This story was originally published by Grist and is reproduced here as part of the Climate Desk collaboration.

It has been 20 years since New Orleans’ faulty levee system failed during Hurricane Katrina, causing a flood that claimed almost 1,400 lives and inflicted more than $150 billion in economic damage. The catastrophe was so bad that some doubted the city could continue to exist at all — the US House speaker at the time declared that rebuilding New Orleans “doesn’t make sense” and that much of it “could be bulldozed.”

Rather than just patch up the damage, which would have left one of the country’s most iconic cities exposed to every future storm, the federal government doubled down on flood protection, building a new $14.4 billion levee system that ranks as one of the most sophisticated anywhere in the world. 

Over the course of a decade, the US Army Corps of Engineers rebuilt and expanded almost 200 miles of levees across three parishes. It outfitted every major channel and canal with a gate that could swing shut during surge events. On the east side of the city, where storm surge had overtopped its old levees, it built the Lake Borgne Surge Barrier, a 2-mile wall that could stop as much as 26 feet of surge. On the three canals where it had built shoddy flood walls, it built new ones and massive pump stations that can remove an Olympics-sized swimming pool of water from the city every 3.5 seconds. It also decommissioned the Mississippi River-Gulf Outlet, or “Mr. Go,” a large shipping channel that had destroyed protective marshland around New Orleans and funneled Katrina’s storm surge into the city.

But for all the success of the new levee system, the future of New Orleans remains uncertain. 

The sea levels around the city are rising by about half an inch every year as climate change warms the oceans and melts glaciers. The city itself is sinking even faster than that, with some sections of the levee system settling by almost 2 inches each year — faster than the rate of change that the Corps projected when it built the system. This elevation change makes the new levee system less effective with each year, requiring constant repairs and expansions. 

Even landmark structures like the Lake Borgne barrier may lose a few feet off their protection capacity by the middle of the century. That would put them within a hair’s breadth of being topped by storms such as Hurricane Michael, which delivered almost 20 feet of surge to Florida in 2018. 

“Since 2005, several storms have made landfall on the Gulf Coast that far exceed the stated design capacity of the new ‘risk reduction system,’” said Andy Horowitz, a historian at the University of Connecticut and the author of a book on Hurricane Katrina. “It’s just chance, or luck, that one of them didn’t hit New Orleans. One day, inevitably, one will.”

The Corps maintains that the system is working as designed, but federal and state cuts could jeopardize the system’s resilience even further. The Trump administration has already eliminated funding for the Corps and the Federal Emergency Management Agency (FEMA) for key resilience projects and levee inspections. Republican-controlled Louisiana is following suit. Protecting New Orleans through the end of the century, against climate-fueled hurricanes, will require the exact whole-of-government effort that the Trump administration is trying to end.

“The system that we have is a good system,” said Sandy Rosenthal, a citizen activist and the founder of the website Levees.org. Rosenthal was responsible for exposing the Corps’ original design errors after Katrina. “But for the first time since the levees were completed, I’m actually concerned.”

New Orleans has been an engineered city for centuries. Subsidence and wetlands loss have driven the city to sink below sea level, turning it into a kind of bowl between the Mississippi River and Lake Pontchartrain. Even the French settlers of the early 18th century had to use levees to keep the city from flooding. Almost the entire perimeter of New Orleans is now lined with either earthen levees or concrete walls. When it rains, pumps carry water up and out of the bowl, the same way you would bail out a canoe. 

This levee system has had many iterations, but the one that existed at the time of Hurricane Katrina was the federal government’s project. The Army Corps of Engineers, which is the nation’s flood-protection agency, had built around 125 miles of barricades around the city over the second half of the 20th century.

The best way to describe this system is the old Woody Allen quip about restaurants: “The food here is terrible, and the portions are too small.” The Corps made serious engineering mistakes when it built flood walls along canals that funnel water away from the city’s densest neighborhoods. But even the levees it built “correctly” in the eastern part of the city, closest to the Gulf of Mexico, were too small. In other parts, there were no defenses at all.

