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New ARS Study Shows U.S. Beef Is Not a Significant Contributor to Global Warming

Photo courtesy of the Agricultural Research Service

An Agricultural Research Service (ARS)-led team has completed a comprehensive life-cycle analysis quantifying the resource use and various environmental emissions of beef cattle production in the United States. Their results so far indicate that U.S. beef’s contribution to climate change is small percentage of the country’s Greenhouse Gas emissions, and were not a significant contributor to long-term global warming.

“The environmental footprint of producing beef has long been debated,” said Marlen Eve, ARS deputy administrator for natural resources and sustainable agricultural systems. “One challenge is that the impacts extend beyond just those associated with growing the animals and include the impact of producing feed and other inputs. This is further complicated by the diversity of ways that beef cattle are managed and fed. It is important to have an accurate quantification of these impacts to provide a baseline against which production system sustainability can be assessed and improved.”

C. Alan Rotz, Agricultural Engineer, USDA-ARS-Pasture Systems and Watershed Management. His collaborators are former ARS research associate Senorpe Asem-Hiablie, Greg Thoma of the University of Arkansas-Fayetteville and Sara Place, with National Cattlemen’s Beef Association, which is partially funding the study. The team began its beef life-cycle analysis in 2013 and published the first of two sets of results in the January 2019 issue of the journal Agricultural Systems.

The aim of the study is to establish baseline measures that the U.S. beef industry can use to explore ways of reducing its environmental footprint and improve sustainability. Led by ARS agricultural engineer Alan Rotz, the team’s analysis encompassed an array of different types of cattle operations, reflecting a beef supply chain that’s among the most complex food production systems in the world. The scope of the analysis spanned five years, beginning in 2013); seven cattle-producing regions; and used data from 2,270 survey responses and site visits nationwide. This ensured the results weren’t limited to a single region, where climate, soil, production practices and other factors can differ from other parts of the country, added Rotz, with ARS’ Pasture Systems and Watershed Management Research Unit in University Park, Pennsylvania.

Among the results to emerge thus far:

The seven regions’ combined beef cattle production accounted for 3.3 percent of all U.S. GHG emissions. By comparison, transportation and electricity generation together made up 56 percent of the total in 2016 and agriculture in general 9 percent

Fossil energy (for example, fuel) use in cattle production accounted for less than 1 percent of the total consumed nationally.

Cattle only consumed 2.6 pounds of grain per pound of beef cut weight (or, butchered carcass weight), which was comparable to pork and poultry.

Beef operations in the Northwest and Southern Plains had the highest total water use (60 percent combined) of the seven regions analyzed. Irrigating crops to produce feed for cattle accounted for 96 percent of total water use across all the regions.

“We found that the greenhouse gas emissions in our analysis were not all that different from what other credible studies had shown and were not a significant contributor to long-term global warming,” Rotz said.

We’re Doing Well – But We Might Do Even Better

Two areas for potential improvement are water use and reactive nitrogen losses. Water use is increased in the West where U.S. beef cattle are concentrated. Reactive nitrogen losses (at 1.4 teragrams or 15 percent of the U.S. total) mainly in the form of ammonia can lead to smog, acid rain and algal blooms, for example, and potentially pose a public health concern.

The purpose of the analysis wasn’t to identify the top-performing regions or most efficient types of operations, said Rotz, but rather to systematically measure the use of fuel, feed, forage, electricity, water, fertilizer and other inputs to raise beef cattle throughout the country—from birth to slaughter.

Using a computer program called the “Integrated Farm System Model” (IFSM), his team also estimated net releases of reactive forms of nitrogen such as ammonia from manure and urine, as well as the three major greenhouse gases (methane, carbon dioxide and nitrous oxide). The gases are so-named for their tendency to trap heat in the atmosphere and contribute to warming of the earth’s surface, extreme weather patterns and other global climate change events.

In the next six months, the team will combine the results of its IFSM analysis with postharvest data from other sectors of the beef supply chain—namely, processing, packing, distribution, retail, consumption and waste handling. That phase will be accomplished using the open-source life-cycle assessment program “OpenLCA.

Together, these data will be used to generate a national assessment of the beef industry’s resource use, economics, net losses of GHG and other emissions, providing a critical tool for sustainably producing beef as an important source of lean protein and nutrients.

What Does This Mean to You?

There’s been a lot of talk about reducing meat consumption ever since the United Nation’s Food and Agriculture Organization’s 2006 report, “Livestock’s Long Shadow,” came out. That report concluded that livestock production contributes “about 18 percent of the global warming effect – an even larger contribution than the transportation sector worldwide. Livestock contribute about 9 percent of total carbon dioxide emissions, but 37 percent of methane and 65 percent of nitrous oxide.” They subsequently changed their reporting based on input from Dr. Frank Mitloehner, University of California – Davis, but those changes were not as visible as the original report.

Check this On Pasture article for more about Mitloehner’s review of the FAO report.


This new ARS study reinforces one of Mitloehner’s issues with the 2006 report: the figures provided are global and therefore don’t reflect the differences in livestock greenhouse gas emissions in developed vs. developing nations. In some areas of the world, the impact of livestock production is much larger than in others. It’s all good news for those of use raising meat for our communities.

Thanks to Jan Suszkiw for the press release that contributed significantly to this article.

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Kathy Voth
Kathy Voth
I am the founder, editor and publisher of On Pasture, now retired. My career spanned 40 years of finding creative solutions to problems, and sharing ideas with people that encouraged them to work together and try new things. From figuring out how to teach livestock to eat weeds, to teaching range management to high schoolers, outdoor ed graduation camping trips with fifty 6th graders at a time, building firebreaks with a 130-goat herd, developing the signs and interpretation for the Storm King Fourteen Memorial trail, receiving the Conservation Service Award for my work building the 150-mile mountain bike trail from Grand Junction, Colorado to Moab, Utah...well, the list is long so I'll stop with, I've had a great time and I'm very grateful.


  1. Whilst it is pleasing to see some more reason figures for this metric.
    It’s a stretch to 3.3% is not a “significant contribution” to GHG emissions.
    3% is still HUGE.
    It needs to be negative 1-2% at least. If the meat industry wants to maintain any credibility going forward.

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