The Global Flood Protection Benefits of Mangroves

TLDR

Coastal flood risks are rising rapidly. The study provides high‑resolution estimates of the economic value of mangrove forests for flood risk reduction worldwide and develops a probabilistic, process‑based valuation of their effects on averting damages to people and property. The authors couple spatially‑explicit 2‑D hydrodynamic analyses with economic models to evaluate mangrove flood protection, yielding benefits exceeding $US 65 billion per year. The analysis shows that mangroves avert over $US 65 billion in annual flood damages, protect 15 million more people if lost, and deliver the greatest economic benefits to the USA, China, India, Mexico, Vietnam, India, and Bangladesh, with many 20‑km coastal stretches near cities receiving more than $US 250 million annually.

Abstract

Coastal flood risks are rising rapidly. We provide high resolution estimates of the economic value of mangroves forests for flood risk reduction every 20 km worldwide. We develop a probabilistic, process-based valuation of the effects of mangroves on averting damages to people and property. We couple spatially-explicit 2-D hydrodynamic analyses with economic models, and find that mangroves provide flood protection benefits exceeding $US 65 billion per year. If mangroves were lost, 15 million more people would be flooded annually across the world. Some of the nations that receive the greatest economic benefits include the USA, China, India and Mexico. Vietnam, India and Bangladesh receive the greatest benefits in terms of people protected. Many (>45) 20-km coastal stretches particularly those near cities receive more than $US 250 million annually in flood protection benefits from mangroves. These results demonstrate the value of mangroves as natural coastal defenses at global, national and local scales, which can inform incentives for mangrove conservation and restoration in development, climate adaptation, disaster risk reduction and insurance.