Rising ocean temperatures have pushed the planet past its first climate tipping point, scientists warn.
The collapse of coral reef ecosystems worldwide marks a stage of ecological damage that may no longer be reversible.
According to researchers, the widespread decline of coral reefs underscores the urgent need to curb greenhouse gas emissions. They warn that without rapid action, other vital systems - such as ice sheets, rainforests, and ocean currents - could face similar irreversible impacts. Over the past two years, coral bleaching events have become increasingly severe, leaving vast stretches of reefs lifeless and colourless.
A new report from the University of Exeter revealed that the fourth global coral bleaching event began in January 2023 and has already affected more than 84% of the world’s coral ecosystems. “Tipping points can no longer be considered a future risk,” said Steve Smith, a lead author and social scientist at Exeter.
Coral ecologist Michael Studivan from the University of Miami stressed that it was not a distant threat, adding that the current bleaching event pointed out that the crisis was happening at that moment.
The report also draws attention to other looming risks, including ice-sheet collapse, rising sea levels, and the Amazon rainforest dieback. However, it also notes that potential positive tipping points could emerge through social and economic shifts, such as the adoption of clean energy.
Coral reefs act as environmental indicators. Under heat stress, corals expel the symbiotic algae that provide them with nutrients and colour, leading to bleaching. The loss of coral ecosystems threatens biodiversity, fisheries, and coastal protection, putting millions of livelihoods at risk.
Scientists emphasise that to prevent further planetary tipping points, rapid emission reductions and sustainable environmental policies are crucial. They warn that the collapse of coral reefs signals a global ecological crisis already underway.