93 Percent Of The Great Barrier Reef Is Practically Dead

The Great Barrier Reef -- the largest living structure on Earth -- is dying as a result of El Nino and climate change.

This week, scientists from the ARC Centre of Excellence for Coral Reef Studies completed an extensive survey of the iconic reef and found that 93 percent has been impacted by the most severe coral bleaching event on record.

"We’ve never seen anything like this scale of bleaching before," Terry Hughes, convenor of the National Coral Bleaching Taskforce, said in a statement. "In the northern Great Barrier Reef, it’s like 10 cyclones have come ashore all at once."

Coral bleaching is a phenomenon in which stressed corals expel algae and turn white. If not given time to recover, bleached corals can perish.

The Great Barrier Reef, the world's largest reef system, is located off the coast of Queensland, Australia, and extends more than 1,400 miles. It consists of some 3,000 individual reefs and is home to more than 100 islands.

Of the 911 reefs surveyed, only 68 -- 7 percent -- escaped bleaching, while between 60 and 100 percent of corals are severely bleached on 316 reefs, according to Hughes.

In an interview with National Geographic, Mark Eakin of the National Oceanic and Atmospheric Administration’s Coral Reef Watch program called the situation "extremely depressing.”

“Having such a large area of the [Great Barrier Reef] affected this severely by bleaching, especially in the northernmost region, where the corals are least affected by local human impact, is very troubling," he said.

ARC's Andrew Baird said in a release that north of Port Douglas, roughly half of bleached corals have died, and at some individual reefs the mortality rate is "likely to exceed 90 (percent)."

While the forecast is bleak, scientists say communities can help by reducing local threats, including pollution, sedimentation and unsustainable fishing practices.

“To solve the long-term, global problem, however, we need to better understand how to reduce the unnatural carbon dioxide levels that are the major driver of the warming," according to Jennifer Koss of NOAA's Coral Reef Conservation Program.