Climate change is starving the world's coral reefs beyond the point of recovery, confirms a new study by the National Oceanic and Atmospheric Administration.
After analyzing data of 100 reef locations around the world from 1980 to 2016, scientists have discovered that abnormally warm waters have been causing coral bleaching or coral whitening to occur more frequently in the recent years. Back in the 1980s, reefs still had up to 30 years of healing period between stressful episodes, but now, that window has been alarmingly reduced to six years.
This is not enough time for corals to recuperate, as even the fastest-growing of its species would take at least 10 to 15 years before making a full recovery from intense bleaching. Reefs, on the other hand, require an even larger window comprised of several decades.
Should climate conditions persist, scientists have predicted that bleaching could start occurring at an annual rate in the next decades.
Corals Suffer In Warm Ocean Temperatures, Reveal Scientists
Scientists explain that corals are invertebrates that thrive mostly in tropical climates. They secrete a natural compound called calcium carbonate to form their protective skeletons and take on a variety of vibrant colors due to microscopic algae called zooxanthellae that live in their tissues.
Collectively, reefs play a critical role in maintaining ecological balance and are considered as the underwater equivalent of rainforests. Not only do they serve as habitats for marine animals, but they are also responsible for producing a portion of the oxygen that humans breathe. Without them, coastlines are also left exposed to the full force of storm surges.
Unfortunately, corals are sensitive to temperature changes. They have been found to experience thermal stress when ocean temperatures rise, and they respond by expelling zooxanthellae. As a result, they turn completely white in color and become susceptible to diseases as the algae also happen to be their primary food source.
Bleached corals are not yet dead, says NOAA in a separate report. Although they have a higher mortality risk, these corals can still survive through improved conditions and sufficient recovery time.
El Niño Brings Mass Bleaching From 2014 To 2017
In 2014, scientists were anticipating a global El Niño event. It never formed, but it caused mass coral bleaching. Data recorded by NOAA Coral Reef Watch's satellite show that during the three-year episode, 70 percent of the world's reefs experienced thermal stress, which resulted in bleaching.
Most affected locations include the Great Barrier Reef, Kiribati, Jarvis Island, and Guam, where corals were bleached each year from 2013 to 2017.
Following the global catastrophe, scientists call for more research to explore mechanisms that would help corals survive in warm conditions.
"While our only real chance for their survival is to reverse climate change, a nugget of hope exists — that the corals may be able to adapt to their changing environment," says Dr. Gergely Torda of the ARC Centre of Excellence for Coral Reef Studies at James Cook University.
As early as 2016, Torda and other scientists have already pointed out in a paper that the window of opportunity to rescue the world's coral reefs from going extinct is "rapidly closing."