Cows and Climate Change: A Closer Look

The extent to which meat production contributes to climate change is hotly contested

by Andre Mayer – CBC News

Earlier this year, when U.S. congresswoman Alexandria Ocasio-Cortez first started promoting the Green New Deal — the Democratic proposal to mobilize government to address climate change and income inequality — she made comments about the significant impact of “cow farts” on carbon emissions.

That concerned Frank Mitloehner, an esteemed animal science professor at the University of California, Davis, who tweeted at AOC, telling the rookie lawmaker that “meat/milk” was only responsible for four per cent of greenhouse gas emissions in the U.S.

“Curbing our reliance on gasoline vehicles and air travel is far more consequential because fossil fuel-related activities are the 800lb gorilla”

 

In an interview with CBC, Mitloehner said agriculture is “often depicted in a negative way. And that’s unfortunate, because agriculture should be an important solution to [climate change], and could be. Plus, we all have to eat.”

Ocasio-Cortez’s comment reflected a broader concern about the amount of methane released in beef production. (For the record, bovine burps are the main culprit.) As far as greenhouse gases go, methane is in some ways more concerning than carbon dioxide — a 2014 assessment from the Intergovernmental Panel on Climate Change (IPCC) said methane traps heat 28 times more than CO2.

Mitloehner pointed out, however, that methane only stays in the atmosphere for about a decade. CO2, on the other hand, stays up there for 1,000 years or more. In a hypothetical scenario, Mitloehner said, if you operated a dairy with a steady herd of 1,000 cows over 50 years, after the first decade, “you’re not adding new, additional methane to the atmosphere.”

Researchers have been looking at a number of ways of reducing methane on farms — such as feeding cows seaweed — but Mitloehner said their impacts are still being studied.

While raising cattle provides income to farmers and food for the masses, it also has ecological benefits.

“From a natural resources perspective, Canadian beef producers are stewards to over 44 million acres [16 million hectares] of grasslands, and that plays a critical role in carbon storage,” said Monica Hadarits, executive director for the Canadian Roundtable on Sustainable Beef, the non-profit group that promotes the efforts of the beef industry to meet green goals.

A 2018 study by the Joint Research Centre in Nature Climate Change showed that soil is a highly effective sink for greenhouse gases — and the urine and manure of grazing cows are key to keeping soil healthy. But the study also said that farmers must balance the use of fertilizers in order to minimize the release of nitrous oxide, a greenhouse gas that is nearly 300 times as heat-trapping as CO2.

Mitloehner spends a fair amount of time on social media addressing misconceptions about the climate impacts of agriculture. Earlier this week, he tweeted at the BBC for overstating the environmental virtues of going vegan.

In terms of cutting carbon emissions, he said curbing our reliance on gasoline vehicles and air travel is far more consequential. As Mitloehner wrote in a tweet, fossil fuel-related activities are “the 800lb gorilla.”

Source: CBC News