Detecting Methane Emission Sources in California: a Case-Study of Scientist/Decision-Maker Interactions

Reducing anthropogenic methane emissions is a high priority for the state of California as a strategy to meet near-term greenhouse gas emissions targets. However, implementation of an effective, cost-efficient methane mitigation plan requires local-to-regional scale information on methane sources, and cooperation of diverse stakeholders. We hypothesize that methane "super-emitters," large point sources thought to contribute disproportionately to anthropogenic methane emissions, are logical mitigation targets. We outline a tiered observing strategy involving satellite, aircraft, and surface observations to identify these super-emitters and their contribution to regional methane emissions. We demonstrate this approach with field studies of agricultural and oil and gas sources in California's San Joaquin Valley with cooperation a multi-stakeholder team. This partnership between researchers, regulators, and methane emitting industry took advantage of data sharing, site access, and complementary measurement approaches to identify appropriate methane mitigation targets. This experience suggests that collaborative partnerships that leverage multiple observational methods will be required for identifying methane mitigation targets and crafting regionally appropriate methane mitigation policy.