Report: Climate Change Could Cause Mass U.S. Migration

April 27, 2017 by

Migration to escape sea level rise could radically reshape the U.S. population landscape, and not just in coastal areas, according to a recent study.

The author, Mathew Hauer, an applied demographer with the Carl Vinson Institute of Government at the University of Georgia, found that all states and 56 percent of the nation’s counties could be affected in some way by net migration associated with a 1.8-meter average sea level rise by 2100 – as is forecast in some projections.

Hauer believes that 13.1 million Americans could migrate away from coastal areas through the end of this century.

The migration won’t merely consist of people fleeing flooded areas. Florida could lose more than 2.5 million residents with that level of sea level rise, while Texas could see the influx of nearly 1.5 million additional residents, according to the study.

“SLR migrants are expected to comprise both intra- and inter-state migrations, and no state is left untouched by SLR migration,” the study states.

Hauer used data from the Internal Revenue Service to produce his findings. Because people are required to file taxes and disclose their residence annually, the IRS is a great source for tracking migration trends, according to Hauer.

He used county-by-county migration data from the IRS dating back to 1990 and projected those trends out to 2100 to get an idea of where coastal residents impacted by rising sea levels would likely be moving. He used a methodology known as an unobserved components model – a time-series forecasting technique to examine things like cycles, seasonal affects, etc.

Hauer also looked at potential future mitigation efforts, such as building sea walls, raising properties and roads, beach and marsh nourishment, pumps – some studies show that adaptive infrastructure costs for sea level rise could reach $421 billion per year.

Despite these possible measures, the study shows that many people who can afford to move likely will move as opposed to living in water-inundated areas.

“They will likely move short distances where they have economic opportunities and can stay close to family,” Hauer said.

And then there will be those who cannot afford to move or just won’t for one reason or another.

According to the study, at the end of the century there could be millions of “trapped” people because they cannot move – or haven’t moved far enough.

“These results suggest that many people displaced by SLR could find themselves or their descendants exposed to SLR, even with migration as an adaptation, as sea levels continue to rise past the year 2100 with migration that constitutes relocation to present safe, but ultimately vulnerable, coastal communities,” the study states.

Society will also face the massive infrastructure challenges of accommodating millions of these migrants headed for large, unprepared inland municipalities, that impacts of which have yet to be studied, the study noted.

“For many destinations, such as Riverside California, Phoenix Arizona, Las Vegas Nevada, and Atlanta Georgia, already experiencing water management and growth management challenges, the SLR migrants who wash across the landscape over the coming century could place undue burden in these places if accommodation strategies are left unplanned,” the study states.

While Hauer feels the numbers of migrants are noteworthy, he wasn’t too taken aback by the fact that people tend to get up and move when Mother Nature comes bearing down.

“A lot of the findings confirmed what the literature has suggested about environmental migration,” he said.

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