Sources of methane within the United States include all sources important on a global basis, but with larger fractions coming from anthropogenic activities.[1] The oil and gas industries and animal agriculture are estimated to be the two largest sources within the U.S., each accounting for approximately 25% of total emissions.[2] Wetlands, landfills, and coal mines are estimated to account for 23%, 15%, and 7% of emissions, respectively.[3] While significant uncertainty exists concerning the total U.S. emissions from each of these sources,[4] there exists confidence that cumulatively, anthropogenic activities represent a large fraction of U.S. emissions, and that each of these sources represents a significant contribution to U.S. emissions.[5]
[1] Greenhouse Gas Reporting Program 2015, Epa, https://www.epa.gov/ghgreporting/ghg-reporting-program-data-sets (last visited Nov. 3, 2017).
[2] J.D. Maasakkers et al., Gridded National Inventory of U.S. Methane Emissions, 50 Environ. Sci. Technol. 13123 (2016), 10.1021/acs.est.6b02878.
[3] Id.
[4] A. R. Brandt et. al., Methane Leaks from North American Natural Gas Systems, 343 Sci. 733 (2014), 10.1126/science.1247045; S. M. Miller et al., Anthropogenic Emissions of Methane in the United States, 110 (50) Proc. Natl. Acad. Sci. 20,018 (2013), doi:10.1073/pnas.1314392110; A. J. Turner et al., A Large Increase in U.S. Methane Emissions over the Past Decade Inferred from Satellite Data and Surface Observations, 43 Geophys. Res. Lett. 2218 (2016), doi:10.1002/2016GL067987; L.M. Bruhwiler et al., U.S. CH4 Emissions from Oil and Gas Production: Have Recent Large Increases Been Detected? 122 J. Geophys. Res. Atmos. 4070 (2017), doi:10.1002/2016JD026157.
[5] A. J. Turner et al., A Large Increase in U.S. Methane Emissions over the Past Decade Inferred from Satellite Data and Surface Observations, 43 Geophys. Res. Lett. 2218 (2016), doi:10.1002/2016GL067987
For more information, please contact the Guide Author, Ekrem Korkut, Research Assistant at The Center for Agricultural and Shale Law.
Email: EZK137@psu.edu
The Center for Agricultural and Shale Law
Penn State Law
The Pennsylvania State University
329 Innovation Blvd., Suite 118
University Park, PA 16803
Phone: (814) 865-4290
Fax: (814) 865-3851