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Great Barrier Reef at risk of 'collapse', scientists warn
Australia's Great Barrier Reef is at very high risk of extreme and widespread bleaching and "ecosystem collapse" linked to this year's El Niño weather phenomenon, leading scientists warned Tuesday.
Often dubbed the world's largest living structure, the reef stretches 2,300 kilometers (nearly 1,430 miles) along Queensland's coast and is a major tourism draw for Australia.
This month, it avoided being listed as endangered, despite the United Nations reporting "utmost concern" about mass coral bleaching and the impact of climate change.
Morgan Pratchett, a marine conservation ecologist at Queensland's James Cook University, told the International Coral Reef Symposium in Auckland, New Zealand, that the "extreme El Niño" posed a significant concern.
"It's not outside of the realm of possibility that the next major disturbance will lead to localized species extinctions ... and widespread ecosystem collapse," Pratchett said.
This year's El Niño is expected to break records for its overall strength as it warms surface temperatures in the central and eastern equatorial Pacific Ocean, bringing worldwide changes in winds, pressure and rainfall patterns.
"It's a very high likelihood that we'll see very high severity and large-scale mass bleaching on the Great Barrier Reef," Pratchett said.
UNESCO has been monitoring the reef annually since 2021, when it warned it was at risk of being placed on the list of World Heritage sites "in danger."
Hard coral cover across the reef declined substantially in 2024–2025, with above-average water temperatures causing the reef's sixth mass coral bleaching event since 2016.
Extreme weather, land-based runoff, coastal development and predation by the crown-of-thorns starfish were also placing the reef under pressure.
Ove Hoegh-Guldberg, a professor of marine studies at the University of Queensland, said government inaction had threatened coral reefs worldwide.
"This could be the precursor to the loss of humans," he said.
"If you were on a big boat, like the Titanic, and someone comes up to you and says the boat's going down, you bloody well get on those lifeboats and start acting and do stuff."
"We're not doing that. The ship is starting to sink in a really massive way, and we're not seeing it as what it is."
"It is so serious."
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Citation: Great Barrier Reef at risk of 'collapse', scientists warn (2026, July 21) retrieved 21 July 2026 from https://phys.org/news/2026-07-great-barrier-reef-collapse-scientists.html
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