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The False Comfort of Higher Seawalls

What high-risk communities really need to do to protect themselves from catastrophe.

Jeff J. Mitchell/Getty Images

Two weeks ago, Super Typhoon Hagibis barrelled into Japan, unleashing “unprecedented” rain that caused floods and landslides. At least 80 are dead, thousands of homes in Japan’s main island were flooded, damaged or without power. What’s worse, Japan was drenched by further back-to-back storms last week.

The country has spent billions of dollars on infrastructure in an effort to cope with natural disasters like typhoons: At least 40 percent of Japan’s 22,000-mile coastline is lined with seawalls, breakwaters, or other structures meant to protect against storms, high waves and tsunamis. But with vicious weather events like Hagibis becoming the norm, governments everywhere will be forced to consider whether such costly technocratic solutions are sustainable—and if not, what to replace them with.

This man-will-conquer-nature attitude isn’t a uniquely Japanese problem: “This risk is even worse in the U.S., as we continue to build to past weather events driven standards instead of future risk,” former FEMA administrator Craig Fugate pointed out in a tweet, “Let Japan be a lesson.”

Most years, communities can overcome a small common flood, but eventually one will come along that’s bigger than what was planned for, James Doss-Gollin, a doctoral student at the Columbia Water Center, told me. As the risks get bigger and bigger, the tendency is to build bigger infrastructure, as Japan has done. “That often only gives people the illusion of safety,” he adds.

It’s been over two years since Hurricane Harvey brought Houston to its knees. Prior to that, America’s energy capital thought it was prepared for a major hurricane like Harvey. The entire city directs water into a series of bayous, canals and reservoirs—2,500 miles of channels for moving water—then on into the Gulf of Mexico. Most Houstonians casually accept this drainage system that keeps them dry, albeit precariously, in a former wetland. But Harvey’s 27 trillion gallon rain dump forced authorities to deliberately flood west Houston to keep two main reservoirs from failing. The flooding damaged or destroyed nearly 135,000 homes and killed 88 people.

As climate change races towards us, hurricanes are growing more destructive. Studies have suggested that today’s climate made Harvey more intense than it might have otherwise been. Such storms will become more frequent. Basic physics dictates that a warmer atmosphere holds more water, meaning that heavy downpours are becoming all the more common and intense as the world heats up. An ever-changing and transmogrifying enemy is hard to tackle: “It highlights the need to consider that our hazards are changing over time, and that we should be considering those changes in the design of our infrastructure,” Antonia Sebastian, a flood engineer at Rice University, said in a 2017 press release on her and other scientists’ Harvey-related research.

An investigation by The Texas Tribune and ProPublica in 2016 found that Houston was a “sitting duck” for the next big hurricane. Last year, Harris County, which includes Houston, passed a $2.5 billion flood control bond—a mere drop in the bucket toward the $30 billion estimated to be needed just to protect against a 100-year flood. (For reference, Harvey was considered a 500-year flood—and it was Houston’s third in three years.)

While Hurricane Harvey’s biblical onslaught on Houston will be remembered as one of the most destructive hurricanes to ever strike the United States, the city is far from the only place in the U.S. vulnerable to disastrous flooding or other natural disasters. Countering them with large infrastructure investments has many downsides, including exacerbating inequality, Daniel Aldrich, a political scientist and director of the Security and Resilience Program at Northeastern University, told me. After all, infrastructure is often erected to protect vulnerable settlements—which are usually poorer settlements—because more affluent areas have the means to build new homes in less vulnerable areas. Case in point: New Orleans’s failed levees during Hurricane Katrina disproportionately affected the poor neighborhoods which sat below sea level, housing around 30 percent of the population.

And then there are the profiteers who cash in as the climate crisis takes hold across the United States. In a disaster capitalism free-for-all, firms win publicly financed contracts to rebuild an area struck by natural disasters while paying little if any tax on their profits. After Hurricane Katrina, many—including the occasional corrupt politician—have made a fortune from rebuilding New Orleans. The goal: wipe out the old pre-hurricane city and capitalize it instead. This only forces development in high-risk areas. When the next big disaster comes, that can be catastrophic.

New flood protection infrastructure can lead to low perceived risk, increased development, and thus amplified impacts when extremes eventually occur. It’s not enough to build a sea wall and call it a day. Investing not just in levies, but also in flood-resistant homes, and moving local infrastructure can make high-risk areas more resilient.

But physical infrastructure is only one component. “Rather than just being about a wall or structure that’s in place—something that’s very static, something that can be destroyed, something that has to be rebuilt—we could build a society itself where shocks are part of the system,” Aldrich said. Social ties, it turns out, matter when it comes to disasters.

A community where neighbors knock on doors of those who needed help and escort them out of harm’s way, where the elderly in nursing homes are part of evacuation trials and training, is a more resilient community. Neighbors, Aldrich said, will likely serve as first responders during any crisis. In the wake of Hurricane Harvey, for instance, the “Cajun Navy” consisted of thousands of volunteers self-organizing and self-coordinating to rescue people caught in floods; people turned to social networks such as Facebook and Twitter to connect with volunteers after the 911 line became overloaded.

A few organizations are spearheading these kinds of efforts throughout the country. Aldrich has worked with non-profit BoCo Strong in Boulder, Colorado which was formed in the wake of the state’s historic deluge in 2013, in which more than 18,000 homes suffered some level of flood damage. “After a natural disaster, the main focus is typically on restoring physical infrastructure and making it more resilient, while social infrastructure is frequently ignored or forgotten,” the group writes in its website. Instead, BoCo Strong focuses its efforts on encouraging local residents to devise their own plans for mitigating future crises. The organization promotes conversations between local residents and civil society organizations in order to help strengthen connections and think about the needs of the area. Last year, the organization announced an initiative known as ‘Resilience for All’ that would hire and train cultural brokers—“people whose background and skills enable them to bridge two cultures and serve as an advocate or connector,” according to the Longmont Daily Times-Call.

Time and time again, Aldrich’s research has shown that societies with this kind of social infrastructure in place have lower mortality rates in the wake of an environmental calamity; after the triple disasters that struck Japan on March 11, 2001—earthquake, tsunami, and nuclear meltdown—Aldrich found that social networks, not necessarily proximity to climate-ready infrastructure, were critical predictors of survival. “Even though all of these societies supposedly have the physical infrastructure, the reality was we couldn’t find any measurable impact from those big seawalls,” Aldrich says.

In the coming decades, as communities in high-risk locations face larger and fiercer storms, and low-risk locations start to become high-risk locations, disaster preparedness will become a top issue for many governments. The data from global warming’s early years—and storms—suggests policymakers might want to update their toolkits.