Reducing pollution and curbing overfishing won't prevent the severe bleaching that is killing coral at catastrophic rates, according to a study of Australia's Great Barrier Reef. In the end, researchers say, the only way to save the world's coral from heat-induced bleaching is with a war on global warming.
The researchers conducted aerial and underwater surveys of the Great Barrier Reef, which has experienced three major bleaching events, the worst of which occurred last year. The scientists found that the severity of bleaching was tightly linked to how warm the water was. In the north, which experienced the hottest temperatures, hundreds of individual reefs suffered severe bleaching in 2016, regardless of whether the water quality was good or bad, or whether fishing had been banned. That means even the most pristine parts of the reef are just as prone to heat stress as those that are less protected.
The research also illustrated the gravity of the situation facing the 2,300-kilometer (1,400-mile) Great Barrier Reef. The team found 91 percent of the reef has been bleached at least once during the three bleaching events. Even more alarming, Hughes said, is that a fourth bleaching event is already underway. Corals need years to recover from bleaching, so back-to-back events increase the possibility that the bleached coral will die.
The study shows that very intense coral bleaching events are no longer isolated and are happening more regularly, said coral reef scientist Julia Baum of Canada's University of Victoria. That assertion has been further bolstered by the Great Barrier Reef's latest bleaching event, which began a few weeks ago and which Baum says has stunned scientists.