A methane data revolution is just around the corner, making it possible to move beyond generic emission factors that attempt to estimate the release of methane pollution, and to replace them with more accurate empirical measurements of what is actually happening on the ground. This is crucial for effective mitigation measures. The International Methane Emissions Observatory (IMEO) of the United Nations Environment Programme (UNEP) is poised to catalyse rapid climate action informed through these new data, with a programme of science studies, industry partnerships, the design of a robust measurement, reporting and verification (MRV) framework, a satellite alert and response system, and a team of several dozen methane experts.