Seawalls offer a false sense of security as oceans rise

Recently, I was interviewing disaster survivors in northeastern Japan, which basically amounted to asking people to relive the worst moment of their lives in excruciating detail. It’s a common, if uncomfortable, task for journalists, but these conversations were especially hard. I was asking about a disaster that had killed around 20,000 people more than a decade ago, on March 11, 2011. Surely locals were tired of talking about it.

So, I was surprised when people who experienced the earthquake and tsunami that hit Japan’s Tohoku region that day did not walk away or shame me for asking questions. They pulled up a chair. For many, it turned out, the only thing worse than remembering the disaster was forgetting its lessons — especially when it came to seawalls.

I heard stories of brothers, grandparents and wives who either did not evacuate their coastal homes after the magnitude 9.1 earthquake struck, or who fled, only to return just before the massive tsunami hit. In 2011, parts of Tohoku had been protected by decades-old fortifications. Many people believed these walls would protect them.

Afterward, researchers quantified the cost of that false sense of security. They found that seawalls had encouraged development in vulnerable places, exacerbating the damage. People who lived behind large barriers took longer to evacuate. And the death toll had been highest in communities that had recently built fortifications or where people had no memory of tsunamis.

I’m a climate reporter, and the lesson that I took from my conversations with survivors of the 2011 disaster is that our faith in simple infrastructural adaptations like seawalls will come back to haunt us.

In recent months, winter storms and high surf have battered the U.S., sending water pouring over seawalls from Seattle to Salem, Mass. Protective walls were breached in Narragansett, R.I.; Miami and Gulfport, Fla.; Ocean City, Md.; Cape May, N.J.; Hampton, N.H.; and Mystic, Conn. In California, storms carried on a string of atmospheric rivers have topped barriers in Cayucos, San Diego, San Francisco, San Luis Obispo and Ventura.

The damage hasn’t always been devastating, but that’s no cause for complacency. In Japan, I learned that many of the walls that toppled in 2011 had been built after World War II, when the country churned out concrete to spark its addled economy. In 1960, a magnitude 9.5 earthquake off the coast of Chile sent a wave barreling across the Pacific Ocean, and by the time it reached the shores of Japan, it was just shy of the height of the newly built walls. To many, it looked like they would always hold.

Recent storms have been substantial, even deadly. But like the 1960 wave, they are the pale ghosts of what’s possible.

Last year, our planet saw record heat on land and sea. Melting Arctic glaciers and collapsing ocean currents have fueled fears of runaway sea-level rise. And yet, we continue to build in the path of disaster, “expanding continuously and rapidly into present-day flood zones,” as one study explained. Once we’ve settled in those places, we have no choice but to protect ourselves from inevitable dangers.

This is where it appears the lessons of 2011 are fading fast.

In Puget Sound, where the sea has risen 4 inches since 1950, one-third of the coast is already walled off. Now, climate models predict another 15-inch rise by 2050, and beachfront homeowners are risking legal trouble hurrying to build taller walls and bulkheads to protect their properties, even as the state pushes for softer measures. Washingtonians are part of a national trend.

By 2040, Americans could spend more than $416 billion fortifying their coasts. New Yorkers are deliberating a potential five-mile-long wall across New York Harbor. Miami is considering a 20-foot-high seawall across Biscayne Bay. Charleston, S.C., has earmarked $1 billion for an 8-mile-long seawall. Cape May, N.J., is poised to spend $16.2 million to build another wall in the shadow of many like it that have already failed.

Even in Japan, in coastal towns where the tsunami exposed seawalls as ineffective and even counterproductive, the government has doubled down. The country is nearly finished erecting a gray concrete curtain of barriers that sometimes reach 50 feet high — twice as tall as previous walls — at a cost of more than $250 billion. These monstrosities will smother beaches and erase views of the sea, but they are not high enough to block another 2011-sized wave.

It’s not that seawalls are a universally bad idea; it’s that they’re always our first idea, our knee-jerk, simple reaction to a complex problem. And they carry unintended consequences. In Japan, I met frustrated people who fought government proposals for new walls out of fear that they would damage beach ecosystems, harm tourism, and sever the connection between fishing villages and the sea. The walls were built anyway.

Studies in the Salish Sea, the inland marine waters of Washington and British Columbia, have shown coastal armoring kills Chinook salmon, disrupts tidal flows, increases acidity, redirects the force of waves onto others along the waterline and mangles beach ecosystems that support much more life.

The region is now engaged in a costly effort to remove existing fortifications, and it’s encouraging, at least, that some beaches have been shown to rebound when allowed. At the Olympic Sculpture Park, for instance, the insects, crustaceans, worms, snails and clams that feed Chinook salmon were back on the menu less than a year after concrete armoring was removed and habitat restored. In other cases, removing our mistakes risks causing even more harm.

What really scares many like me, though, is that the concrete being poured and stacked all along the coast will pave the way to history repeating. These massive bulwarks have an insidious effect: While physically blocking views of the ocean, they also conceal the threat of what lurks on the horizon. Shielded from a daily reminder of the risk, it’s much easier to go on developing in places increasingly vulnerable to flood, consuming at an unsustainable pace and burning fossil fuels like the planet isn’t warming.