Summary Report The Global Value of Mangroves for Risk Reduction Mangroves protect coastlines by decreasing the risk of flooding and erosion. Authors: The Nature Conservancy: M. W. Beck, D. Trespalacios, K. Pfliegner University of California Santa Cruz: S. Narayan Environmental Hydraulics Institute “IHCantabria”, University of Cantabria: Í. J. Losada, P. Menéndez, A. Espejo, S. Torres, P. Díaz-Simal, F. Fernández, S. Abad Bündnis Entwicklung Hilft: P. Mucke, L. Kirch Photo credits: Pg 1: Mangrove roots under water. Jardines de la Reina, Cuba. © I. Shive; Pg 2: Mangroves on Lembongan Island, Bali. © K. Arnold; Pg 7: Children planting mangrove seedlings. © UNISDR; Pg 9: Enipein Mangrove Forest Reserve, Pohnpei, Micronesia. © N. Hall; Pg 10 Insert: Planting mangroves in Siargao, Philippines. © U. Meissner, Background: Mangroves along Mahé Island, Seychelles. © J. Houston; Pg 12: Mangroves near Tarobi village, West New Britain, Papua New Guinea. © M. Godfrey Design: N. Gruden (Graphic Design), B. Bruhns (Management), MediaCompany May 2018 Suggested Citation: Beck, M. W. , S. Narayan, D. Trespalacios, K. Pfliegner, I. J. Losada, P. Menéndez, A. Espejo, S. Torres, P. Díaz-Simal, F. Fernandez, S. Abad, P. Mucke, L. Kirch. 2018. The global value of mangroves for risk reduction. Summary Report. The Nature Conservancy, Berlin. doi: 10.7291/V9930RBC Supported by: based on a decision of the German Bundestag This project is part of the International Climate Initiative (IKI). The Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) supports this initiative on the basis of a decision adopted by the German Bundestag. Additional support for this work was provided by the World Bank. The Global Value of Mangroves for Risk Reduction and Climate Adaptation Mangroves act as natural defenses that protect people and property from flooding, reduc­ ing coastal risk. Yet these protective benefits are often not fully accounted for in policy and management decisions, and mangroves continue to be lost. This work rigorously values the social and economic coastal protection benefits provided by mangroves. By identifying where these natural coastal defenses provide the greatest flood reduction benefits, this work informs policies for adaptation, sustainable development, and environmental restoration. Key Points ++ This work uses a rigorous integrated hydro­ dynamic approach to value the flood protec­ tion services of mangroves, and identifies where mangroves provide the greatest benefits. ++ Mangroves reduce exposure and vulnera­ bility. These combined benefits are most ­im­portant for countries in West and East Africa, Central America and the South Pacific. ++ Mangroves reduce annual flooding to more than 18 million people. Without mangroves 39% more people would be flooded annually, and flood damages would increase by more than 16% and US $82 billion. ++ Mangrove restoration can be a highly cost effective strategy for risk reduction. Hundreds of thousands of hectares have already been restored. ++ Vietnam, India, Bangladesh, China, and the Philippines receive the greatest benefits from mangroves in avoided flooding of people. ++ China, USA, India, Mexico and Vietnam receive the most benefits in terms of annual avoided damages to property. ++ These results can inform strategies for adaptation and risk reduction, including the development of tools that use the risk reduc­ tion benefits of mangroves to pay for their restoration. The Global Value of Mangroves for Risk Reduction – Summary Report | 3 Figure 1: Mangroves prevent erosion and reduce the force of waves, storm surge and flooding. Coasts at Risk More than 60% of the world’s population lives on the coast. Coastal development and climate change are dramatically increasing the risks of flooding, erosion, and extreme weather events for millions of vulnerable people, important infrastructure, and trade. In the last 30 years, the amount of the world’s Gross Domestic Product (GDP) annually exposed to tropical cyclones has increased by more than US $1.5 trillion. Insurers alone have paid out more than US $300 billion for coastal damages from storms in the past 10 years1. Governments worldwide are dedicating billions of dollars to reduce risks from disasters and climate change. Unfortunately, most of our global investments in coastal protection are destined for “grey infrastructure”, such as seawalls, that remain vulnerable to coastal risks and fail to ada