We have constructed a simple model to estimate full-cycle CO2 emissions of a gas resource, as a function of its production efficiency, contaminants (CO2 and H2S), and commercialisation (LNG or pipelines) . Compared with the life-cycle emissions of oil, CO2 per boe is seen to be c0-20% lower for LNG and c50-75% lower for piped gas. Leading resource types are shown in the data-file.