Methane mitigation for cattle producers and the climate

Cattle ranchers face attacks for everything from the amount of land they use to how much their cattle burp.

"Ruminants are the ultimate upcyclers. They have the unique ability to turn low quality feed and food that has no human nutritional value into high protein meat and milk," says Garth Boyd, a partner at The Context Network. "This unique ability comes with a downside of enteric emissions of methane from the digestion process."

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As conversations around agriculture and climate change continue, Frank Mitloehner, a University of California, Davis, air quality Extension specialist, says it's not too late for cattle to be part of the solution.

"It's not to say livestock doesn't have an impact on climate," Mitloehner says. "They do, but it's important that we understand the nuance around it."

Methane's Role in Climate Change

Climate scientists traditionally measure greenhouse gases by their global warming potential (GWP100), comparing each gas to carbon dioxide (CO2), Mitloehner says.

"Greenhouse gases form a blanket around the Earth, trapping the heat from the sun," Mitloehner says. Methane and nitrous oxide trap heat from the sun about 28 and 265 times, respectively, more than CO2. However, there's more nuance to it than methane and nitrous oxide being the obvious bad guys.

Mitloehner says the GWP100 overestimates the warming potential of methane by a factor of four because it fails to account for atmospheric removal of methane.

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"Methane is produced by various sources, including livestock, but methane is also destroyed," Mitloehner says. "That leads to a difference in the life span of these gases. Life span refers to how long these gases remain in the atmosphere. Let's say we drive a car and put CO2 into the atmosphere. It stays there for a thousand years. In contrast, methane, once it's emitted, stays in the atmosphere for a short period of time, namely a little over a decade."

Methane released by cattle is part of the biogenic carbon cycle, a process in which carbon is recycled by plants, animals, and the atmosphere. This cycling of atmospheric carbon vastly differs from the emissions put out by burning fossil fuels, Mitloehner says.

"CO2 is a stock gas. It accumulates in the atmosphere, and it never goes down," Mitloehner says. "Currently, methane is treated as if it were a stock gas, too, as if every time our cows belch or manure decomposes, it accumulates in the atmosphere. But we know it doesn't. We know methane is not accumulating because methane is not just produced, but also destroyed through a process called hydroxyl oxidation. That makes methane a flow gas."

Stable Methane Removal

The natural atmospheric removal of methane implies if emissions from livestock remain stable, the climate warming caused by ruminants will be near stable, meaning they are not having a negative effect on climate, Mitloehner says.

"If you have a constant herd of beef, dairy, and other livestock, then the amount of methane these animals put out is constant because an equal amount of what's produced is also destroyed," Mitloehner says. "That means the constant amount of methane coming from a constant cattle herd leads to constant warming and not additional warming."

In theory, this means a reduction of emissions by livestock producers could actually help cool the planet.

"When you drastically reduce methane, let's say about 35% over 30 years, then you induce strong, negative warming, or cooling," Mitloehner says.

Minimizing Methane

Livestock producers in the United States have made great strides in reducing their environmental impact of their production practices, says Hannah Thompson-Weeman, vice president of strategic engagement for the Animal Agriculture Alliance.

"There's been a lot of exciting work in the dairy and beef communities when it comes to sustainability and mitigating climate impact," she says.

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For example, the U.S. beef industry has reduced its greenhouse gas emissions per pound about 40% while producing more beef per animal, Thompson-Weeman says. In California, dairy producers are paid incentives to cover their manure lagoons, capture biogas, and convert it to be used in vehicles.

"The conversion of biogas from dairies to this renewable natural gas is considered the most carbon-negative fuel type there is, meaning you are net reducing warming by doing this," Mitloehner says. "As a result, our dairy farmers who do this are paid very high incentives through the low carbon fuel standard credit."

Shifting Roles

By reevaluating methane in livestock production, producers can shift their role in climate discussions. "We have to find ways to reduce methane," Mitloehner says.

"We have to be aggressive about it because once we are, we will be a solution in our fight against climate change."

Emerging technologies and innovations have already shown potential.

"There has been tremendous focus from public and private research institutions on finding ways to decrease methane emissions," says Boyd. "There have been a couple breakthroughs with feed additives that decrease methane emissions. Cattle will play an important role in the future to help solve climate change."

As innovations to produce more product with less continue, the carbon footprint of animal products will naturally decrease.

"Many people think modern agriculture is bad for the climate and environment, but the opposite is true, Mitloehner says.

By taking a proactive approach, producers have a real opportunity within their reach.

"The agricultural sector needs to understand this and take it by the horns," Mitloehner says. "There's a significant opportunity to take what was considered a liability and turn it into an asset."