Fig. 3: Comparative effect-size analysis of projected impacts on coral reefs among a small subset of available studies and three warming scenarios.

Calculated mean effect sizes (Hedges’ g ± 95% CIs) represent the magnitude of projected impacts on model outputs (i.e., coral reef metrics) across three global warming scenarios (1.5–2 °C, 2–4 °C, and >4 °C). Model outputs (mean ± 1 Std) used in this analysis were extracted from n = 39 individual modeled scenarios across eight published studies, and represented in Fig. 4. Mean effect sizes were derived from differences between projected estimates of coral reef metrics for the end-of-century (2090–2100) and the baseline period (2000–2015) (cf. “Methods” section). Hedges’ g, a common effect-size metric ranging from −∞ to +∞, signifies no impact at zero, positive values indicate ecological benefits, and negative values signify adverse effects. The 95% CIs represent variability among scenarios within each study and warming scenario (Supplementary Data 3). Analyzed coral reef metrics include percent reef cells at risk (black), percent habitat change (blue), and percent coral cover change (red). Circles and triangles denote studies using thermal threshold and continuous variable techniques for modeling heat stress, respectively. Open symbols represent global-scale projections, while closed symbols denote regional-scale projections. Source data are provided as a Source Data file.