In terms of carbon, grass-fed beef is not the greenest option
In general, cattle can be divided into two nutritional camps: those that are grass-fed for most of their lives but are then moved to feedlots where they receive a grain diet in the final stages before slaughter; And those who are kept on a straight diet of grass from pasture throughout their lives. Respectively, these two groups are known as “ready grains” and “final pastures.”
Pasture-fed cattle make up a staggering 33% of global beef production, and research has already shown that these grass-fed animals have a higher carbon footprint. But new One plus The paper is the first to show how large this number is and why.
The key difference in the new work is that its authors looked beyond emissions from feed production, cows belching methane, and other aspects of direct production. They also took into account emissions from converting natural habitat to pasture, which figures most prominently in the life cycle of cows that have finished off pasture.
The researchers called this the “opportunity cost of carbon”: the storage of potential lost carbon that comes with converting native habitat to pasture to feed grass-hungry cows.
To make these calculations, they looked at data from a mix of 100 pasture-finished and grain-finished livestock farms, spread across 16 countries, and calculated the carbon footprint of each. This estimate was the collective sum of direct production emissions, the amount of carbon sequestered in pasture soils (which varies depending on how pastures are managed), and the carbon opportunity cost mentioned above.
What this international comparison revealed was that pasture-ready livestock farms had 20% higher production emissions than whole grain farms, a figure that matches those reported in previous research. But the most surprising part of this result is that when both soil sequestration and the opportunity carbon cost of using converted pasture were taken into account, the carbon footprint figure rose to a staggering 42%. In fact, the impact of land use is so large that it generates more emissions on average than direct beef production.
“I was surprised by how large the carbon cost of beef land use is,” says Daniel Blaustein-Rigto, director of food and agriculture at the Breakthrough Institute, who led the research. “We estimated that the carbon footprint from land use is more than double the carbon footprint from burping cows, growing feed and manure, and other agricultural activities.”
He and his colleagues have found that the farming systems with the highest emissions are pasture-finished livestock raised on degraded fields with little or no pasture management—for example, where manure is not handled properly. Other calculations have also shown a clear relationship between increased land use intensity and increased carbon emissions.
The key point in all of this is that pasture-raised beef is significantly higher in carbon than the finished grain alternative, which may actually be the better environmental choice.
But this challenges the elite status of these pasture-fed meats. “I don’t want to encourage carbon tunnel vision,” Blaustein-Rigto warns. “People choose grain-fed or grass-fed beef based on a variety of personal preferences, values and beliefs such as the perception that grass-fed cattle have better welfare. Our study does not address these. But it provides more comprehensive data on the carbon benefits and costs of different types of beef.” cows, allowing for more informed decisions.
So how can we put this information to good use? Blaustein-Rigto hopes to see people think more holistically about the real life-cycle costs of beef production, which has excluded land-use impacts for too long.
On the other hand, the study’s findings may inspire better farming methods, as beef production grows around the world. “Producing beef more efficiently, with a smaller land footprint, has huge carbon benefits, greater than typically thought,” he says.
Blaustein-Rejto et al. the. “The opportunity cost of carbon increases the carbon footprint advantage of grain-based beef.” One plus. 2023
Photo by Hennie Stander on Unsplash
(tags for translation)cows