Testing the relationship between bleaching severity and climate change during the fourth large-scale coral bleaching event

The Fourth Global Coral Bleaching Event unfolded amidst the accelerating impacts of climate change, underscoring the urgent need to reassess the relationship between coral bleaching trends and climatic shifts. This study examined the influence of sea surface temperature (SST) anomalies and cumulative thermal stress, quantified by Degree Heating Weeks (DHW), on coral bleaching rates from early 2023 to mid-2024. Satellite-derived coral risk data were analyzed for correlation with field survey data. The results revealed that SST anomalies alone were insufficient to significantly predict coral bleaching events. However, a significant positive correlation was found between DHW and coral bleaching rates, indicating that cumulative thermal stress is a critical predictor of bleaching events. This finding emphasizes the necessity of implementing an effective monitoring and early warning system based on DHW thresholds to mitigate the impacts of coral bleaching, especially given the increasing frequency of such events in the context of climate change.