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Do “cow farts” cause global warming?

cow

While it makes for endless dad jokes, it’s a myth that cow farts cause global warming.

Cows actually burp out methane as their complex ruminant digestive systems break down plant materials, explains Dr. Sara Place, an animal scientist with the National Cattlemen’s Beef Association.

Critics often cite global averages to suggest that cattle are one of the biggest emitters of greenhouse gas, but those figures don’t tell the whole story, Place says.

Research shows that removing all livestock and poultry from the U.S. alone would only reduce global greenhouse gas emissions by 0.36 percent.

Specifically, cattle farming in the United States is the most environmentally friendly and sustainable in the world, she says.

In the last 40 years, the U.S. cattle herd has shrunk by one-third, yet U.S. farmers are producing more beef today than they did in the 1970s, Place notes.

We're also reducing emissions within the dairy industry, too. In 1950, the U.S. had 25 million dairy cows. Today, we only have 9 million. The herd has shrunk drastically, but with those 9 million cows we are producing 60% more milk, according to Dr. Frank Mitloehner of U.C. Davis.

That means that the dairy industry’s carbon footprint is down by two-thirds in the U.S. since 1950. That’s a substantial reduction in carbon dioxide and methane emissions. Fewer cows means fewer cow burps (and cow farts).

U.S. farmers are adopting improved tools and methods to help make cattle farming more effective, efficient and environmentally friendly.

Cattle farmers have also invested their own dollars in decades-worth of research into sustainable livestock farming, Place notes. They are sharing new ideas and innovations with each other. When farmers use their resources effectively, everyone wins. 

These include new sustainable farming practices, changes to cow diets (to reduce those dad-joke burps and farts), and better breeding and genetics for the cows themselves. Cows may still belch, but farmers are producing more with fewer cows. Herds are down but we’re producing more dairy and beef than ever. That's helping to drive down greenhouse gases like carbon dioxide and methane.

Something else to keep in mind is that methane, which some critics say is the larger issue for cattle farming, is a much more potent gas for trapping heat. But it’s also one that decays in 10 years. Carbon dioxide lasts in the air for hundreds of years. So once a cattle farm has been around for 10 years (and many have been around for generations), there are no new increases in methane emissions.

The same number of cows release methane at the same rate (or less, with dietary improvements). And herd sizes decreasing by two-thirds means methane emissions are better than steady: they have dropped over the years.

Dr. Place tells us, “Beef is an incredibly nutritious food. It’s a tasty food, and it’s a sustainably produced food,” Place says. “You can feel confident in your food choices, that it’s responsibly raised and the care that goes into (raising beef for) your plate is serious.”

This piece was originally published on April 2, 2019, and was updated on July 17, 2020.

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