Environmental impact of animal agriculture

Emily Carter 

Domestic agriculture is responsible for the start and progression of human society, but at the present, it is becoming one of the biggest players in our demise. Population growth and climate change are major stressors on livestock production. By 2050, demand for meat products is expected to increase, and so are the environmental impacts associated with them. Animal agriculture negatively contributes to global greenhouse gas (GHG) emissions, our dwindling water supply, land use change, food insecurity, air pollution, deforestation, and biodiversity loss.

The livestock industry produces 14.5% of GHG emissions, which equates to exhaust emissions from every plane, car, train, or ship. The main GHGs emitted from the livestock industry are carbon dioxide, nitrous oxide, and methane. The GHG of most concern is methane, which is created by enteric fermentation and emitted by belching. Use of manure and other synthetic fertilizers for feed production, the processing of feed, and the transport of it contributes to 45% of total greenhouse gas emissions from livestock. Energy usage is estimated to account for 20% of emissions in the livestock industry. Other sources of emissions from the livestock sector are from land use change, feed production, animal production, manure, processing, and transport. The process of transporting food crops to livestock is a large reason for the transportation impact. 

Animal production is the largest use of space in the world, and contributes to air pollution, soil destruction, and decreased water supply. The space used for animal production has not changed since 1991, which reflects the intensification that occurs on those lands. Farmland now takes up one third of the planet. Of all farmland, livestock takes up 83% and contributes to 60% of total greenhouse gas emissions. Dairy and livestock are responsible for 65% of livestock emissions.

Livestock production also requires a significant portion of freshwater resources. This table shows the amount of water required to produce each food listed or to sustain the particular animal.

One hamburger660 gallons 
One pound of beef1,799 gallons
Chicken 468 gallons
Pork576 gallons
Sheep731 gallons
One egg53 gallons
Gallon of milk880 gallons
One pound of corn108 gallons
Soybeans 216 gallons
Rice449 gallons
Wheat132 gallons

There is a negative feedback between the production of quality livestock products and the effects of climate change: livestock negatively impacts climate change and climate change negatively affects livestock production.

Animal agriculture represents a threat to food security. Currently, over 820 million people suffer from hunger. Livestock consumes a lot of calories, proteins, and micronutrients in the form of grains, legumes, and starches that could be fed to hungry people. In some areas, livestock contributes to food security. In other areas, livestock is detrimental because it makes land unsuitable for other types of agriculture. Currently, meat and dairy only account for 18% of calories and 37% of protein. Therefore, switching to a more plant based diet globally would increase protein. 

What we can do 

Today, 54% of the general public believes in climate change, 38% of people think climate change is a crisis, and 38% think it is a major problem. Additionally, 37% think we need to make major sacrifices to combat the issue, and 48% think we need to make minor changes. 

There are both minor and major changes that can be made. In addition to turning off the sink when brushing our teeth, taking shorter showers, and recycling, avoiding meat and dairy products helps preserve the environment, animal lives, and our health. A new report published in The Lancet, recommends a plant-based diet that largely avoids meat, dairy, and sugar. Additionally, to address climate problems, it is recommended that people cut meat, dairy, and sugar consumption by half. Generally, a plant-based diet is less resource-intensive, even though some products require more water or land than others. 

Removing meat and dairy from your diets is the biggest way to reduce your individual impact on the planet. A 2016 study showed that by adopting a vegan diet emissions could be reduced by as much as 70%, and 63% for a vegetarian diet. Additionally, if dairy and meat farms were replaced with vegetable farms, farmland could be reduced by 75% and still feed the entire world. Eating less beef has an especially high impact because beef contributes a significantly high proportion of livestock GHG emissions while also being low in protein relative to the resources used. 

Quality land is key for sustaining the population. Supplying 10 billion people with food is a top concern among scientists today. Current research in environmental science implies that dietary shifts are necessary in order to reduce the negative effects of agriculture on climate change and the effect of climate change on agriculture, which occur as a negative feedback loop. 

Sources: Carbon Footprints, Elsevier, The Guardian, LA Times. NPR, United Nations, Washington Post, Yale Climate Communication