The local (or locavore) food movement focuses on the concept of “food miles” as a barometer of environmental impact and sustainability. Foods that travel less between producer and consumer are overwhelmingly perceived as more eco-friendly.
Thus, despite the inherently resource-intensive nature of raising animals for food, many advocates for environmentally responsible eating promote local animal agriculture as part of a sustainable food system.
But while there are many good reasons to source our food closer to home, prioritizing local foods is not inherently the most eco-friendly food choice.
This is because a food’s environmental impact isn’t just based on food miles. The full carbon footprint of a given food is based on a measure known as Life Cycle Assessment (LCA).
Factors that affect a food’s LCA are energy use, water use, land use, greenhouse gas emissions, harvesting methods, packaging materials, storage and preparation techniques, and other production and post production-related activities.
An authoritative study published in Environmental Science & Technology found that even though food is generally transported long distances, food-related greenhouse gas (GHG) emissions primarily derive from the production phase, accounting for 83% of the average U.S. household’s food carbon footprint.
Transportation or food miles represent only 11% of the LCA carbon “foodprint.”
Because animal foods require vastly more energy and resources to produce than plant foods, a dietary shift away from animal products can be far more effective than simply buying local as a means of lowering one’s food-related environmental impact.1
Pastured Organic vs. Industrial Production
Consider that even with more than 98% of all farmed animals in the U.S. currently being raised by intensive (factory farm) methods — that is, using very little space and land per animal — nearly a third of all the land in the U.S., is devoted to rangeland, pasture, or other grazing lands.2,3
With 95 million cattle, we would need, by the most conservative estimates, 250 million acres to convert all U.S. dairy and beef operations to pastured systems. That’s more than 10% of all the land in the country. Indeed, Harvard researchers found that shifting all U.S. beef production to pastured would require 30% more cattle and 270% more land to fulfill current levels of consumption.
And that’s just cattle. Nearly all of the nine billion chickens used for meat and eggs in the U.S. are confined indoors. We would need astronomically more land than actually exists to pasture even half of these chickens and the millions of pigs, sheep, goats, and turkeys currently being raised in confinement operations.
Animal agriculture is a main driver of human-caused climate change.
The United Nations has noted that the “livestock sector” is responsible for more greenhouse gas emissions than ALL transportation combined.
The increased land use necessary to more “humanely” farm animals often results in even higher emissions of harmful GHGs. In general, pastured or otherwise unconfined animals gain weight more slowly than confined animals because they are allowed more movement. Organically-raised animals grow even more slowly because they aren’t permitted growth-promoting hormones or antibiotics.
It’s estimated that grass-fed cows produces up to four times more methane than grain-fed cows. Because cows fatten more slowly on grass than on grain, pastured cows take significantly longer to reach slaughter weight than feedlot cows, emitting more methane and nitrous-oxide along the way.
Methane is one of the fastest-growing GHGs, responsible for some 40% of global warming since the Industrial Revolution. Animal agriculture is the largest human-caused source of methane in the United States, with cattle contributing the vast majority of these emissions.
The Harvard study found that if all U.S. beef production shifted to pasture, the methane footprint per unit of beef would increase by 43%, increasing the U.S.’s total methane emissions by approximately 8%.
Methane traps significantly more heat than carbon dioxide; it is 86 times more potent than CO2 over a 20-year time frame. At the same time, it stays in the atmosphere for a much shorter period, leading experts to urge that slashing methane is now our single greatest and quickest strategy for slowing warming by 2040.
What the focus on eating local and/or so-called humane animal products overlooks is the massive inefficiency and waste of resources inherent in cycling plant proteins through animals in order to eat the animals — from whom we obtain only a small fraction of the total available protein and calories when compared to consuming plant foods directly.
Most of the energy/calories animals consume is used to fuel their own physiological processes. Beyond that, it takes up to one hundred times more water and eleven times more fossil fuel to produce animal protein than equal amounts of plant protein.6
As Dave Simon writes in Meatonomics: The Bizarre Economics of Meat and Dairy:
The Global Implications of Our Food Choices
Yet analysis of global agricultural yields finds that better use of existing croplands could feed four billion more people simply by shifting away from growing crops for animal feed and fuel, and instead growing crops for direct human consumption.9
Reallocating croplands in this way could increase available global food calories by 70 percent, according to researchers above.
So when it comes to making the most sustainable food choices, the focus should not be on eating local meat, dairy, and eggs, but on eating less of these foods — or, better yet, eliminating them entirely.
As the authors of Food-Miles and the Relative Climate Impacts of Food Choices in the United States conclude:
“Shifting less than one day per week’s worth of calories from red meat and dairy products to… a vegetable-based diet achieves more GHG reduction than buying all locally sourced food.”
1. Weber, Christopher L. and Matthews, H. Scott. “Food-Miles and the Relative Climate Impacts of Food Choices in the United States.” Environmental Science & Technology 42, no. (10) 2008: pp 3508–3513.
2. USDA, Natural Resources Conservation Service. Land Use.
3. Mcwilliams, James. Just Food: Where Locavores Get It Wrong and How We Can Truly Eat Responsibly. Back Bay Books, 2009. p.135.
4. Worldwatch Institute. Livestock and Climate Change.
5. Simon, Dave. Can Animal Foods Be Produced Sustainably?.
6. Pimentel, David and Marcia Pimentel. Food, Energy and Society. CRC Press, 2007.
7. Oppenlander, Richard. Comfortably Unaware. Beaufort Books, 2012.
8. Foley, Jonathan A. et al. Solutions for a Cultivated Planet. Nature 478.7369 (2011): pp. 337-342.
9. Cassidy, Emily et al. Redefining Agricultural Yields: From Tonnes to People Nourished Per Hectare. Environmental Research Letters 8.3 (2013).