According to a new study, without mangroves, flood damages would increase by more than $65 billion annually. The natural coastal defences mangrove forests provide globally reduce annual flooding significantly in critical hotspots.
Mangrove forests occur in more than 100 countries around the world, but many have been lost due to an increase in aquaculture, as well as coastal industry and development. The rising sea levels and intensifying impacts of hurricanes caused by climate change is increasing the risk of coastal flooding, and conservation and restoration of natural defences such as mangroves offers cost-effective ways to mitigate and adapt to these changes. According to the authors, mangrove forests can be easily restored to make people and property safer.
“Mangroves provide incredibly effective natural defences, reducing flood risk and damages,” said Pelayo Menéndez, a postdoctoral fellow in the Institute of Marine Sciences at UC Santa Cruz and lead author on the paper.
The researchers provided high-resolution estimates of the economic value of mangrove forests for flood risk reduction across more than 700,000km of coastlines worldwide. They combined economic models and engineering to provide the best analyses of coastal flood risk and mangrove benefits. Their results show when, where, and how mangroves reduce flooding, and they have identified innovative ways to fund the protection of mangrove forests using economic incentives, climate risk financing and insurance.
Their study carefully valued the social and economic coastal protection benefits provided by mangrove forests globally. Many 20km coastal stretches, particularly those near cities, receive more than $250 million annually in flood protection benefits from mangroves.
“Now that we can value these flood protection benefits, it opens all kinds of new opportunities to fund mangrove conservation and restoration with savings for insurance premiums, storm rebuilding, climate adaptation, and community development,” said coauthor Michael Beck, research professor in the Institute of Marine Sciences at UC Santa Cruz. “Mangroves are resilient and can grow like weeds, even around cities, if we give them half a chance.”
Indeed, projects across Vietnam, Philippines, and Guyana have restored 100,000 hectares of mangroves. By identifying the places where mangroves provide the greatest flood reduction benefits, this study can help to inform policies for adaptation, sustainable development and environmental restoration.
The researchers are now working with insurance companies, the World Bank, and various conservation groups to use these results for risk reduction and planning for the conservation of mangrove forests.
To read the full paper, “The Global Flood Protection Benefits of Mangroves”, click here.
Photograph by Maxwell Ridgeway. Diagram courtesy of World Bank and Punto Aparte.
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