8. Meat and Dairy: Major Problem or Part of the Solution?
Questions about animal agriculture and climate change touch students’ daily lives and choices. Many students are already experimenting with eliminating or reducing meat and dairy in their diets for various reasons, including personal health and animal welfare. Some are emotionally invested in the topic. A growing number of schools offer Meatless Mondays or meatless entrées every day.
Claims on the internet and in other media about meat’s impact on climate vary widely (see below). Evaluating these claims through research, discussion, or classroom debate is both an opportunity for students to better understand the issues and their own positions and an exercise in critical thinking and media literacy.
Under the headline “Fight Climate Change by Going Vegan,” People for the Ethical Treatment of Animals (PETA) argues, “If you’re serious about protecting the environment, the most important thing you can do is stop eating meat, eggs, and dairy foods.”1 A Stanford Environmental Law Journal article calls animal agriculture “One Industry That Is Destroying Our Planet and Our Ability to Thrive on It.”2 Another article says that animal agriculture is “the world’s leading driver of climate change.”3
On the other hand, the Soil Association in the UK concludes that “Grass-fed livestock has a critical role to play in minimising carbon emissions from farming.”4 And Judith D. Schwartz’s thesis is summarized in the title of her 2013 book, Cows Save the Planet.5
Systems Perspective: When trying to evaluate the discrepancies between claims like these, one question to ask is “What is being measured, and what is left out?” Or, in systems terms, “Where are the boundaries of the system under discussion being drawn?”6
For example, a “fact sheet” from the industry group American Meat Institute (AMI) features a pie chart titled “Only 2.8 Percent of [Greenhouse Gas] Emissions Come from Animal Agriculture.”7
Though its headline could be read as referring to all of animal agriculture, the Meat Institute’s 2.8 percent figure applies just to the United States. It derived its statistics from an annual inventory of greenhouse gas emissions conducted by the EPA since the 1990s. Under “Agriculture,” EPA measured only direct emissions. (Other emissions sources that might relate to agriculture, such as transportation and energy, were separate categories.)
Note: As of this writing, an undated version of the most recent inventory report is available on the EPA website.8 That document continues to state that all data tables “will be made available for the final report published on April 15, 2017” and notes, “You can electronically download this document on the U.S. EPA’s homepage at http://www3.epa.gov/climatechange/emissions/usinventoryreport.html.” That page, however, reads, “Thank you for your interest in this topic. We are currently updating our website to reflect EPA’s priorities under the leadership of President Trump and Administrator Pruitt.” What this suggests for the future of this research or its availability is not clear.
The direct emissions in the EPA inventory were from two animal agriculture sources: enteric fermentation and manure management.9 Enteric fermentation is a natural part of digestion in ruminants such as cattle and sheep. Microorganisms in the animals’ stomachs break down grass and grains, which the animals can’t otherwise digest. In the process, methane (CH4) is released— “cow farts” in the popular parlance,10 though it’s mostly belches. Additional CH4 is released through anaerobic decomposition of manure, especially liquid slurry in manure lagoons or holding tanks. According to an EPA overview of greenhouse gases (still available as of this writing), methane had, pound for pound, 25 times the impact of CO2, because of its greater heat-absorbing ability.11 The breakdown of livestock manure also releases a second gas, nitrous oxide (N2O), with almost 300 times CO2’s heat-trapping ability.
To reach its claim that animal agriculture is responsible for just 2.8 percent of greenhouse gas emissions, the Meat Institute took the EPA’s estimate of the total CH4 and N2O released into the atmosphere from all sources and multiplied that by the proportion attributed to direct emissions from enteric fermentation and manure management.12
But do direct emissions tell the whole story?
Livestock’s Long Shadow is a 2006 report from the Food and Agriculture Organization of the United Nations (FAO) that some have credited—and some have blamed—for raising public concern about animal agriculture and climate.13 Its most frequently cited conclusion is that the livestock sector is responsible for 18 percent of global GHG emissions, a higher share than transport. (FAO issued a new report in 2013, with a revised figure of 14.5 percent, based, it said, on more detailed analysis and improved data sets.14)
To reach their 18 percent conclusion, the FAO authors drew a much wider boundary around what to measure than did the Meat Institute. They went beyond direct emissions and took a “life-cycle” approach that included, among other things, emissions associated with growing crops to feed the livestock. They calculated the emissions due to deforestation and other land use changes to clear space for grazing and growing feed; release of gases from plowing land to grow the feed; emissions in the manufacture of nitrogen fertilizer for growing feed; emissions from the fertilizer after it is applied; on-farm use of fossil fuel for lighting, heating, and operation of farm equipment; production and transport of processed and refrigerated animal products; and so on.
