Jerri-Lynn here. I read this post about coral bleaching with great sadness. I once took a short safari out of Cairns, in Queensland, northern Australia, during which I spent four days diving along the Great Barrier Reef.
Queensland enforces tough restrictions on recreational divers, who are forbidden by law to dive deeper than fifteen meters, even though standard diving licenses certify such divers to descend to thirty meters. In addition, in Queensland, divers must exit the water within 40 minutes of entering; elsewhere, a standard recreational dive usually lasts an average of 45 minutes, up to a full hour maximum. I imagine Queensland sees more than its fair share of inexperienced divers, drawn to strike ‘diving the Great Barrier Reef ‘ off of a personal travel bucket list. Imposing conservative limits on all divers is a means by which to limit fatal accidents.
The diving memory I treasure most from that excursion was when I rounded a corner to see seven humphead parrotfish, methodically pummelling the reef with their massive heads, feeding on the chunks of coral they dislodged. The visibility was perfect and bright sunlight illuminated them from above; I think we were no more than about twelve meters deep.
These fish were once common, but alas, as with most of the world’s marine life, that’s no longer true throughout much of their former range. I’d previously glimpsed single humphead parrotfish when diving elsewhere. Larger schools are still not uncommon on the Great Barrier Reef. Nonetheless, I was very lucky to have chanced upon these fish as they were feeding. I spent most of my remaining 40 minutes watching them. I looked for a video that documented something similar to the remarkable scene I witnessed and this is the best I could come up with.
After I finished my diving tour, I hopped a shuttle to Cooktown, the farthest one can go in that part of Australia without your own wheels. I spent nearly a month there in a pleasant guesthouse, writing, and learning a bit about Australia.
Cooktown was named for Captain James Cook, whom many older Australians were taught in school ‘discovered’ Australia – a view now regarded as a myth (see this article from The Conversation, Captain Cook ‘discovered’ Australia, and other myths from old school text books).
Cook’s ship, the Endeavour, a British Royal Navy research vessel, ran aground on a shoal of the Great Barrier Reef in 1771 near what’s now known as Cooktown. Cook limped into the mouth of what’s now called the Endeavour River and spent seven weeks undertaking repairs.
Some impressions from that time and from memory (as I don’t have my diary from this trip to hand): Falling asleep on a park bench sited along the banks of the river, to wake up and see a massive crocodile swimming by not far from where I’d just been snoozing. Thanks goodness he was in the water and oblivious to me. I was certainly aware of him, as I watched him veer around the small jetty where tourists often queued to board tour boats.
I spent another morning with a local birder who tried to help me distinguish between lesser and greater frigate birds, while two dozen of these birds soared far overhead. Normally, these birds are pelagic, but this group had been blown onshore by a fierce storm. I watched as a bird dived down to seize a fisherman’s fish. Alas, for the bird, the the fisherman had hooked the fish, and when the bird grabbed it, he jerked the line, violently, several times, deliberately killing the bird. The bird guide turned away in disgust. A rare bird, exterminated, by a fisherman frustrated that the bird had seized ‘his’ fish.
I visited a local museum, learning about the nineteenth-century gold rush that had caused Cooktown’s population to balloon, so that by the turn of the century, it was the second largest township in Queensland. What I remember most vividly were the museum’s memorials to the many men from even this remote corner of the country who lost their lives fighting for the British Empire in the Great War.
There were a couple of decent restaurants in town, but I often dined at a local servicemen’s club – I can’t recall the name but I’m sure an Australian reader may jog my memory in comments – which served meals to the public. The food wasn’t anything special, perhaps because many of those I saw at the club seemed to be there not to eat but to play slot machines. Some exhibits attested to Australia’s military history, especially the role played by the Australian military in the Vietnam War.
One day, I hitched a lift to the top of the tallest hill in the area. With the gold rush long come and gone, Cooktown had shrunk back down in size. The town was no longer very busy, with only a smattering of largely Australian tourists, many intent on fishing, with some using their own vehicles to venture further into the wildest parts of northern Queensland. I saw no signs of package tours designed to lure hordes of divers here, to see flora and fauna, and explore local historical sites. So, the view offshore onto the Great Barrier Reef was perhaps not that different than the one Cook had seen during the late eighteenth century. IIRC, I’d read that he’d ascended the same hill to study the surroundings, and to figure out how to get the Endeavour, once repaired, past the reef and back to open seas.
I wondered whether Cook ever despaired that he’d not be able to get out of there. Royal Navy officers of that period, however, were a resourceful lot, and as all Australians know, Cook did sail safely away, to undertake a further two voyages. His explorations eventually came to an abrupt and sorry end in 1779, however, when he was killed in the Hawaiian islands, after encounters with the King of Hawaiʻi, Kalaniʻōpuʻu and native Hawaiians, turned violent.
