THE FACTS: Cows fart. That contributes to global warming. But cow burps are worse for the climate.
“Cows are pretty disgusting eaters, with methane coming from both ends,” said Christopher Field at the Stanford Woods Institute for the Environment. “But most of it comes from burping.”
Field cited the “classic quote from the technical literature” on the topic: “Of the CH4 (methane) produced by enteric fermentation in the forestomach 95% was excreted by eructation (burp), and from CH4 produced in the hindgut 89% was found to be excreted through the breath.’”
In a nutshell, belches are bad news.
At Tuscia University in Viterbo, Italy, environmental scholar Giampiero Grossi said methane emitted by ruminant livestock accounts for about 5.5% of the greenhouse gasses that come from human activity. More than 70% of livestock emissions are from cattle, he said.
“Ruminants are a significant source of methane,” which traps more heat than carbon dioxide but doesn’t last as long in the air, said Kristie Ebi, director of the Center for Health and the Global Environment at the University of Washington in Seattle. “The belches have to do with digesting their food” in the stomach compartments, not intestines, and that fermentation produces methane.
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