In North Carolina, the nation's second-largest hog-producing state, hog lagoons are major contributors to air and water contamination. Today, over 92% of North Carolina’s 10 million hogs are raised on factory farms, which are located in the environmentally sensitive area of North Carolina’s Coastal Plain East of I-95. These factory farms don’t resemble the small family-run hog farms they replaced.

North Carolina’s swine industry generates about 13 million pounds of manure and urine a day. The waste is flushed from barns into open-air lagoons, which release tons of methane gas. One pig’s waste equals 10 times the waste of one person according to Dr Mark Sobsey of UNC, Chapel Hill. Every day, those 10 million pigs produce “fecal waste” equivalent to 100 million people.

Fish deaths in the Neuse and other rivers of eastern North Carolina are directly linked to nutrient pollution. The hog industry is one of the leaders in nutrient production. The pollution of these nutrients has been linked to Pfiestera—a toxic organism that attacks both fish and people causing neurological damage and other serious health problems.

Water and Air Pollution
48 Billion land animals are bred, fed, transported, slaughtered, and transported again worldwide every year. 10 Billion of these are in the United States.

Livestock production is resource intensive, using 70% of the world's agricultural land, 30% of the total land surface, and 8% of the water used by humans. It's also energy intensive, producing 1,485 tons of CO2-equivalent greenhouse gases per person per year. That's the amount that is saved by driving a Prius.

In the United States livestock are responsible for 55% of soil erosion and sedimentation, 37% of pesticide use, 50% of antibiotic use, and 33% of nitrogen and phosphorus pollution of fresh water.

Animal agriculture (breeding, feeding, collecting waste, transporting to slaughter, processing, cold storage, transporting to stores) in the United States accounts for 9% of CO2, 37% of methane and 65% of nitrous oxide emissions.

By shifting entirely to a plant-based diet Americans could reduce greenhouse gas emissions equivalent to 8,000 miles driven per year.

Studies supporting animal agriculture negative impact on the environment

United Nations
"Livestock are one of the most significant contributors to today's most serious environmental problems," senior UN Food and Agriculture Organization (FAO) official Henning Steinfeld said. "Urgent action is required to remedy the situation."
Read the complete article: "Rearing cattle produces more greenhouse gases than driving cars, UN report warns".

University of Chicago
A study published by the University of Chicago shows that a person adopting a vegetarian lifestyle, including no components from the animal world, contributes more to halting global warming than a person who drives a Prius.
Read the complete article: "Diet, Energy, and Global Warming".

Carnegie Mellon University
Researchers at Carnegie Mellon University reported in a 2008 study that diet has a greater impact on climate change than food miles.
Carnegie Mellon press release
Paper published in the Environmental Science & Technology journal

Meat consumption
Americans now use meat and dairy products to provide 30% of our energy and 50% of our protein needs. This pattern of eating produces major environmental damage, is neither biologically necessary nor healthy for us, and entails widespread systematic cruelty to animals. Worldwide meat consumption has increased five-fold in the past 50 years and is expected to double again in the next 50.

Animal feed production
Animals consume 70% of the wheat, corn, and other grains that we produce. Every pound of plant protein consumed by animals yields only 3/4 pound of animal protein: the conversion of total calories is even less efficient.

Deforestation
In the tropics most deforestation is driven by the need for pasture and cropland for animal feed crops. Worldwide 20% of all pasture area (75% in dry areas like the Western United States) has been severely damaged by overgrazing, compaction, and erosion. Loss and degradation of habitat that results from the destruction of forest and natural grassland is a major factor in the global loss of biodiversity and the decline of ecosystems.

Ocean degradation
33% of ocean fisheries has already collapsed because of over fishing and pollution. If this rate of loss continues, there will be practically no wild seafood left in the oceans by 2050.