The world’s coral reefs, from the Great Barrier Reef off Australia to the Seychelles off East Africa, are in grave danger of dying out completely by mid-century unless carbon emissions are reduced enough to slow ocean warming, a new UNESCO study says.
And consequences could be severe for millions of people.
The decline of coral reefs has been well documented, reef by reef. But the new study is the first global examination of the vulnerability of the entire planet’s reef systems, and it paints an especially grim picture. Of the 29 World Heritage reef areas, at least 25 of them will experience twice-per-decade severe bleaching events by 2040—a frequency that will “rapidly kill most corals present and prevent successful reproduction necessary for recovery of corals,” the United Nations Educational, Scientific and Cultural Organization concluded. In some areas, that’s happening already.
“These are spectacular places, many of which I’ve visited. Seeing the damage being wrought has just been heartbreaking,” says Mark Eakin, a reef expert with the National Oceanic and Atmospheric Administration, and a lead author of the new report. “We’re to the point now where caction is essential. It’s urgent.”
By 2100, most reef systems will die, unless carbon emissions are reduced. Many others will be gone even sooner. “Warming is projected to exceed the ability of reefs to survive within one to three decades for the majority of the World Heritage sites containing corals reefs,” the report says. (UN announces new biosphere reserves, while U.S. removes some.)
Reefs, often referred to as the rainforests of the oceans, occupy less than one percent of the ocean floor, but provide habitat for a million species, including a fourth of the world’s fish. They also protect coastlines against erosion from tropical storms and act as a barrier to sea-level rise.
“It is terrifying to think of the repercussions of the global and large scale loss of reefs,” says Ruth Gates, director of the Hawaii Institute of Marine Biology in Kaneohe, Hawaii. “The reduction in food supplies, the lack of coastal protection as the reef collapses and subsequent land erosion will make some places unlivable and people will have to move. And that’s not even mentioning the collapse of reef-related tourism.”
In the past three years, 25 reefs—which comprise three-fourths of the world’s reef systems— experienced severe bleaching events in what scientists concluded was the worst-ever sequence of bleachings to date. The Great Barrier Reef was especially hard hit. Other reefs that experienced severe bleaching include the Seychelles, New Caledonia, 750 miles (1,210 kilometers) east of Australia, and the United States, off Hawaii and Florida.
https://news.nationalgeographic.com/2017/06/coral-reef-bleaching-global-warming-unesco-sites/