Global opportunities for climate-resilient coral reef conservation to 2050

Kyle J A Zawada, Emily Darling, Stacy D Jupiter , Timothy R McClanahan, Joseph M Maina

Climate change is accelerating the decline of coral reefs, yet some locations may retain conditions that support persistence under future warming. We compiled 45,064 coral field observations from 1960–2025 and 42 climate, biophysical, and human-pressure predictors to train machine-learning ensembles estimating coral cover and community composition in 2020 and 2050. We then used a multi-objective optimization framework to select, within each ecoregion, 30% of the reef area (consistent with the GBF 30x30 target) that jointly maximized current and future coral cover, community composition, spatial cohesion, and model certainty as indicators of climate resilience. Finally, we evaluated our results against three global coral reef habitat layers, including two products from the Allen Coral Atlas (visible reef extent and a coral habitat subset) and a UNEP-WCMC global distribution of coral reefs. The three layers identify between 36,466 to 167,352 km2 of coral reef areas with relatively high projected persistence to survive climate change, spanning 79 to 81 national EEZs and 57 to 60 territories and jurisdictions. These findings show how empirical observations and multivariate machine learning can be combined to map candidate climate-resilient reefs at fine resolution, and reveal their uneven but widespread global distribution. While predictive skill was modest and varied among provinces, our results identify candidate locations with the highest probability of sustaining functioning coral reef futures rather than definitive priorities, and should be combined with local knowledge, national assessments and improved monitoring data to inform conservation policy, finance and management.