Global Methane Assessment methodology

The findings in the Global Methane Assessment are the result of modelling that uses five state-of-the art global composition-climate models to evaluate changes in the Earth’s climate system and surface ozone concentrations from reductions in methane emissions. Results allow for rapid evaluation of impacts from methane emissions and the benefits from mitigation strategies to the climate and ground-level ozone formation and, air quality, public health, agricultural and other development benefits. The assessment results are also available in a web-based decision support tool that allows users to input different methane emissions reduction goals to calculate the multiple benefits at a national level. 

The five models that participated in the assessment are:

  • the CESM2(WACCM6) model developed at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, US (Danabasoglu et al. 2020; Gettelman et al. 2020)
  • the GFDL AM4.1/ESM4.1 (Horowitz et al. 2020; Dunne et al. 2019) model developed by NOAA in Princeton, New Jersey, US
  • the Goddard Institute of Space Studies (GISS) E2.1/E2.1-G model developed by the NASA in New York, New York, US (Gillet et al. 2021; Kelley et al. 2020)
  • the MIROC-CHASER model developed jointly by the Atmosphere and Ocean Research Institute, the University of Tokyo, Kashiwa, the National Institute for Environmental Studies (NIES), Tsukuba, the Japan Agency for Marine-Earth Science and Technology, Yokohama, and Nagoya University, Nagoya, Japan (Sekiya et al., 2018; Watanabe et al. 2011; Sudo et al. 2002)
  • the UKESM1 model developed jointly by the Met Office, Exeter, UK, and the United Kingdom’s academic community (Archibald et al. 2019; Sellar et al. 2019)