When Katrina sent storm surge barreling toward New Orleans, the old system failed in at least six places. The wall of water rushed over the tops of the levees, and the canals that were supposed to channel water out of the city shattered, flooding neighborhoods with water and silt. FEMA bungled the emergency response and took several days to deliver critical supplies, turning the disaster into a true humanitarian crisis.

Katrina itself was not all that powerful, especially compared to the Category 5 monsters that now strike the Gulf in most years, but it exposed every engineering flaw in the Corps’ structure. The American Society of Civil Engineers called it “the worst engineering catastrophe in US history.”

Despite some initial skepticism about the cost of the rebuild, the federal government’s response was to throw money at the problem. In the decade after Katrina, Congress allocated more than $14 billion to the Army Corps of Engineers to protect the whole city against a hypothetical 100-year storm, or one that has a 1 percent chance of happening in a given year. It was classified as a repair project, rather than new construction, which meant the feds picked up the entire tab.

The new Hurricane and Storm Damage Risk Reduction System (HSDRRS) comprises a network of hundreds of discrete projects touching every corner of the city. It no longer purports to offer “hurricane protection,” as the previous system did, but rather “risk reduction.”

“The new system that’s in place now is the first time New Orleans has ever had a complete approach to dealing with water,” said Ed Link, a civil engineer at the University of Maryland. Link helped lead the government-appointed task force that evaluated the Katrina levee failures. “The old system was not a system — we called it a ‘system’ in name only.”

The Corps completed the major pieces by 2012 and finished its final work by 2018, a remarkable turnaround time for an agency that often spends two or three decades on major capital projects. The system passed its earliest tests: New Orleans took 9 feet of storm surge from Hurricane Isaac in 2012 and took another direct hit from Category 5 Hurricane Ida in 2021. During these storms, things worked the way they were supposed to: The storm surge barriers kept out the waters of the Gulf, and the pump stations stopped rainwater from flooding the city. Rosenthal said Ida showed that the system “passed the ultimate test.”

Whether it will always pass that test is another question. The federal government no longer maintains the system; that job is now the responsibility of the Southeast Louisiana Flood Protection Authority. 

Though now in local hands, the authority still relies on the Corps for levee-inspection funding. The Trump administration has already cut its budget, with Republicans in Congress proposing even further reductions. The Corps said it doesn’t have the money to inspect New Orleans’ levees this year or next. Much of the system’s maintenance funding also comes from local governments, some of which have chafed at the cost of keeping the levees at the Corps’ standards after Katrina. 

Louisiana’s new Republican governor, Jeff Landry, has also attempted to take control of the Southeast Louisiana Flood Protection Authority this year, giving himself more influence over what had been an independent board and slashing funding for line items like cutting levee grass. His moves to undo post-Katrina governance reforms caused three members to resign in March. Landry has selected a new board chair, fired that chair, and installed a new chair through what critics say may be illegal means.

If that wasn’t enough, New Orleans is still sinking. The city pumps its drinking water from underground aquifers, and levees farther up the Mississippi River have blocked the sediment that once replenished the delta on which the city sits. In addition, the Gulf of Mexico itself is rising by a few millimeters a year due to global warming. With these two factors combined, the relative sea level rise in Louisiana is higher than almost anywhere in the world.

The Corps was aware of climate change when it built the new system, but it was planning for a moving target. Congress gave the agency enough money to build a flood network that would protect against a “100-year flood” event, but the height required to protect against such an event changes each year as land subsides and the Gulf of Mexico rises. Because these rates are very hard to predict, and may be accelerating, the Corps has to inspect the levees at regular intervals and elevate the ones that are sinking fastest. 

“The 100-year criteria is no longer a valid way to design things, primarily because it changes all around now,” Link said. “We added a certain amount of subsidence and a certain amount of sea level rise to our calculations, but we didn’t put enough.”

Corps spokesperson Ricky Boyett said the agency is confident that the system will provide 100-year protection through 2057, provided it has the money to lift up the earthen levees every few years. It also said it is preparing to expand the system west toward Baton Rouge and studying how to extend that 100-year level of protection for New Orleans through at least 2073, even with further subsidence.

