Outgoing thermal flux for a pure CO₂ atmosphere on an Earth gravity planet (𝑔 = 9.81 m/s²) are shown for gray atmosphere model with different assumptions. The results of the full RT in a vertically extended atmosphere (“Full RT”) is used for benchmarking (solid lines). The models are compared for the same surface temperatures and pressures, where different surface pressures are indicated by variations in color. Left panel: Results of the gray atmosphere model is shown for ĸ₀(CO₂) = 0.001 m²/kg (dashed lines) and ĸ₀(CO₂) = 0.05 m²/kg (dash- dotted lines). Right panel: Results of the corrected gray atmosphere is shown (dash-dotted lines) in comparison to the Full RT calculations.