A new analysis by 15 climate scientists suggests the Environmental Protection Agency's estimate of methane emission is inaccurate. The emissions could be 1.5 times higher than previously anticipated by the EPA. (File/UPI/Maryam Rahmanian) | License Photo
Nov. 26 (UPI) -- Methane emissions in the U.S. in the last decade are 1.5 times more than previously calculated, according to a new analysis by 15 climate scientists.
The analysis, published in the Proceedings of the National Academy of Sciences, suggests that emissions from livestock and cows may be two times higher than previously estimated and emissions from fossil fuel extraction in south-central U.S. is five times higher than the Environment Protection Agency's estimates.
The study looked at 12,700 measurements of atmospheric methane in 2007 and 2008. It was sharply in contradiction to EPA reports and estimates from the European Commission.
The EPA has maintained that emissions from man-made and natural sources have been steadily declining. This April the agency reduced its methane discharge estimates from 1990 to 2010 by 8 to 12 percent, citing this steady decline.
Scot Miller of Harvard University and principal author of the study said their findings show the significant effect of methane on atmospheric temperatures rising.
“Our study shows that there could be large greenhouse gas emissions in places in the country where we may not necessarily have accounted for them.” he said.
This study differs from others because it uses actual measurements of methane concentrations. This is compared to the EPA's approach to estimating methane released, per cow for example.
Programs run by the National Oceanic and Atmospheric Administration and the Department of Energy generated 5,000 air samples from communication towers across the country and 7,700 more from an aircraft monitoring program.
The causes for these emission could not be ascertained but the researchers say that could be investigated using other techniques. While CO2 is the prevalent greenhouse gas in the atmosphere, methane's contribution to global warming is 21 times more than CO2 over a 100-year period.
[The New York Times]
[Proceedings of the National Academy of Sciences]