Scientists have confirmed the third-ever global bleaching of coral reefs is under way and warned it could see the biggest coral die-off in history.
Since 2014, a massive underwater heatwave, driven by climate change, has caused corals to lose their brilliance and die in every ocean. By the end of this year 38% of the world’s reefs will have been affected. About 5% will have died forever.
But with a very strong El Niño driving record global temperatures and a huge patch of hot water, known as “the Blob”, hanging obstinately in the north-western Pacific, things look far worse again for 2016.
For coral scientists such as Dr Mark Eakin, the coordinator of the US National Oceanic and Atmospheric Administration Coral Reef Watch programme, this is the cataclysm that has been feared since the first global bleaching occurred in 1998 .
“The fact that 2016’s bleaching will be added on top of the bleaching that has occurred since June 2014 makes me really worried about what the cumulative impact may be. It very well may be the worst period of coral bleaching we’ve seen,” he told the Guardian.
The only two previous such global events were in 1998 and 2010, when every major ocean basin experienced bleaching.
Professor Ove Hoegh-Guldberg, director of the Global Change Institute at the University of Queensland, Australia, said the ocean was now primed for “the worst coral bleaching event in history”.
“The development of conditions in the Pacific looks exactly like what happened in 1997. And of course following 1997 we had this extremely warm year, with damage occurring in 50 countries at least and 16% of corals dying by the end of it,” he said. “Many of us think this will exceed the damage that was done in 1998.”
After widespread devastation was confirmed in the Caribbean this month, a worldwide consortium of coral scientists joined on Thursday to sombrely announce the third-ever global bleaching event – and warn of a tenuous future for the precious habitat unless sharp cuts were made to carbon emissions.
Since the early 1980s the world has lost roughly a fifth of its coral reefs. Hoegh-Guldberg said the current event was directly in line with predictions he made in 1999 that continued global temperature rise would lead to the complete loss of coral reefs by the middle of this century.
“It’s certainly on that road to a point about 2030 when every year is a bleaching year … So unfortunately I got it right,” he said.