The production of meat has a more significant negative impact on the environment than probably any other industry. In the last 300 years, over half the trees in the United States have been cut down in exchange for immense fields of corn, soybeans, oats, grass and hay, which are primarily used to feed livestock. In addition, the vast majority of land currently used to raise cattle in the U.S. are the public rangelands in the west. Livestock grazing in these areas has been the major cause of soil erosion and desertification, the process by which an area becomes a desert. Overgrazing of cattle and sheep herds in the western rangelands has contributed to the elimination of more plant species in the United States than any other cause.
The demand for cheap beef has driven the scope of environmental destruction to the Central American rainforests where ranching has contributed to deforestation, species extinction, and more loss of biodiversity than any other activity in this part of the world. The tropical rainforests provide a substantial part of the Earth's oxygen, house the majority of the planet's land vegetation, and are home to more species of plant and animal life than anywhere else on Earth. With every acre destroyed, more species are threatened with extinction and carbon dioxide pollution increases, adding to the global warming problem. At the same time, the atmosphere is robbed of oxygen that would have been generated by that vegetation.
Animal agriculture guzzles huge amounts of water, particularly for irrigation used to grow feed crops. In addition, fertilizer, pesticide, herbicide and livestock waste runoffs all severely pollute our nations waterways. Animal excrement and fertilizer have been blamed for a large percentage of the nitrogen and phosphorus released into U.S. rivers. Furthermore, the millions of tons of non-recycled waste produced by livestock each year - which is substantially more concentrated than domestic raw sewage - generally ends up untreated in both surface and ground water. By simply changing our food choices, we can have a significant positive impact on our environmental future.