This study, by the National Academies of Science, Engineering, and Medicine, analyzes how to improve measuring, monitoring, reporting, and inventory development of human-caused (anthropogenic) methane gas emissions.
Methane is the second most prevalent greenhouse gas emitted in the United States. Although it is shorter-lived in the atmosphere than carbon dioxide, methane is more efficient at absorbing heat. More accurate inventories of human-emitted methane in the United States and a framework for long term monitoring and reporting would help improve the scientific bases of strategies for reducing emissions.
At the request of NASA, NOAA, EPA, and DOE, this study will examine approaches to measuring, monitoring, reporting, and developing inventories of anthropogenic emissions of methane to the atmosphere. The geographic scope of this study is limited to the United States. This study will assess published inventories of U.S. methane emissions, characterize their uncertainty, and identify opportunities for improving these estimates.
Where does methane come from?
According to the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2013, prepared by the EPA, anthropogenic emissions in the United States in 2013 were from natural gas and petroleum systems (29%), enteric fermentation (26%), landfills (18%), coal mining (10%), manure management (10%), and other sources (8%).