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Clearing the Air on Methane
Jacquelyn Prestegaard-Wilson, PhD | Extension Livestock Sustainability Specialist
Texas A&M Department of Animal Science
A microscopic molecule is the subject of much controversy in the climate conversation. In the cattle industry, we recognize methane (CH₄) mostly as a natural byproduct of digestion in ruminant animals. As the world continues to disagree on what to do about its changing climate, a spotlight is increasingly falling on agricultural practices and their contributions to global greenhouse gas (GHG) emissions. This article explores what methane is in the context of beef production, why it’s such a hot topic right now, and what can be done to mitigate its impact in the beef sector.
What does methane do?
Methane, carbon dioxide (CO₂), and nitrous oxide (N2O) trap heat that is reflected from the Earth’s surface – like the glass walls of a greenhouse. Their presence in the atmosphere is necessary for maintaining stable temperatures that support life around the globe. The gases do not trap heat equally: methane (CH₄) is about 28 times more effective than carbon dioxide (CO₂) at trapping heat in the atmosphere over a 100-year period. However, methane remains in the atmosphere for around 12 years before it is mostly converted into CO₂ through chemical reactions. During its time in the atmosphere, methane has a significant warming effect but is simultaneously being removed.
If methane is emitted at a consistent rate over a long period, it is also removed at a similar rate, creating a balance that prevents additional warming. However, any significant and sudden change in methane emissions—either an increase or a decrease—can disrupt this balance, leading to warming or cooling effects on the Earth’s surface.
Why is methane such a hot topic today?
The overwhelming majority of reputable climate scientists report that human activity is causing an imbalance in GHG in Earth’s atmosphere. The Intergovernmental Panel on Climate Change (IPCC) reports that the primary contributors to this imbalance are the extraction, processing, and combustion of fossil fuels. The methane in natural gas, oil fields, and coal seams was formed millions of years ago through geological processes. These underground gases have not been a part of our GHG “ledger” for millennia. Thus, when released, they add excess warming potential to the atmosphere. Agriculture, including livestock production, is another source of GHGs.
How are methane and beef cattle connected?
In the beef industry, CH₄ is primarily produced during the digestive process of ruminants. Cattle have a unique digestive system that allows them to break down fibrous feeds through a process called enteric fermentation. During this process, specific microorganisms in the rumen break down feed, producing methane as a byproduct, which is then expelled by the animal through burping.
Methane emissions from cattle are a natural part of the digestive process and have been occurring for millennia. However, since CH4 is such a potent GHG, some agencies have raised concerns about the contribution of beef production to climate change. These discussions often omit the role of ruminants in the biogenic (produced by living organisms, versus by geological phenomena) carbon cycle (Figure 1.) The methane belched by ruminants degrades over time into CO2, which is then fixed by plants as part of photosynthesis. Ruminants consume the plants, and the cycle continues.
Despite this, general disagreement regarding the true impact of ruminant agriculture on global warming potential persists. To meet its ambitious climate targets, Denmark has taken a radical step by announcing a tax on farmers based on their CO₂-equivalent (CO₂e) production. In other words, starting in 2025, Danish farmers will be taxed for their methane emissions, making Denmark the first country to impose such a tax.
Mitigation strategies for methane emissions
Thanks to improved genetics and management strategies, the amount of methane produced per pound of beef has dropped significantly in the past several decades. Still, there are plenty of measures the industry is taking to further mitigate their emissions. These include:
- Feed additives. Certain feed additives can reduce methane production during digestion. For example, a compound called 3-nitrooxypropanol (3-NOP) has shown promise in reducing methane emissions from cattle by inhibiting the enzymes that produce methane in the rumen.
- Dietary changes. High-quality forages, grains, and supplements can improve feed efficiency and reduce the amount of methane produced per unit of beef.
- Genetic selection. Breeding cattle that are suited to their environment has an indirect effect on methane emissions via improved efficiency.
- Improved manure management. Methane is also produced from manure decomposition. Alternative manure management practices, such as anaerobic digestion, can capture methane and convert it into biogas, which can be used as a renewable energy source.
- Pasture management. Implementing sustainable grazing practices can enhance soil health and carbon sequestration, indirectly reducing methane emissions. Rotational grazing and maintaining healthy pasture ecosystems are key components of this approach.
The road ahead
Producers, researchers, and policymakers must work together to develop and implement realistic strategies for reducing methane emissions. By embracing technological advancements and incentivizing sustainable practices for farmers and ranchers, the beef industry can actually play a significant role in mitigating climate change while continuing to provide highly nutritious protein to the world.
For more information, contact Jacquelyn Prestegaard at j.prestegaard@agnet.tamu.edu