13 Million People in the US May Be Displaced by Sea-Level Rise by 2100

April 12, 2016 | Joanne Kennell

Calgary, Alberta flood
Photo credit: Ryan Quan/flickr (CC BY-SA 3.0)

Is your county at risk?

According to a recent study, rising sea levels could force 13 million people in the US from their homes by the end of this century. This is three times higher than previous studies have projected.

Mathew Hauer, a demographer at the University of Georgia in Athens, says that until recently, most studies that predicted the risks associated with rising sea levels used current population numbers with projections of future sea levels. The problem with that, he says, is that the predictions become “outdated almost immediately.”

“Coastal communities are some of the most rapidly growing communities in the world, so you have to account for the fact that these areas are growing,” says Hauer to New Scientist. “Using current data, we’re underestimating what the future growth in coastal communities is likely to do in terms of placing people at risk of sea-level rise.”

SEE ALSO: Map Shows US Cities Drowning Under Rising Sea Levels

Combining projected population growth with the scenarios given by the US National Oceanic and Atmospheric Administration (NOAA) on predicted sea-level rise, Hauer and his colleagues found that a 1.8-meter (6-foot) rise by 2100, which is near the top end of NOAA’s predictions, could result in 13.1 million people being displaced.

A smaller 0.9-meter (3-foot) rise would displace 4.3 million, but that’s still a three-fold increase on previous estimates. All of the results have been published in the journal Nature.

However, the effects will vary for different parts of the country’s coast, with 70 percent of those being displaced living in the southeastern states, such as North Carolina, where, according to New Scientist, it is illegal for policymakers to base measures for coastal management on predictions of accelerated sea-level rise. So bizarre.

Not so surprising, Florida is forecast to account for half of the total number of people displaced, and communities in South Carolina, Virginia, and New Jersey are also at risk of large population displacements.

Athanasios Vafeidis at the University of Kiel in Germany, who studies the risks of sea-level rise, says it is important to look at socioeconomic changes that can affect these impacts of these changes. He doesn’t think the number of people displaced will be quite as high as predicted because people will adapt to the changing shoreline.

SEE ALSO: 10 Cities in Danger of Going Under

“It’s very important to show what is potentially at stake to communicate the costs of inaction,” says Vafeidis to New Scientist. “But we also need to communicate the benefits of adaptation. How well we adapt will be the main determinant of future impacts.”

Hauer hopes that his new predictions will help politicians and planners make smart decisions and invest in adaptations to deal with rising sea-levels. “If you deploy infrastructure in areas that are growing, you might be protecting more people in the future than you’re currently protecting, making it a better investment,” he explains.

If you want to know what your state will look like after a 3- or 6-foot rise in sea levels, check out this interactive map.


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