Figure 4. Constrained estimates of ECS suggested by interannual (\(\psi\)) and decadal (\(\sigma_{b}\)) temperature variability metrics. The original Cox et al. (2018a) constraint is shown for comparison. Error bars indicate 66% confidence intervals. ECS values for each GCM are also shown (black) to illustrate model spread. The IPCC 66% confidence interval is shaded gray.