I heard something to do with Nitrogen and …cow farts(?) I am really unsure of this and would like to learn more.
Answer -
4 Parts
- Ethical reason for consuming animals
 - Methane produced by cows are a harmful greenhouse gas which is contributing to our current climate crisis
 - Health Reasons - there is convincing evidence that processed meats cause cancer
 - it takes a lot more calories of plant food to produce the calories we would consume from the meat.
 
Details about the answers are in the comments


It’s a false choice. Land not used for grazing could be rewilded, which provides benefits in both biodiversity and carbon fixing.