Thermal emission and absorbed flux as a function of the mean surface temperature. Blue and purple solid lines are OLR and ASR, respectively, while the blue and purple dashed lines are their clear-sky equivalent (csOLR and csASR). Black dots are the stable states and the blue solid line is the runaway greenhouse for an insolation equal to 400 W m⁻². The simulation setup is a waterworld with 1 bar of nitrogen without CO₂ (W1). For comparison, the red line is the OLR computed with the 1D reverse version of the Generic-PCM which uses the same radiative transfer module and assume a fully saturated atmosphere (named the 1D reverse version of LMD-Generic in Chaverot et al. 2022). The green line is the OLR computed using a 1D reverse model assuming a subsaturated atmosphere (saturation mixing ratio less than 5%) from Goldblatt et al. (2013). The flux and temperature values are averaged over a two-year period and the colored areas are the 1 sigma uncertainties due to variability on the fluxes calculation.