Stable isotopic composition (13C and 2H) of methane (CH4) emission sources. European Methane Isotope Database, based on measurements carried out during the MEMO2 project (https://h2020-memo2.eu) Methane Isotopic signatures from previous literature, reported by Sherwood et al. (2017, 2021), and in other literature sources. Sherwood, O.A., Schwietzke, S., Arling, V.A., Etiope, G., 2017. Global Inventory of Gas Geochemistry Data from Fossil Fuel, Microbial and Burning Sources, version 2017. Earth Syst. Sci. Data 9, 639–656. https://doi.org/10.5194/essd-9-639-2017 Sherwood, O.A., Schwietzke, S., Lan, X., 2021. Global δ13C-CH4 source signature inventory 2020. Available at: https://doi.org/10.15138/qn55-e01