English: This chart plots the absorption coefficient of water vapor and carbon dioxide, for electromagnetic radiation with wavenumber values (i.e., frequency divided by the speed of light) in the range 200-1600 cm^-1 (wavelengths in the range 6.25-50 microns).

Note that, in the vicinity of its 15-micron absorption band, CO₂ is a much stronger absorber than is water vapor. This is relevant to the greenhouse effect because Earth strongly emits thermal radiation in this range. Water vapor is a stronger absorber than CO₂ for radiation with wavenumbers/frequencies at the left or right side of the plot.

Results are for sea-level atmospheric pressure, a water vapor concentration of 0.25%, and a CO₂ concentration of 420 ppm.

The figure was generated using calculations done by the HAPI 1.2.2.0 software package available at http://hitran.org/hapi (Reference: R.V. Kochanov, I.E. Gordon, L.S. Rothman, P. Wcislo, C. Hill, J.S. Wilzewski, "HITRAN Application Programming Interface (HAPI): A comprehensive approach to working with spectroscopic data," J. Quant. Spectrosc. Radiat. Transfer 177, 15-30 (2016) DOI: 10.1016/j.jqsrt.2016.03.005), using spectroscopic data from the HITRAN database.