2014/05/12 by Brendan Byrne, Colin Goldblatt
Earth and Planetary Sciences · Environmental Science · Physics and Astronomy · #Astro and Planetary Science #Atmospheric Ozone and Climate #Atmospheric and Environmental Gas Dynamics #Atmospheric pressure #Atmospheric sciences #Bar (unit) #Climate change #Climatology #Environmental science #Geology #Global warming #Greenhouse effect #Greenhouse gas #HITRAN #Meteorology #Physics #Radiative forcing #Radiative transfer #Spectral line #astro-ph.EP #physics.ao-ph
paper · pdf · doi:10.5194/cpd-10-2011-2014
This is the final version which was accepted for publication in climate of the past. The reference for the discussion version is: Byrne, B. and Goldblatt, C.: Radiative forcings for 28 potential Archean greenhouse gases, Clim. Past Discuss., 10, 2011-2053, doi:10.5194/cpd-10-2011-2014, 2014
openalex publication_date 2014/05/12 · arxiv created 2014/09/05 · arxiv updated 2014/09/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract. Despite reduced insolation in the late Archean, evidence suggests a warm climate which was likely sustained by a stronger greenhouse effect, the so-called Faint Young Sun Problem (FYSP). CO2 and CH4 are generally thought to be the mainstays of this enhanced greenhouse, though many other gases have been proposed. We present high accuracy radiative forcings for CO2, CH4 and 26 other gases, performing the radiative transfer calculations at line-by-line resolution and using HITRAN 2012 line data for background pressures of 0.5, 1, and 2 bar. For CO2 to resolve the FYSP alone, 0.21 bar is needed with 0.5 bar of atmospheric pressure, 0.13 bar with 1 bar of atmospheric pressures, or 0.07 bar with 2 bar of atmospheric pressure. For CH4, we find that near-infrared absorption is much stronger than previously thought, arising from updates to the HITRAN database. CH4 radiative forcing peaks at 10.3, 9, or 8.3 W m−2 for background pressures of 0.5, 1 or 2 bar, likely limiting the utility of CH4 for warming the Archean. For the other 26 HITRAN gases, radiative forcings of up to a few to 10 W m−2 are obtained from concentrations of 0.1–1 ppmv for many gases. We further calculate the reduction of radiative forcing due to gas overlap for the 20 strongest gases. We recommend the forcings provided here be used both as a first reference for which gases are likely good greenhouse gases, and as a standard set of calculations for validation of radiative forcing calculations for the Archean.