Study: Coastal Nature Reduces Risk from Storm Impacts for 1.3 Million U.S. Residents

Written by Robert Lalasz on . Posted in Learn

2348465076_880eeb019c_z Jorge Rodriguez Flickr storm in San Juan PR web

Editor’s Note: How can natural shorelines help protect us from nature’s fury in the form of coastal storms? In a recent interview with PBS MetroFocus Host Rafael Pi Roman, The Nature Conservancy’s Chief Scientist Peter Kareiva discusses the latest science assessing the risk of storm surge facing millions of people living along U.S. coastlines and the role of natural defenses. The interview will air on MetroFocus in the Sandy-affected New York and New Jersey regions tomorrow at 7:30 p.m. on WLIW and on Thursday, Aug. 29, at 8:30 p.m. (Thirteen) and 10:30 pm (NJTV). Read more about the study Kareiva co-authored with the Natural Capital Project in today’s post adapted from Cool Green Science.

Katrina, Sandy, Andrew: iconic names….and indelible examples of how nature can kill and destroy.

But could nature actually help reduce our risk from…nature? Specifically: could sand dunes, oyster and coral reefs, sea grasses and other coastal natural habitats blunt the effects of coastal storms — like surges and flooding? Could they even reduce the risk of fatalities and property loss from such storms?

They already are — for at least 1.3 million people and billions in property value along the U.S. coastline, according to a new study just published in the journal Nature Climate Change. Neglecting those habitats, the study adds, could double the number of U.S. residents at “high hazard risk” from storms — including hundreds of thousands of poor and elderly.

And with sea-level rise projected to make storm surges much worse over the coming decades, coastal nature might become even more important in reducing risk from coastal storms.

“This study shows how key a role nature plays in protecting our nation’s coasts, and it tells us where habitats matter the most for that purpose,” says Katie Arkema, the study’s lead author and a Stanford University scientist associated with the Natural Capital Project.

“If we lose these habitats, we will either have to make massive investments in engineered defenses or risk greater damage to millions of people and billions in property.”

16% of Immediate US Coastline at ‘High Hazard’ Risk; Florida, New York and California Benefit the Most from Coastal Habitats

Coauthored by scientists with the Natural Capital Project and The Nature Conservancy, the new study offers the first map of where natural habitats reduce coastal-storm risk for lives and property values along the entire U.S. coastline.

Key findings from the study:

  • About 16% of the immediate U.S. coastline (within one kilometer of the shore) is classified as in “high      hazard” areas — home to 1.3 million people and  $300 billion in residential property;
  • 67% of the U.S. coastline is protected by natural habitat — which, if lost, would double the number of      poor families, elderly people and total property value in the areas at highest risk from coastal hazards such as storm surges.
  • Florida, New York and California are the states where coastal habitats defend the greatest number of people (including the elderly and the poor) and the greatest amount in property values from storm risk.
  • Sea-level rise will increase the amount of highly threatened people and property by 30-60% by the year 2100.

“California, Florida and New York have both a lot of people at risk from coastal storms and intact coastal and marine ecosystems that are playing a very big role in terms of reducing that risk,” says Arkema. (New Jersey and Massachusetts rank just behind those states in both categories. See Figure 1 for more details.)

“And our analysis shows that, if you were to lose or degrade habitats in these places, you’d double or almost double the number of people at risk in each state.”

‘Engineering Shouldn’t Be the Default Solution’ for Our Coastlines

The study doesn’t factor in projected population increases or continued building construction along U.S. shorelines through 2100. It also only indexes risk for that 1-kilometer sliver of shoreline, and not the millions of people inland who might be affected by extensive storm surges.

But that doesn’t diminish the relevance of the findings to coastal communities thinking about how to combat the effects of storms and sea-level rise, according to Peter Kareiva, chief scientist at The Nature Conservancy.

With 23 of the 25 most populous U.S. counties along the coast, he says the data couldn’t be more timely — especially since many planners don’t have good information on the full risk-reduction value of their natural habitats.

“Hardening our shorelines with sea walls and other costly engineering shouldn’t be the default solution,” says Kareiva. “They might be appropriate in some situations. But now we have data on those places and opportunities where nature contributes the most to protecting our coastal communities — and giving us all the other benefits it can provide, such as recreation, fish nurseries, water filtration and erosion control.”

Bob Lalasz directs science communications for The Nature Conservancy.

Photo by Flickr user Jorge Rodriguez/Used under a Creative Commons license. (Storm in San Juan, Puerto Rico.)

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