THE survival of the Great Barrier Reef hinges on urgent steps to combat climate change and reduce global warming, new research has found.
The researchers behind the report, entitled Global Warming and Recurrent Mass Bleaching of Corals, warn attempting to stop the bleaching through any other means will not be sufficient.
“Climate change is the single greatest [threat] to the Great Barrier Reef,” co-author Prof Morgan Pratchett, from Queensland’s James Cook University, told the BBC.
“It all comes down to what the governments in Australia and around the world do in terms of mitigating further rises in temperatures.”
The study, published in the journal Nature, examines three major bleaching events on Australian reefs occurring in 1998, 2002 and 2016, but was unable to take into account the latest mass bleaching event occurring this year.
— CoralCoE (@CoralCoE) March 15, 2017
Warm seas around the reef killed some two-thirds of a 700km stretch of coral in 2016 after warm water caused the coral to expel living algae, triggering it to calcify and turn white, a process known as bleaching.
That was the worst die-off of coral ever recorded at the reef, amounting to approximately 22 percent of the reef being killed off in one hit.
While coral is able to recover from bleaching with time, the study warns the increased occurrence of bleaching events gives certain areas a “slim” chance of ever recovering to its former state.
“Given time, coral can recover from bleaching, but the problem comes when you get repeated events. With less time between them, capacity for the coral reef community to recover diminishes rapidly,” Janice Lough, senior principal research scientist at the Australian Institute of Marine Science, told Reuters.
And as the effects of climate change continue to be felt the world over, the likelihood of repeat events is increasing.
“With rising temperatures due to global warming, it’s only a matter of time before we see more of these events. A fourth event after only one year would be a major blow to the reef,” Terry Hughes, the report’s lead author, told The Guardian.
— Terry Hughes (@ProfTerryHughes) March 15, 2017
The study found 91 percent of coral on the reef had suffered from bleaching over the past two decades, caused predominantly by underwater heatwaves, showing local improvements to water quality or fishing controls had made no impact in protecting the coral.
“Local management of coral reef fisheries and water quality affords little, if any, resistance to recurrent severe bleaching events,” the report concluded, “even the most highly protected reefs and near-pristine areas are highly susceptible to severe heat stress.”
Hundreds of individual reefs were bleached last year regardless of their zoning classification. The report found those reefs in no-entry and no-fishing zones were still susceptible to damage.
“Bolstering resilience will become more challenging and less effective in coming decades because local interventions have had no discernible effect on resistance of corals to extreme heat stress, and, with the increasing frequency of severe bleaching events, the time for recovery is diminishing,” the report reads.
These findings raise serious questions about Australia’s long-term conservation plan for the reef, which does not afford enough focus to tackling climate change and instead invests heavily in lifting water quality.
Following the 2016 mass bleaching event, the Great Barrier Reef Marine Park Authority called for a ban on all new coal mines in Australia to protect the reef from climate change.
Graeme Kelleher, who was the first chief executive of the authority, a position he held for 16 years, said:
“Australia cannot have a healthy Great Barrier Reef and a continuing coal industry.”
Despite the warnings, Australia continues to forge ahead with major mining operations and plans to expand their mining capability.
Queensland premier, Annastacia Palaszczuk, is in India this week to lobby Adani Group to proceed with the controversial Carmichael mine.
The project is a proposed thermal coal mine in the north of the Galilee Basin in Central Queensland. It has stirred intense controversy about its claimed economic benefits, its financial viability, and the damaging environmental impacts it will likely have on the surrounding area, including the reef.
Hughes said the report shows how foolish the government was being by pursuing the mine project, not only for the carbon emissions but the dredging and marine traffic through the reef.
“In its weakened state, the reef cannot afford the Adani mine,” he said.
The report comes in the same week as Unesco considers an “in-danger” listing for the Great Barrier Reef should the Queensland government fail to make good on conservation efforts and implement measures to curb bleaching, a move the report points out as vital and urgent.
“Securing a future for coral reefs, including intensively managed ones such as the Great Barrier Reef, ultimately requires urgent and rapid action to reduce global warming.”
Additional reporting from Reuters