Less than two weeks after my visit to New Orleans, and exactly seven years after Hurricane Katrina shattered the Big Easy, Louisiana found itself under siege again. This time the culprit was Hurricane Isaac, a huge Category 1 storm that stalled over the southern part of the state, dumping between 12-24 inches of rain on land and sending 11 feet of sea surge up against rebuilt levees. Its 80mph winds howled for more than two days, knocking out power to more than half a million people. Although Isaac was no Katrina, it certainly was a serious storm. It also reminded residents of their vulnerability.

“We didn’t think it was going to be like that,” one said. “The storm stayed over the top of us. For Katrina, we got eight inches of water. Now we have thirteen feet.”

“This is worse than Katrina,” said another resident. “Katrina came through, did her damage and was gone.”

Still, the rebuilt levees and other improved protections, constructed to the tune of $14 billion, did their job, according to the Army Corps of Engineers. Residents were better prepared this time as well, including the deployment of new storm-proof homes in poverty-stricken, low-lying areas that were devastated by Katrina.

Here’s a photo from this week’s storm:


What isn’t clear yet is how the region’s wetlands and coastal marshes fared under Isaac’s blows. Scientists have determined that for every mile of coastal wetlands, storm surge can be reduced by three to eight inches. If the buffer of wetlands between the sea and a city is miles deep – as it once was – then those inches can be the difference between a city under water and a city free from floods (recall that parts of New Orleans are six feet below sea level). One of the reasons why Katrina devastated the region was due to the loss of this buffer. That’s because there has been an incredible loss of coastal wetlands over the decades as a result of human manipulation of the mighty Mississippi River. Sediment that once spread out over the marshes during a flood is now channeled way out into the Gulf of Mexico.

As I learned on my recent visit, efforts are being made to restore some of the region’s wetlands so that they might again provide their buffering function. As a collateral benefit, the amount of carbon dioxide that coastal plants absorb and store in the soil – called blue carbon – as part of this restoration effort is potentially very high. Since both of these ecosystems services have important benefits for humans, as well as other living organisms, you might think that some of the $14 billion spent on repairing the damage caused by Katrina went into the restoration of critical wetlands. The truth is almost none of it did. But even if money had been available, what would state and federal officials have done with it?

I put the question to my hosts, Dr. John Day and Dr. Sarah Mack, as we drove around looking at restoration projects. Their answer was both simple and extraordinarily complicated: let the Mississippi River be free. The river created the marshes and wetlands with its silt, they said, and only the river can recreate them, at least on a scale that matters. The river needs to be unshackled so that it can flood again, spreading its bounty of silt across the delta, building up the wetlands. Simple.

The complicated part, of course, is implementation. What are the chances, I asked the scientists, that the Mississippi could be freed from its bondage to do its good work again? Nil, they admitted. For one thing, the Mississippi is a transportation lifeline to America’s heartland, with billions and billions dollars’ worth of goods plying its waters each year. Everyone upriver who depends on the Mississippi for food, fuel, and commerce doesn’t give a damn about healthy wetlands and won’t abide any plan substantially alters the river’s fixed course. Powerful economic and political forces would block any attempt to unshackle the great river.

What was the answer then, other than the small restoration demonstration projects that I was being shown? If we can’t let the river be free, I asked, what are the chances of properly buffering New Orleans and other urban centers in the long run?

Nil, they said again. And that makes the prognosis grim. “Another Katrina is inevitable,” Dr. Day said, “it’s just a matter of when. And there’ll be another Katrina after that.”

Watching Isaac’s progress, I felt a strong case of the carbon blues. We know what to do, how to do it, and what the results will be if we don’t. And still we do nothing except apply bandaids. And repair power lines and bail water, as residents did this week. To many, Hurricane Isaac was a success story – the levees held! To scientists, however, it was a reaffirmation of the inevitable Category 5 storm over the horizon. Maybe the next time I’m in New Orleans I’ll try the local drink called a ‘hand grenade’ after all!

In any case, this is a good place to take a break for a few weeks while I take a vacation. Here’s a photo of where we are heading: