Agriculture, especially the mass production and slaughter of animals, is reshaping the earth’s biosphere. Scientists say we are now living in the Anthropocene age, a geologic epoch dominated by human activity and a fossil record that will be marked by chicken bones and plastic. A study published in Proceedings of the National Academy of Sciences found that 70% of birds on earth today are domesticated, mostly chickens. In the case of mammals, just 4% live in the wild, and an astounding 96% are domesticated, mainly farm animals. We are destroying nature and exploiting billions of farm animals (trillions if you include fish), which causes intolerable suffering to both human and nonhuman animals, and harms the earth.
Large farms can produce more waste than some U.S. cities. According to the Centers for Disease Control and Prevention, a farm with 800,000 pigs could produce over 1.6 million tons of waste each year. That amount is one and a half times more than the annual sanitary waste (sewage) produced by the city of Philadelphia.

80% of all antibiotics sold in the United States are sold for use in animal agriculture. In order to prevent the spread of disease in the crowded, filthy conditions of confinement operations, producers feed farm animals a number of antibiotics. Upwards of 75% of the antibiotics fed to farm animals end up undigested in their urine and manure. Through this waste, the antibiotics may contaminate crops and waterways.
Animal agriculture is responsible for more greenhouse gas emissions than every car, bus, train, boat, airplane, and any other mode of transportation on the planet combined, according to a report published by the FAO. According to the same report, animal agriculture is responsible for 37% of all human-caused methane emissions.