A new report from an environmental advocacy group warns a dozen South Carolina communities could be averaging two floods per-month in the next 20 years if sea levels continue rising at the current rate.
The Union of Concerned Scientists (UCS) released a new report Wednesday identifying areas across the country which would be hit by “chronic inundation” — at least ten percent of its usable land affected by floods on average every other week — under a moderate sea rise. The group used the 2014 National Climate Assessment’s forecasts for “low,” “intermediate” and “high” sea level scenarios to create three potential outcomes if the ocean’s water level continues to increase.
Lead author Erika Spanger-Siegfried said the popular vacation spots of Edisto Beach and Kiawah Island would see at least 10 percent impacts by 2035 under even intermediate conditions. “It’s no longer a question of ‘if’ sea levels are rising and accelerating, it’s more a question of ‘when’ and ‘where’ sea level rise would impact us along the coast,” she told South Carolina Radio Network.
The group used tide gauge records and flood maps to calculate which areas would be impacted depending on the amount of emissions and glacial ice melts. The “intermediate” impact anticipates a continuing increase in worldwide carbon emissions until mid-century and ice melts increasing at the current rates.
The same moderate impact shows the situation will worsen by 2060. UCS estimates about 41 percent of Kiawah will face chronic inundation under those conditions, while 27 percent of Edisto will be impacted. Downtown Charleston, James Island, Green Pond, St. Helena Island and Sheldon will also see at least 15 percent of their non-wetland geographic area impacted. Hilton Head, Johns Island, Mt. Pleasant, McClellanville and the Waccamaw Neck would also be impacted at least 10 percent. By 2080, Beaufort, Hilton Head Island, Johns Island, Mt. Pleasant, Port Royal, and Waccamaw Neck will also cross the 15 percent “chronic inundation” threshold.
“The areas within those that flood on that frequent basis are places where people will need to make investments in order to stay there,” Spanger-Siegfried said. “Or they’ll need to think about home elevation, accommodating the water or really retreating from those places entirely.”
Under the “high” scenario, roughly 71 percent of Kiawah and 41 percent of Edisto would be inundated by 2060. Meanwhile, downtown Charleston, Hilton Head, James Island, Sheldon and St. Helena Island would see at least a quarter of their region hit by constant flooding.
The group warns coastal towns need to start planning now to handle the increase in flooding. It recommends the federal government update flood risk maps using higher sea level expectations, discourage coastal development in areas more likely to see flooding and work to maintain or renovate existing properties so they will not be as badly impacted by future floods.