Methane is a potent greenhouse gas, trapping far more heat in the atmosphere than carbon dioxide. The study, published Monday, says methane emissions from livestock flatulence and belching, along with those associated with oil and gas drilling, are much greater than estimated.
"Overall, we conclude that methane emissions associated with both the animal husbandry and fossil fuel industries have larger greenhouse gas impacts than indicated by existing inventories," the study's authors wrote.
The study finds total U.S. methane emissions are 1.5 times to 1.7 times greater than estimated by the Environmental Protection Agency and the international Emissions Database for Global Atmospheric Research, respectively.
The study's authors say the way in which emissions were examined accounts for the difference. Led by Harvard University's Scot Miller, the authors say the EPA and EDGAR examined emissions from the point source while their study measured what was actually present in the atmosphere.
"Most strikingly, our results are higher by a factor of 2.7 over the south-central United States, which we know is a key region for fossil-fuel extraction and refining," Miller said in a statement. "It will be important to resolve that discrepancy in order to fully understand the impact of these industries on methane emissions."