For the second consecutive year, mass coral bleaching is devastating the Great Barrier Reef, Australia’s lead management agency for the reef confirmed on Friday.

The latest coral bleaching, a phenomenon that can result in coral dying off, is part of a larger event that has damaged the world’s largest reef over the past two years. Global warming is fueling the phenomenon, as warming ocean waters put corals at serious risk.

The news comes after Australian government experts and researchers from the Australian Institute of Marine Science surveyed the Great Barrier Reef between Townsville and Cairns last week. It was the first aerial survey conducted this year, and the news was grim.

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The examination found severe bleaching in offshore reefs ranging from north of Ingham to the area near Cairns. “This year more bleaching is being observed in this central part of the Reef, which last year escaped widespread severe bleaching,” Australia’s Great Barrier Reef Marine Park Authority said in a statement.

The survey confirmed anecdotal evidence collected by visitors to the reef, as well as other reef surveys completed by marine park rangers and commerical operators, the park’s director of reef recover, Dr. David Wachenfeld said.

“Mass bleaching is occurring on the Great Barrier Reef for the second consecutive year,” he confirmed.

Widespread coral bleaching during back-to-back summers is particularly toxic, as it does not leave enough time for the corals to fully recover.

“This is the first time the Great Barrier Reef has not had a few years between bleaching events to recover,” said Dr. Neal Cantin from the Australian Institute of Marine Science.

The environmental organization Greenpeace has also been documenting the bleaching, and is trying to sound the alarm worldwide.

“I’ve been photographing this area of the reef for several years now and what we’re seeing is unprecedented,” conservation photographer and marine biologist Brett Monro Garner said in a statement last week. “Just a few months ago, these corals were full of colour and life. Now, everywhere you look is white. The corals aren’t getting the chance to bounce back from last year’s bleaching event. If this is the new normal, we’re in trouble.”

In 2015, UNESCO placed the Great Barrier Reef on its watchlist due to concerns about the Australian government’s handling of the site.