Comparison of Model Prediction with Existing Studies.

Porites corals from five reefs reported in six previous studies were used to evaluate the accuracy of our skeletal growth model in predicting coral skeletal density. These corals were collected from reefs in the Galapagos, the Andaman Sea, the Great Barrier Reef, the Caribbean, and the Arabian Gulf (9, 30, 54–56, 74). Other than the three parameters estimated above with Bayesian methods, other parameters required for our model prediction include E, r_o, T_d, seawater temperature, salinity, and carbonate chemistry (from which R_ECM is calculated). Among these, only E was reported in all of the studies. When not reported, r_o and T_d values were estimated either from studies conducted at nearby reef sites or from taxonomic averages for each species (details are in SI Text). In situ measurements of seawater carbonate chemistry, SST, and salinity, whenever available, were used to calculate R_ECM; when not available, pH, DIC, salinity, and temperature outputs from the CESM-BGC run were averaged over the time period that skeletal growth parameters were measured and used to estimate R_ECM. As none of these studies determined carbonate chemistry of the coral ECM, we estimated the coral pH_ECM based on the pH_ECM ∼ pHsw correlation observed in laboratory Porites manipulation experiments (23), which cover a pH_sw range similar to these studies (i.e., 7.19–8.09 vs. 7.23–8.15).