Loss of Louisiana marsh lands highly likely as sea levels rise, study shows

The marshlands on the coast of Louisiana could disappear in the next 50 years as sea levels continue to rise due to global warming, according to a study published in Science Advances Friday.

The wetlands at the base of the Mississippi River have crossed a “tipping point,” according to the study, which is based on hundreds of measurements of the Mississippi Delta. 

According to the study, the Louisiana wetlands have survived when the sea levels rise 3 millimeters per year over long periods of time. 

However, sea level rise in the area is slightly above that benchmark currently, and could reach up to 6 to 9 millimeters per year in 50 years, the study found. This increase would result in the wetlands being completely disappeared by ocean water. 

“We are, if you believe this study, past the tipping point,” Torbjörn Törnqvist, a professor of geology at Tulane University in New Orleans who led the study, told the Washington Post.

“We know that the rate of sea level rise, even with the best action you can imagine, it’s still going to ramp up further,” he added. “Given the slowness of the ocean response, it’s going to last for a very long time.”

The study also underscores the risks New Orleans faces as a city that’s prone to hurricanes. The wetlands weaken storm surges and protect the city, according to the news source. The city also has man-made flood protection built by the U.S. Army Corps of Engineers following the devastating floods of Hurricane Katrina in 2005. 

The state is creating vast “sediment diversions,” which would redirect the flow of the Mississippi River away from New Orleans, according to the newspaper. 

“If we do that in a targeted way, just downstream of the largest population center, which happens to be where I live, maybe that portion of the delta can be sustained for a bit longer than if we do nothing,” Törnqvist told the Post, referring to New Orleans. “I think a couple of decades is incredibly valuable because it could be the difference between a somewhat managed retreat versus complete chaos.”