We calculate CH4 radiative forcing from the analysis of outgoing thermal radiation (OTR) fluxes obtained by the MODTRAN radiative code for five climate atmospheric models and various methane concentrations (0.8, 1.8, and 2.5 ppm). OTR values decreased by ~ 0.15% compared to the pre-industrial era. Seasonal and spatial variations in OTR fluxes at current methane rates reach ~ 13%. To date, due to the increasing CH4 concentration in the Earth’s atmosphere, methane RF is estimated at between -0.482 and -0.266 W/m2.
radiative forcing, methane, outgoing thermal radiation, MODTRAN
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