What’s the beef with climate change?
Your hamburgers are safe, no one is coming to take them away from you contrary to what you may have heard recently. But if you are looking to make lifestyle choices that limit your impact on the environment, decreasing your meat intake might just be the thing. Livestock come with a significant environmental footprint, quite literally, utilizing (and often degrading) upwards of 30% of the planet’s land surface, which includes a variety of permanent pasture as well as arable land that could be used for farming. In addition, the management of cattle comprises a significant component of the agriculture sector’s contribution to climate change.
Cows, and sheep, goats and other ruminant animals, contribute methane as a by-product of their digestion, as well as from their manure. Everyone’s likely heard of climate change’s center-stage bad guy, carbon dioxide or CO2, but methane (CH4) is a rising star, excuse the pun. Although methane is emitted globally at amounts lower than CO2, that amount has been rising. Not only that, but not all greenhouse gases have the same effect: methane has a global warming potential (GWP) in the range of 28 to 36 over a period of 100 years. GWP is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time, relative to the emissions of 1 ton of carbon dioxide. This means that a molecule of methane in the atmosphere absorbs as much as 28 times more energy than a molecule of CO2. On the flip side, methane has a much shorter lifetime in the atmosphere comparatively. Methane is also a precursor to ozone and livestock manure also contributes nitrous oxide: both ozone and nitrous oxide are greenhouse gases.
In a 2006 study by the Food and Agriculture Organization (FAO) of the United Nations, it was calculated that livestock account for approximately 18% of global greenhouse gas emissions — that’s more than transportation. Livestock contribute upwards of 28–32% of all human-derived methane emissions; other notable anthropogenic sources of methane include landfill waste, refineries, and extraction and use of natural gas. In addition, the livestock sector is growing faster than another other agricultural sector. Both global meat and milk production are on track to double in the period from 2000 to 2050. How does this all add up?
- Fermentation: An individual cow releases between 30 and 50 gallons of methane per day through enteric fermentation, which amounts to 150–265 pounds (70-120 kg) per year. Multiply that amount by the approximately 1.5 billion cows and bulls found world-wide.
- Feed production and manure storage: Almost 60% of the global biomass harvested worldwide enters the livestock sector as feed or bedding material. Greenhouse gas emissions from feed production account for about 45% of the livestock sector, including nearly half from manure deposited on pastures or applied on farmland as fertilizer.
- Population: As of 2017, the world population (of humans) increased to 7.6 billion inhabitants and more people are eating meat, not only due to population rise, but also due to the combined factors of urbanization and economic prosperity.
What about poultry and pigs? As you can see in the figure below, most other species included in animal agriculture emit far less than cattle. This doesn’t mean that these animals don’t have their own significant footprint outside of greenhouse gas emissions. While living as a graduate student in North Carolina, I became very aware of the presence and impacts of large-scale pig farms, identified as concentrated animal feeding operations or CAFOs. The large amounts of animal waste generated in CAFOs are a source of air, water and land contamination. It is not uncommon to hear of people living downwind of pig waste lagoons complaining of various health issues, such as migraines.
There is some ongoing work to devise a fix to this bovine emission problem, including feed additions such as algae and garlic, utilization of silvopasture, and alteration of the management and storage of manure. It should be noted, however, that livestock also lend to the degradation of water and land, as well as being a source of greenhouse gas emissions. Land is often cleared for pasture, leading to a loss of wooded ecosystems and native biodiversity. Deterioration of the land through overgrazing, compaction and erosion can lead to desertification. Clearing of tropical and rain forests for agricultural use is responsible for an extra 2.8 billion metric tons of CO2 emissions per year. The livestock sector also utilizes large supplies of water, as well as degrading water via contamination with animal wastes, hormones and antibiotics.
How does eating hamburgers compare to driving a car? Ooohh, that’s a tough one. The emissions from a car can be very accurately measured, as direct emissions, based on fuel efficiency, distance traveled, etc. However, the greenhouse gas emissions estimated from animal agriculture are a combination of direct and indirect measurements: obviously, we can’t really measure exactly how much any individual cow is contributing at any time, at least not easily. Also, carbon dioxide is the main greenhouse gas emitted from cars, which has longer term effects than the methane emitted from ruminant animals. Looking at warming impacts on the atmosphere over time, cows have a greater near-term impact than cars. The adverse impacts from fossil fuel exploration and processing needs to be considered in addition to tail-end vehicle emissions. And it goes without saying that the treatment of animals on large-scale farms can also frequently be less than humane. So, the answer to which action is worse, eating cows or driving cars, depends on your perspective.
“Nothing will benefit human health and increase chances for survival of life on Earth as much as the evolution to a vegetarian diet.’ Albert Einstein.
In summary, we can see that decreasing or completely eliminating beef and dairy products from your diet can make a difference — certainly as a greater number individuals make the same decision. When I was in college, I excluded meat from my diet for about a year out of compassion for animals. Needless to say, college cafeterias didn’t know how to cater to vegetarians in the 1990s; if I remember correctly, a dish called “vegetable kugel” was the (only) entree choice on most days. Hopefully vegetarian and vegan choices have improved now that “meatless” days in schools has become a new trend. The choice to radically reduce or outright eliminated your intake of meat and dairy requires some careful thought about balancing nutrition, and great care should be taken with growing children. This also touches on some personal responsibility and equity issues: wealthier people are often the ones producing the most emissions based on food and transportation choices. When much of the world is suffering from hunger or malnutrition, or desperate for a decent wage, the choice to act on climate may rest primarily with those that have the luxury to choose.
If this path isn’t for you, fret not, for there are many ways that you can still make a change in your lifestyle that benefits the world around you. Being mindful of your food choices and understanding the adverse impacts involved in the “cradle to grave” production of food is a minimalist platform that we can all stand on. As a first step, I suggest following the inspirational recommendations of campaigns such as Drawdown EcoChallenge, which draws on the comprehensive list of climate actions described in the book Drawdown. If you eat a steak tomorrow, the world will not end (or at least not because of your steak); however, if NOBODY does anything to mitigate climate change, then we’ll continue to stew in a pot set to boil. Whatever you choose, I wish you a future of decreased emissions.