A rapidly closing window for coral persistence under global warming
A rapidly closing window for coral persistence under global warming
Bozec, Y.-M.; Adam, A.; Nava, B. A.; Cresswell, A. K.; Haller-Bull, V.; Iwanaga, T.; Lachs, L.; Matthews, S. A.; McWhorter, J. K.; Anthony, K. R. N.; Condie, S. A.; Halloran, P. R.; Ortiz, J.-C.; Riginos, C.; Mumby, P. J.
AbstractCoral reefs around the world are threatened by recurrent marine heatwaves causing mass coral bleaching and mortality. Mitigating future warming impacts requires strategic management that adopts a long-term lens. Global analyses of projected heatwaves are critical for decision-making but how disturbance refugia, coral life-histories and adaptation interact with warming is unknown. Here, we simulate coral eco-evolutionary dynamics across >3,800 individual reefs of Australia iconic Great Barrier Reef under the current suite of climate projections. We forecast a rapid coral decline before mid-century regardless of emissions scenario. Under the most likely warming, corals may continue to decline throughout the century. However, corals may recover after mid-century provided that warming does not exceed 2 degrees Celsius, allowing thermal adaptation to keep pace with temperature changes. Higher emission scenarios would drive most reefs to a near collapse. Future resilient reefs were mostly found in bleaching refugia, which also possessed a greater diversity of thermal phenotypes. Although cool-adapted corals disperse to thermal hotspots, there was no evidence of \"gene swamping\" undermining thermal adaptation. While opportunities exist to build management strategies that promote adaptation in thermal refugia and warm spots, curbing the rate of warming by 2050 is crucial for coral persistence.