Livestock farms and feedlots in North America may be emitting far more methane, a potent greenhouse gas, than currently assumed, according to a review published in the journal Environmental Research Letters. The scientists who conducted the review said it means other nations that increasingly adopt factory farming could also be producing more methane than expected.
Each year, the EPA estimates methane from livestock as part of a greenhouse gas inventory. Researchers from New York University and Johns Hopkins University said the EPA does not verify its estimates by drawing air samples. Several atmospheric studies over North America in the past decade found methane concentrations that were 39 percent to 90 percent higher than estimates from the EPA and other agencies, they said.
“It’s increasingly likely that methane emissions from farmed animals could be higher in North America than is often being reported,” said Scot Miller, an assistant professor at Johns Hopkins and co-author of the review.
Livestock belch methane as part of digesting their feed. Manure also emits methane.
The review is available here.