The Great Barrier Reef has experienced its largest annual decline in live coral cover in two of three surveyed regions since monitoring began in 1986, according to a new report by the Australian Institute of Marine Science (Aims). The study documents the severe impact of the early 2024 mass coral bleaching event, described as the most widespread and severe on record for the reef.
In the northern section, between Cooktown and Cape York, coral cover fell by 25% due to bleaching, two cyclones, and flooding. The southern section, from Mackay to north of Bundaberg, saw a 30% drop. Both regions recorded their highest annual decreases ever. The central section experienced a 13% decline, having escaped the worst heat in 2024.
Dr Mike Emslie, who leads the long-term monitoring program at Aims, said coral cover is becoming increasingly volatile. “It has been a pretty sobering year of surveys with the biggest impacts I have seen in the 30-plus years I have been doing this,” he said. “This volatility is very likely a sign of an unstable system.”
Emslie warned that the reef may reach a tipping point where coral cannot recover between major disturbances. “We will ultimately get to a tipping point where coral cover can’t bounce back because disturbances come so quickly that there’s no time left for recovery,” he said. “We have to mitigate the root causes of the problem and reduce emissions and stabilise temperatures.”
The report comes ahead of the federal government's announcement of its 2035 emissions reduction target. WWF Australia's head of oceans, Richard Leck, urged the government to set a target consistent with limiting global warming to 1.5°C, stating, “This is the one action the government can take to give the reef a fighting chance.”
