Local human disturbances on coral reefs negate potential climate refugia

Marine heatwaves pose a growing threat to coral reefs globally, prompting divergent theories on where corals might survive in the near future. However, global predictions of climate refugia often overlook local human disturbances that can negate their benefits. We quantified the relationships between marine heatwaves, local human pressures, environmental conditions, and stony-coral cover using a mixed-effects spatio-temporal Bayesian model. We examined where local human disturbances suppress geographical climate refugia and tested four environmental refugial hypotheses based on latitude, remoteness, depth, and turbidity. While some refugia remained unimpacted by local human disturbances, we identified many potential refugia that are currently suppressed by local human disturbances. The most effective refugia were reefs that experience naturally moderate turbidity. We highlight where local intervention could create or restore climate refugia that are otherwise suppressed by local human disturbances. Reducing local human disturbances in these regions could vastly expand the area of functioning climate refugia. Local human disturbances, such as pollution and land-use change, globally suppress coral reefs, particularly inshore, turbid reefs, that may be climate refugia if local stressors were reduced, based on 12,892 coral-reef sites and Bayesian analysis.