Coral Reef Status Report: 9.5% Hard Coral Loss, GCRMN 2026
Why in the news
The Global Coral Reef Monitoring Network (GCRMN) published its seventh reef-health report. It points to bleaching stress nearly every year and recovery gaps down to about 4-6 years.
Key facts
- Live hard coral cover sits roughly 9.5% under the 1980-2009 baseline, falling steeply since 2010.
- 2023-24 brought the fourth global mass bleaching episode; about 87% of reefs met record heat stress in 2024.
- Cover dropped 8.9% from 2023 to 2024, the biggest single-year relative fall ever logged.
| Heat stress of 8 degree-weeks or more (linked to widespread bleaching and die-off) | Share of reefs |
|---|---|
| 2024 | 42.6% |
| 2025 | 27.4% |
About reefs
- Built mainly by coral polyps in colonies, in warm, shallow, clear, nutrient-poor tropical seas.
- Polyps release calcium carbonate (CaCO3); skeletons stay after death and new corals grow over them for thousands of years.
- Value: about 25% of marine species, protection from waves and storms, fisheries and tourism.
Bleaching and threats
- Warm water stresses coral, which expels zooxanthellae, loses colour and food, and turns bone-white; prolonged stress kills it.
- Threats: ocean warming, ocean acidification, pollution, overfishing, sedimentation, coastal development, destructive fishing.
Exam angle
- Report by: GCRMN (7th edition).
- Algae lost in bleaching: zooxanthellae; reef-building compound: calcium carbonate.
- Latest global bleaching event: 4th (2023-24).