Anthropogenic emissions of methane in the United States
November 25, 2013
Anthropogenic emissions of methane in the United States
Significance
Successful regulation of greenhouse gas emissions requires knowledge of current methane emission sources. Existing state regulations in California and Massachusetts require ∼15% greenhouse gas emissions reductions from current levels by 2020. However, government estimates for total US methane emissions may be biased by 50%, and estimates of individual source sectors are even more uncertain. This study uses atmospheric methane observations to reduce this level of uncertainty. We find greenhouse gas emissions from agriculture and fossil fuel extraction and processing (i.e., oil and/or natural gas) are likely a factor of two or greater than cited in existing studies. Effective national and state greenhouse gas reduction strategies may be difficult to develop without appropriate estimates of methane emissions from these source sectors.
Commentary on the study:
Bridge Out: Bombshell Study Finds Methane Emissions From Natural Gas Production Far Higher Than EPA Estimates | ThinkProgress.
Huffington Post coverage:
NY Times coverage:
Harvard University Press Release:
Link to Study:
Anthropogenic emissions of methane in the United States
http://www.pnas.org/content/early/2013/11/20/1314392110.abstract
GDACC 
