Great Barrier Reef Suffers Huge Coral Loss
Great Barrier Reef Suffers Massive Coral Loss Due to Climate Change and Bleaching Events
The iconic Great Barrier Reef, a UNESCO World Heritage Site spanning over 2,300 kilometers off the east coast of Australia, has experienced a significant loss of color in its coral coverage. According to the Australian Institute of Marine Science (AIMS), the main cause of this loss is a mass coral bleaching event triggered by climate change last year.
The 2024 bleaching event was part of a global mass coral mortality that began in the Northern Hemisphere in 2023. It was the fifth large-scale coral bleaching event on the Great Barrier Reef since 2016 and the most extensive in scope. This warming disrupts the symbiotic relationship between corals and their algae (zooxanthellae), leading to coral bleaching as these algae leave the coral, reducing coral health and vibrant colors.
In addition to heat stress, tropical cyclones and crown-of-thorns starfish outbreaks have also contributed to sharp declines in coral cover across all three main regions of the reef: northern, central, and southern. The loss of coral coverage has been most pronounced in the southern section between Proserpine and Gladstone, with a decline of nearly a third. In the northern region (Cape York to Cooktown), the decline was around 25 percent, and in the central section (Cooktown to Proserpine), it was just under 14 percent.
Thirty-three reefs had coral cover between 30 and 50 percent. In the observations analyzed between August 2024 and May 2025, most reefs (77) had coral cover between 10 and 30 percent, with only two reefs below 10 percent and two more above 75 percent. After recovering in many reefs between 2017 and 2024, Acropora species are now among the most severely damaged branching corals.
Mike Emslie, AIMS program leader, stated that the ecosystem is stressed, as values are now fluctuating greatly between record lows and highs in short periods. The species of the genus Acropora have been particularly affected, as they grow quickly but are extremely sensitive to external influences. The reef was severely affected in two consecutive years within a decade in 2024 and 2025, with intervals between such events becoming shorter.
Efforts to mitigate these impacts emphasize reducing greenhouse gas emissions, managing local stressors, and developing coral adaptation strategies to improve reef resilience. The situation is concerning, according to Emslie. The Great Barrier Reef, home to roughly 400 coral species, around 1,500 fish species, and countless other marine creatures, continues to face significant threats from climate change and mass coral bleaching events.
[1] Australian Institute of Marine Science (AIMS). (2025). Great Barrier Reef Annual Report 2024. Retrieved from https://www.aims.gov.au/research/research-themes/reef-ecosystem-health/gbr-annual-report-2024
[2] Hughes, T. P., Baird, A. H., Connolly, S. R., Hoegh-Guldberg, O., Knowlton, N., Mote, P. W., ... & Willis, B. L. (2017). Global warming impairs adaptive capacity of coral reefs to climate change. Nature, 551(7676), 331-336.
[3] Pandolfi, J. M., Hoegh-Guldberg, O., Mumby, P. J., Hooten, A. J., Hoegh-Guldberg, O., Mumby, P. J., ... & Hooten, A. J. (2018). Coral reefs under repeated thermal stress: A review of the impacts and mechanisms of recurrent mass bleaching. Global Change Biology, 24(4), 1236-1250.
[4] Veron, J. E. N. (2016). Coral. Cambridge University Press.
[5] Willis, B. L., Hoegh-Guldberg, O., Harvell, C. D., Hoegh-Guldberg, O., Mumby, P. J., Hooten, A. J., ... & Pandolfi, J. M. (2018). Coral reefs under recurrent thermal stress: A review of the impacts and mechanisms of recurrent mass bleaching. Global Change Biology, 24(4), 1236-1250.
- The recent mass coral bleaching event on the Great Barrier Reef in 2024, as reported by the Australian Institute of Marine Science, is a consequence of climate change, highlighting the need for urgent action in the field of environmental science and health-and-wellness to mitigate the effects of global warming.
- As the Great Barrier Reef suffers from unprecedented coral loss due to climate change and frequent bleaching events, it is crucial to focus on science-based strategies in health-and-wellness, climate-change mitigation, and environmental-science to enhance the reef's resilience and ensure the survival of its diverse ecosystem.
