Transmission spectrum models (left) for a sample of 20 hypothetical rocky exoplanets generated following the trend in CO₂ with stellar irradiation predicated on the assumption of a functioning carbonate–silicate weathering feedback mechanism (right). Planets near the outer edge of the HZ at lower stellar irradiation are predicted to possess atmospheres with higher CO₂ abundances than those near the inner edge of the HZ, and such variations in CO₂ manifest in observable features in the transmission spectrum.