Sydney, Australia – The Great Barrier Reef, one of the world’s most spectacular natural wonders, is facing unprecedented damage due to record ocean heat, a new study reveals. Coral bleaching on Australia’s Great Barrier Reef has reached “catastrophic” levels, with more than 50% of affected corals near an island in the reef’s south dying in the most severe bleaching event on record, researchers say.

Last year, the reef suffered its worst summer on record, with soaring ocean temperatures causing the seventh mass bleaching event. Corals turn white when stressed by marine heat waves, expelling algae from their tissue and losing their vibrant colors. The main culprit behind the devastation is the burning of fossil fuels, which has led to global temperature increases. Additionally, the El Niño weather pattern has accelerated coral damage by heating ocean temperatures in the region.

A team of Australian scientists from the University of Sydney monitored 462 coral colonies at the reef’s One Tree Island over five months, observing a high mortality rate among corals. By May, 370 colonies were bleached, and by July, 52% of the bleached corals had died. Some coral species experienced a mortality rate as high as 95%, with researchers witnessing the beginning of “colony collapse” as dead skeletons detached from the reef.

The devastating effects of the mass bleaching event highlight the urgent need to protect coral reefs, not only for their biodiversity but also for food security and coastal protection, according to lead author Maria Byrne. The researchers stress the importance of immediate and effective management interventions to safeguard these ecosystems, as the resilience of coral reefs is being tested like never before.

Covering nearly 133,000 square miles, the Great Barrier Reef is home to over 1,500 fish species and 411 hard coral species, contributing significantly to the Australian economy through tourism. The authors of the study warn that mass bleaching events are becoming more frequent, emphasizing the need for urgent global action to meet ambitious climate and emissions targets.

The study’s implications extend beyond ecology and conservation to communities that rely on the reef for fishing, tourism, and coastal protection. The severity of the damage seen in a previously resilient and protected part of the reef serves as a wake-up call for policymakers and conservationists to prioritize strategies that enhance coral reefs’ ability to withstand climate change.