Extended Data Fig. 4: Prior and posterior distributions of carbon cycling parameters.

R₀ (a) represents the airborne fraction of CO₂ during the preindustrial, and r_t (b) and r_c (c) capture the decreasing absorption efficacy of land and ocean carbon sinks with rising global temperatures and CO₂ concentrations, respectively. Note that r_c and r_t are not well-constrained by the observational record. The posterior mean r₀ is 33.8 years, which is between that of Millar et al.’s (2017) value of 32.4 years, and Smith et al.’s (2018) value of 35 years.