by Allie Molinaro

Factory farming causes unspeakable suffering for animals, but did you know that it is also having calamitous impacts on our climate? Here, we break down factory farming's greenhouse gas emissions and how, with coordinated action, we can help protect both animals and our climate. 

The Numbers 

According to the United Nations Food and Agriculture Organization (FAO), animal agriculture generates over 14.5% of global greenhouse gas emissions. That is more than the exhaust emissions from the world's cars, trucks, planes, and ships combined. Some evidence suggests that animal agriculture's emissions are closer to 16.5% of global emissions, even higher than the FAO's calculation.  

Only about 27% of these emissions are carbon dioxide, while the rest are nitrous oxide (29%) and methane (44%). This is important because nitrous oxide and methane are more potent greenhouse gases than carbon dioxide. That means that while methane and nitrous oxide do not last as long as carbon dioxide, they trap heat more intensely. Methane is about 30 times more powerful than carbon dioxide, and nitrous oxide is about 270 times more powerful. 

Carbon dioxide, methane, and nitrous oxide each come from different factors and processes associated with animal-based food production. The livestock sector's carbon dioxide emissions come from land use change (for instance, cutting down rainforests to create cow pastures or soybean fields for feed), the production of pesticides and fertilizers used to grow feed, electricity use on farms and in slaughterhouses, and the transportation of feed, chemicals, animals, food products, etc. Nitrous oxide emissions mainly come from soil, wastewater treatment from meat and poultry processing, and pig and poultry manure. Methane emissions come from both manure and enteric fermentation in ruminant animals like cattle, sheep, and goats as they digest (informally known as "cow burps"). According to the Environmental Protection Agency (EPA), U.S. livestock animals produced 241 million metric tons of methane (measured in CO2e) in 2019, which was more methane than the petroleum and natural gas sectors combined. Manure from chickens, pigs, and other farmed animals also produced 19.6 MMT CO2e of nitrous oxide, more than the nation's cars, trucks, ships, trains, and planes combined.  

Moreover, while the United States's emissions from other sectors are decreasing, its emissions from animal agriculture are increasing. For instance, methane emissions from natural gas fell by 15.7% from 1990 to 2019, thanks in part to government initiatives to fix pipeline and equipment leaks. Meanwhile, methane emissions from the livestock sector increased by 8.4% over the same period as a result of increasing cattle production. Similarly, nitrous oxide emissions from vehicles have decreased by almost 60% since 1990 as a result of national vehicle emissions standards and other actions, but nitrous oxide emissions from livestock manure have increased by over 40% due to increasing meat and poultry production. 

One of the reasons why the livestock industry is so emissive is because of its sheer size. There are over 80 billion farmed animals worldwide, way more than the number of cows, pigs, chickens, and other farmed animals that the Earth can naturally support. Over 60% of them are raised in intensified conditions on factory farms. All these animals need land, feed, and other inputs, produce manure and methane, and require vast amounts of energy for slaughter, processing, and transport.  

Thus, meat production and consumption is a key driver of climate change. Research suggests that even if the world stopped using fossil fuels today, our current food system makes keeping global warming below 1.5° C impossible. If we are to have a livable future, we must take action to address animal agriculture's greenhouse gas emissions. 

Solutions 

Despite this grim-sounding scenario, there are ways to reduce greenhouse gas emissions from animal agriculture significantly, and many of them can be implemented immediately.

1. Reduce consumption of animal-based food by shifting to plant-based diets.

Reducing the number of animals within our food system is the most impactful way to save animals and protect our climate. Multiple international bodies, including the International Panel on Climate Change (IPCC), FAO, C40 Cities, EAT-Lancet Commission, and numerous scientific research papers have identified shifting to plant-based diets as a major pathway for reducing greenhouse gas emissions. They also cite several co-benefits, such as improved animal welfare, reduced land use, increased nutrition, better food security, and reduced health risks from zoonotic diseases, pesticides, and antibiotic resistance. While entirely eliminating all animal-sourced foods maximizes these benefits, most of the research suggests that climate targets can be achieved even with moderate consumption of animal-based foods, so long as other sectors (transportation, energy, etc.) reduce their emissions as well.

