The farm animal production sector is the single largest anthropogenic user of land, contributing to soil degradation, dwindling water supplies, and air pollution. The breadth of this sector‘s impacts has been largely underappreciated. Meat, egg, and milk production are not narrowly focused on the rearing and slaughtering of farm animals. The animal agriculture sector also encompasses feed grain production which requires substantial water, energy, and chemical inputs, as well as energy expenditures to transport feed, live animals, and animal products. All of this comes at a substantial cost to the environment.
One of animal agriculture‘s greatest environmental impacts is its contribution to global warming and climate change. According to the Food and Agriculture Organization (FAO) of the United Nations (UN), the animal agriculture sector is responsible for approximately 18%, or nearly one-fifth, of human-induced greenhouse gas (GHG) emissions. In nearly every step of meat, egg, and milk production, climate-changing gases are released into the atmosphere, potentially disrupting weather, temperature, and ecosystem health. Mitigating this serious problem requires immediate and far-reaching changes in current animal agriculture practices and consumption patterns.
The Humane Society of the United States, "An HSUS Report: The Impact of Animal Agriculture on Global Warming and Climate Change" (2008). Impact of Animal Agriculture. 3.