Detectability strength of (a) Proterozoic-like, (b) Archean-like, and (c) Venus-like CO₂ abundances between 0.8 and 2.0 μm for a subset of SNRs, in this case 6, 10, 14, 18, and 20. The light pink circles portray an unconstrained detection, the magenta diamonds portray a weak detection, and the purple squares portray a strong detection, which align with the lnB classifications defined in Table 2. The 68% credible region is shaded in gray. The true value of the CO₂ abundance is marked by the horizontal dashed black line.