A new study revealed that U.S methane emissions are 50 percent higher than the estimated level reported by the Environmental Protection Agency (EPA). Researchers cited that the federal agency estimation did not include other methane sources such as broken natural gas pipes and livestock.
Researchers from the Carnegie Institution of Science's Department of Global Ecology led by associate professor Anna Michalak used data gathered by the NOAA's Earth System Research Laboratory (ESRL) Global Monitoring System. The ESRL conducts sustained observations and research related to world distributions, trends, sources and sinks of atmospheric constituents that are capable of forcing change in the climate of the Earth.
They measured the emissions recorded in 2007 and 2008 from the ground, telecommunications towers, and from the aircraft. They found that the methane level in the U.S had underestimated other sources which may mean that methane contributes to climate change than previously thought. They recommend that the EPA should set a limit to prevent the drastic effect of methane in the environment as the emissions are five times higher than the EPA estimate.
"It's really a very clear signal" of how much methane U.S. industry and other sources emit,” said Michalak in an interview with the USA Today.
Co-author Steven Wofsy was uncertain of the cause of the significant discrepancy on their measurement and that of EPA’s. He suggested that it may be because the federal agency missed to include all the possible sources of methane. However, they were still uncertain of the actual source if it the emissions were from the drilling, processing, or refining.
“The fossil fuel industry are probably an important source of methane gas emissions in that part of the country,” said co-author Scot Miller to Bloomberg.
According to EPA, methane contributes to nine percent of the greenhouse gases emitted in 2011. Though it traps more heat in the atmosphere compared to carbon dioxide, it doesn’t stay longer in the atmosphere.
The study was published in the Nov. 25 issue of the Proceedings of the National Academy of Sciences.
