Coral bleaching is a widespread problem. Now, it isThe fourth time in seven-years, the Great Barrier Reef was visited by the crew. As the world has heated up more and more, there’s less and less chance for corals to recover.
The Morrison government announced this year that it would be launching a Plan worth A$1 BillionTo 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. It doesn’t mention the elephant in the room. The world’s largest living assemblage of organisms is facing collapse because of one major threat: climate change.
The window of opportunity for action is closing. This has been a warning that scientists and we have given for many decades. Australia has doubled down its coal and natural gas exports Subventions of $20 billionThese two years have been the most productive. These fossil fuels produce carbon dioxide and other greenhouse gasses when they are burned. This heat traps more heat into the atmosphere, which also warms the ocean.
If the federal government is to save the reef, they must address the root cause. This means phasing out exports and fossil fuel use as fast 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 phenomenon such bad news?
Past bleaching events have been linked to El Niño events. Stable atmospheric conditions can lead to calm, cloud-free periods that heat 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 can bring heat to the deeper oceans, which means lower temperatures for corals. This is not the case.
Global warming means corals are already close to their bleaching threshold, and it doesn’t take much heat to tip the balance. The reef has seen water temperatures rise several degrees above the long-term average. The corals are feeling it.
Bleaching events are increasing four times in seven years. According to predictions, bleaching will be an annual event in just over 20 years. It might not take that long.
The first time you saw bleaching in person is something that you will always remember. Jodie, co-author, said that it was 2016 on Lizard Island, a pristine area of the reef that was free from human impacts and water quality problems. The water was shockingly hot. We could see that the temperatures we had been simulating for 2050 in our laboratories were already present on our dive computers.
The corals were pushed to their limits by the marine heatwave for a week. Corals can become fluorescent when they are exposed to heat stress. Others turn stark white. Then the water goes murky – that’s death in the water. It’s heartbreaking to see. Marine scientists are often in grief at the moment.
If they have a recovery period, corals can recover from bleaching. Annual bleaching can mean that there isn’t enough time to recover. 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. Some fish can migrate to cooler waters further south but corals are at risk of ocean acidification due to 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 should the next government do?
The evidence is overwhelming. We can see it with our own eyes. We’re barrelling towards catastrophic levels of warming, and there’s not enough action.
According to the report, policies offered by our two major parties won’t save the reef. Research in progressClimate 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. One thing is certain: every tenth is important.
We need leaders who care 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 some people who doubt that humans can change climate. However, the changes are now evident.
The words “unprecedented” and “record-breaking” are starting to lose relevance for natural disasters because they are used more and more. The 2019/20 Black Summer Megafires was a major threat to Australians. 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 think to be “virtually impossible without the influence of human-caused climate change”. This includes the rapid impact on coral reefs around the world.
We need government policies that match the urgency and scale of the threat. It is essential to get to net zero as soon 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.
Australia is the only developed country with more to lose from climate inaction. However, there are more benefits to switching to clean energy through new economic opportunities and new jobs as well as better protection of our natural treasures.