Can cattle combat climate change?

Our new six-part video series examines the cattle-grazing carbon cycle; the role of carbon sequestration in mitigating climate change; upcycling and byproducts; the differences between methane and carbon dioxide; and agriculture's role in combating climate change. 

In the vast landscapes where cattle roam and plants flourish, intricate ecological processes unfold, shaping the air we breathe and the ground beneath our feet.

At Archbold’s Buck Island Ranch in Lake Placid, Florida, a team of interdisciplinary researchers has been studying the carbon emissions and sequestration potential of the 10,500-acre ranch that is home to more than 3,000 beef cattle. Among Archbold’s research partners are a team of agricultural scientists from Alltech, a global company that creates nutritional solutions that improve the health and performance of plants and animals and lower the environmental impact of the agri-food industry.

Together, Archbold’s research alliance has created a model for estimating the ranch’s carbon footprint — and the results have been astounding.

On average, Buck Island Ranch sequesters more carbon each year than it emits. It is a net-carbon sink!

The research has shown that carbon-negative beef production at Archbold’s Buck Island Ranch is possible — and that same potential may extend to other beef ranching operations around the world.

“Every year, we sequester 1,201 tons of CO₂ equivalent,” said Dr. Betsey Boughton, director of agroecology at Archbold. “And all of this work is scalable to other parts of the world.”

This information surprises many people who think of agriculture solely as a source of emissions.

“The narrative people have heard is that cows are bad for the environment,” she said. “So, we’re like, ‘Well, hang on, it’s not so simple.’ Grazing animals can actually change the function of grasslands. Cows are eating the grass and not allowing as much decomposition to happen on the ground. Without cows, we actually see more carbon emitted.”

“We’re trying to let people know that it is not just this black-and-white answer,” she added. “It is complicated, and we need to think about the whole story.”

Though it is a complex issue, the research has shown that agriculture can be one of the most powerful weapons in the fight against climate change.

This collaboration has discovered a deeper understanding of the cattle-grazing carbon cycle, one that is not solely focused on greenhouse gas (GHG) emissions from the animal but also on photosynthesis, natural GHG emissions from the land, and the sequestration of carbon in the soil.

This six-part video series (runtime: approximately 21 minutes) explores how grazing cattle affect the carbon cycle, the role of carbon sequestration in mitigating climate change, and other key insights the collaborative research alliance has unveiled.

Part 1: Air and Land

The research alliance, led by Dr. Boughton, probes the intricate relationship between cattle and the environment to discover the impact of cattle on the ecosystem and vice versa.

Instead of relying on standard carbon GHG emissions estimates, the research team at Archbold’s Buck Island Ranch uses eddy flux towers to directly measure GHGs in the atmosphere and evaluate carbon capture by the soil. They also gather soil samples, maintain a soil sample database, and track cattle-grazing patterns using GPS. By comparing past records of cattle and pasture management, plant growth and soil biodiversity with present data, they can analyze how changes in nutrition and management practices impact the ranch’s ecosystem.

With the assistance of Alltech E-CO₂, Archbold used historical operations and economic data to model total ranch GHG emissions over multiple years. Next, Alltech helped connect Archbold with the University of Illinois and HabiTerre, a technology company that monitors, measures and analyzes environmental impact, to create a GHG emissions model on the ranch that included sequestration.

Located within the headwaters of the Florida Everglades, Buck Island contains a combination of improved pastures, semi-native pastures, woodlands and wetlands. According to Dr. Boughton, the fact that Buck Island is a net-carbon sink is particularly noteworthy because the land is very wet.

“We have more emissions than other places because we are so wet. Nineteen to 30% of the methane emissions from our pastures are from cattle, but the rest is from these wet soils and wetlands,” she said. “So those are a really big source of methane that people don’t always acknowledge.”

Drier locations could be even larger carbon sinks. Those locations likely have fewer emissions, but the carbon sequestration potential could be the same or even larger.

Part 2: Ruminant Animals and Methane

Ruminant animals like cattle and sheep have a unique digestive system characterized by a large chamber in the front of their stomach. This chamber, called the rumen, is filled with various microorganisms such as bacteria, yeast, protozoa and fungi. These microorganisms aid in the digestion of substances that humans cannot digest, such as grasses and non-protein nitrogen.

Methane, a natural byproduct of this fermentation process in the rumen, takes center stage as researchers explore innovative methods to measure and mitigate its production. One way to measure methane production is through in vitro fermentation models such as Alltech IFM. Encouraging the microbial population in the rumen to produce less methane is seen as a viable and natural approach to reducing methane emissions in ruminant animals.

