Over the past 10 years, the beef and dairy industries have increasingly become a favorite whipping boy among politicians and activists who concern themselves with the climate change issue. While much of this is mere rhetoric, the resulting damage to the industry’s image is nevertheless a real and concerning issue.
While politicians and celebrities may be content simply to rail publicly against “farting cows,” the emerging plant- and cellular-based protein sectors base most of their marketing on the supposed environmental impact of cattle, which is now largely taken for granted in the public arena. How much market share they may claim in the future depends directly on their ability to denigrate the cattle industry.
While it is undeniable that cattle do produce greenhouse gases (GHGs), new science and an increased understanding concerning how these gases work in our atmosphere are increasingly indicating that the livestock sector’s contribution to climate change is likely being overstated.
Additionally, new technologies are emerging that, if implemented, could put cattle in the position of being a help, rather than a hindrance, in the push to reduce humanity’s overall impact on the climate. And, according to at least one expert, this opportunity may be coming sooner than we think.
According to Environmental Protection Agency (EPA) estimates, within the U.S., livestock production accounts for 4 percent of all GHGs produced annually, primarily in the form of methane. Cattle are estimated to be responsible for half of this number.
Worldwide, the United Nations estimates livestock’s contribution at 14.5 percent. While this difference is largely due to differing and potentially less-efficient production practices in some parts of the world, it is this number that is most often cited by detractors of the U.S. cattle industry.
[inline_image file=”f7d1be9eac5e357b7fc9ce5bc013e708.jpg” caption=”Dr. Frank Mitloehner is a professor and air quality specialist in cooperative Extension in the Department of Animal Science at UC Davis.”]
Additionally, under the current system of measuring, all gases produced are mathematically converted to their equivalency with carbon dioxide (CO2) in terms of warming potential. Methane, for example, carries a warming potential 28 times that of CO2.
Thus, the tonnage of methane produced each year is multiplied by 28 in order to get a number equivalent to the warming potential of CO2. According to Dr. Frank Mitloehner, however, directly comparing the two gases in this way ignores the very different ways they behave in the atmosphere.
Methane’s cycle
Mitloehner, a professor and Extension specialist at University of California, Davis (UC Davis), has spent his career studying the air quality and climate issues surrounding both dairy and beef production, and has long been recognized as a leading voice in the debate surrounding these issues.
Unlike CO2, which once added remains in the atmosphere in increased concentrations, Mitloehner explains that methane enters and leaves the atmosphere in a cycle that lasts roughly 10 years. Thus, counting every ton of methane produced as new carbon injected into the atmosphere represents a major flaw in the way that livestock’s contribution to the problem is tallied.
The cycle begins, Mitloehner explained, with plants absorbing carbon from the atmosphere via photosynthesis. Once cattle consume the plants, some of this carbon is released back into the air in the form of methane, either enteric (from the gut) or from manure, where it remains for a decade. At the end of this period, the methane breaks down and is converted to CO2, at which point it is absorbed by plants to begin the cycle again.
“That carbon released by the animal is not new and additional carbon,” Mitloehner said. “It originated from the atmosphere. If the size of the livestock herd remains constant, then the amount of methane stays constant too,” he added.
[inline_image file=”65dddc21f862d3238ab389988b984222.jpg” caption=”Professor Ermias Kebreab with the UC Davis Department of Animal Science.”]
“Constant herd size equals constant concentrations of methane in the atmosphere, so there is no addition. We’re already limiting our additional warming, simply by not increasing the size of the livestock herd.”
Carrying that idea forward, points out Mitloehner, if the industry is able to reduce its methane emissions, the result should be regarded as a net benefit to the climate situation overall.
“At that point, we are pulling carbon out of the atmosphere,” he said. “That is a negative warming impact, so cattle can be part of the solution to climate change.”
While reducing the amount of methane produced by a living animal may pose a complicated problem, Mitloehner and another UC Davis researcher, Dr. Ermias Kebreab, are attempting to do just that. And the results, at first blush, are striking.
