Flood damage would double without coral reefs: study


  • Loss of coral reefs around the world would double the damage from coastal flooding, and triple the destruction caused by storm surges, researchers said June 12. Coupled with projected sea level rise driven by global warming, reef decline could see flooding increase four-fold by century’s end.

About the Study:

  • Without coral to help absorb the shock, a once-in-a-century cyclone would wreak twice the havoc, with the damage measured in the tens of billions of dollars, the team calculated.
  • Coral reefs serve as natural, submerged breakwaters that reduce flooding by breaking waves and reducing wave energy,
  • Not all coral reefs are declining, and reefs can recover from bleaching, overfishing and storm impacts.
  • Much of the world’s 71,000 kilometres of coastline with shallow reefs — concentrated in the tropics — has been decimated by coastal development, sand mining, dynamite fishing and runoff from industry and agriculture.
  • Coral is also highly sensitive to spikes in water temperature, which have become sharper and more frequent with climate change. A marine heatwave in 2016, for example, killed off nearly 30 percent of Australia’s iconic Great Barrier Reef. 
  • Global coral reefs risk catastrophic die-offs if Earth’s average surface temperature increases two degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels, earlier research has shown.
  • The countries most at risk from coral reef loss are Indonesia, the Philippines, Malaysia, Mexico and Cuba, each of which could avoid $400 million in damage per year if reefs are maintained. Saudi Arabia, the United States, Taiwan and Vietnam would also become significantly more vulnerable to flooding with severe coral erosion.
  • Mangrove forests, for example, also protect against storm surges and serve as nurseries for dozens of aquatic species. They are disappearing at the rate of one-to-two percent per year, scientists say. Likewise, bee populations that pollinate tens of billions of dollars worth of crops each year are collapsing.

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