The worst damage from hurricanes doesn't always come from wind. In fact, some of history’s most damaging hurricanes—like Sandy, for example—were very low-power but caused massive amounts of destruction because they sat over land for long periods of time and just dumped water. As new science is starting to reveal that hurricanes are slowing down (which you can read more about in the previous story in this series about hurricane research and also in the forthcoming story about hurricanes and climate change), the storms are picking up larger and larger amounts of water on their way to landfall and then spending days sitting in place raining.
There are a whole slew of major problems with the amount of water that a hurricane brings with it. The first one is that in the U.S. we have largely destroyed our wetlands, which—when they are naturally occurring—act as barriers to high waves and also sponges to absorb excess water. Another is that the U.S. government has passed laws that reduce insurance rates in places that are prone to flooding, which encourages people to build and rebuild in flood-prone regions and hides the amount of risk they are taking by doing that. Combine this with a lack of infrastructure upgrades and a lack of planning for future storms and you have a recipe for disaster.
The Essential Wetlands
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The term wetlands refers to areas of land that meet the sea—that means either salt marshes in the north or mangroves in the south. If it wasn’t for human encroachment and development, most of the U.S. coastline would be made up of salt marshes. Wetlands are essential for the prevention of flooding for two reasons. First, they are sponges that soak up water. Second, because most salt marshes get up to about 6 feet tall (and mangroves get even higher) they can act as barriers for storm surge—when the force of hurricane winds push ocean water up onto the shore. Mangroves are even more successful at protecting us from surge as their deep roots trap sediment and give them strong stability.
Unfortunately, however, our wetlands are at risk. California, for example, has lost about 90 percent of its coastal marshes. In many parts of the country they have been lost to real estate (parking lots, housing developments, and coastal roads are popular on the seaside) and in places where they remain they are beginning to be drowned by sea level rise.
Even with such a great loss, what little wetlands remain have helped us immensely. According to Mike Beck, the lead marine scientist at The Nature Conservancy, despite the degradation of our wetland systems around the country, even with a storm as destructive as hurricane Sandy, the existing wetlands probably saved the Northeast from more than $625 million in damages during that storm. “Not only that but we looked across many different storms in the industry’s models and wetlands are reducing about 15 percent of annual expected damages,” he says.
In addition to seaside building, another part of the reason that marshes are in danger, he says, is that development upstream on rivers—like dams and river diversions—are blocking the normal sediment that comes downstream and gets caught in the marshes. The sediment helps the marshes grow tall and, perhaps, outpace sea level rise. “Even if you think about why is the Southeast Louisiana problem happening, it’s because we’re diverting water—all the sediment from the Midwest is going into a single waterway and being sent out into the Gulf of Mexico. In other places we’re building dams or dykes that are holding back water and sediments and not allowing them to reach the coast.”
The key takeaway, says Beck, is that if we plug the benefits of wetlands and mangroves into our existing insurance models we can make some really good financial arguments for not only saving them but also rebuilding them: While salt marshes are protecting us from about 15 percent of damage from hurricanes, “in other work we did with the World Bank and the German International Climate Initiative, we showed mangroves work even better. They’re reducing 20-25 percent of annual expected damages. And work we just published found coral reefs show a 50 percent expected reduction.”
In other words, it might actually be more cost-effective to invest in rebuilding these regions of the country than to simply pay for the damage that’s done once they’re gone. Though Beck says The Nature Conservancy has been making progress spreading this message to insurance companies and local governments (and there have been some restoration efforts underway), there are other forces at work in the opposite direction.
Government Against the Tide
As Hurricane Florence began its onslaught of North Carolina we were reminded of statewide policies that prevented any real protection from the storm. In 2012, the state passed a law banning state agencies from using climate change science to invest in coastal protection. And it’s well worn territory that the nation’s infrastructure as a whole is outdated and certainly less and less able to stand up to the growing power of our new, bigger, badder hurricane season.
But one of the most problematic policies, according to Kerry Emanuel, an atmospheric scientist at the Massachusetts Institute of Technology and one of the world’s leading experts on hurricanes, is the fact that the U.S. government actually incentivizes people to live directly in the path of our worst storms. “It’s not an accident that we have a lot of economic activity and people in risky places. It’s a direct result of very unwise policies unique to the United States,” he says.
Emanuel is referring to the National Flood Insurance Act, a policy that was created in 1968, which ensures that the cost of flood insurance policies don’t reflect the actual amount of risk incurred by policyholders. Wealthy policy holders with expensive flood insurance policies, he says, use political clout to push their representatives to put caps on the cost of their insurance. “It’s a subsidy,” he says. “The insurance industry is regulated for the same reason banks are— to make sure they have enough capital to pay you when the time comes. But that regulation has been seriously corrupted by political pressure. The people who live on Cape Cod and Martha's Vineyard, for example, feel they pay too high a premium on their private insurance and so states like Massachusetts cap insurance premiums.”
By subsidizing the cost of living, working, and doing business in highly risk-prone areas the government has essentially incentivized people to build in the places most likely to flood (places that would be better off with wetlands instead of condos). Combine this with National Disaster Relief programs and you have very little risk to any real-estate owner. There’s no reason not to put a building directly in harm’s way: your insurance premiums won’t reflect the risk you’ve taken and the government will help pay for you to rebuild. “This is why people are building flimsy houses and infrastructure and living in risky places. We pay them to do that,” says Emmanuel.
It’s About Communicating Risk
All of these problems put together come down to how we communicate risk. If we truly wanted to, we could move away from the coasts. We could stop building in the most risky places and protect our homes and towns from being devastated by flooding again and again. But we are doing a terrible job of communicating risk to people, enough so that they chose to make these changes and invest in infrastructure upgrades and wetland restoration.
“The only way for you to find out about your risk and for it to matter to you is through the insurance premium. If you find out it’s going to cost you way too much to insure [a building] that will make you think twice,” says Emmanuel. “We know people won’t retreat. We keep doing that experiment over and over. Go to Houston, everyone is rebuilding. Go to Sandy Hook, New Jersey, they’re rebuilding. It’s human nature to build it back the way it was before unless some market force [changes things].”
The Nature Conservancy’s Beck is more optimistic. He’s been working with companies that determine insurance risk to input wetland data into their models and hoping that storm recovery policies can start to recognize the financial benefit of restoration work. He’s also been talking to FEMA and the Government Accountability Office. “If we didn’t present [wetland restoration] in money terms they go: ‘Well what does it matter?’ But if I can tell you the annual expected benefit [of wetlands] that’s a game-changer,” he says. “I’m never, ever, ever saying if you just restored habitats your risk would disappear, never. It’s a combined solution that potentially is a game-change for the tens of billions of dollars we use to manage our coastline. That’s what gives me some hope.”
However we go about re-adjusting the way we see our coastlines we’re going to have to do it fast. Intense and persistent hurricane season is not our future—it’s our now. Next week we’ll talk about why our warming planet is allowing these monster storms to hold more water than ever before. As the planet gets hotter the flood risk from every hurricane that passes over our cities is increasing. It’s time to adapt and recognize the risk is real and growing.
