Farming — whether it's raising livestock for meat or growing crops — does have an impact on the environment. According to the Food and Agriculture Organization of the United Nations, since the mid-1980s, an area the size of India has been deforested to accommodate livestock. Cattle are particularly tough on the land, physically and chemically. As they graze, they compact the soil as they walk, hardening it and making it difficult for new vegetation to emerge. This can also make the soil more susceptible to erosion, limiting its ability to retain nutrients. Chemically, waste from cattle can burn and destroy vegetation and change the nitrogen levels of the soil. Raising cattle also accounts for 8 percent of global water usage and produces 18 percent of greenhouse gas emissions. For these reasons, some consumers feel the only way to be completely green at the dinner table is to forgo meat altogether since raising crops does not have the same dramatic effects on the land.