Great Barrier Reef 2024–2025 Mass Bleaching
Recent Developments
012025: AIMS reported the Great Barrier Reef experienced its sixth mass bleaching since 2016, with surveys across 281 reefs in the Torres Strait, the northern GBR, and parts of the central region.
022025: AIMS’ annual condition summary reported hard coral cover declined substantially across the GBR, with regional declines of 14% to 30% versus 2024 and some individual reefs down by as much as 70.8%.
032024: AIMS confirmed the fifth mass bleaching event on the GBR, with high to extreme bleaching across all three reef regions and the largest spatial footprint ever recorded on the reef.
042024–2025: NOAA/ICRI identified the ongoing fourth global coral bleaching event as extending from 2023 into 2025, with bleaching-level heat stress affecting 84.4% of the world’s coral reef area by 30 September 2025.
Interventions
- AIMS long-term monitoring and aerial surveys of reef condition, bleaching prevalence, and coral cover across the GBR.
- GBRMPA and related Australian reef-management programs focused on reef surveillance, impact assessment, and local stressor reduction such as crown-of-thorns starfish control and water-quality management.
- NOAA and ICRI global coral-bleaching monitoring and event tracking under the fourth global bleaching event framework.
What Works
- Reducing local stressors such as poor water quality, crown-of-thorns starfish outbreaks, and other compounding pressures can improve reef resilience when heat stress occurs, which AIMS identified as important in interpreting 2025 coral-loss patterns.
- Long-term monitoring and rapid aerial/in-water assessments help target response efforts and document damage patterns, as shown by AIMS’ 2024 and 2025 survey program.
How to Help
- Donate to reef-science and reef-restoration organizations working on the Great Barrier Reef, such as AIMS-aligned conservation partners.
- Support climate-policy and emissions-reduction advocacy, since heat stress is the main driver of mass bleaching events identified in the cited reports.
- Volunteer with local marine conservation groups involved in reef monitoring, restoration, or education.
Make an Impact
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Verified Organizations
Organizations Helping(22)
AMCS campaigns to reduce local threats to the Reef such as water pollution, industrialization, and unsustainable fishing. They mobilize public support to hold governments accountable for environmental commitments, promote legal protections, and push for sustainable policies like gillnet phase-outs and improved water quality standards to enhance reef resilience against climate change.
The Foundation pioneers large-scale coral restoration using advanced technology, including growing heat-tolerant coral larvae in micro-nurseries and deploying them to vital reefs. They focus on restoring 50 key reefs by 2031 and expanding globally. Their programs include the Reef Restoration and Adaptation Program (RRAP) and community-led conservation, integrating Indigenous knowledge and sustainable financing to scale restoration efforts.
This organization contributes to Great Barrier Reef protection by improving catchment condition and reducing pollutants that flow to coastal waters. Its work includes land rehabilitation, erosion control, and water-quality projects that help reduce chronic stress on reefs and improve coral recovery potential after bleaching events.
