Discovery leaves scientist questioning when Great Barrier Reef will 'reach its limit'
After nearly four decades of monitoring the Great Barrier Reef, a new research trip has shown scientists the reef is being killed off faster than it can recover.
Disturbing new photographs taken at some of the Great Barrier Reef's most popular tourist spots have left scientists wondering when it will reach its "limit". Snapped by divers during an extensive survey, they show numerous sites have been degraded following serious and extensive mass bleaching, two cyclones and flooding.
Leader of the Australian Institute of Marine Science's (AIMS) Long-Term Monitoring Program, Dr Mike Emslie, said it's clear the World Heritage site has been resilient to pressures from climate change and coral has even shown signs of growing back in some areas over the last decade. But as disturbances become more frequent the reef is being killed off faster than it can recover.
“I don’t think we can just throw our hands up in the air and give up. The Great Barrier Reef to this point has shown itself to be remarkably resilient,” Emslie told Yahoo News following weeks of monitoring the tropical waters on board the ship Cape Ferguson.
“Obviously, there are limits. And you have to wonder how close we are to those limits.”
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How bad was the coral loss on the Great Barrier Reef?
AIMS specifically examines coverage of hard coral, the animal that forms the rigid calcium carbonate skeletons that are the backbone of reefs. It found coral cover on 12 of 19 reefs between Lizard Island and Cardwell had declined following unprecedented warming and extreme weather events between December, 2023 and March, 2024.
The losses ranged from 17 per cent to 72 per cent. Losses around the Cooktown-Lizard Island sector were at their highest in 39 years of monitoring, while further south in Cairns around a third of coral was reported lost. The Innisfail sector faired better, with coral cover relatively unchanged.
What's it like under the water at Lizard Island?
With its white sands and luxury five-star resorts, the region is still a thriving tourist hub. But under the water, the situation is far from pristine.
“I’ve been in the water around those reefs for 30 years, but this time I was looking at what was basically a graveyard,” Emslie said.
“In some places 95 per cent of coral colonies were dead. They were still standing, but they were covered in algae. Some of the ones that were alive were infected with disease due to the levels of stress that these bleaching events cause. Because even if coral survives it can subsequently succumb to disease.
“It is quite confronting. It is very sad.”
Littered between areas of devastation were patches of coral that gave Emslie glimmers of hope. And the mortality rate would often vary significantly within a single reef.
“In the worst impacted areas, from the shallow waters down to the bottom, all the corals were dead. But then you could go 200 metres around the corner and things would look pretty good,” he said.
“There's certainly some refuges out there, but it's the cumulative nature of the impacts and the frequency that they're occurring is allowing less time for recovery. The prognosis moving forward is this is the start of the curve. It's only going to get worse from here unless we take some pretty drastic immediate action to curb these greenhouse gas emissions.”
Is there a way we can save the Great Barrier Reef?
There have been global calls from conservationists for the Great Barrier Reef to be listed as “in danger” because the UNESCO World Heritage site is rapidly dying.
Doing so could help the site secure more funding, but it would also likely negatively impact its reputation as a tourism destination and Environment Minister Tanya Plibersek and her predecessor Sussan Ley have successfully fought off attempts to list it.
World Wide Fund for Nature-Australia said the AIMS report confirmed its “worst fears” about bleaching. It called on the federal government to commit to an emissions reduction target of at least 90 per cent below 2005 levels by 2035, and to stop approving new fossil fuel projects.
“The Great Barrier Reef can bounce back but there are limits to its resilience. It can’t get repeatedly hammered like this. We are fast approaching a tipping point,” its head of oceans Richard Leck said.
The Australian Marine Conservation Society echoed these concerns, saying the only way to keep the reef off the “in danger” list was to slash greenhouse gas emissions.
"We know what needs to be done. We need more action to battle climate change and stronger nature laws. Without immediate measures, we risk losing one of the world’s most treasured ecosystems,” its reef campaign manager Dr Lissa Schindler said.
Related: Timing of minister's controversial 'celebration' sparks uproar
The Albanese government has resisted changes to national environment laws that would require it to consider the emissions damage caused by big emitting projects before they are approved.
This week, the Greens dropped a demand that this "climate trigger" be included in much needed environmental reforms, as they tried to reinvigorate negotiations.
“While the government has refused to back a climate trigger, the reality facing our planet is stark: every new coal and gas mine Labor approves makes the crisis worse,” Senator Sarah Hanson-Young said as she promised to return to the issue next election.
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