Spectra ¹²CO₂ and ¹³ CO₂ for models with different destruction rates at a spectral resolving power R = 2200 appropriate for JWST-MIRI. The abundance floor is taken to be 10⁻⁸. The black line shows the model results for a constant abundance as used in Bosman et al. (2017). The regions were the Q-branch flux is extracted is shown in the black lines. The ¹³CO₂ Q-branch is blended with the ¹²CO₂ P(23) line. The neighbouring P(21) line is indicated. Note that the models with destruction rates of 10⁻¹¹ and 10⁻¹⁰ s⁻¹ are indistinguishable in their ¹²CO₂ spectra.