A new sustainability study has hit headlines. The conclusions are reminiscent of the infamous “Livestock’s Long Shadow,” telling readers that beef is the least sustainable of all.
The journal article by lead researcher Gidon Eshel—“Land, irrigation water greenhouse gas, and reactive nitrogen burdens of meat, eggs, and dairy production in the United States”—was published in the July 21 issue of the journal Proceedings of the National Academy of Sciences (PNAS).
It called itself a “top-down” approach to measuring the inputs of all of the major animal-based protein sources in the U.S. The protein sources were measured according to how much land, irrigation water, and reactive nitrogen (Nr) are required to produce the feed for those industries, as well as how much greenhouse gas/gases (GHG) each industry releases. Ultimately it found that beef is the least sustainable when compared to pork, chicken, eggs, and dairy.
“Beef is consistently the least resource-efficient of the five animal categories in all four considered metrics,” stated the article’s results section. “Producing one megacalorie [slightly over 1 million calories] of beef requires 28, 11, 5, and 6 times the average land, irrigation water, GHG, and Nr of the other animal categories.”
The study looked at USDA data on land usage, irrigation water usage, and nitrogen application. For GHG emissions, the study used numbers from pre-existing life cycle assessments of the five protein sources.
The data presented in the article shows beef using about 64 percent of the nitrogen consumed (via application to feed crops) by the five protein sources, is responsible for about 62 percent of the GHG emissions, uses roughly 76 percent of the irrigated water, and about 89 percent of the land use.
“[The data’s] clearest message is that beef is by far the least environmentally efficient animal category in all four considered metrics,” the article reiterated.
The researchers made a point of noting how much of beef’s land use—and in some cases, dairy’s land use—was attributable to pasture. On the other hand, the other four protein sources tend to be produced using modern confinement management practices. That has the potential of being an apples-to-oranges comparison. But the researchers anticipated that complaint.
“A possible objection to the conclusion
is that beef production partly relied on pastureland in the arid West,
land that is largely unfit for any other cultivation form. Whereas most
western pastureland is indeed unfit for any other form of food
production, the objection ignores other societal benefits those arid
lands may provide, notably ecosystem services and biodiversity. It
further ignores the 0.16 million km2 of high-quality cropland used for
grazing and the 0.46 million km2 of grazing land east of 100 degrees
west that enjoy ample precipitation and that can thus be diverted to
Uncertainty and response
To the researchers’ credit, for as certain as they are on their conclusion, they openly cite many areas of uncertainty inherent in their study. The relatively short journal article was overflowing with notes on missing or incomplete information, areas where more research is needed, and its own limitations.
“We do not claim to cover all important environmental impacts of livestock production. Rather, we focus on key metrics that can be reliably defined and quantified at the national level with currently available data.”
This was an important detail to Kim Stackhouse- Lawson, PhD, Director of Sustainability Research for the National Cattlemen’s Beef Association (NCBA), a contractor to the Beef Checkoff Program.
“The PNAS study represents a gross over-simplification of the complex systems that make up the beef value chain, a point which the authors acknowledge,” she said in a prepared statement sent to WLJ.
“The Beef Checkoff Program has recently completed the largest life cycle assessment ever conducted for a food supply chain, which showed that the beef industry in the United States is on a path of continuous improvement. Between 2005 and 2011, the U.S. beef industry improved environmental and social sustainability by 7 percent.”
The NCBA life cycle assessment showed significant efficiency improvements in beef efficiency between the date markers compared. Additionally, it examined the sustainability of beef to a minute degree of detail as well as including elements of cultural sustainability concerns.
“The fact is the U.S. beef industry produces beef with lower greenhouse gas emissions than any other country. The conclusions in this study only serve to confuse consumers about the fact that including beef as part of a healthy diet can co-exist with a healthy environment in the United States, as recently evidenced by the beef life cycle assessment.” — Kerry Halladay, WLJ Editor