We developed the first global maps of natural geological CH₄ flux and isotopic values which can be used for new atmospheric CH₄ modelling. The maps, based on updated, measured and theoretically estimated data, show that the highest geo-CH4 emissions are located in the Northern Hemisphere (N. America, Caspian region, Europe, Siberian Arctic Shelf), and that geo-CH₄ is less ¹³C-enriched than what has been assumed so far in other studies. Other CH₄ sources can now be estimated with higher accuracy.