Large-scale meat production has serious implications for the world's climate. Animal waste releases methane and nitrous oxide, greenhouse gases that are 25 and 300 times more potent than carbon dioxide respectively.

Dirty and crowded conditions on factory farms can propagate sickness and disease among the animals, including swine influenza (H1N1), avian influenza (H5N1), foot-and-mouth disease, and mad-cow disease (bovine spongiform encephalopathy).

These diseases not only translate into enormous economic losses each year—the United Kingdom alone spent 18 to 25 billion dollars in a three-year period to combat foot-and-mouth disease—but they also lead to human infections. Mass quantities of antibiotics are used on livestock to reduce the impact of disease, contributing to antibiotic resistance in animals and humans alike. Worldwide, 80 percent of all antibiotics sold in 2009 were used on livestock and poultry, compared to only 20 percent used for human illnesses.

Antibiotics that are present in animal waste leach into the environment and contaminate water and food crops, posing a serious threat to public health. The amount of meat in people's diets has an impact on human health as well. Eaten in moderation, meat is a good source of protein and of important vitamins and nutrients, such as iron, zinc, and vitamins B3, B6, and B12.

But a diet high in red and processed meats can lead to a host of health problems, including obesity, diabetes, cardiovascular disease and cancer.

Eating organic, pasture-raised livestock can alleviate chronic health problems and improve the environment. Grass-fed beef contains less fat and more nutrients than its factory-farmed counterpart and reduces the risk of disease and exposure to toxic chemicals.