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Experts: The Great Barrier Reef cannot be saved

Two-thirds of the reef is at risk of dying. It’s time to focus on maintaining rather than improving it, scientists say.

Photo of a healthy and unhealthy fire coral
Photo of a fire coral that experienced severe bleaching in the 2016 mass bleaching event.
The Ocean Agency / XL Catlin Seaview Survey / Richard Vevers

It’s official. The Great Barrier Reef cannot be saved.

The prognosis comes from the Australian government’s Reef 2050 advisory committee, made up of experts and scientists responsible for managing the reef’s future.

In the more optimistic times of 2015, the committee put out a report on how to best preserve the reef. But now two of the committee’s experts have told the Guardian that the plan is no longer feasible “due to the dramatic impacts of climate change.”

Instead, they recommend that the goal be revised to “maintain the ecological function” of the Great Barrier Reef. And the reef may now have a better shot of being listed as a “World Heritage site in danger,” a designation the Australian government has fought for for years.

Record temperatures have killed almost half of the coral in the Great Barrier Reef

One reason for the bleaker forecast for the reef is the record ocean temperatures for the second year in a row that produced mass bleaching along the reef, leaving almost half of the coral dead.

The latest aerial surveys released by scientists in April show a recent bleaching event almost as severe as the record bleaching of 2016 that left two-thirds of the reef damaged. Bleaching occurs when extreme heat forces algae to abandon coral, turning them pale white.

In 2016, El Niño was responsible for a spike in ocean temperatures, which led to an unprecedented level of bleaching along the northern third of the reef. Scientists found as many as 95 percent of the corals surveyed in 2016 were severely bleached.

Bleaching is not necessarily fatal for coral, but 2016 was also the highest level of coral mortality ever recorded on the Great Barrier Reef. In the worst-affected area, a 435-mile region in the north near Cooktown, Australia, as much as 67 percent of shallow-water corals died.

This year, scientists says climate change and rising ocean temperatures are behind the bleaching of the reef, with bleaching spread further south, hitting the middle third particularly hard. Only the southern third of the reef is unharmed.

Map of coral bleaching incidents along the Great Barrier Reef
Source: Australian Research Council Center of Excellence for Coral Reef Studies
Sarah Frostenson / Vox

Scientists say it’s too soon to calculate this year’s coral death toll, but it’s already clear the damage extends further south than last year.

Bleached coral reefs can recover, but rising ocean temperatures are making this increasingly difficult

Scientists have now documented four major bleaching episodes along the Great Barrier Reef — 1998, 2002, 2016, and now 2017 — which means that most of the reef has undergone some form of severe bleaching in the past 18 years. (If you want to read more about why recent bleaching events are putting the reef in serious jeopardy, you should check out Brad Plumer’s excellent explainer).

Corals can bounce back from bleaching. But recovery is a slow and uneven process, particularly for coral that are centuries old.

“It takes at least a decade for a full recovery of even the fastest-growing corals, so mass bleaching events 12 months apart offers zero prospect of recovery for reefs that were damaged in 2016,” said James Kerry, one of the researchers at James Cook University’s Australian Research Council Center of Excellence for Coral Reef Studies, in a statement on the most recent findings.

Chart showing the process for how a coral is bleached.

Complicating coral recovery now is the fact that the bouts of bleaching are growing longer and more severe, while the much-needed recovery periods are shorter and less frequent.

The culprit? Record-high ocean temperatures that don’t appear to be dropping anytime soon. As you can see in the map below, this February marked yet another unseasonably hot month. NOAA’s Coral Reef Watch recorded abnormal heat stress at nearly every point along Australia’s eastern coast from February 21 to 27, 2017.

Map of bleaching alerts in February 2017 along the Great Barrier Reef
Light tan means an area is under heat stress. Orange areas are under a bleaching warning. Light red means bleaching is likely, and dark red indicates mortality of coral is likely.
Source: NOAA’s Coral Reef Watch
Sarah Frostenson / Vox

Mark Eakin, coordinator of Coral Reef Watch, told NASA that this is alarming because the current bleaching along the Great Barrier Reef is ongoing.

“Unlike past global bleaching events (in 1998 and 2010) that lasted less than 12 months, this event is in its 33rd month and shows no sign of stopping,” he said. “It has been the longest, most widespread, and most damaging coral bleaching event ever recorded.”

What’s more, some experts believe efforts to combat coral bleaching have been in vain. Jon Brodie, a researcher at James Cook University and water quality expert, told the Guardian that projects to improve Australia’s water quality, which were at the heart of the government’s response, were failing.

“Last year was bad enough, this year is a disaster year,” Brodie told the Guardian. “The federal government is doing nothing really, and the current programs, the water quality management is having very limited success. It’s unsuccessful.”

The real answer to stop coral bleaching lies in reducing our CO2 emissions, which are causing ocean waters to warm. But emissions are not on track to stay below the 1.5 degrees Celsius threshold, and coral reefs could perish if the planet continues to warm.

As Terry Hughes, head of the Australian Research Council Center of Excellence for Coral Reef Studies, said in a statement, the “window to do so is rapidly closing.” Otherwise, we are looking at unabated bleaching of the reef.

Here’s a short video researchers compiled of aerial shots that capture the extent of bleaching along the Great Barrier Reef in 2017:

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