Dunes, Reefs and Kelp Forests Protect US Coast from Climate Change

As sea levels rise and as storms become more severe, coastal areas are at risk for flooding that can cause billions in damages. There are ways to protect coastlines, though. Researchers are pointing out the importance of coastal forests, coral reefs, sand dunes and wetlands when it comes to keeping storm surges at bay and preventing national disasters.

Coastal habitats are vital in the U.S. Coral reefs can keep waves from eroding beaches as waves break over them instead of on the sand; wetlands can naturally absorb water and prevent flooding; and kelp forests can mitigate the impact of waves. In addition, these habitats provide vital areas for fish and other species to thrive.

In the latest study, researchers synthesized a hazard model for the U.S. coast. Essentially, they found out which areas were most at risk for storm surge and which areas had the greatest coastal protection. They used ecosystem data, projected climate scenarios, socio-economic data and property values. In all, they identified nine habitats and ranked the level of protection each gave to the coast.

"We have to look at the shoreline elevation, wave exposure and whether it's rocky or muddy to determine where habitats become important for protection," said Katie Arkema, an ecologist involved in the study, in an interview with Nature.   

After ranking these habitats, the researchers then identified areas with the highest exposure to flooding and erosion under five current and future climate scenarios with and without the habitat present. This allowed them to see exactly how the coasts fared and how important these habitats were for preserving the areas.

In the end, the researchers found that the number of people and total property value at risk could double by the end of the century if habitats are lost. Currently, researchers estimate that a total of 2.1 million people and $400 to $500 billion will be exposed to the highest risk hazard.

It's not just about whether habitats are capable of providing coastal protection," said Arkema in an interview with National Geographic. "It's also where they matter for people and for property. We really wanted to figure out where habitats are reducing exposure and also where those locations overlap with coastal property values and human populations that need to be protected."

The findings show the major importance of these coastal habitats. They can absorb water and keep waves from washing ashore.  In the future, it will be more important than ever to preserve these locations and restore them.

The findings are published in the journal Nature Climate Change.