The impact of high-intensity, large-scale livestock farming on the environment, particularly in terms of greenhouse gas (GHG) emissions, has been in the spotlight in recent years, with estimates of agriculture’s contribution to total emissions ranging from 18 to 51 percent. As a result, there is an increasing ‘back-to-basics’ movement, calling for a reduction in meat consumption for the sake of the planet.
However, this latest paper claims that many of the animal-based foods that people intuitively consider to be more environmentally friendly, such as grass-fed beef, locally produced eggs and organic milk, could actually be more harmful than their corn-fed, remotely produced or conventional counterparts.
The paper, Demystifying the Environmental Sustainability of Food Production, argues that “attention should be focused on strategies that make a long-term, positive contribution to enhancing sustainability, rather than focusing on ‘quick-win’, low impact solutions.”
In particular, lead author Dr Jude Capper, assistant professor of dairy science at Washington State University, argues that focus should shift from impact per animal or per facility, to volume of meat or milk produced, compared to resources necessary for its production. This is based on the life cycle assessment (LCA) model used by the Environmental Protection Agency in order to assess environmental impacts, taking into account all inputs and outputs.
This shift is necessary, the authors argue, in order to meaningfully consider how to efficiently feed an expanding population with an increasing appetite for animal protein.
While they admit that GHG emissions per cow have increased dramatically since 1944 – from 13.5kg in CO2 equivalents to 27.8kg – when using the life cycle assessment of productivity, they say that emissions per kilogram of milk fell from 3.7kg in 1944 to 1.4kg in 2007.
“Consumer and governmental perceptions of strategies and production systems used to reduce environmental impact are often simplistic and appear to be based on misconceptions that do not consider potential negative trade-offs,” they wrote.
Grass-fed vs. corn-fed
For example, although it may seem intuitively correct to assume that beef cattle fed on pasture will have a lower carbon footprint than cattle fed on corn, they argue that the amount of energy used to produce each kilogram of animal protein is generally not taken into account.
The authors point out that grass-fed cattle have an extra energy requirement for grazing activity, and that cattle fed on pasture grow more slowly – and have a lower weight at slaughter – than animals fed corn.
“Each day added to the finishing period adds an extra daily maintenance cost, which must be accounted for in the environmental impact of the final product,” they wrote.
In addition, they claim that animals raised on pasture-based diets produce more ruminal acetic acid, and therefore more methane.
Referring to the trend toward locally-produced foods, the paper argues that there should be a shift away from a “naïve” view of linear miles from production to consumption, and rather look at the productivity of the transportation system. “As a result of high capacity cargo volumes in modern transportation systems, food can be efficiently moved over long distances and remain highly fuel efficient and thus environmentally friendly compared to locally-grown food”.
However, the authors only examined fuel consumption, which they admit is only the “most basic of considerations that must be considered”.
The full paper can be accessed online here.