Methane in the atmosphere increased by 5.7±1.2 ppb per year from 2007-13. In the year 2014, growth was extreme at 12.5±0.4 ppb, occurring at all latitudes. Simultaneously, the carbon isotopic ratio of atmospheric methane shifted to significantly more negative values. Why is methane rising, especially in the tropics, where growth has been strongest? Are sources increasing? Can fluxes and their isotopic signatures be constrained? Or are sinks decreasing? Is this a climate change feedback, and if so, what are the implications for the future? This symposium will welcome all contributions addressing these and related problems constraining global and regional methane budgets.
In addition methane is an attractive target for efficiently cutting greenhouse emissions. We encourage contributions that assess anthropogenic sources, with special emphasis on new advances, such as the use of high-precision mobile measurements and drones; flux calculation from methane plumes, especially from coal and gas extraction; use of isotopic signatures and co-emitted VOCs to identify sources. The symposium will welcome contributions on these and other techniques for pinpointing leaks and advancing emission reduction methodologies.