Different claims from different reports can also result from different methods for expressing quantities of greenhouse gases other than CO2. Because different greenhouse gases absorb different amounts of heat and remain in the atmosphere for different lengths of time, quantities of greenhouse gases are usually expressed as “CO2e,” (carbon dioxide equivalent). Another standard, Global Warming Potential (GWP), calculates the amount of energy that one ton of a gas will absorb over a given period of time, relative to one ton of CO2. The time period typically used to calculate GWPs is 100 years. Some observers have argued that 20 years is more appropriate for a gas such as methane, which does not stay in the atmosphere as long. Taking the shorter period results in a given amount of methane being treated as the equivalent of much more CO2. As a result, the same amount of methane can be reported in one study as nearly three times as much CO2e as in another study.
(Students may also encounter assertions that the volume of emissions due to animal agriculture is much higher than the FAO estimates.15 Some of these can be traced to a 2009 article, not peer-reviewed, that included factors explicitly rejected by the FAO and most researchers, such as CO2 breathed out by animals.)
There are a couple of additional questions that can be starting points for student research and discussion. First, if animal agriculture’s contribution to climate change is an issue, is the problem due to the animals or to the agriculture? Specifically, how much is the result of practices of industrial animal agriculture—large herds in confined spaces, huge liquefied manure storage lagoons, chemically grown monocultures of corn and soy for feed, heavy use of nitrogen fertilizer, and so on? Could animal agriculture practiced differently have a different effect on climate? The FAO, for one, estimates that greenhouse gas emissions by the livestock sector could be cut by as much as 30 percent simply through wider use of existing best practices and technologies.16
Second, does animal agriculture prevent or lessen any climate problems? Without animal manure, for example, how much additional synthetic fertilizer would be required for growing crops, at what cost to the environment, including to the climate?
Nicolette Hahn Niman, a rare cattle rancher who is also a vegetarian, argues that “[G]razing animals are absolutely essential to properly functioning ecosystems.”17 Danielle Nierenberg and Sarah Small, writing for Food Tank, note that “Raising livestock provides livelihoods for an estimated one billion people…. Livestock can provide a nutritious source of protein for women and families, manure for fertilizer, fuel for stoves and heat, transportation, consumption of food scraps and waste, and management of weeds and insects.”18
The ability of living soil to sequester carbon represents what many scientists believe is one of the best opportunities—perhaps the best—to lower the level of greenhouse gases in the atmosphere. Livestock may play an important role. “Since pasture is the largest anthropogenic land use, improved pasture management could potentially sequester more carbon than any other practice,” according to the FAO.19
A significant portion of grazing lands may not be as appropriate for other kinds of agriculture such as crop production. Cornell University professor emeritus David Pimentel and coauthor Marcia Pimentel write, “Cattle, sheep, and goats will continue to be of value because they convert grasses and shrubs on pastures and rangeland into food suitable for humans. Without livestock, humans cannot make use of this type of vegetation on marginal lands.”20
How pasture is managed is crucial. “The key thing is putting the right number of animals in the right place at the right time and for the right reason,” says Wendy Millet, director of TomKat Ranch Educational Foundation.21 That organization is one of a number of projects, among them the Carbon Cycle Institute22 and other research sponsored by the Natural Resources Conservation Service,23 that are committed to scientifically testing a variety of approaches to “climate-smart” ranching, including regenerative (sometimes simply called “managed”) grazing.24
Peer-reviewed research published in Agricultural Systems in May 2018, suggests that carbon sequestration from adaptive multi-paddock (AMP) finishing systems has the potential to offset greenhouse gases from enteric fermentation, manure storage and handling, etc. during this phase of the cattle’s life cycle. Researchers from Michigan State University and the Union of Concerned Scientists concluded that finishing systems in which cattle are grazed—and rotated between pastures to avoid overgrazing—rather than confined to a feedlot could constitute net carbon sinks. If effectively implemented over a large area, the authors say, total carbon sequestration could be increased substantially. 25
“The right number of animals in the right place” might mean raising less meat overall, possibly at higher prices to consumers. For instance, the methods described in the Agricultural Systems study required twice as much land for the same amount of livestock as feedlot methods. Many authorities, even those who do not promote a vegetarian or vegan diet, believe that there are good reasons besides climate for reducing the amount of meat raised and eaten in much of the world. A report by Chatham House, the Royal Institute of International Affairs, in London, concludes, “Among industrialized countries, the average person consumes around twice as much as experts deem healthy. In the United States, the multiple is nearly three times.”26
Among other recommendations, the Chatham House report suggests that governments consider a carbon tax on food products similar to taxes being imposed on sugary drinks, for the sake both of public health and combating climate change. “The idea that interventions like this are too politically sensitive and too difficult to implement is unjustified,” says Laura Wellesley, the lead author of the report. “Our research indicates that any backlash to unpopular policies would likely be short-lived as long as the rationale for action was strong.”27
What do students think?