New Study Puts a Dollar Figure on Protection From Coral Reefs

It’s long been known that natural coastal ecosystems blunt some of the worst effects of storms and sea-level rise. Now a new study puts a dollar figure on some of those savings. Coral reefs off the U.S. coasts currently provide $1.8 billion in flood protection to property owners annually, researchers found.

Individual reefs off of Hawaii and Florida do particularly valuable duty, the study estimated. A little over 100 kilometers of these reefs provide more than $10 million of flood protection per kilometer of reef. The most valuable, situated off of Honolulu, provides $154.3 million in protection each year alone, while another half-dozen block more than $50 million in flood damage a piece.

The study was published in the journal Nature Sustainability, the result of a partnership between the University of California, Santa Cruz, and the U.S. Geological Survey. It’s intended to inform coastal managers working on flood mitigation, coastal defense, transportation, and hurricane response and recovery.

“Valuing the flood risk-reduction service of existing ecosystems is one step toward managing them as natural infrastructure,” said lead author Borja Reguero, an associate researcher at UC Santa Cruz. “This study provides new local information on how reefs protect communities at the building-block level, while maintaining a national focus for policy purposes.”

The researchers said they were able to combine advances in computer models predicting wave action caused by storms with high-resolution maps of topography and coral distribution to build probabilistic risk frameworks for property, economies, and infrastructure.

Warming waters and ocean acidification have damaged reefs all around the world, causing them to shrink at an alarming rate. Management and restoration efforts require resources, so the authors focused on the places where failure to act would have particularly grim financial consequences.

They estimated that if the reefs continue to degrade by even one more meter of height, the number of properties in severe flood risk zones delineated by the government would increase 23%. The number of people potentially affected by annual floods would increase by 62%, while projected damages would rise by $5.3 billion.

©2021 Bloomberg L.P.

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