96% of coral reef systems could disappear by 2075
Oct 23,2026: Almost every coral reef ecosystem on the planet is at high risk of collapse by 2075, a global assessment released on Thursday has found, with warming oceans and heat waves the main drivers.
The International Union for Conservation of Nature announced the findings on the sidelines of a U.N. biodiversity conference in Albania. It said some 96% of shallow-water reef systems are already critically endangered and could disappear by 2075.
The Red List of Coral Reef Ecosystems assessment, the first of its kind, was led scientifically by Mishal Gudka.
“The risk of coral reef collapse is escalating, but this must be a wake-up call rather than a cause for despair,” said Gudka. “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.”
The study covered 127 tropical and subtropical ecoregions, taking in 72,726 square miles (188,362 square kilometers) of coral reefs globally. It named climate change the “single most consistent threat driving coral reef decline worldwide.”
Some of the world’s best-known reef systems are among those classed as critically endangered, the highest level of threat. They include 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.
The findings add to a run of bleak news for coral reefs, which are critical sources for seafood and tourism and often serve as buffers from coastal erosion and storms. Sometimes dubbed “rainforests of the sea,” they have some of the world’s richest biodiversity. They support a quarter of marine species as well as coastal communities and businesses.
When a reef collapses, hard corals disappear and are replaced by algae, rubble and sponges. The reef then no longer supports a diverse ecosystem that can include everything from tiny invertebrates to reef fish like grouper.
“Coral reefs are one of the clearest vital signs of the ocean’s health,” Grethel Aguilar, the IUCN director general, said in a statement. “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.”
A week ago, another study in the journal Nature by the IUCN found that nearly 44% of reef-building coral species face an elevated risk of extinction due to climate change. A year ago, a survey found that harmful bleaching of the world’s coral has grown to include 84% of the ocean’s reefs, the most intense of its kind in recorded history.
The year 2024 was Earth’s hottest on record, and much of that is going into oceans. The average annual sea surface temperature of oceans away from the poles was a record 69.57 degrees Fahrenheit (20.87 degrees Celsius).
Beyond combating rising global emissions, experts said efforts to reduce pollution, overfishing and coastal development can help reefs survive.
Andrew Baker, director of the Coral Reef Futures Lab at the University of Miami, sought to inject some hope after reviewing the assessment. He said stopping global warming and pollution isn’t the only way to save corals.
“It means finding new ways to restore corals using emerging technology and innovative approaches,” he said, “that can throw a lifeline to struggling reefs and buy us critically needed time to make these transitions.”
