There is a silent army out there protecting our coasts from invasion — a second Coast Guard, if you will. This army has protected us not from war, but from hurricanes, floods and other catastrophes.

Loxahatchee Slough in Palm Beach County, Florida
Wetlands, like Loxahatchee Slough in Palm Beach County, Florida, act as a coastal buffer. Credit: Kim Seng,

I’m talking about coastal buffers — the mangrove forests, wetlands and oyster beds that protect us from hurricanes, floods and other catastrophic natural events. A new report published in Nature Climate Change finds that without these important natural defenses, twice as many Americans would be exposed to storm surges. That’s more than 1.4 million people who live within a kilometer of either coast, not to mention billions of dollars in property value that would be at risk.

And that’s just the risk that today’s storms would bring without coastal buffers. The researchers also modeled several scenarios of rising sea levels expected in the coming century. They found that by 2100, as many as 2.1 million people will likely be living in “high hazard” areas compared to the current 1.4 million people. That’s an additional 700,000 people who will depend on coastal buffer ecosystems to protect their lives and homes from extreme weather events. Scarily, that’s the best-case scenario, as the study did not take projected population growth into account.

But for all their importance, these ecosystems are not always valued as they should be. Though destruction of wetlands has slowed since the 1970s, we are still losing more than 13,000 acres a year. Mangroves are faring better in the United States — being protected in Florida — but worldwide, the outlook is not so good. Only 6.9 percent of the planet’s mangroves are officially protected, according to a 2010 U.S. Geological Survey study. In the last half a century, we’ve lost 50 percent of the world’s mangroves, largely due to the increase in industrial shrimp farming.

Of course, these ecosystems are not the only factor in how well coasts are protected from severe weather. There’s also infrastructure to take into account, as well as policy regarding how close to the shore developers can build. But what the study makes clear is that without this silent army of ecosystems, people would face substantially more risk from extreme weather events.

That’s why many of our Global ReLeaf projects work to restore these ecosystems. We’re reforesting wetlands in Illinois and South Carolina. Through our work with Alcoa Foundation and China Mangrove Conservation Network in Fujian Province, China, and the Sumatran Orangutan Society in Indonesia for example, we’re helping organizations in places with fewer protections for mangroves preserve those important trees to help protect coast dwellers and us all.