Seaweed as a solution
In a recently published study, Kebreab and other researchers found that adding small amounts of a specific variety of red seaweed to feedlot rations could significantly reduce methane production. When fed at 0.5 percent of the total ration, the seaweed was found to reduce methane production by 80 percent in steers fed a high concentrate ration, and nearly 70 percent in those fed a higher fiber ration.
[inline_image file=”a4a825644ebc42fc9bfbbb62c90b003d.jpg” caption=”This red seaweed, asparagopsis taxiformis, was mixed with the steer’s normal feed in order to reduce methane emissions from the cattle.”]
“This seaweed has an active ingredient, called bromoform, that it accumulates in its cells,” Kebreab explained. “Bromoform disrupts an enzyme that is needed for methane formation in ruminants.”
Instead of methane, he said, the cattle vent more hydrogen. The carbon that would have gone to methane formation is instead retained by the animal, an effect that the study found also led to a 14 percent increase in feed efficiency. “That carbon has the potential to be used for other purposes,” Kebreab said. “So it’s being redirected.”
The difference in success between high- and low-fiber diets, he explained, is due to the fact that high-fiber diets produce more methane overall. “In the low-fiber diet, there is simply less methane to overcome,” said Kebreab.
[inline_image file=”35bdd9a8fde0fd9deea9a2939606e02a.jpg” caption=”An open-air contraption measures the methane in the cattle’s breath as they eat. The research has found a small amount of seaweed can dramatically reduce enteric methane emissions.”]
While he does theorize that higher concentrations of seaweed in the diet may reduce emissions further, he is quick to point out that, scientifically speaking, this remains to be seen. “There’s a lot of work still to do,” he said. “We’re still a long way off from actually getting it out there.”
Despite his caution, Kebreab is optimistic about the possibilities of seaweed as a practical solution to methane production. In addition to the desired effect, results of his study also showed no effect on meat quality or animal health, and it also appears that early work towards a supply chain may be underway.
“People are already trying to cultivate it, and it looks like it can be grown fairly readily,” he said. “We’re very hopeful that it will be part of the solution moving forward.”
Other solutions
Alongside Kebreab’s work, Mitloehner is also conducting similar research looking at the possibilities of certain essential oils, tannins, and other substances with the potential to reduce enteric methane. “There are 30 or more well-known additives, but only a handful actually work,” Mitloehner said. “Between (Dr. Kebreab) and I, we’ve looked at the most important ones.”
Continuing research, he said, is focusing on whether any unintended consequences—either to food quality or animal health—exist, as well as attempting to develop a product that can be introduced via a bolus, rather than through continual feeding.
“In five years, we’re going to have a solution,” he said. “That’s something that makes me very optimistic.”
[inline_image file=”bdac2a290f8d46627dd7a63d533ffafb.jpg” caption=”Professor Ermias Kebreab with the Department of Animal Science at UC Davis with dairy cows at the UC Davis dairy barn.”]
Because the issue of climate change and livestock’s role is a contentious one, it is not unusual for producers to react to the problem defensively, or even to fall into the trap of treating climate change as a political problem, rather than a scientific one. While this reaction is understandable, Mitloehner points out that it does nothing to solve the problem.
“Regardless of your political conviction, if the people who buy your products have a major concern, and you say you don’t care, then you are missing the mark as so many have for so many years, and it hasn’t gotten us anywhere,” he said.
Instead, he points out, it is important to focus on the strides that are being made. “We have quantified the effects of animal agriculture—we know what it is,” Mitloehner said. “We also know that part of the old narrative is incorrect, because we did not account for methane correctly.
“A strong reduction in methane, say 20 percent over 12 years, can offset all the other greenhouse gases produced by the industry, leading to a situation where a sector can become climate neutral,” he adds. “Not carbon neutral, climate neutral. That means that sector no longer affects the climate in any way. That is the path that agriculture is running on.
“Farmers produce the food that we all need,” Mitloehner said, “but if they can do so without affecting the environment in a negative way, why wouldn’t they?”
