Coral cover on parts of Great Barrier Reef highest in decades

Part of the Great Barrier Reef is experiencing its highest coral cover on record, according to an annual report from the Australian Institute of Marine Science, though the reef still faces risks.

The report found that fast-growing corals in the central and northern parts of the reef have helped the areas increase hard coral cover to 33 and 36 percent respectively, a 36-year high for both zones.

The researchers attributed this change to low heat stress and fewer acute events, like cyclones or mass coral bleaching, in 2020-2022 compared to 2016-17, but cautioned these stressors are expected to increase in future years, straining the world’s largest coral reef system.

“In periods free from intense acute disturbances, most GBR coral reefs demonstrate resilience through the ability to begin recovery. However, the reefs of the GBR continue to be exposed to cumulative stressors,” the researchers wrote in the report released Thursday.

The reefs currently have between 10 and 50 percent coral cover, though nearly half had cover below 30 percent. 

Earlier this year, Australian scientists reported that more than 90 percent of the reef had been bleached, a heat-stress effect caused by global warming.

Intense heatwaves and tropical cyclones are also expected to curb the Great Barrier Reef’s recovery. The southern area of the reef decreased in cover since 2021 — attributed to an outbreak of a starfish that feeds on coral.

“While the observed recovery offers good news for the overall state of the GBR, there is increasing concern for its ability to maintain this state,” the report concluded.

Australia pledged $700 million earlier this year to protect the reef against climate change and global warming.

On Thursday, the Australian prime minister announced she’ll deny approval for a coal mine too close to the reefs.