Researchers are working on developing feed additives to reduce methane in cattle, but it’s understood that methane is necessary for proper fermentation. Pushing methane reduction beyond a certain threshold, usually above 30% inhibition, can lead to negative effects on diet digestibility and animal performance.

Part 3: The Difference Between Methane and CO₂

Understanding the distinction between carbon behavior in fossil fuel production and agriculture is crucial, especially in discussions about livestock’s impact on global warming. Fossil fuel production involves a unidirectional release of CO₂ into the atmosphere, unlike the cyclic process in agriculture.

Animal production is a component of the carbon cycle, which describes how carbon moves within the system. Simply measuring the carbon emissions from animals overlooks the carbon absorbed by the ecosystem and the carbon input into the animals.

Photosynthesis, the process by which plants convert carbon dioxide into carbohydrates, is vital for sustaining life on Earth. When plants are consumed by cows, the cows digest the plants’ energy, emitting CO₂ and methane in the process.

While methane is a concern, it typically breaks down in the atmosphere within 10 to 12 years, returning as CO₂, resulting in no net contribution of carbon.

Removing methane from the environment has a cooling effect, unlike CO₂, which continues to contribute to global warming. Data from the National Oceanic and Atmospheric Administration shows that CO₂ has been primarily responsible for global warming since industrial times, rather than methane or CFCs.

Put simply, CO₂ is a stock gas with no natural removal cycle and a long lifespan. Stock gases accumulate over time because they stay in the environment. In contrast, methane is a flow gas that has a natural removal cycle through chemical reactions that occur in the atmosphere — and it can be absorbed by soil and vegetation.

Part 4: Cows and Upcycling

“Cows are a very important part of our food security picture,” said Dr. Vaughn Holder, Alltech’s beef research director. “Cows have the unique ability to take things that we can’t eat and turn them into things that we can eat. This is a concept that we call upcycling, where they make more human-edible protein than they actually consume.”

That means cows convert non-edible resources into nutritious food, such as high-quality milk and meat.

In addition, cows efficiently utilize byproducts that would otherwise pose disposal challenges. If these byproducts were composted instead of being processed through dairy cows, their carbon footprint would increase by five times. If they were sent to landfills, their carbon footprint would increase by 50 times.

Understanding these implications is vital when considering changes to food systems, highlighting the role cows play in mitigating greenhouse gas emissions.

Part 5: Grazing and Photosynthesis

Cattle grazing significantly influences the carbon cycle by increasing root growth, reducing decomposition, and changing plant composition. Research demonstrates that pastures with grazing cattle can have a net cooling effect on the environment due to increased carbon capture and reduced emissions.

Dr. Holder explained, “When you pull those cattle off of that pasture, the methane production drops slightly because you’ve taken the cows’ methane out of the story. But then, [without cows] that the sequestration by the environment goes away significantly. You actually end up with a pasture that is net emitting with no cattle on it. So now not only do you not have any food being produced off of that pasture, but that pasture is now emitting more carbon, more greenhouse gas equivalents than it was in the winter when there were cattle on it.”

Removing cattle from these pastures leads to decreased carbon sequestration and increased emissions, highlighting the interplay between grazing, plant growth and carbon cycling. Grazing practices affect not only carbon uptake by plants but also the retention of carbon in the soil, emphasizing the role of cattle in carbon sequestration.

“We have to think about this as a holistic system,” Dr. Holder said. “We have to consider the emissions and the uptake by the land and how our management practices affect that carbon sequestration.”

Part 6: Carbon Sequestration

Carbon sequestration involves transferring CO₂ into the soil, maintaining a balance between inputs and outputs. Root growth of plants and microbial activity in the soil play crucial roles in converting captured carbon into a more permanent form. Studying the soil microbiome is key to understanding and enhancing carbon sequestration.

“I do think there’s an interesting win-win situation here for ranchers in carbon sequestration because typically the practices that improve carbon sequestration also improve forage production,” Dr. Boughton said. “So things like irrigation or rotational grazing, legume integration, all of those things increase productivity.”

Well-managed grazing systems can positively impact carbon sequestration, while overgrazing has a negative effect. Future research aims to apply models developed at Buck Island Ranch to understand carbon sequestration worldwide.

Overview video: An additional six-minute video offers an overview of the Archbold-Alltech Research Alliance.

About Archbold Biological Station

Archbold’s mission is to build and share the scientific knowledge needed to protect the life, lands and waters of Florida, and beyond. Learn more about its mission at archbold-station.org.