Methane is a component in the global carbon cycle. It plays important roles in the global climate system and in determining background air quality. Despite its significance, large uncertainties still exist in methane's global budget, particularly for sources that vary over small spatial and temporal scales, such as wetlands. There are ongoing bottom-up approaches to reduce these uncertainties at the process level that meld measurements of fluxes and ecosystem parameters with process-based models and there are top-down approaches using space-based and in situ measurements of the spatial distribution of methane combined with atmospheric transport models. This session will gather experts taking both approaches to: 1) communicate current information on the mechanisms of methane emission from wetlands, rice paddies and other sectors (such as vegetation, landfills, industrial emissions, and oceanic emissions); 2) communicate the current state of in situ and satellite observations of methane abundance and land cover, field experiments of methane emissions, and modeling at various spatial scales; and 3) promote synthesis and coordination between bottom-up and top-down approaches in reducing uncertainties and expanding our quantitative understanding of methane emissions from the earth's surface.