A UC Davis professor’s research is challenging some commonly accepted concepts about global warming and raising a few hackles.
The dispute doesn’t involve denialists or outliers though. It’s statistics, not skeptics.
Specifically, Frank Mitloehne, professor of animal science and an air quality specialist, recently called out some activists who he said are scapegoating cattle to promote vegetarianism and veganism.
“All of livestock combined, that’s all livestock species, plus feed, assessed in a very holistic way, contribute a total of 4.2 percent,” he said. “That’s obviously a very different number compared to what people have been hearing recently.”
The figure includes the entire cycle in the US, including growing and processing feed, transporting animals for slaughter, refrigeration and distribution.
Globally, livestock emit 14.5 percent of greenhouse gas emissions, according to the UN — three and a half times the proportion in the U.S.
The difference is demographic. As the world’s richest nation, Americans use more energy, travel more and ship more items longer distances than the international average.
In the U.S., Mitloehner said, 31 percent of greenhouse gas emissions arise from energy production. Transportation accounts for 27 percent.
Mitloehner’s figures fly in the face of other research. A 2009 report by the Worldwatch Institute, an environmental organization, contradicts those findings.
The group says the UN’s computer models left out some important factors. Worldwatch estimated that livestock are responsible for about half the world’s greenhouse gas emissions. That figure has been used to advocate vegetarianism and demands to reduce meat consumption.
Sujatha Jahagirdar is a policy specialist with the Food and Agriculture Program at the Natural Resources Defense Council. She said livestock is more consequential, but did not directly contradict Mitloehner.
“There’s no question that beef is one of the most intensive greenhouse gas emission, greenhouse gas emission foods out there,” Jahargirdar said. “Producing a pound of beef creates about 34 times the greenhouse gas emissions that pound for pound the equivalent amount of beans or other types of legumes.”
By weight, beef has about 15 percent more protein than beans.
Mitloehner chaired a United Nations Food and Agriculture Organization committee that quantified livestock’s carbon footprint. He said advocates are conflating global figures with American ones. Mitloehner said the hyper efficiency of US livestock production — considered industrial by critics — paired with Americans’ heavy energy usage and largely inefficient transportation systems skew the stats.
He said statistics can confuse. Livestock produce a tremendous slice of the greenhouse gas pie in Ethiopia and Paraguay compared to the US. That’s not caused by especially gassy cows. Generally, Ethiopia’s sparser highway system and less robust access to electricity leave livestock as by far the largest emitters. Paraguay’s small population but huge cattle industry push livestock to the top of the list there.
Misunderstanding models and numbers can lead to falsehoods entering the public discourse.
“Recently I watched a TV show and the moderator said, and I quote, if you drive a Prius and you eat one burger a week, then that’s the same as driving a Hummer,” Mitloehner said. “Some people find that cute. It’s really not cute, because, it is misleading and it’s false and it puts us on the wrong path for solutions.”
Mitloehner is concerned that focus on livestock will prevent policymakers and the public from focusing efforts on transportation and energy production — areas where small changes would have the biggest impacts.
Jahagirdar however, insists it’s a false choice.
“I think the idea that it’s a zero-sum game —it’s either focus on transportation or focus on livestock — is not the right way to look at it,” she said. “We need to reduce emissions all the different ways that we can and use all the tools in our toolbox. We need to make cars cleaner, we need to drive less, and then we also need to eat more climate friendly diets, which would also incidentally make us all heathier people.
With some influential opinion-makers still convinced that global warming is a nefarious hoax, the disagreement over blame and proportional causes may seem academic. Regardless, it’s probably not a bad thing to walk a little bit more softly on our planet.
