Parts of Australia’s iconic Great Barrier Reef, famed for its gorgeous colours and biodiversity, suffered the largest decline of coral on report final yr after a marine heatwave bleached huge swathes of arduous coral, a new report has discovered.
The reef had its worst summer season on report in 2024 when the world underwent a uncommon global mass coral bleaching event impacting dozens of nations. Surging water temperatures mixed with an El Niño climate sample prompted careworn corals to expel algae and lose their colour.
An official analysis launched on Wednesday now reveals the reef misplaced between 1 / 4 and a 3rd of its arduous coral cowl throughout three predominant areas, in line with the Australian Institute of Marine Science (AIMS). In some areas, notably hard-hit reefs misplaced as much as 70% of their residing coral.
The 2024 bleaching occasion “had the largest spatial footprint ever recorded on the (Great Barrier Reef),” the report found. “The declines in the north and south were the largest in a single year since monitoring began 39 years ago.”
NCS witnessed the widespread bleaching in visits to the Great Barrier Reef in 2024 – and to the Ningaloo Reef on Australia’s western coast in 2025 – throughout which one scientist described the devastation as like “wildfires underwater.”
The large loss throughout the two,300-kilometer (1,400-mile) ecosystem is particularly discouraging after it skilled vital progress in the previous couple of years, with some fast-growing corals that helped the reef get well from earlier bleaching.
But these corals “were known to be extremely vulnerable and one bad summer away from losing those gains,” the report stated – including that these fears got here true final yr, with the fast-growing corals among the many most severely impacted.
“It raises the prospect that the Great Barrier Reef may reach a point from which it cannot recover,” it warned.
Covering almost 133,000 sq. miles (345,000 sq. kilometers), the Great Barrier Reef is the world’s largest coral reef, residence to greater than 1,500 species of fish and 411 species of arduous corals.
It contributes billions of {dollars} to the Australian economic system annually, primarily by tourism, and is promoted closely to overseas guests as one of many nation’s – and the world’s – best pure wonders.
But all that’s at risk, with activists and scientists warning with rising urgency over the previous decade that the reef’s future is in danger.
Severe mass bleaching on the Great Barrier Reef had beforehand been noticed in 1998, 2002, 2016, 2017, 2020 and 2022. Corals can get well from bleaching if the temperatures return to regular, however they’ll perish if the water stays hotter than common.
Water temperatures spiked once more early this yr throughout Australia’s summer season, peaking in March and inflicting much more bleaching – although its impacts haven’t but been absolutely measured and weren’t included on this report.
Oceans at the moment are storing 90% of the surplus warmth from international warming — and every of the final eight years has set a new record for the quantity of warmth saved within the ocean.
The destruction of marine ecosystems would ship an efficient loss of life sentence for round 1 / 4 of all species that rely on reefs for survival, scientists warn. Reefs additionally present important safety for coastlines, decreasing the affect of floods, cyclones and sea stage rise.
The bleaching is “a call to action,” stated the non-profit Queensland Conservation Council on Wednesday after the report’s launch.
The council, the height physique for dozens of Queensland’s setting teams, referred to as on state and nationwide leaders to cut back emissions and shut down coal energy stations. Australian is transitioning to renewable power, like different developed nations, however critics say it’s not occurring quick sufficient.
“The coral reefs of the future are unlikely to look like those of the past. The loss of biodiversity seems inevitable,” the report learn, urging extra analysis into reef adaptation and safety whereas the world works to cut back greenhouse fuel emissions.
Correction:
This story has been up to date to mirror that particular areas of the Great Barrier Reef noticed their largest coral declines on report final yr.