The Global Value of Mangroves for Risk Reduction

TNC scientists and partners at the Environmental Hydraulics Institute IH Cantabria have produced a ranking of countries that receive the greatest risk reduction benefits from mangroves, relative to their vulnerability.The Global Value of Mangroves for Risk Reduction- available in both a Summary Report and a Technical Report– uses rigorous hydrodynamic and economic models to value the coastal flood protection services of mangroves globally, and then identifies the places where mangroves provide the most benefits to people and property. This work applies an approach that is commonly used in engineering and insurance sectors, and quantifies protection benefits of mangroves as the amount of flood damages avoided because of the presence of mangroves.

Mangroves prevent erosion and reduce the force of waves, storm surge and flooding.

These results demonstrate that mangrove conservation and restoration can be an important part of the solution for reducing risks to coastal communities. Here are some of the key findings from this work:

  • 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 annually
  • Vietnam, India, Bangladesh, China, and the Philippines receive the greatest benefits from mangroves in terms of avoided flooding of people
  • China, USA, India, Mexico, and Vietnam receive the greatest benefits in annual flood damages to property
  • The countries that receive the greatest overall risk reduction benefits from mangroves are Guinea, Mozambique, Guinea-Bissau, Sierra Leone, and Madagascar.

By providing ranked value of the protection benefits provided by mangroves globally, this work enables mangroves to be better managed as natural coastal infrastructure within policy and management decisions worldwide.

The map shows where mangroves provide the greatest flood reduction benefits for property. The values represent the difference in annual expected damages in US $ millions with and without mangroves per 100 km of coast.