What is it with this modern obsession with not eating meat? Meat is good. It's healthy, it's very sustainable, it's got an incredible protein:volume ratio, and it's delicious.
"Food production requires application of fertilizers containing phosphorus, nitrogen and potassium on agricultural fields in order to sustain crop yields. However modern agriculture is dependent on phosphorus derived from phosphate rock, which is a non-renewable resource and current global reserves may be depleted in 50–100 years."
Raising animals to eat is a much less efficient use of non-renewable phosphate than eating plants ourselves.
Source: Dana Cordell, Jan-Olof Drangert, Stuart White. 2009. The story of phosphorus: Global food security and food for thought. Global Environmental Change, Volume 19, Issue 2, Pages 292-305.
http://www.sciencedirect.com/science/article/pii/S0959378008...