Why Are Cows Bad for the Environment and What Can You Do?

Life on factory farms is not kind to cattle or the environment. Before the rise of factory farming, cows would typically live on small to medium-sized farms in herds of ten to 100 that would get to graze outdoors on grass pastures. At one point, the kind of family-owned farms that might bring bucolic images of well-tended animals to mind were fairly standard across the United States. Then a shift toward factory farming changed that dynamic—and with those changes came issues like crowded living conditions and mismanagement of animal waste, which continue to have grim implications for both animal welfare and the environment today.

As of 2019, Sentience Institute estimated that 99% of farmed animals in the US live on factory farms. For cows, over 70.4% of them live on factory farms where they are confined to filthy, crowded indoor sheds, and are not allowed to graze, nurse their babies, or socialize with their herds like they would in their natural environment. These inhumane living conditions also cause pollution from animal waste and methane gas that directly impacts the planet on every level—contaminating our air, our water, and our land.

Dairy and beef production have a notable effect on climate change, partially because cows produce substantial amounts of methane when they digest their food. Methane is a greenhouse gas, meaning it affects the climate and the temperature of the earth. Greenhouse gases trap the sun’s heat within the atmosphere, creating planetary warming. This in turn leads to extreme weather conditions like high heat, wildfires, intense hurricanes, and rising sea levels.

What are the sources of methane emissions?

Methane emissions come from a variety of human-influenced and natural sources, including:

• Agriculture
• Coal mining
• Landfills
• Oil and natural gas systems
• Wastewater treatment
• Industrial processes
• Natural wetlands

Of these, 50-65% of methane emissions stem from human activities: primarily energy, industry, agriculture, land use, and waste management.

In factory farming, cows and their manure release methane emissions that contribute to climate change. Consider that each cow produces an average of 81.5 pounds of waste every day, and multiply that by 9.4 million dairy cows in the US alone. Cows in the wild would spread across great distances, and their waste could fertilize the land without causing harm. But in animal agriculture, fertilizer runoff from manure can cause pollution to freshwater sources like rivers and streams.

Relatedly, agriculture, forestry, and land use accounts for approximately 18.4% of global greenhouse gas emissions. That’s more than planes, trains, cars, ships—or the transportation sector overall. 5.8% of global greenhouse emissions are directly linked to livestock production and manure.

Why is methane bad for the environment?

Methane is a powerful greenhouse gas that traps approximately 30 times more heat than carbon dioxide. It also accounts for about 20% of global greenhouse gas emissions. Because of human-related activities like animal agriculture, methane concentrations in the atmosphere have more than doubled over the last two centuries. This has significant repercussions on global warming, causing climate change and unusual weather patterns.

How do livestock produce methane?

Cows and livestock like sheep and goats are ruminants: meaning, animals with stomachs that have four distinct chambers. Ruminant animals regurgitate and chew their food after they swallow it, and emit methane both through their digestion process and through their waste.

Diet can have a significant effect on how much methane cows produce. For example, studies show that digesting grass and hay produces more methane than other food sources, like corn. As scientists seek to help turn the tide of the harm from greenhouse gases like methane, some are exploring ways to reduce methane emissions by adjusting what cows eat.

But back to biology: while some believe that farmyard flatulence is the reason behind high levels of methane emissions, belching turns out to be the true culprit.

Livestock greenhouse gas emissions percentage

On a global scale, livestock emit 14.5% of all greenhouse gases in the environment (carbon dioxide, methane, nitrous oxide, and fluorinated gases)—and according to a United Nations report, over half of those gases come directly from cows. A study out of the University of California, Davis, reports that one cow can “belch 220 pounds of methane, which is 28 times more potent than carbon dioxide,” each year. Over the first 20 years after methane reaches the atmosphere, it has more than 80 times the warming power of carbon dioxide—the primary greenhouse gas in vehicle emissions.

Are cows bad for the environment?

Cows themselves aren’t bad for the environment—but when they’re raised and slaughtered by the millions, in factory farms that prioritize profit, the environment suffers. Animal agriculture is one of the largest sources of climate-altering gases in the world, particularly in meat and dairy production. Aside from methane emissions from cows, part of the pollution problem stems from cow manure. Manure holds phosphorus and nitrogen, and when it’s used on fields as fertilizer, rainfall can cause manure to run off into water sources. Animal crowding on factory farms can also create a phenomenon known as manure overload, which happens when fields become saturated with chemical fertilizer and manure. Because the plants and soil are literally overloaded with nutrients, the runoff seeps into groundwater. When this happens, the resulting water pollution can be far-reaching, “leading to the spread of waterborne pathogens and the growth of harmful algal blooms.”

There are other issues, too. Forests and wetlands naturally absorb and store carbon, but that land becomes a carbon source when those ecosystems are cleared for farming. Cutting down trees releases carbon dioxide back into the atmosphere, leading to excess carbon emissions. Deforestation presents an ongoing threat to our environment, driving both the climate crisis and biodiversity loss.

Why is cow methane bad?

“If cows were their own country,” writes Sarah Kaplan for the Washington Post, “they would be the third-biggest greenhouse gas emitter in the world.”

Cows release a powerful greenhouse gas called methane into the atmosphere as they digest their food. Cows are ruminants, or animals with multi-chambered stomachs, whose food ferments during the digestion process. This produces methane, a gas that’s then emitted when cows burp. Methane is highly effective at trapping heat, which directly impacts global warming and the climate crisis.

How do cows contribute to global warming?

Cows contribute to global warming through the production of methane, a greenhouse gas that leads to climate change. Cows emit methane as they digest their food, then pass gas. A study out of the University of California, Davis shows that belching is a primary source of methane from cows.

“Methane from cattle is shorter lived than carbon dioxide, but 28 times more potent in warming the atmosphere,” says Dr. Frank Mitloehner, a professor and air quality specialist at the Department of Animal Science at UC Davis.

Cow methane versus car emissions

While it’s challenging to draw a direct comparison between cows and cars, we can look to statistics that address global greenhouse emissions by sector. When it comes to agriculture versus transportation, the agriculture industry takes the lead on global greenhouse gas emissions. A more detailed view shows that livestock emissions may be slightly less than those in the transportation sector as a whole—but that doesn’t account for the ways in which factory farms contribute to environmental pollution through fertilizer emissions, runoff, and more.

While comparing cow methane to car emissions is a bit like comparing apples to oranges, the truth is that both do create pollution that contribute to climate change, and have detrimental effects on our environment.

Why is eating cows bad for the environment?

As climate change escalates and our global population increases, eating beef is an increasingly unsustainable dietary choice.

In their book Cowed, Denis Hayes and Gail Boyer Hayes assert that eating a pound of beef has more impact on climate change than burning a gallon of gasoline. Their reasoning follows the trajectory of raising cows on factory farms: from the energy it takes to grow crops and fertilize fields, to the gasoline that powers the farm equipment and transports cattle to slaughter, to the energy it takes to power vehicles to drive to the supermarket, purchase the beef, and cook it at home.

On the plus side, research suggests that trading in steak for beans “once a week for a year” can leave about 331 kilograms of carbon dioxide out of the atmosphere.

What you can do

Choosing a plant-based diet is among the most impactful ways you can help protect our planet. When you leave animals off your plate, you reduce your environmental footprint and help stop the depletion of the earth’s natural resources. If we can lessen the demand for meat, we can also lessen the abusive and inhumane treatment of cows on factory farms—and reduce their environmental impact.

Learn more about why adopting a plant-based diet is a compassionate choice for the earth, for the animals, and for your health.