The estimated probability density function (PDF) of η derived from patch experiments that show significantly different ( P values below 0.01) global-mean surface temperature to baseline experiment. Each plus sign indicates the hydrological sensitivity estimated from the corresponding patch experiment. Vertical dashed black lines denote the approximate upper and lower bounds of η estimated from current GCMs, respectively, whereas the vertical dashed red line denotes the water vapour increase rate suggested by the Clausius–Clapeyron (CC) relation. The blue area indicates a decrease in convective mass flux ( Δ {M}_{rm{c}}/{M}_{rm{c}}<0 ) and a slowed-down circulation, whereas the red area denotes an increase in convective mass flux ( Δ {M}_{rm{c}}/{M}_{rm{c}}>0 ) and a speed-up circulation.
