Coral reefs worldwide, including the Great Barrier Reef, have faced severe damage from recent bleaching events caused by rising ocean temperatures. A 2025 study published in Coral Reefs highlights the devastating impact of the 2024 Fourth Global Coral Bleaching Event at Lizard Island, revealing up to 92% coral mortality. Using drone-derived imagery, the research underscores the vulnerability of coral ecosystems to climate change and the urgent need for action to protect marine life.
The Role of Drone Technology in Coral Research
A key factor in the success of this study was the use of drone technology, which enabled researchers to capture high-resolution imagery of coral reefs before, during, and after the bleaching event. The drones, specifically DJI Mini 3 Pro and Autel Evo II models, provided unparalleled precision, allowing researchers to document the extent of coral bleaching and assess coral mortality over large areas. Professor Jane Williamson, one of the senior authors of the study, noted the significant advantage of using drone-derived imagery: “Using drone-derived imagery, we followed the amount of bleached and living coral during and after the bleaching event,” she said. “Use of this technology lets us upscale the effects of the bleaching event over larger areas but still at high precision.”
Drone technology has proven invaluable in providing a comprehensive and accurate assessment of reef conditions, particularly in areas that are difficult to access by traditional means. This ability to monitor large sections of the reef system at a high resolution is crucial for tracking the long-term health of coral ecosystems and identifying the areas most at risk from climate change.
Unprecedented Coral Mortality Rates
The data from the study is both alarming and sobering. Dr. Vincent Raoult, the lead author of the research, highlighted the severity of the bleaching event: “This marks one of the highest coral mortality rates ever documented globally.” The research revealed that coral mortality rates in some areas of Lizard Island surpassed 92%, with certain sections seeing total collapse. The implications of this finding are far-reaching, as Lizard Island has long been considered a resilient part of the Great Barrier Reef. Despite experiencing some environmental challenges in recent years, including cyclones and Crown-of-Thorns starfish outbreaks, the reef had shown signs of recovery in prior years. However, the 2024 bleaching event proved catastrophic, overwhelming the reef’s ability to bounce back.
The mortality rate at Lizard Island is particularly concerning when viewed in the context of lower heat stress compared to other parts of the reef. Dr. Raoult noted, “Despite lower heat stress at Lizard Island compared with other parts of the Great Barrier Reef, the mortality rate is unprecedented.” This underscores the sensitivity of coral ecosystems to even modest increases in ocean temperature. As global warming continues, coral reefs around the world will likely face even greater threats, with the potential for irreversible damage if immediate action is not taken.
The Long-Term Threat to Reef Resilience
The findings from this research are especially concerning given the increasing frequency and intensity of extreme heat events predicted for the near future. Professor Williamson’s statement underscores the urgency of addressing climate change: “Our results are concerning for coral resilience, considering the increasing frequency and intensity of extreme heat events predicted for the near future, with potentially irreversible consequences for reef ecosystems such as those studied in our Great Barrier Reef.”
Coral reefs are vital to marine biodiversity, supporting a wide range of marine species and providing essential ecosystem services such as coastal protection. The loss of coral cover not only affects marine life but also has significant socioeconomic consequences, particularly for communities reliant on coral reefs for tourism and fishing industries. With the increasing severity of climate-induced stressors, coral reefs face a real risk of collapse, and the recovery process could take decades, if not longer.
The research team is now running additional surveys at Lizard Island to track potential recovery over the next several years. These efforts are part of a broader initiative to monitor and protect coral reefs across Australia, including funding from the Australian Museum Lizard Island Critical Grant.