Mangroves protect coastal economic activity from hurricanes

Background

With more frequent and severe weather events anticipated due to climate change, coastal communities are interested in practical coastal defense interventions to protect their public and private assets and prevent disruptions to economic activity from tropical storms. Studies have documented mangrove forests’ ability to reduce wave action, wind velocity, and storm surge, making mangroves a cost-effective form of coastal protection. Yet, the relationship between how large a mangrove belt must be to provide significant protection and how mangroves mitigate tropical storm effects and economic damages is still unknown.

Goals and Methods

This study uses remote sensing data from Central America over 2000 to 2013 and a storm damage model to estimate economic activity, potential hurricane damage, and mangrove protection. The authors use nightlights (i.e., the amount of human-made light visible at night) as a proxy for short-term economic activity and quantify hurricane damages from a wind speed model, focusing on cyclone data from Costa Rica, El Salvador, Honduras, Guatemala, Nicaragua, and Panama. They calculate the extent of mangrove protection using a damage function and a regression equation to estimate the causal impact of mangrove forests on coastal economic activity protection.

Conclusions and Takeaways

Hurricanes have negative effects on short-term economic activity in Central America, with an estimated 16% decrease in economic activity from a modeled category 3 hurricane. Coastal lowlands without protection from dense mangrove vegetation to buffer high wind speeds and storm surge suffer a 17% reduction in short-term economic activity. However, increasing the width of mangrove belts can decrease the impacts of hurricanes on short-term economic activity, which would increase coastal community resilience. A category 3 hurricane can decrease short-term economic activity by 24% in an area with less than 1 km of mangrove width, whereas areas with a mangrove width over 1 km are relatively unaffected. These results indicate that large-scale mangrove conservation and restoration projects can have significant resilience against tropical storm damage.