Why tens of thousands of US climate refugees could end up in Kentucky and Indiana

Note: President Trump is expected to announce Thursday afternoon his decision on whether the United States will exit the International Paris climate agreement, or join Syria and Nicaragua on the outside.

The United States can expect massive population shifts as the weight of climate change bears down and sea levels rise perhaps six feet by the end of the century.

As many as 13 million Americans living in coastal areas could be flooded out by 2100, according to research by University of Georgia demographer Mathew E. Hauer and associates last year. 

Hauer more recently made calculations that attempt to identify where they may end up.

And tens of thousands appear to be headed toward Kentucky, Indiana, Ohio and Tennessee.

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The findings, published in Nature Climate Change, detail how every state and several hundred cities or metro areas could be affected, including Louisville, Lexington, Indianapolis, Cincinnati and Nashville.

First, the biggest losers: The low-lying Miami area could have as many as 2.5 million people displaced by rising seas; New Orleans, 500,011; and the New York City region, 50,804.

The largest gains: Austin, Texas, with as many as 818,938 climate refugees; Orlando, Florida, 461,411 and Atlanta, 320,937.

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Those numbers assume coastal areas do no mitigation to reduce impacts from sea-level rise. But even with mitigation, such as sea walls, these climate refugee numbers will be huge, according to the research.

“People tend to migrate short distances, to places with economic opportunities, and to places with pre-existing social or kin ties,” Hauer said in an email. “If you look at the top destinations, places like Austin, Orlando (and) Atlanta, they tend to be relatively close to coastal communities, have pretty robust economies, and likely contain pre-existing social or kin ties.

“Conversely, places in the Midwest are far from coastal communities.”

I’ve written — most recently in a May 21 special climate change report for the Courier-Journal — that Louisville could experience a population increase from coastal refugees. That’s in part, experts have told me, because of what could be more reliable water supplies from being located along the Ohio River, which is fed by a very large watershed.

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Hauer’s modeling puts some real science behind my informed speculation.

His study estimates that the Louisville metro area could add as many as 15,732 people looking for higher ground by 2100. That would be on top of any other growth we might have.

For example, city planners already project a 131,135 population increase by 2040 for Louisville and Jefferson County alone, or 17.7 percent.

One of the key points of Hauer’s work is that whether a city will lose population or gain population because of these population shifts, they’ll need to be prepared.

Thinking ahead surely can’t hurt.

Reporter James Bruggers writes this Watchdog Earth blog. Reach him at 502-582-4645 and at jbruggers@courier-journal.com.

Selected cities’ population gains from sea rise migration:

• Nashville, 52,673
• St. Louis, 17,796
• Indianapolis: 15,917
• Clarksville, TN/Fort Campbell, KY: 15,045
• Louisville/Southern Indiana: 15,732
• Cincinnati/Northern Kentucky: 14,197
• Lexington: 4,864
• Elizabethtown/Fort Knox: 2,409

Source: Matthew E. Hauer/University of Georgia