The annual expected damages from flooding would double globally without coral reefs according to a study in Nature Communications this week. This finding demonstrates that coral reefs not only provide coastal protection benefits to people and property, but also flood-protection savings.
Michael Beck and colleagues use flooding models to estimate the annual expected benefit of coral reefs for protecting people and property globally. They compare flooding for scenarios with and without reefs for four storm events based on the probability that they will occur, the latter scenario assuming a one metre decrease in coral reef height and roughness. They find that for extreme events (100-year storm events, which have a 1% chance of happening in any given year), flood damages would increase by 91% to $272 billion without reefs. They also show that Indonesia, Philippines, Malaysia, Mexico and Cuba have the most to gain from reef management, with annual expected flood savings exceeding $400 million each.
The authors warn that although flattening of coral reefs has been observed in several locations globally, some areas of the globe have reefs in good condition, with some even growing. Therefore, the effects reported are not foregone conclusions, but underscore the importance of considering the economic valuation of reefs to inform policy.