Graphical Abstract

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Patra, P. K., T. Saeki, E. J. Dlugokencky, K. Ishijima, T. Umezawa, A. Ito, S. Aoki, S. Morimoto, E. A. Kort, A. Crotwell, K. Ravi Kumar, and T. Nakazawa, 2016: Regional methane emission estimation based on observed atmospheric concentrations (2002–2012). J. Meteor. Soc. Japan, 94, 91-113.
https://doi.org/10.2151/jmsj.2016-006  Graphical Abstract with highlights

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Highlights:

• Methane (CH₄) participated prominently in global warming and air pollution chemistry over the past one century. However, anthropogenic emission inventories of CH₄ suffer from large uncertainties, due to the lack of country-specific sectorial emission factors, timing of new technology implementation and the underlying statistics, especially for the developing countries.
• We have developed a new inverse modeling system for estimating CH₄ emissions from 53 regions of global land for the period of 2002-2012, using the JAMSTEC’s atmospheric chemistry-transport model (ACTM) and observations of atmospheric CH₄ at 39 sites (Fig. 1).
• Our results suggest that CH₄ emission level and the rate of emission increase have very likely been overestimated for the East Asia region by the inventory estimates. The rate of CH₄ emission increase in the tropics is found to be in good agreement with that obtained from the inventory estimates, and can be attributed mainly to an increase in livestock population (Fig. 2).