The Moist Greenhouse is Sensitive to Stratospheric Temperature

In this Research Note, I use my single-column climate model to explicitly show that the moist greenhouse surface temperature threshold is sensitive to stratospheric temperature. I argue that this explains most of the discrepancy between 1-D and recent 3-D computations of the moist greenhouse threshold for M-star planets given that calculated stratospheric (and upper atmospheric) temperatures are higher than what are usually assumed in 1-D calculations. I suggest that collaborations between the two sets of modelers would lead to greater understanding of the moist greenhouse threshold. I also discuss implications for habitability if high stratospheric temperatures are a common feature on M-star planets near the inner edge.