Where appropriate, a shift to diets with a higher share of plant protein, moderate intake of animal-source foods and reduced intake of saturated fats could lead to substantial decreases in GHG emissions. Benefits would also include reduced land occupation and nutrient losses to the surrounding environment, while at the same time providing health benefits and reducing mortality from diet-related non-communicable diseases.

A whopping 42% of the world's habitable land is dedicated to livestock production, meaning that repurposing this land for reforesting and restoring habitats also presents a major opportunity to store carbon. One study found that if we reduce livestock production and allow the leftover animal agriculture land to reforest to its natural state, the highest meat-eating countries (including the U.S.) could cut emissions by 61% and remove almost 100 gigatons of carbon dioxide from the atmosphere.

2. Restore on-farm ecosystems through regenerative practices.

All farmed animals can play a beneficial role in the environment so long as they are allowed to live how they would naturally. For instance, rotational grazing/foraging is a regenerative livestock practice that allows animals to move from pasture to pasture in a way similar to how they would roam in the wild. This helps stimulate plant growth and helps soil life while giving the grass and soil time to recover from grazing and trampling so they can continue to thrive. Silvopasture is another regenerative technique that incorporates trees into livestock pastures, which improves soil health, provides natural shade, and increases carbon storage. Some regenerative practices for crop production include:

• No-till (eliminates tilling, thereby minimizing soil disturbance to prevent killing soil life) 
• Cover cropping (edible or non-edible plants are planted to grow in between the regular crop growing season to maintain soil health) 
• Ecological pest management (the use of natural techniques to keep pests away, such as planting diverse crops and creating habitat for natural pest predators instead of using chemicals) 

• Food forests (multiple types of crops are planted among each other to mimic natural plant diversity)  

A less studied but critical component of reducing livestock-related emissions is improving soil health. Healthy soil contains millions of microorganisms such as bacteria, fungi, protozoa, nematodes, microarthropods, earthworms, and other life that—when functioning properly—store massive amounts of carbon in their bodies. However, many practices associated with livestock production and feed production, such as tilling, applying pesticides and inorganic fertilizers, cutting down forests, storing manure in lagoons, etc., kill these organisms, causing carbon to be released into the atmosphere. Preliminary research suggests that if all the world's soils were restored to a healthy state, we could bring atmospheric carbon down to safe levels in as little as 6-15 years.

3. Research and scale alternatives to traditional meat production.

Researchers and food innovators are finding ways to produce meat products that eliminate the need to harm animals and produce fewer greenhouse gases through cellular agriculture. Cellular agriculture produces meat and other animal-sourced foods from cultured cells. Current studies suggest that cellular agriculture technology may reduce greenhouse gas emissions by 92%, land use by 95%, and water use by 78%. The IPCC and the FAO have named cellular agriculture a top area of interest in reducing food-related greenhouse gas emissions. While the technology still needs time to perfect and scale, when combined with plant-based dietary shifts, regenerative agriculture, and restoring nature, cellular agriculture could seal the deal on a sustainable future.

While much of the knowledge and technology for reducing food-related emissions already exists, scaling and expanding the right practices will be essential to averting a climate crisis. Learn more about how CIWF is helping businesses and lawmakers implement best practices for both climate and animal welfare. 

Learn more about the animal cruelty issues associated with factory farming.

As Campaign Manager, Allie Molinaro works to advance Compassion USA's state and federal policy work, thought leadership, and activist mobilization. She focuses her work on placing factory farming in a broader context, highlighting its impacts not only on animal welfare but also on pollution, climate change, public health, and social justice. Allie holds an M.S. in Environmental Policy and Sustainability Management from The New School and a B.S. in Environmental Science from the University of Connecticut.