“The goal is always to stay ahead of it,” Boyett said. The major concrete structures, like the surge barrier, were built with enough spare height to last through 2057, but only if sea levels rise as the Corps predicted — and new research from Tulane University suggests that these structures are sinking too. 

The Corps also readily admits that bigger storms are possible. The HSDRRS would reduce the damage from these storms, but would not stop them altogether. As for whether it will ever build a 200-year or 500-year system, one that would be robust enough to stop supersized storms such as Hurricane Ian or Hurricane Michael, the Corps can offer no guarantees. Such funding would depend on Congress, which tends to act after big disasters rather than before them.

Another problem is that levees are only supposed to be one part of a broader approach to resilience, and the federal and state governments are now neglecting the other parts of that approach. Landry, the Louisiana governor, just scrapped a $3 billion sediment diversion project that would have created 30,000 acres of new hurricane-slowing wetlands, bowing to pressure from a vocal group of oyster fishermen. The city, meanwhile, has pursued a novel project to slow down subsidence by capturing rainwater, but that project depends on funding from federal resilience programs that President Donald Trump is trying to cut. 

“I’m not minimizing the importance of the hard levees and the other structures, but the natural stuff is as important, if not more important,” said Charles Allen, a New Orleans activist who founded an organization to support the flooded Lower Ninth Ward after Katrina. He now serves as the Gulf Coast community engagement director at the National Audubon Society. “We can’t just throw up something, turn our back, and say, ‘Oh, it’s gonna be fine.’ … Now two decades have passed, and we are still fiddling.” 

In the meantime, the hard levees are all New Orleans has.

Massive civil works projects like the HSDRRS may soon look like the product of a bygone era. The second Trump administration has purged the federal civil service and called for drastic reductions to government spending, and Trump has said he wants the states to take on a greater share of disaster preparedness costs. If that model continues past his presidency, it might threaten the Corps model of proposing large capital projects that depend on money from Congress, the projects that can extend a city’s probable lifespan by a century or more. 

While the new system isn’t perfect, it does demonstrate what the government can do if it tries, says Horowitz. 

“I used to think of the post-Katrina ‘risk reduction system’…as the bare minimum, but subsequent events have reminded me that, of course, Congress could have done less,” he said. “It could have done nothing, which has been its response to many crises since. It could even engage in action that makes matters worse.”

This story was originally published by Grist and is reproduced here as part of the Climate Desk collaboration.

On Tuesday, after a ferocious Santa Ana windstorm blew through Southern California, a severe brush fire broke out in the wealthy Pacific Palisades neighborhood of Los Angeles, burning at least 1,000 structures and forcing hundreds of thousands of residents to evacuate as of Thursday morning. Another large brush fire broke out near Pasadena around the same time, killing at least two people. Together the two blazes threatened some of the most valuable homes and businesses in the United States. The damage from the Palisades Fire alone could exceed $10 billion, according to a preliminary estimate from JP Morgan.

If this estimate holds true, it will test insurers’ commitment to a market that has been teetering on the verge of collapse for the better part of a decade now. Over the past five years, California has become a poster child for what climate-fueled weather disasters can do to a state’s home insurance market. Following a rash of historic wildfires in 2017 and 2018, insurance companies have fled the state, dropped tens of thousands of customers in flammable areas, and raised prices by double-digit percentages.

Until recently, elected officials have taken few major steps to address the crisis. But late last month, after more than a year of drafting, California’s insurance commissioner unveiled a set of reforms that he claimed will bring companies back into the fold as they take effect this year. 

“This is a historic moment for California,” said Ricardo Lara, the state’s insurance commissioner, when he revealed the rules in December. “With input from thousands of residents throughout California, this reform balances protecting consumers with the need to strengthen our market against climate risks.”