And now, back to the topic at hand: what might be done to save the Great Barrier Reef before it’s too late.
By Jodie L. Rummer, Associate Professor & Principal Research Fellow, James Cook University, and Scott F. Heron, Associate Professor in Physics, James Cook University. Originally published at The Conversation
Widespread coral bleaching has now occurred on the Great Barrier Reef for the fourth time in seven years. As the world has heated up more and more, there’s less and less chance for corals to recover.
This year, the Morrison government announced a A$1 billion plan to help the reef. This plan tackles some of the problems the reef faces – like poor water quality from floods as well as agricultural and industrial runoff. But it makes no mention of the elephant in the room. The world’s largest living assemblage of organisms is facing collapse because of one major threat: climate change.
Our window of opportunity to act is narrowing. We and other scientists have warned about this for decades. Australia has doubled down on coal and gas exports with subsidies of $20 billion in the past two years. When these fossil fuels are burned, they produce carbon dioxide and other greenhouse gases that trap more heat in the atmosphere that also warms the ocean.
If our next federal government wants to save the reef, it must tackle the main reason it is in trouble by phasing out fossil fuel use and exports as quickly as possible. Otherwise it’s like putting bandaids on an arterial wound. But to help the reef get through the next decades of warming we’ve already locked in, we will still need that $1 billion to help reduce other stressors.
Why is This New Bleaching Event Such Bad News?
Past bleaching events have been linked to El Niño events. Stable atmospheric conditions can bring calm, cloud-free periods that heat up the water around the reef. That can bring extreme summer temperatures – and that is when corals bleach.
This year is a La Niña, which can bring warmer-than-usual temperatures but also tends to bring more clouds, rain, and storms that mix up the waters. These usually spread the heat to the deeper parts of the ocean and mean lower temperature for corals. Not this time.
Global warming means corals are already close to their bleaching threshold, and it doesn’t take much heat to tip the balance. Water temperatures across the reef have been several degrees hotter than the long-term average. And the corals are feeling the heat.
Four times in seven years means that bleaching events are accelerating. Predictions have suggested that bleaching will become an annual event in a little over two decades. It may not be that long.
You always remember the first time you see bleaching in real life. For co-author Jodie, that was in 2016, off Lizard Island, a previously pristine part of the reef far from human impacts or water quality issues. The water was shockingly warm. Looking at our dive computers, we saw that the temperatures we had been simulating in our laboratories for 2050 were already here.
For a week, the marine heatwave pushed the corals to their limits. When corals experience heat stress, some initially turn fluorescent while others go stark white. Then the water goes murky – that’s death in the water. It’s heartbreaking to see. Grief is common among marine scientists right now.
Corals can recover from bleaching if they get a recovery period. But annual bleaching means there is not enough time for proper recovery. Even the most robust corals can’t survive this year after year.
Some people hope the reef can adapt to hotter conditions – but there is little evidence it can happen fast enough to outpace warming. While some fish can move to cooler waters further south, corals face ocean acidification, yet another problem caused by carbon dioxide emissions. As CO₂ is absorbed by the ocean, the changed chemistry makes it harder for corals to build their skeleton (and for other marine organisms to form a shell). There’s no safe place for corals to go.
What Does the Next Government Need to Do?
The evidence is clear. We see it with our own eyes. We’re barrelling towards catastrophic levels of warming, and there’s not enough action.
As it stands, policies on offer by our two major parties will not save the reef, according to new research by Climate Analytics. Current Coalition emissions reduction targets of 26-28% by 2030 would lead to a 3℃ warmer world, which would be devastating for the Great Barrier Reef.
Labor’s policies of a 43% reduction by 2030 still lead to 2℃ of warming. The teal independents and the Greens have policies compatible with keeping warming to 1.5℃, though how to achieve those goals is unclear. What is clear is that every tenth of a degree matters.
We need leaders who are serious about climate action. Who can acknowledge the truth that the problem is real, that we’re causing it, and that it’s hurting us right now.
There are still a few people sceptical that humans can change the climate. But today the changes are apparent.
The words “unprecedented” and “record-breaking” are starting to lose relevance for natural disasters because they are used more and more. Australians faced the 2019/20 Black Summer of megafires. This year we’ve had major flooding. Marine heatwaves have killed off almost all of Tasmania’s giant kelp.
But climate impacts are also being seen around the world – extraordinary drought gripping California, fires in melting Siberia and events scientists consider to be “virtually impossible without the influence of human-caused climate change”. That includes the accelerating impacts on coral reefs worldwide.
We need government policies matching the scale and urgency of the threat. That means getting to net zero as soon as possible. It isn’t only about the reef – it’s about all land and sea natural systems vulnerable to climate change, and the people who rely on them.
No developed country has more to lose from inaction on climate than Australia. But no country has more to gain by shifting to clean energy, through new economic opportunities, new jobs, and better protection for our natural treasures.