Seas are rising too fast to save much of the Mississippi River Delta, scientists say

The state of Louisiana is proceeding with ambitious plans to redirect the Mississippi River and rebuild some of its rapidly vanishing wetlands — but even this massive intervention may not be enough to save the most threatened lands from fast rising seas, scientists concluded in a study published Wednesday.

This amplified color mosaic shows the Mississippi Delta in 2014. 

The study uses a methodology called “optical dating” to study how the river built an area called the Lafourche subdelta in coastal Louisiana, where the Mississippi dumped loads of sediment as much as 600 years ago, when it changed paths. The technology lets scientists identify the last time that long-buried sand was exposed to sunlight and, therefore, determine the rate at which the river naturally built up land by carrying sediment downstream.

“What we found was that, on average, it produced somewhere between 6 and 8 square kilometers of land per year, and the shoreline migrated seaward by somewhere between 100 and 150 meters per year,” said Torbjorn Tornqvist, a Tulane University geologist who was one of the study’s authors. “Those numbers in themselves I find pretty impressive.”

Read Chris Mooney’s story from The Washington Post - “Seas are rising too fast to save much of the Mississippi River Delta, scientists say.”