Articles | Volume 32, issue 3
Ann. Geophys., 32, 277–283, 2014
Ann. Geophys., 32, 277–283, 2014

ANGEO Communicates 26 Mar 2014

ANGEO Communicates | 26 Mar 2014

Global annual methane emission rate derived from its current atmospheric mixing ratio and estimated lifetime

G. R. Sonnemann1,2 and M. Grygalashvyly1 G. R. Sonnemann and M. Grygalashvyly
  • 1Leibniz-Institute of Atmospheric Physics at the University Rostock in Kühlungsborn, Schloss-Str.6, 18225 Ostseebad Kühlungsborn, Germany
  • 2Max-Planck-Institute for Solar System Research, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany

Abstract. We use the estimated lifetime of methane (CH4), the current methane concentration, and its annual growth rate to calculate the global methane emission rate. The upper and lower limits of the annual global methane emission rate, depending on loss of CH4 into the stratosphere and methane consuming bacteria, amounts to 648.0 Mt a−1 and 608.0 Mt a−1. These values are in reasonable agreement with satellite and with much more accurate in situ measurements of methane. We estimate a mean tropospheric and mass-weighted temperature related to the reaction rate and employ a mean OH-concentration to calculate a mean methane lifetime. The estimated atmospheric lifetime of methane amounts to 8.28 years and 8.84 years, respectively. In order to improve the analysis a realistic 3D-calculations should be performed.