Coral Reefs as Coastal Protection
Published at: July 17th, 2021 by Carin JantzenThis month marks the beginning of the Atlantic hurricane season, and forecasters are anticipating another year of heightened storm activity. Coral reefs are an essential natural defense, protecting coastal communities from waves and floods.
According to the National Oceanic Atmospheric Administration (NOAA), "a likely range of 13 to 20 named storms, of which 6 to 10 could become hurricanes, including 3 to 5 major hurricanes is expected." This outlook is based on warmer than average sea-surface temperatures in the tropical Atlantic and climate factors, such as the El Niño-Southern Oscillation (ENSO). In addition, the National Hurricane Center (NHC) began issuing regular Tropical Weather Outlooks as early as May 15 this year, weeks ahead of the hurricane season's official start on June 1.
When these storms release their destructive potential, coral reefs play a critical role in protecting our coastlines. According to the 'Reefs at Risk' report by the World Resources Institute, "over 150,000 km of shoreline in 100 countries receive at least some protection from coral reefs." They serve as a coastal buffer from waves, storms, and floods, helping to prevent loss of life, property or infrastructure damage, and erosion. Reef-building species, like the endangered elkhorn coral (Acropora palmata), act as natural breakwaters and protect our coastlines by absorbing up to 90 percent of the wave energy. Unfortunately, this Caribbean species suffered a massive decline during the last decades. If reefs are damaged or destroyed, the absence of this natural barrier can conversely increase the impact of wave action on coastal communities.
A recently published paper considers "the hazard risk reduction benefits of U.S. coral reefs to exceed US $1.8 billion annually". In addition, the U.S. Geological Survey estimates that "with a 1-m loss in reef height, the 100-year floodplain would increase across the U.S., imperiling 51,000 people and $5 billion in property and economic activity." On a global scale, an early study from 2003 placed the net value of coral reefs for flood protection at $9 billion per year. Another more recent publication estimates that the topmost 1 meter (approx. 3 ft) of coral reefs provides flood reduction benefits during 25-year events resulting in $36 billion avoided damages of global capital. Thus, coral reefs play an incredibly important role in defending shorelines worldwide. If these valuable ecosystems disappear, wealthy countries will have to heavily invest in artificial coastline protection. Less privileged coastal communities, however, may face a permanent loss of homes and businesses.