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Super pollutants: the fastest lever to slow near-term warming
Super pollutants – short-lived but intensely powerful greenhouse gases like methane, black carbon and hydrofluorocarbons – are responsible for a large share of the warming we're experiencing today. Because they break down in the atmosphere far faster than CO2, cutting them delivers a near-immediate cooling effect, buying critical time before we bypass climate tipping points.
Right now, our work in this space centres on methane, the largest and most tractable of these gases, where states and regions hold real regulatory power over its three largest sources:
– Agriculture (~42% of methane emissions).
– Energy (~38% of methane emissions).
– Waste (~20% of methane emissions).
Introducing the Subnational Methane Action Coalition (SMAC)
9 November, 2026
Under2's dedicated vehicle for methane action is the Subnational Methane Action Coalition (SMAC).
Founded at COP28 in 2023 by the State of California and Climate Group, SMAC brings together state and provincial governments worldwide to cut methane emissions in support of the Global Methane Pledge. Climate Group coordinates the coalition with support from the Global Methane Hub, in partnership with the Center for Law, Energy and the Environment (CLEE) at UC Berkeley and the California Environmental Protection Agency (CalEPA).
Members get technical support tailored to their methane profile, from tools like Carbon Mapper and Climate TRACE for satellite-based emissions data through to policy guidance from CLEE. They share best practice with peer governments facing the same abatement challenges, build tailored reduction plans, and can apply for pilot project grants that fund new approaches to cutting emissions on the ground.
SMAC is free to join and open to state, regional and provincial governments. It now spans five continents and continues to grow toward a 40-member target by March 2027.
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