun. Isn’t all of Florida going to have its water table turn salty? Isn’t much of the West Coast cliffs a hundred feet high? Then what about the drought spreading east from the arid southwest, making agriculture more difficult in what’s now the breadbasket? What about the unpredictability, killing the harvest with floods one year and wildfires or drought the next? Yes, people move to nearby familiar places where they have kin or buddies–but in a future where the entire South is too hot and electricity is spotty or too expensive, their kin in Baton Rouge are likely to be packing up too. Where jobs are won’t be the big deal much longer–it will be where farming is feasible so forget arid places, or places where it floods often. Then there’s the matter of the reception immigrants get from places holding their own, perhaps barely. Currently there is obsession with national borders but that may dissolve in the difficult future we face.

  • mwildfire

    Sorry, I’m culturally illiterate as I don’t watch TV. What does 18 cent mean?

  • mwildfire

    Sure, orchards help but they need to be on lightly sloped, cleared land too. And won’t do any better in areas where the groundwater is polluted by the gas or petrochemical industry.

  • didactic1

    In a radically decentalized confederation and with shrinking of world trade as consequences of climate infuse commerce, light industry can also thrive in valleys and riverfront communities.

  • didactic1

    Read history. Read. Not TV.

  • didactic1

    Maine and VT leaking population too.

  • mwildfire

    I read a great deal and have never come across this phrase. Stop being mysterious, what are you talking about?

  • mwildfire

    Really? I tried to get out of WV a couple of times, and VT was where I wanted to go or maybe Maine–because I hate cities, VT is the only place that’s both truly rural and truly progressive. But I found that I just couldn’t afford land there. I was told in 2008 that this was because New York City people bought up land in Vermont after 9/11…so i suppose that drove the price up but not the population, as those people stayed in NYC, just held the land as a Plan B.

  • didactic1

    Moderate income and older people leave.

  • didactic1

    What a moron.

  • mwildfire

    BULLshit. You don’t get to call me a moron because I don’t understand a phrase you refuse to define. Perhaps you just made it up.

  • D Turgeon

    I blocked him a long time ago; suggest you do the same.