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Animal Agriculture: How Bad Is It for Climate Change and the Environment?

December 7, 2021

Meat producers want you to believe that eating meat is natural, but there's nothing natural about factory farming, which imprisons billions of sentient beings and, like fossil fuel production, is a leading cause of large-scale climate destruction. Read on to find out more about this secretive industry and its effects on the environment.  

What Is Animal Agriculture?

Animal agriculture is the commercial rearing of animals for their flesh, milk, eggs, wool, or skins. Global demand for these products has soared in recent decades, leading to the rapid expansion and intensification of the animal agriculture industry. Small, diversified farms have now been largely replaced by huge industrial operations that hold tens of thousands of animals indoors in close confinement.

What Is Animal Agriculture Called?

Factory farming and livestock production are two of the most common names given to animal agriculture. Factory farming refers to a system of raising fast-growing animals in extreme confinement. Livestock refers to the domesticated land animals who are used in agriculture and is a word that many animal rights advocates—who say that animals are individuals and should not be property—reject.

You might also hear people refer to the animal agriculture industry as Big Ag or Big Meat and Dairy. All of these terms refer to a group of giant meat and dairy companies that dominate the industry from farm to fork.

What Is the Purpose of Animal Agriculture?

The primary purpose of animal agriculture is to produce food for human consumption. In order to make a profit, farms seek to maximize the production of meat, milk, eggs, and dairy while keeping costs as low as possible. As we will see, this way of farming comes at a great cost to our people, animals, and the planet.

What Are the Different Types of Animal Agriculture?

There are many different types of animal agriculture, but the factory farming of chickens, pigs, and cows are three of the most prominent.

Factory-Farmed Chickens

According to estimates by the Sentience Institute, a nonprofit animal rights think tank, as of 2019 99.9 percent of chickens farmed for meat in the U.S. are raised in factory farms. Crammed into sheds in such high densities that there is no room to even move around, these birds are denied any opportunity to engage in their natural, instinctive behaviors. In 2020 alone, the U.S. poultry industry slaughtered more than nine billion broiler chickens, the overwhelming majority of whom never saw daylight until they left the farm for the slaughterhouse.

Factory-Farmed Cows

If you picture grassy fields when you think about beef and dairy farming, you may be surprised to learn that around 70 percent of cows in the U.S. are factory farmed. While most cows in the US spend the first few months of their lives on pastures (if you drive across the western United States it is difficult not to see cows grazing), after which they are moved to feedlots, or Concentrated Animal Feeding Operations (CAFO’s) where they are denied  access to pasture for grazing. Cows in these facilities are typically confined spaces where have no choice but to stand in their own feces.

Factory-Farmed Pigs 

Pigs are not all that different from the dogs we share our homes with in terms of intelligence and sociability, but there is a stark contrast when it comes to the way that they are treated. Around 98 percent of pigs in the U.S. are raised in factory farms. Pregnant sows and mother pigs are kept in metal cages. Conditions are so bad that around one-third of pigs do not even live long enough to be slaughtered.

Why Is Animal Agriculture Bad?

Animal agriculture is a leading cause of animal suffering and the intensification of the industry in recent years has caused myriad issues. Among these are the extreme confinement of farmed animals, antibiotic misuse, and animal abuse.

Intense Confinement 

Imagine that you are in a dark, poorly ventilated shed with so many other people that you can’t even stretch out your arms or take more than a few steps. This is how farmed animals spend their entire lives. Farms keep animals in close confinement to save space and maximize the efficiency of the business, but this inevitably comes at great cost to the animals’ well-being. 

Abuse of Antibiotics

In order to compensate for the unhealthy conditions inside factory farms, animals are routinely fed low doses of antibiotics. When used to treat infections, antibiotics can save the lives of both people and animals, but the misuse of these medicines in animal agriculture can create drug-resistant bacteria. The farming industry uses 65 percent of antibiotics sold in the U.S.

Animal Abuse

Farmed animals have every aspect of their lives controlled for economic gain by people who see them primarily as units of production. It is sadly not unusual for farmed animals to be kicked, punched, thrown, beaten, and dragged. 

As well as being subject to sporadic violence, animals are also made to suffer thanks to routine farming practices. They undergo painful bodily mutilations including the burning of a calf’s horn tissue with a hot iron (disbudding), the shortening of an animal’s tail with a knife (tail docking), and the trimming of a chicken’s beak with a hot blade (debeaking). Additionally, females are forcibly impregnated either to produce litter after litter of babies who are then taken from them and ultimately killed, or, if they are dairy cows, because they only make milk after they have recently given birth.

How Does Animal Agriculture Affect Global Warming?

Although often overlooked in conversations about climate change, animal agriculture is a major driver of global warming and biodiversity loss. As we will see below, the industry destroys ecosystems, releases huge quantities of greenhouse gases, wastes vast amounts of water, and is a major source of pollutants. 

