Australia’s Great Barrier Reef has lost half its corals in past 25 years

The attention from Unesco raises the question; is the reef really in mortal danger?

“Yes,” say five high-profile marine scientists who wrote to Unesco to thank them for shining a light on the situation: professors Hughes and Ove Hoegh-Guldberg, of the Australian Research Council’s Centre of Excellence for Coral Reef Studies; Andrea Grottoli, president of the International Coral Reef Society; Johan Rockström, of the Potsdam Institute for Climate Research in Germany; and pioneering American marine biologist Dr Sylvia Earle.

The Great Barrier Reef faces two main threats, explains Hughes; marine heatwaves caused by climate breakdown and declining water quality associated with river run-off.

Five years ago, Australia averted an earlier attempt to have the reef inscribed on the “in danger” list by developing the Reef 2050 Plan, setting water quality targets to minimise the amount of sediment, pesticides and herbicides flowing offshore, towards the reef. However, any progress made has not halted the degradation.

“Australia itself has documented the failure to reach these targets,” Hughes says.

The five scientists believe the Australian government should accept the assistance of Unesco. “The whole point of being listed ‘in danger’ is that it triggers a plan,” Hughes says. “There are many World Heritage properties that have been on, and then off, the World Heritage in Danger list. One example is the Galapagos, another is the Belizean fringing reef. Those countries worked with Unesco to work out the problems.”

One of the main reasons the Australian government is sensitive about the reef is its importance to tourism. In a typical non-Covid-19 year, the reef contributes about A$6.4 billion (US$4.7 billion) to the Australian economy and supports 64,000 jobs. The government worries that if tourists suspect the reef is dying, they will not visit.

Some support the Master Reef Guide Programme, which ensures high-quality information is disseminated in the hope that it will inspire reef protection and personal action on global warming.

Climate breakdown threatens corals around the world, including the smattering around Hong Kong. Science and innovation are needed now more than ever, but need to target the right areas.

In 2018, the Australian government invested A$440 million in the Great Barrier Reef Foundation, which now spearheads 43 research projects aimed at helping reefs become more resistant to climate change.

These projects include coral seeding of damaged areas by assisted larval transport in a fine net. Another involves “cloud brightening” – the projection of seawater into the air with the intention that tiny salt crystals join clouds, strengthening their ability to deflect sunlight and thus keeping the water below cooler.

However, many scientists believe these approaches are ineffective. “It’s still very much at the Petri dish phase, a lot of this research, and without dealing with the causes of temperature rise, it’s a complete and utter waste of time,” Hughes says.

He says future marine heatwaves are likely to kill off many of the replanted or newly seeded corals, and the sheer scale of the reef makes these projects impractical. “It would take about 250 million adult corals to increase the coral cover on the Great Barrier Reef by one per cent.”

It’s important to note, however, that the reef is not dead. The latest Great Barrier Reef Outlook Report, produced by the marine park authority in 2019, assessed 31 components of ecosystem health, taking into account physical, chemical and ecological processes, coastal ecosystems and disease and pest outbreaks.

The report found that about 60 per cent of ecosystem health components assessed remained in “good” to “very good” condition, while the rest were in “poor” or “very poor” condition.

Designated tourist sites occupy around seven per cent of the Great Barrier Reef Marine Park, and most remain healthy, offering experiences that are still worthy of international acclaim.

To experience the reef for myself, I head to Lizard Island, north of Cairns. The island is home to the Lizard Island Resort and Lizard Island Research Station, owned by the Australian Museum.

In just a few fin kicks from the beach, I encounter the vitality that a healthy reef supports: a curious juvenile green turtle, a harmless black tip reef shark and a shimmering giant clam in aquamarine.

Since 2014, Lizard Island has suffered two cyclones and four bleaching events, when warming water forces corals to expel the algae living in their tissues, putting them under great stress. Although scientists say the species composition is not the same as it was before 2014, the coral here is doing well, given the circumstances.

“It was annihilation, unbelievably bad,” says Dr Anne Hoggett, director of the Lizard Island Research Station, of the recent bleaching and cyclones. “And [the coral] has come back, not everywhere, but in some places – amazingly.”

However, Hoggett, who has lived on Lizard Island for 30 years, warns that the conditions that caused the bleaching are becoming more frequent. “Every summer now, we’re on a knife-edge. The background temperatures of the ocean now mean that every summer there’s danger of a major bleaching event. It’s down to whether wet season conditions come in at the right time to lower that heat. Hoping for a change in the weather is not a great management strategy.”

Whether the Great Barrier Reef is added to the Unesco in Danger list or not, Australia, and the world, need to pay attention to those figurative cinematic scientists trying to raise the alarm.

“Australia is very much aware of the science,” Hughes says. “But they’re in denial about their responsibility for climate change.”