PRESS RELEASE
Corals at Elevated Risk of Extinction
Nearly half of Reef-Building Coral species face elevated relative risk of extinction
Mombasa, Kenya – 5 February 2026
This assessment provides the most comprehensive evaluation to date of global extinction risk among reef-building corals, and a stark warning of the accelerating increase in global threats to coral reefs. It also highlights the challenges we face in addressing major data and knowledge gaps on the status of species at global scales, at the same time as having to take urgent decisions to reduce the drivers of global declines in critical species and ecosystems.
David Obura
DIRECTOR, CORDIO East Africa
Co-Chair, IUCN SSC Coral Specialist Group
A global reassessment of reef-building corals has found that 44% of species are threatened with extinction. But in the years since the assessment period ended, the fourth global coral bleaching event and startup of the strongest El Niño ever recorded place corals in even greater jeopardy. The assessment stresses that every tenth of a degree of warming avoided can help preserve coral biodiversity and reef functions.
Of greatest concern to the authors is that the assessment was completed before the extraordinary increase in ocean temperatures and fourth global coral bleaching event of 2023–2025. The authors therefore caution that the proportion of coral species currently at risk is likely higher than the 44% captured by the assessment. The current ramp-up in the super El Niño of 2026-27 further exacerbates risk to corals.
Conducted by the International Union for Conservation of Nature Species Survival Commission Coral Specialist Group, the study reassessed the 892 reef-building coral species on The IUCN Red List of Threatened Species™, drawing on data and expertise from more than 60 coral experts globally.
The study updates the first global IUCN Red List assessment of reef-building corals, first completed in 2008. The findings, which use data up until 2020, reveal a marked deterioration in the status of reef-building corals over this period.
Of the 774 species for which sufficient data were available (excluding those listed as Data Deficient), 340 (or 44% of assessed species) fell into the highest risk categories and are therefore threatened with extinction. Thirty-three are classed as Critically Endangered, 251 Endangered, and 56 are Vulnerable. The threats to reef-building corals were last assessed for the IUCN Red List in 2008, at which time one third were found to be threatened.
Climate change is the main threat to reef-building coral species, determining the final status of over 90% of species at highest risk. The assessment used multiple sources of evidence, including global coral-cover trends and projections of future severe bleaching events (both over three decades), and biological traits associated with vulnerability, to create a comprehensive overview of extinction risk.
The coral Red List Index – a metric used to track changes in extinction risk over time – shows the species are facing accelerating increases in risk, the index worsening from 0.96 before 1998, to 0.89 in 2008 and then 0.74 in 2024 (where a value of 1 means no species face high risk, and 0 means all are extinct).
A major update to the global picture of coral extinction risk
The number of reef-building coral species considered in this assessment increased from 845 in the previous assessment to 892, while improved knowledge reduced the number classified as Data Deficient from 141 to 118.
The results also show that extinction risk is not distributed evenly among coral groups or regions. In the Indo-Pacific, 43% of assessed species were classified as threatened, compared with 50% of assessed Atlantic species.
Some important reef-building groups face particularly high levels of risk. Among Indo-Pacific Acroporidae, 191 of 279 species—68%—were classified as Endangered. This family includes staghorn corals (Acropora) and plating corals, encrusting corals (Montipora), corals that contribute substantially to the three-dimensional structure and complexity of reefs.
“Coral reefs are experiencing rapid environmental change, but responses vary greatly among species and regions. Improving data on regional to local variation in coral and reef responses to threats, in particular global warming, and in coral species and population traits and responses will improve future reassessments of extinction risk and help managers take action to protect and restore corals around the world.” – Dr Francoise Cabada-Blanco, Co-Chair of the IUCN Coral Specialist Group and Professor at the University of Portsmouth, UK.
Every tenth of a degree of avoided warming matters
The reassessment provides a snapshot against a rapidly changing climatic background. Responses to warming differ among coral species, populations and locations, meaning the future of coral reefs cannot be understood as a simple threshold between survival and disappearance.
It also reaffirms that corals show the most rapid decline in status (increase in extinction risk) of all comprehensively-assessed groups (compared to mammals, sharks and rays, birds, amphibians and cycads). The Red List Index for corals is declining at -0.07 to -0.094 points per decade compared to -0.002 to -0.039 per decade for others, as per the Red List index scale.
Both this variation and urgency make action at every increment of warming important: the more warming that can be avoided, the more coral diversity, ecosystem function and opportunities for adaptation can potentially be retained, supporting regeneration.
Reducing the drivers of climate change and other causes of reef decline is therefore fundamental to slowing the escalating extinction risk facing reef-building corals, alongside stronger conservation and management of resilient reefs.
The assessment covers all reef-building corals, which are found in shallow, warm water habitats and form the colourful reefs seen in tropical and sub-tropical ocean areas. Red List assessments of cold-water corals, which are found in colder, deeper waters around the world and do not depend on sunlight, are ongoing.
Publication DETAILS and Contacts
Full paper: Cabada-Blanco, F., Obura, D., Polidoro, B. et al. (2026). Nearly half of reef-building corals face elevated relative risk of extinction. Nature. https://doi.org/10.1038/s41586-026-11263-3
AUTHOR CONTACTS:
Dr. David Obura
Director, CORDIO East Africa
Co-Chair, IUCN SSC Coral Specialist Group
Email: dobura@cordioea.net
Dr. Francoise Cabada-Blanco
Co-Chair of the IUCN SSC Coral Specialist Group
Email: francoise.cabada-blanco@port.ac.uk
RESEARCH FUNDING:
Funding was provided by The MSC Foundation; National Geographic Species Recovery Grant; New College of Interdisciplinary Arts and Sciences, Arizona State University; CORDIO East Africa; IUCN Species Survival Commission; Eurofins Foundation; Zoological Society of London; Lee Kong Chian Natural History Museum, National University of Singapore; Portsmouth University. The Global Coral Assessment was led by the IUCN SSC Coral Specialist Group, working with fellow Red List Partners including Arizona State University and Senckenberg Museum, as well as the Marine Biodiversity Assessment Unit at Old Dominion University and CORDIO East Africa. Over 160 experts from around the world have been involved in the Global Coral Assessment over the past decade.