Mass coral die-offs occur when the global temperature is 1.2 °C higher than pre-industrial averages. The report compiled by this large team of scientists confirmed that we have long surpassed this threshold.
“The most important yet challenging thing everyone can do is to not look away and ignore this problem,” said sociologist Manyana Milkoreit from the University of Oslo (Norway), who contributed to the report, in an interview with Science Alert.
The most vibrant underwater gardens on Earth—from the Great Barrier Reef in Australia to the Sombrero Reef in Florida—are being destroyed by caused by human activities. Overall, researchers have documented four major coral bleaching events, two of which occurred in the last decade. During this time, the Great Barrier Reef experienced bleaching in 2016, 2017, 2020, 2022, 2024, and 2025.
“In the past two years, the world has experienced warming of 1.5 °C; the heatwaves resulting from this have caused unprecedented of 80 percent of reefs worldwide,” noted Tim Lenton, an Earth ecosystem researcher from the University of Exeter (UK).
Instances of mass bleaching are now occurring more frequently, leaving reefs with little chance to recover. Meanwhile, the mass die-off of corals threatens countless marine species and flora that call these reefs home.
And that’s not all, the scientists pointed out. According to Lenton, reefs are a source of livelihood for half a billion people. The ecosystem services provided by reefs are valued at more than two trillion dollars annually. The researcher also believes that corals could recover, but only if humanity can cool the planet. However, given the current state of affairs, efforts to restore reefs seem futile. Lowering global temperatures appears increasingly unrealistic, especially as greenhouse gas emissions continue to rise.
Lenton believes that under these circumstances, by the end of the century, the planet will be by 2.5-3 °C. At that point, we will be facing numerous irreversible climate tipping points.
The researchers emphasized in their report that corals are just the first warning sign of a point of no return in the climate crisis. With each additional degree of temperature rise, more of Earth’s life-supporting systems will be pushed to the brink of no return, leading to their decline.
“This grim situation should serve as a wake-up call: if we do not take decisive action now, we will also lose the Amazon rainforest, ice sheets, and vital ocean currents. In that case, humanity faces a truly catastrophic end,” painted a bleak picture Mike Barrett, chief scientist at the UK branch of the World Wildlife Fund (WWF-UK). And as it stands, people are already dying due to climate change.
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