Without coral reefs, annual flood damages from storms could double globally

Physical and Biological Sciences News

Coastal development and climate change are increasing the risk of flooding for communities across the globe. Coral reefs, which provide a first line of defense against coastal flooding in countries around the world, are being lost rapidly. A new study investigating how much people and property are protected by coral reefs, and what is at stake if our reefs are lost, shows that coral reefs cut the cost of all flood-related damages around the world in half.Published June 12 in Nature Communications, the study (“The global flood protection savings provided by coral reefs”) uses models commonly applied in the engineering and insurance sectors to quantify and value the flood reduction benefits provided by coral reefs worldwide. Coral reefs serve as natural, submerged breakwaters that reduce flooding by breaking waves and reducing wave energy. The study compares the flooding that occurs now with the flooding that would occur on coastlines with coral reefs if just the topmost 1 meter of living coral reef were lost.
Significant losses of coral reefs are already happening, according to first author Michael Beck, research professor of ocean sciences at UC Santa Cruz and lead marine scientist at the Nature Conservancy.
“Unfortunately, we are already losing the height and complexity of shallow reefs around the world, so we are likely already seeing increases in flood damages along many tropical coastlines,” he said. “Our national economies are normally only valued by how much we take from nature. For the first time, we can now value what every national economy gains in flood savings by conserving its coral reefs every year.”
Without living coral reefs, the annual expected damages from flooding would double, increasing by $4 billion. The costs from frequent storms would triple. If coupled with sea level rise, flooding could quadruple. For the big 100-year storms, flood damages could increase by 91 percent to $272 billion.
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