The easiest way to reduce your greenhouse gas emissions, I’ve argued, is to eat less meat. Because the emissions generated by the production of beef, pork and chicken (in that order) exceeds those of plant-based protein, going meatless for a day or two each week makes a difference.
But curbing meat consumption won’t make nearly as much of a difference as driving a more efficient cars, some experts says–although comparing the climate impacts of Big Mac, a lentil stew, a Ford 150 truck and a Prius is a devilishly complicated business.
Bob Langert, vice president of corporate social responsibility at McDonald’s, recently pointed me to an interesting new publication that explores this issue, and others. Sustainable Diets: Food for Healthy People and a Healthy Planet (available as a PDF here) report on a series of workshops held last year by the well-respected Institute of Medicine that brought together environmental scientists, nutrition experts, government officials and business people to look at the effects of diet on the planet and on human health.
One of the experts, Frank Mitloehner, a professor in the department of animal science at the University of California at Davis, who is chair of an FAO group studying the environmental impact of livestock, offered a defense of beef. He tried to put in perspective the claims of activists who urge consumers to eat less meat for environmental reasons.
The report says:
In Mitloehner’s opinion, although scientists would agree that food choices are an important environmental emission source, they would also agree that food choices pale in comparison to transportation choices or energy production and use choices.
To illustrate his point, Mitloehner cited a U.S. Environmental Protection Agency estimate that 33 percent of all GHG emissions are associated with production and use of energy and 27 percent are associated with use of transportation (EPA, 2013). Compare those figures to GHG emissions in the United States from the entire livestock sector, all species, based on life-cycle assessment9 at 3.4 percent (EPA, 2012). According to Mitloehner’s calculations, of that 3.4 percent, approximately 1.8 percent comes from the beef sector. Thus, GHG emissions from livestock in developed countries are dwarfed by carbon footprint contributions from other, larger sectors (e.g., transportation, energy, industry). The same is true of other developed countries.
Mitloehner questioned the impact of “Meatless Mondays” or “Beefless Mondays.” If 300-plus million people were to go beefless on Mondays, that would cut the 1.4 percent figure by a factor of 7 (number of days in the week), which would amount to a 0.2 percent reduction in the total greenhouse gas footprint. Mitloehner said, “While this is not nothing … it will not even compare to what we see from the transportation sector.”
Mitloehner may be right. He is especially critical of a 2006 FAO report that estimated that livestock contributes 18 percent of all GHG emissions, and those emissions were greater than those from the transportation sector. This number has been quoted widely but, he said, the comparison was inappropriate because livestock emissions were analyzed using a full lifecycle assessment, and then compared to transportation emissions that included only tailpipe emissions.
A very different view was put forth by Emily Cassidy of the Institute on the Environment at the University of Minnesota, who with colleagues including Jon Foley has worked to quantify the environmental impacts of diet. The report says:
Americans consume a lot of meat, more than 110 kilograms per person per year, even though the nutritionally recommended amount is only about 23 kilograms per person per year (FAO, 2013). If meat consumption were to be reduced by 75 percent, to 30 kilograms per person per year, with the lost weight being compensated by fruits and vegetables, cereals, and other foods, what would happen to the environmental footprint of the U.S. diet?
Cassidy’s calculations suggest that such a reduction would significantlychange the environmental impacts associated with the U.S. food system. Specifically, a 75 percent reduction in meat consumption would result in a 27 percent reduction in land use, a 31 percent reduction in water use, and a 46 percent reduction in GHG emissions.
It’s complicated, no? One problem is that using global or even national averages when talking about the carbon impacts runs roughshod over important differences in farming and ranching practices, the electricity mix, shipping and a gazillion other variations. Did the corn that was grown and fed to the cow that was turned into a Big Mac require irrigation? Was the electricity fed to the Prius generated by a coal-fired power plant or by hydropower? Which has a greater carbon impact, salmon from Alaska or chicken from the Delaware shore? Climate change is a global problem, but all emissions are local, as Ory Zik has noted in developing his startup company Energy Points, which uses Big Data to analyze environmental tradeoffs.
So…if you want to reduce your carbon footprint, should you eat less beef or buy a the Prius? The answer is, it depends. It sure looks as if switching to a Prius will have a bigger impact, but of course it’s easier to skip a few meals with meat than to buy a new car. What’s more, the health and environmental impacts of meat production in confined animal feeding operations (CAFOs) go well beyond climate, including the need to dispose of animal waste, potential water pollution, pesticide and fertilizer overuse to produce feed, antibiotic use and resistance, air quality and animal welfare issues.
Happily, it’s not an either or. You can cut meat consumption and drive a more efficient car.
Meantime, companies like McDonald’s, Walmart and Cargill are working together to limit the environmental impact of beef production through the Global Roundtable for Sustainable Beef, which is all to the good.
That said, it would be so much simpler and more sensible to put a tax on carbon emissions and use price signals to speed the transition to a low-carbon economy. Pricing carbon emissions into the costs of goods and services–electricity, gasoline, food and everything else–would unleash the power of markets and drive producers and consumers to smarter and greener choices.