Environmental impact of livestock
Livestock have a large negative impact on the environment, through greenhouse gases, nitrogen pollution, deforestation, and ammonia, which contributes to acid rain.
Livestock, when used for meat, also use far more resources than the same amount of nutrients in vegetable form (e.g. grains or legumes).
See Environmental impact of livestock for more detail.
Factory farming, with its emphasis on production and efficiency through the accumulation of many small gains, causes many animal welfare problems.
Traditional farming may not have been concerned with the happiness of animals, but in its more natural setting, the animal was likely to have a more varied experience and room to move. Certified organic farming follows something closer to this model, and certification generally includes animal welfare criteria.[verification needed]