Global Coral Reefs Face High Risk of Collapse Within 50 Years, Study Warns
A new assessment indicates that 96% of shallow-water reef systems are critically endangered due to warming oceans and heat waves.
Nearly all of the world's coral reef ecosystems are at high risk of collapse within the next 50 years, primarily due to warming oceans and marine heat waves, according to a global assessment released Thursday. The International Union for Conservation of Nature (IUCN) found that 96% of shallow-water reef systems are already critically endangered and could disappear by 2075.
Prominent reef systems such as the Great Barrier Reef in Australia, the Coral Triangle in the Western Pacific Ocean and Southeast Asia, the Mesoamerican Barrier Reef System, and the Red Sea coral reefs are all listed as critically endangered, the highest threat level.
"The risk of coral reef collapse is escalating, but this must be a wake-up call rather than a cause for despair," said Mishal Gudka, the scientific lead of the global IUCN Red List of Coral Reef Ecosystems assessment, the first of its kind. "Coral reefs have shown a remarkable ability to bounce back from devastating bleaching events. Pockets of surviving, resilient coral reefs can still remain in the future, so we must do everything within our reach to set them up for success."
Coral reefs are vital for marine biodiversity, supporting a quarter of all marine species. They also provide essential sources of seafood and tourism, act as buffers against coastal erosion and storms, and are critical for coastal communities and businesses. When a reef collapses, hard corals are replaced by algae and rubble, leading to the loss of the diverse ecosystem that supports a wide range of marine life.
"Coral reefs are one of the clearest vital signs of the ocean’s health," said Grethel Aguilar, the IUCN Director General, in a statement.
The assessment, which analyzed 127 tropical and subtropical ecoregions covering over 72,000 square miles of coral reefs globally, identified climate change as the most significant threat to coral reef decline worldwide.
This latest assessment follows previous findings that highlighted the severity of the crisis. A study in the journal Nature indicated that nearly 44% of reef-building coral species face an elevated extinction risk due to climate change. Another survey from a year prior found that harmful coral bleaching had affected 84% of the world's reefs, marking the most intense bleaching event on record.
Last year, 2024, was the hottest year on record globally, with oceans absorbing a significant portion of the excess heat. The average annual sea surface temperature away from the poles reached a record high of 20.87 degrees Celsius (69.57 degrees Fahrenheit).
Experts emphasize that alongside ambitious emissions reductions to combat rising global temperatures, efforts to reduce pollution, overfishing, and unsustainable coastal development are crucial for the survival of coral reefs. "We know what is needed: ambitious emissions reductions, stronger protection and restoration efforts, and sustained investment in resilient coastal ecosystems and the communities that depend on them,” Aguilar stated.