SAN FRANCISCO (CBS SF) -- A new study predicts a grim future for people living in low-lying coastal areas of the Bay Area and across the nation as sea levels rise.
By the end of this century, researchers predict 13.1 million people could be displaced by rising waters. If unchecked, the country could witness mass population movement similar to the Great Migration of African-Americans out of the South during the 1900s.
The study was done at the University of Georgia and published online in the journal Nature Climate Change. It is the first to couple the risk of sea level rise (SLR) with projected population growth, and warns that preventative strategies that don't take both into account, will fail.
Researchers came up with two calculations for projected populations for 319 coastal counties in the U.S. by the year 2100 -- one based on a sea level rise of 6 feet; another based on a 3 feet. Florida stands out as the most at-risk state with more than 6.5 million people impacted, but California ranks third, after Louisiana, when it comes to the projected population at risk. Ironically, the state currently in the grips of a historic drought is at risk of catastrophic flooding in the not-so-distant future.
In the event of a 6-foot SLR, more than a million Californians would be forced to relocate. In San Mateo County alone, nearly 200,000 people would be displaced. In fact, populations in every single Bay Area county would be impacted by coastal "flooding and other hazards from rising seas," according to the study. Given the 3-foot SLR prediction, almost a quarter of a million Californians would be affected. The latter scenario is less dire, but still cause for concern.
Even 3 feet of sea level rise would put millions of U.S. coastal residents at risk, according to study author Mathew Hauer. In a press release, he said he believes current monetary projections grossly underestimate the cost to adapt "coastal flood protection infrastructure."
According to the study, current estimates of annual global cost for adaptation measures in the event of a sea level rise of 3 feet is about $421 billion per year, but it doesn't take into account population growth. Researchers call that number is "deceptively low," and warn the actual cost of relocating a entire communities will increase enormously as populations grow. By the year 2100, the cost of mass relocation due to sea level rise could exceed $14 trillion.
Researchers believe this new data provides a more realistic picture of the future and should spur policymakers to recalibrate their strategies for dealing with sea-level rise in America's most vulnerable coastal regions.
"Adaptation strategies are costly, and these are areas of especially rapid population growth, so the longer we wait to implement adaptation measures the more expensive they become," Hauer said.
CBSSF.com writer, producer Jan Mabry is also executive producer and host of The Bronze Report. She lives in Northern California. Follow her on Twitter @janmabr.
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