There is a lot of information that goes into figuring out the environmental impact producing different kinds of proteins creates. One can look at what it takes to transport protein whether it comes from a local farm or if it is shipped from Brazil. Also consider the resources it takes to produce certain sources of proteins such as water usage for peanuts and compare that need to chicken. Does vegetarianism have a lighter environmental footprint than a person who consumes a large amount of meat? That depends on where their protein source is coming from and how well that facility manages their waste. This website gives a quick overview about proteins environmental impacts and makes general statements about what the average environmental impacts produced by different types of protein. This is a great reference article to help lower your environmental impact while still getting the necessary nutritional benefits from protein.