Following Alessandro Volta's discovery of 'marsh gas' bubbling to the surface of the water along the shoreline of Lago Maggiore in 1776, methane has emerged as the fastest way to mitigate climate change. Given the combination of methane's warming potency, short-lifetime, and role in air pollution, a range of policies have been enacted to reduce emissions from fossil fuel production, agriculture and waste, which, if achieved as part of the Global Methane Pledge, would reduce warming by 0.3-degrees Celsius by mid century. To meet this challenge, a revolution in data observations and access is taking place, alongside innovations in technology, financing, monitoring, reporting and verification. Challenges remain in scaling solutions, addressing hard-to-abate emissions, and understanding Earth system feedbacks from wetlands and the complex chemical sink responsible for methane's removal. This Union Session brings together the methane science and policy community to reflect on historical accomplishments and to frame future actions.