Land Shortage


To raise not just livestock but their food takes up a lot of land. Overall one-third of the planet's arable land is occupied by livestock feed crop cultivation. 

Seventy percent of Brazil's deforested land is used as pasture, with feed crop cultivation occupying much of the remainder.

Sources:

http://science.time.com/2013/12/16/the-triple-whopper-environmental-impact-of-global-meat-production/

https://www.smithsonianmag.com/travel/is-the-livestock-industry-destroying-the-planet-11308007/

https://www.smithsonianmag.com/science-nature/beef-uses-ten-times-more-resources-poultry-dairy-eggs-pork-180952103/