Climate regimes reached as a function of the partial pressures of N₂ and CO₂. For each set of (pN₂, pCO₂ ), it is indicated if the atmosphere is stable (red) or not (blue) to the atmospheric condensation/collapse of CO₂. The black arrows indicate how planets that have an unstable atmosphere would evolve on this diagram. Temperatures (in green) correspond to the rough estimate of the temperature of the cold point, at the stable lower boundary (blue is up; red is down). Simulations were performed assuming a surface albedo of 0.2 (corresponding both to a water ice surface around TRAPPIST-1, or a rocky surface). Water vapor is not included in these simulations. On TRAPPIST-1e, the inclusion of water vapor might substantially increase the temperature of the cold points through transport of latent heat from substellar to anti-substellar regions, and through the greenhouse effect of water vapor. On colder planets, the effect should be marginal.