Climate change and the Louisiana wetlands

World Today

Dean Blanchard is in crisis mode.

Louisiana’s shrimp season is just about to start, and his brand new, $80,000 condenser for his refrigeration unit blew off his roof the day after it was installed.Forecasters say the storm that pounded Blanchard’s Gulf Coast community of Grand Isle was a “mini-tropical storm” – a full month and a half before the start of hurricane season.

“I wouldn’t call it nothing ‘mini,’” says Blanchard, a shrimp wholesaler. “I’d say I had 180 mile-per-hour winds here.”Due to climate change, storms are coming more often, they are more violent, and sea levels are rising. But the marshes that for generations protected Louisiana coastal residents from flooding are all but gone.

The reason dates back to the 1930s when the U.S. government built a series of levees on the lower Mississippi.The levees put an end to catastrophic flooding from the Mississippi, but they also cut off the flow of silt and sand that created the marshes – plush, green storm-surge buffers.

“Right now, we are losing between 12 and 16 square miles a year,” says environmental journalist Bob Marshall, adding that the number is down from 50 square miles a year in the 1970s “because there is a lot less to lose.”

Marsh degradation is not unique to Louisiana.

“This is really the epicenter of what the rest of the coastal world is going to be going through from now on,” Marshall says.Louisiana has come up with a solution: a massive $50 billion coastal restoration plan, spread out over half a century.

The centerpiece is a diversion of the river so that more than 12 percent of the Mississippi’s water and silt pours back into the estuary, allowing sediment to once again create marshlands.

“We think there’s enough mud,” Marshall says. “All the computing models show that if we just do this on a regular basis, once we have these diversions they can run forever.”

Ironically, without one of the world’s worst environmental disasters – the BP Horizon explosion and oil spill in the Gulf of Mexico – restoration wouldn’t be possible. Settlement money from the oil giant is funding a large part of the project.