Global Monthly Emissions of Methane and Its Isotopic Source Signatures for the Year 2019-2021

Global monthly emissions of methane and its isotopic source signatures (d13C-CH4 and dD-CH4) for the year 2019-2021. Estimates are derived using a four-dimensional variational (4D‑Var) data assimilation in the GEOS-Chem Adjoint Model that integrates space‑based observations of methane from the TROPOspheric Monitoring Instrument (TROPOMI), along with in situ NOAA measurements of methane isotopes. For a full description see:Yu, X., Canadell, J. G., Henze, D. K., Patra, P. K., Saunois, M., Cen, X., Lan, X., Riddell-Young, B., Röckmann, T., and Jackson, R. B.: Incorporating methane isotopologues alters tropical and subtropical methane emission estimates. Nature Communications, 17, 6002, 10.1038/s41467-026-72668-2, 2026.