ORNL DAAC Data Release - TM5-4DVAR Global Monthly Source-disaggregated Methane Emissions, 1999-2016
Posted: Thu May 08, 2025 10:29 am America/New_York
ORNL DAAC recently released a new NACP dataset by Basu, S. et al (2025):
TM5-4DVAR Global Monthly Source-disaggregated Methane Emissions, 1999-2016
This dataset holds estimates of methane emissions derived from a dual tracer inversion of atmospheric measurements of CH4 mole fractions and d13CH4 isotopic values.

Figure 1. Methane emissions estimates and trends for microbial and fossil fuel sources. The left panel shows estimates of mean methane emissions from this study as orange bars. Purple and green bars show alternative estimates from atmospheric chemistry from Cantrell (1990) and Wang et al. (2021); these estimates are outside of the error bars for mean estimates from this study. The right panel shows trends in emissions before and after 2007. The majority contribution to trends came from microbial sources.
Citation: Basu, S., X. Lan, S.E. Michel, E. Dlugokencky, and S. Schwietzke. 2025. TM5-4DVAR Global Monthly Source-disaggregated Methane Emissions, 1999-2016. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/2411
TM5-4DVAR Global Monthly Source-disaggregated Methane Emissions, 1999-2016
This dataset holds estimates of methane emissions derived from a dual tracer inversion of atmospheric measurements of CH4 mole fractions and d13CH4 isotopic values.

Figure 1. Methane emissions estimates and trends for microbial and fossil fuel sources. The left panel shows estimates of mean methane emissions from this study as orange bars. Purple and green bars show alternative estimates from atmospheric chemistry from Cantrell (1990) and Wang et al. (2021); these estimates are outside of the error bars for mean estimates from this study. The right panel shows trends in emissions before and after 2007. The majority contribution to trends came from microbial sources.
Citation: Basu, S., X. Lan, S.E. Michel, E. Dlugokencky, and S. Schwietzke. 2025. TM5-4DVAR Global Monthly Source-disaggregated Methane Emissions, 1999-2016. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/2411