A Severe Warning for Marine Life: Nearly Half of Reef-Building Coral Species Threatened with Extinction

A comprehensive global study led by the Coral Specialist Group of the International Union for Conservation of Nature (IUCN) and published in Nature paints an alarming picture regarding the future of coral reefs worldwide.

The study brought together more than 60 researchers globally, including Dr. Tom Shlesinger from the School of Zoology and the Steinhardt Museum of Natural History at Tel Aviv University, and the Interuniversity Institute for Marine Sciences in Eilat, who served as the sole Israeli scientist on the international team.

A Sharp Increase in Extinction Risk

The researchers reassessed the status of 892 reef-building coral species for the IUCN Red List of Threatened Species. Of the 774 species with sufficient data for assessment, 340 (44%) are now classified as threatened with extinction: 33 Critically Endangered, 251 Endangered, and 56 Vulnerable.

This marks a significant deterioration compared to the previous global assessment conducted two decades ago, which estimated that roughly one-third of species were threatened.

Climate change and ocean warming were identified as the primary drivers of this decline, influencing the risk status of over 90% of the species in the highest risk categories. The impact is particularly severe among branching corals in the family Acroporidae, vital for providing structural habitat complexity, where 68% of evaluated species are now threatened.

Current Risk May Be Even Higher

The study's evaluations are based on data compiled through 2020. Consequently, they do not yet account for the impacts of extreme marine heatwaves and the fourth global coral bleaching event spanning 2023–2025, suggesting that current risk levels may be even higher.

"The figure of 44% does not mean that half of all coral species will disappear tomorrow, but rather that nearly half of the evaluated species are already at alarming risk levels," explains Dr. Tom Shlesinger. "Corals build the physical and biological foundation of reef ecosystems. When they suffer, entire marine communities depending on them suffer as well. Even in the Gulf of Aqaba, where certain corals display relative resilience to warming, there is no room for complacency. Protection from local pressures is essential, but it cannot replace the urgent need to mitigate global warming." The findings and their implications were also extensively covered by Zafrir Rinat in Haaretz.

Responsibility for the Future

Despite the severe findings, researchers stress that the future of coral reefs is not yet set in stone. Variations in species resilience show that there is no single temperature threshold beyond which all reefs will perish, and every fraction of a degree of warming prevented plays a vital role in conserving species diversity and enabling reef recovery.