A new study found that the Great Barrier Reef is facing another bleaching phenomenon, causing the death of portions of coral.

Last year, the Barrier saw unprecedented bleaching, caused by hot ocean temperatures resulting in the death of two-thirds of the coral structure. The Barrier also experienced this in 1998 and 2002, but it has never happened two years in a row.

A cruise stops near the Great Barrier Reef. Image Credit: Quicksilver Cruises

“This one won’t be as bad as 2016, but it could be more comparable to 1998 or 2002,” explained Hughes, director of the ARC Center of Excellence for Coral Reefs Studies at James Cook University in Townsville, Australia. “It’s an open question whether it’s the third or second-most-severe,” the scientist said, according to The Washington Post.

Great Barrier Reef can’t go back to its prior state

The bleaching occurs when stress from high temperatures causes coral cells to push out colorful algae, which they rely on for energy. The bleaching doesn’t necessarily mean that the coral will die, but it can lead to it.

Coral’s death depends on whether the bleaching is mild or severe, as well as how long can the coral survive without the algae. The stress increases depending on how hot the temperatures rise and how long they last. In longer and warmer stances, the coral has lower chances of survival.

Hughes talked about the current bleaching on Tuesday, and he will take off for a seven-day flight mission to evaluate the damage to the Great Barrier Reef. He and fellow scientists did the same thing last year when the 2016 bleaching process started. Hughes published a paper in the journal Nature this Wednesday, as a joint effort with over 46 scientific authors, detailing the bleaching that the Reef has experienced so far.

“Globally what’s been happening is the number of these bleaching events is going up and up, and the time interval between them is shrinking. The end game if we don’t deal with emission would be annual bleaching every year” said Hughes.

The study explains that the Great Barrier Reef cannot be brought back to its state prior to the 2016 bleaching. They believe that the structure of corals is likely to be permanently shifted at severely bleached locations in the northern part of the reef.

Running out of time

The Great Barrier is the largest coral structure on Earth, located in the Coral Sea off the coast of Queensland, Australia. It is protected by the government, environmental groups and individuals that try to preserve the reef from illegal fishing and tourists. However, the study says that despite all attempts to protect it, high ocean temperatures must decrease or the measures will make no difference.

The study noted that hundreds of individual reefs were bleached in 2016 regardless of whether they were zoned as no-entry or no-fishing areas. The bleachings are happening with about 1 degree Celsius of warming, and following the Paris climate accord, several countries pledged to keep warming below 2 degrees.

Hughes believes that the world can still have coral reefs if the temperatures are maintained below 2 degrees, but not at 1 ½ degrees. He says that there’s a window of opportunity, but the world’s running out of time.

Source: The Washington Post