Final answer:
Eating a diet rich in legumes decreases water and land use, reduces the carbon footprint, and lowers methane emissions due to decreased livestock agriculture.
Step-by-step explanation:
The environmental impact of a diet where protein is sourced from legumes typically results in reduced water consumption, lower land usage, and a decreased carbon footprint. This is because legumes require less water and land compared to the resources needed for livestock agriculture. Additionally, shifting toward a legume-based diet can help decrease livestock agriculture, which is responsible for a significant portion of deforestation and environmental degradation. Livestock farming contributes to habitat loss, the build-up of greenhouse gases, soil erosion, and changes in rainfall patterns. It's important to note that through reduced livestock farming, there would likely be lower methane emissions as well, since livestock is a major source of this potent greenhouse gas.