Varying detection strength of CO₂ with respect to CO₂ abundance (on the x-axis) and SNR (on the y-axis) at bandpass centers of 1.44 μm (a and d), 1.52 μm (b and e), and 1.63 μm (c and f). For each abundance and SNR, the color corresponds to the strength of the CO₂ detection; the darker the purple, the stronger the detection, and the lighter the pink, the more unconstrained the detection. The top plots (a, b, and c) show CO₂ detection strength for modern H₂O and Archean CH₄. The bottom plots (d, e, and f) show CO₂ detection strength for no H₂O and modern CH₄.