This dataset holds estimates of methane emissions derived from a dual tracer inversion of atmospheric measurements of CH4 mole fractions and d13CH4 isotopic values. The measurements were assimilated in the TM5 4-Dimensional Variational (TM5-4DVAR) source-sink inversion system to estimate methane emissions from fossil fuel, microbial, and pyrogenic sources. These estimates include monthly means of methane emissions from each source and all three sources combined at 1-degree longitude x 1-degree latitude spatial resolution globally and monthly totals across all global grid cells from each source and all three sources combined from 1999 to 2016. The data are provided in netCDF version 4 format.