The Atmospheric Water Vapor Content Effect on Carbon Dioxide and Methane Radiative Forcing in the Troposphere and Stratosphere

According to the IPCC-2021 Report on Climate Change, the atmospheric CO2 and CH4 concentrations have increased by around a quarter for the past 50 years. The CO2 and CH4 radiative forcing due to their concentration growth was calculated for mid-latitudes. The vertical profiles of temperature and humidity were taken from the ECMWF ERA-5 European reanalysis data. An effect of overlapping of H2O absorption bands with CO2 and CH4 bands on the radiative forcing calculation results in the troposphere and stratosphere of midlatitudes with different water vapor content was studied by statistical methods. It was shown that absolute value of the CO2 radiative forcing in the troposphere increases with the atmospheric water vapor content, whereas the CH4 radiative forcing does not depend on the atmospheric total column water vapor.