Nearly All Shallow-Water Coral Reef Ecosystems Face Collapse Risk by 2075
On 22 October 2026, IUCN released its first global assessment of shallow-water coral reef ecosystems under the Red List of Ecosystems. It classified 122 of 127 ecoregions as Critically Endangered, primarily because of projected marine heatwaves through 2075.
Global Coral Reef Ecosystems at Risk of Collapse by 2075
The International Union for Conservation of Nature (IUCN), on 22 October 2026, released its first global assessment under the IUCN Red List of Ecosystems, warning that nearly all assessed shallow-water coral reef ecosystems face an extremely high risk of collapse by 2075. The findings were released during the Convention on Biological Diversity's COP17 in Yerevan, Armenia.
Key Findings of the Assessment
96% critically endangered: Of 127 tropical and subtropical coral reef ecosystems assessed across over 80 countries and territories, 122 (96%) are classified as Critically Endangered, covering 99.8% of the assessed reef area (188,362 sq. km).
Observed versus projected risk: Based solely on historical changes, 24% are Critically Endangered; incorporating projected climate change increases this to 96%.
Already collapsed: The Western Galápagos Islands reef ecosystem is classified as Collapsed; four ecosystems are Data Deficient.
Climate scenario: The assessment uses the IPCC's SSP2-4.5 scenario, projecting approximately 2.7°C warming by 2100.
Species extinction risk: A separate IUCN assessment found that 44% of sufficiently assessed reef-building coral species face extinction threats.
Coral Reefs and Ecological Significance
Corals are marine invertebrates belonging to phylum Cnidaria. Reef-building corals form calcium-carbonate skeletons and maintain a symbiotic relationship with photosynthetic algae called zooxanthellae.
Although coral reefs occupy less than 1% of the ocean floor, they support approximately 25% of marine fish species, sustain fisheries and tourism, and protect coastlines against storms and erosion.
Major Threats
Ocean warming: Marine heatwaves cause coral bleaching through the loss of symbiotic algae. Prolonged heat stress may result in coral mortality.
Overfishing: Depletion of parrotfish and groupers disturbs ecological balance, threatening 63% of reef ecosystems.
Pollution and development: Sedimentation, coastal construction, aquaculture and excessive tourism accelerate degradation.
Other pressures: Stronger storms, freshwater flooding, ocean acidification and crown-of-thorns starfish outbreaks undermine reef resilience.
Ecosystem collapse involves the replacement of living hard corals by algae, rubble and sponges, resulting in the loss of ecological functions.
Implications for India and Way Forward
India's major coral reef regions include the Gulf of Mannar, Gulf of Kachchh, Lakshadweep and Andaman and Nicobar Islands. Their degradation threatens marine biodiversity, fisheries, coastal livelihoods and island protection.
Priority measures include implementing the Paris Agreement, strengthening marine protected areas and Coastal Regulation Zone enforcement, controlling pollution and destructive fishing, restoring damaged reefs and encouraging community-based monitoring.
MCQ
Q. With reference to the IUCN's Global Red List of Coral Reef Ecosystems Assessment (2026), consider the following statements:
The assessment covered 127 tropical and subtropical coral reef ecosystems.
Approximately 96% of the assessed ecosystems were classified as Critically Endangered.
The Western Galápagos Islands coral reef ecosystem was classified as Collapsed.
The assessment included all deep-sea and cold-water coral ecosystems.
Which of the statements given above are correct?
(A) 1 and 2 only
(B) 1, 2 and 3 only
(C) 2, 3 and 4 only
(D) 1, 2, 3 and 4
Answer: (B)
Explanation: The IUCN assessment covered 127 shallow-water reef ecosystems, of which 122 were classified as Critically Endangered. The Western Galápagos Islands ecosystem was already classified as Collapsed. Deep-sea and cold-water coral ecosystems were excluded from the assessment.