Now scientists like Denise Reed are trying to figure out how that disaster is changing the state.
Scientist Denise Reed and Zwerdling head into the marsh. Photo: William Brangham/NOW with Bill Moyers
"Okay, let's get it started," says Reed, "We'll start the engine. OK, we're gonna take that line off first—off last."
We've just left the dock in a scruffy town called Cocodrie, right in the heart of the wetlands. Reed moved here from England, so she could study them for the University of New Orleans. She steers the boat down a bayou—that's the Cajun word for a slow stream— and it looks like we're floating through fields of grass. White pelicans swoop over our heads, and we pass fishing boats draped in nets.
"This marsh that we're gonna look at now," explains Reed. "It's pretty typical of many, many acres, thousands of acres of marsh in southern Louisiana. It's really hanging on the edge."
Reed says here's one reason why: After the Mississippi River built these wetlands, thousands of years ago, this whole region began to subside. And it is still is: all that rich heavy soil that the river used to dump here keeps compressing under its own weight. But that was never a problem in the old days, because the river would keep flooding and dumping more soil on the wetlands, and that would build them right back up.
Reed explains how the wetlands are dying. Photo: William Brangham/NOW with Bill Moyers
"So," continues Reed, "when we built the levees along the Mississippi River, that cut off a supply of fresh water and sediment to these marshes that they would have gotten every three to five years—when a big flood came down the river. And so what that means is that the land is sinking."
The wetlands are literally sinking into the sea: the Gulf of Mexico is essentially drowning them. The moment we get out of the boat, we can feel that this wetland is dying.
Reed says if this were a healthy marsh, we'd be able to walk through the grasses like it was a hayfield. But every time we take a step, we sink up to our calves in water.
"I don't know how many times you fell in over your knees, but I fell in several times. It's full of holes," describes Reed.
Now, if I were just here on my own, sloshing around in this water that we keep falling in, I'd think, "Oh, marsh! That's what it's supposed to be, land and water together. So why is this a sign that this marsh is dying?"
"Well, " explains Reed, "what it tells us is that there's not much holding it together, apart from the plant roots. There's nothing very firm down there. It's not anchored very well."
The Gulf Coast is rich in oil and gas. Photo: William Brangham/NOW with Bill Moyers
"That's bad! And of course we're standing here, right next to a pond. This is not a very big one. When you fly over Louisiana, you can see that there are myriads of ponds this size, and very, very much bigger. But what seems to have happened here is that the plants that were there have said, 'I give up.' The plants die, and when plants die, there's nothing to hold it together, and what you end up with is a pond like this. And that's land loss! This is what coastal land loss is in Louisiana. Something that's a marsh with grass—turning to open water.
And Reed says, there's another reason these wetlands are sick. She says look back at that waterway we just came down, to get into this marsh—notice how straight it is? Nature didn't build lines like that— the energy industry did. In the middle of the 1900s, companies like Shell and Texaco found huge amounts of energy below the wetlands.
"This is the kind of canal that the companies had to dredge through the marsh to actually drill holes to extract oil and gas," says Reed. "There are thousands and thousands and thousands of these across coastal Louisiana."
In fact, when you wind through the wetlands in a boat, you start to think, 'This is wilderness'—the landscape is hauntingly beautiful. Then suddenly, there's a cluster of drilling rigs like a grove of metal trees. That's made energy the biggest industry in Louisiana, but Reed says there's a price: the wetlands are dying much faster where these canals have carved them up.
Seafood is another threatened industry. Photo: William Brangham/NOW with Bill Moyers
"This marsh cannot survive in this state much longer. It's like the edge of a blanket starting to fray. Once it starts, it goes very rapidly," warns Reed.
Satellite photos suggest that if the wetlands keep disappearing, the entire nation could be affected. Americans eat more shrimp and crabs and other seafood from Louisiana than from any state except Alaska; the creatures spend part of their lives in these wetlands. You buy more oil and gas from Louisiana and the Gulf of Mexico than from almost any other state—and a lot of that fuel flows through pipelines under these wetlands. So, researchers say that as the wetlands vanish, some kinds of seafood might disappear, and
you'll have to pay more money to drive your car and heat your home.
Next: Sinking towns