Animal Agriculture and Deforestation  

While people around the world are planting trees to help the planet, meat companies are destroying ancient forests to make room for cattle ranching and soy production. Soy is often associated with vegans and vegetarians, but 77 percent of the crop is actually fed to farmed animals—primarily chickens and pigs. 

Beef production alone is to blame for 41 percent of global deforestation, equal to more than two million hectares of land per year, and 72 percent of deforestation in Brazil. The flesh of cattle who were raised on deforested land ends up on supermarket shelves around the world. Of almost 80,000 tonnes of beef that the U.S. imports from Brazil each year, 55 percent has been linked to the severely deforested Cerrado savanna.. 

Not only does deforestation cause ecological devastation, but it is also a human rights issue due to land-grabbing. Cattle ranchers and soy producers threaten, violently attack, and steal land from Indigenous peoples. 

Animal Agriculture and Greenhouse Gas Emissions

“Converting grass into [meat] is like converting coal to energy. It comes with an immense cost in emissions,” environmental researcher Joseph Poore told the Guardian. Animal agriculture is directly responsible for at least 15.4 percent of global greenhouse gas (GHG) emissions, of which around 24 percent is nitrous oxide (N20), 26 percent is methane (CH4), and 50 percent is carbon dioxide (C02). 

Contrary to popular belief, transportation only accounts for a tiny part (usually less than 10 percent) of a food’s carbon footprint. For example, it accounts for just 0.5 percent of greenhouse gas emissions from beef. This means that swapping meat for plant-based alternatives will reduce your carbon footprint more than buying local meat. 

The farming of ruminants such as cows and sheep, who naturally produce methane when they digest food, makes animal agriculture the biggest source of CH4 (methane) emissions in the U.S. Methane does not live as long in the earth’s atmosphere as carbon dioxide, but it has 86 times more warming potential in the short term.

Animal Agriculture Water Usage and Pollution 

An average of 15,415 liters of water goes into producing just one kilogram of beef. Pulses, by comparison, use 4,055 liters per kilogram and it only takes an average of 322 liters of water to produce a kilogram of vegetables. The water footprints of animal products vary—5,988 liters of water per kilogram for pork and 4,325 for chicken—but are generally higher than that of plants. 

Of all the freshwater used by humans, 92 percent goes into farming. Almost one-third of this is used for animal agriculture, the vast majority (98 percent) of which is used for growing crops to feed farmed animals. 

Animal agriculture also affects our water supplies in other ways. Fertilizers, pesticides, and excess nutrients from animal manure pollute water when they enter runoff and leach into rivers, streams, and other areas of surface water. This causes algal blooms, ocean dead zones, kills aquatic life, and contaminates drinking water. 

How Much Land Is Used for Animal Agriculture?

Unsurprisingly, raising more than 70 billion land animals to kill each year for food requires vast areas of farmland. Although most of these animals are denied the opportunity to graze and are given so little space that they can barely turn around, arable land is needed to grow crops for them to eat. Global meat and dairy production uses an estimated 40 million square kilometers of land, or approximately 38.5 percent of the world’s habitable surface area.

For every kilogram of edible beef, a cow eats 25 kilograms of food. Other animals convert plants to meat more efficiently, but it still takes 6.4 kilograms of food to produce just one kilogram of pork and 3.3 kilograms of food to produce just one kilogram of poultry meat. As a result, animal agriculture uses 83 percent of global farmland but only produces 18 percent of the world’s calories. Switching to a plant-based food system would require growing fewer crops and would therefore free up land that could be used to grow other food crops, to sequester carbon, or to foster biodiversity. 

Is Animal Agriculture Bad for Human Health?

Animal agriculture poses a number of serious threats to human health. Antibiotic resistance, which, as we have seen, is accelerated by the livestock industry’s abusive use of medication, already kills 35,000 people in the U.S. each year.  

Scientists have warned that factory farms will create future pandemics that could be even more dangerous to human health than COVID-19. As you can imagine, diseases spread quickly in poorly ventilated, overcrowded indoor spaces where tens of thousands of genetically similar animals are kept in close confinement. Factory farms around the world are currently home to eight different strains of bird flu, also known as avian influenza, all of which can be deadly to humans. 

Animal agriculture is also a major contributor to climate change, which according to the World Health Organization is “the single biggest health threat facing humanity.” 


The environmental destruction caused by animal agriculture far outweighs any benefits, especially for those who live in developed nations with access to a wide variety of foods. With so many plant-based options available, there is no need to farm animals on such a massive scale. Now more than ever before, our planet needs to shift away from the mass killing of chickens, pigs, and cows and create a plant-based food system in which people, animals, and the planet are treated with respect.