New Orleans Has to Work Fast to Avoid Washing Away by 2050

As climate change brings more and more extreme rainfall to the Gulf Coast, will the city take the necessary steps to protect itself from massive storms?

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Oct 4 2017, 4:31pm

This story is part of VICE's ongoing look at how climate change will have changed the world by the year 2050. Read more about the project here.

I don't need to tell you that New Orleans is seriously at risk from the effects climate change. Hurricane Katrina in 2005 showed what serious flooding can do to a city near the coast that's 50 percent below sea level: A staggering 1,833 people died—more than the death toll of the Titanic, and the damage cost an estimated $160 billion when you factor in all the affected areas. That's about the same as the price of NASA's entire Apollo program in inflation-adjusted dollars.

Katrina's connection (or lack thereof) to climate change was fodder for debate that continues to this day—though it's worth noting the whole field of "extreme event attribution" was only two years old at the time. But more important than rehashing the debate over the extent to which human-caused climate change birthed Katrina is the extent to which we can predict another catastrophic rainfall event by 2050. After all, past predictions have suggested that New Orleans could be gone altogether by sometime late in the 21st century. So is the place already on the verge of being washed away?

"Is New Orleans going to still be there in 2050? Well, heck yeah. And if these plans go through that the state of Louisiana is cooking, it's going to be a pretty good place to be," said Ed Link, a research engineer at the University of Maryland who led an effort by the federal government to figure out why Katrina was so deadly. He's referring to Louisiana's $50 billion master plan for preserving the coast, which includes creating marshes, flood-proofing buildings, and restoring shoreline ridges.

But Link's optimism comes with a hedge. The sustainability and habitability of New Orleans and the surrounding area are a huge question mark right now, and disaster really might be on its way. As civil engineers in and around New Orleans do their work in the coming decades, Link explained, "there's an awful lot of political and economic decisions that get made to lead up to something that ends up being a compromise."

According to the National Climate Assessment, a report prepared by the federal government in 2014, the New Orleans area should expect much of the usual changes to life in a a metropolitan area as the earth heats up: more heat-related deaths and hospitalizations for heat-related respiratory problems. Problems somewhat more unique to the Gulf Coast, according to the report, are shellfish toxins and mosquito-borne illnesses. New Orleans's Lake Pontchartrain—which is actually an estuary—could be among the brackish bodies of water near the coast that will become saltier as sea levels rise and ocean water intrudes into the ecosystem, likely leading to a change in the flora and fauna.

But Hurricane Harvey, which delivered devastating flooding to Houston back in August—and which probably had something to do with climate change—might be a sign of an even more menacing future for the Big Easy. That storm did hit New Orleans, but it was also the most extreme rainfall event in United States history—a preview of what the horrifying future could look like like.

According to Gerry Galloway, another civil engineering professor at the University of Maryland, in the storm preparedness game, the category of a hurricane, from one to five, was once the measure of potential devastation. "We learned from Katrina that's not the case," he said. What people should worry about is rainfall and storm surge (water blown in by hurricane winds), which may seem intertwined if you've never been on the ground during a hurricane, but are actually two distinct phenomena.

"In the months after Katrina," said Galloway, "the big issue was that there was still water in many places that they were pumping out as fast as they could, and then they'd get another storm, or a hurricane would come in and dump more water."

Link agrees: "New Orleans's big threat now is heavy rain." The levees being breached during Katrina were "the more serious source of water," at the time, he told me, but the highest rainfall Katrina dropped anywhere in Louisiana was 15 inches. Compare that to well over 50 from Harvey, and you see the danger. "[If] you're talking about 50 inches of rain over an enclosed bathtub like New Orleans, it's going to be terribly flooded," Link told me. "If Harvey had parked its butt over New Orleans, New Orleans would have had just as much or more flooding as it did during Katrina."

Worryingly, New Orleans is seeing an uptick in extreme rain events these days—a 62 percent increase since 1950, according to a 2015 report from Climate Central. That's a change that Barry Keim, Louisiana's state climatologist, recently told the New Orleans Times-Picayune was "consistent with a warming climate."

As I write this, New Orleans is recovering from a flash flood. When the city floods these days, residents look toward the pump system that ejects water into Lake Pontchartrain—a system that has been mired by infrastructure issues recently. In August, two Sewerage & Water Board members resigned over the pump preparedness scandal, with one blaming Mayor Mitch Landrieu for the problems on his way out the door.

But even without those issues, the pumps would likely be no match for a Harvey-like event featuring more than 50 inches of rain. "The pumps on a good day can only do about an inch of rain in the first hour, and then a half inch of rain in each succeeding hour if you've got them all turned on," Link told me.

A New Orleans floodgate along the Mississippi River. Photo by the author

More bad news: "The residents have to recognize that they have a residual risk from the levee they have right now, if you have a Katrina-like event, or something bigger," Galloway told me. Moreover, with climate change will come sea level rise, and that in turn has the potential to make Katrina-like events, with their once-every-500-years storm surge, into a horrifyingly common phenomenon.

"We don't really know what's going to happen with climate change. We know sea level rise is happening, and it could accelerate, but maybe it won't," Link said. Consequently, there are still debates to be had as Louisiana officials try to budget and execute the state's master plan.

"Do you build the Great wall of China, and bet on the idea that the worst event that could occur will occur? Or do you bet that it's not going to be that bad? It's the uncertainty that makes it a big issue," Link explained.

One thing's for sure: In New Orleans, as with everywhere in the US, it's poor and generally minority communities that suffer the most. In his recent work as a visiting professor at Texas A&M, Galloway told me, he and A&M professor Sam Brody found that "areas that flood tend to be areas where there is low income." That produces a confluence of problems, he said. Sixty-three percent of Americans can't cobble together $500 in an emergency. Meanwhile, the truly poor, he went on, don't have cars, can't afford plane tickets, and may not be able to afford a motel room at a safer elevation, Galloway pointed out.

Still, Galloway told me, "I expect to have a beignet and coffee at Cafe Du Monde in the year 2050." He said the levee may need to be heightened, but New Orleans will at least survive. Then he added, somewhat grimly: "Maybe not all of the city. That may be one of the solutions you have to deal with. You may have to use part of the city for emergency water storage."

By "emergency water storage," he clarified that he meant something like the way China evacuates flood basins, relocating sometimes millions of people during monsoon floods as a form of "water detention." Forced mass migration certainly doesn't sound like an ideal system, and Galloway clarified that he's not proposing it for New Orleans. But if there are desperate times ahead, desperate measures may have to be taken.

Follow Mike Pearl on Twitter.

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