The rules come after months of debate among state insurance officials, lawmakers, insurance companies, and consumer advocates. The biggest change is that California will now require many insurance companies to do more business in what the state calls “distressed areas,” the fire-prone scrubland and mountain regions where insurers are now hiking prices and dropping customers. Companies will soon have to ensure that their market share in these areas is at least 85 percent of their total statewide market share — in other words, if a company controls 10 percent of the state’s insurance market, it must control at least 8.5 percent of the market in fire-prone areas. 

This mandate should push big companies like State Farm and Allstate to pick up customers they’ve dropped in flammable regions like the mountainous north of the state. Some companies have already begun to offer new policies in burned areas in anticipation of the state’s new rules: the insurance company Mercury announced last week that it will be the first insurance company in the state to offer new policies in Paradise, California, which was destroyed in the catastrophic 2018 Camp Fire. The move recognizes the town’s work to mitigate future fires by clearing trees and hardening homes.

The requirement to expand coverage, coupled with recent announcements from companies like Mercury, “should give consumers hope that competition and options will be returning,” said Amy Bach, the head of insurance customer advocacy group United Policyholders, in a statement.

In return for this added coverage, the state is making a few big tweaks that will allow insurers to pass on the price of fire risk to their customers. California is the only state in the country that doesn’t allow insurance companies to use forward-looking “catastrophe models” when they set prices. It also prohibits companies from factoring in the rising costs of reinsurance, the insurance purchased by insurance companies to ensure they’re able to pay out big claims.

These two restrictions have kept prices artificially low for years, and also prevented insurers from planning for climate change impacts, creating a de facto subsidy for homeowners in risky areas. 

“This addresses the major stumbling blocks that companies have been identifying for a decade, so that’s a positive,” said Rex Frazier, the president of the Personal Insurance Federation of California, the state’s leading insurance trade group. 

This trade-off has some residents in fire-prone areas worried. Insurance companies might now have to offer more policies in flammable zones, but they also have more latitude to increase prices. 

“I’m not optimistic that it will improve the experience of the consumer, as the insurers can now pass certain costs onto consumers, which I’m expecting will result in higher premiums,” said Jason Lloyd, who moved to mountainous Lake County last spring. He and his wife came to the area because they wanted to be closer to his wife’s family, but when they made an offer on a home, they learned that they would have to pay more than $8,000 a year for insurance, or else go to the California FAIR Plan, a state-run insurance program that offers minimal coverage. 

Lloyd and his wife later bought another home in Hidden Valley Lake, a town that has taken ambitious steps to reduce flammable vegetation, but their insurance premium is still more than $4,500 a year, more than triple what it was on their last home in Kansas. Lloyd is worried that his insurance company will hike his price further under the new rules.

Other states across the West, such as Colorado and Oregon, are also seeing insurance coverage gaps emerge after big wildfires, though their problems are less acute than those in the Golden State. In Colorado, for instance, officials just recently established a state fire insurance backstop like California’s FAIR Plan, since it’s only in the past few years that customers there have been dropped en masse. California’s grand bargain with the insurance industry provides a blueprint for those other states: If you want to address coverage gaps, you need to give insurers broader authority to set prices. 

Even this might not be enough. The past few years have seen a reprieve from major wildfires like the ones that struck in 2017 and 2018, but this week’s blazes in the Los Angeles area could cause billions of dollars of damage, on par with an event like the Camp Fire.

Joel Laucher, a former regulator and fire insurance expert at the consumer advocacy organization United Policyholders, said the damage from the Los Angeles blazes could lead to further price hikes and more availability gaps.

“These are going to be major losses, certainly,” he told Grist. “Certain areas are definitely going to have new challenges, to the degree that insurers are going to be able to charge to the rate they believe those areas deserve to pay.” Laucher said insurance companies may not decline to renew as many policies as they might have under previous state rules, but they could still avoid selling policies in some of the affected areas.

Frazier, of the insurance trade group, voiced similar concerns. He said another round of monster blazes on the scale of 2017 and 2018 could drive the insurance industry away from the state once again, despite the commissioners’ reforms. 

“If we were to have a couple more unprecedented years, all bets are off,” he told Grist.