Where the ballpark is a good starting question. Is a cow better or worse compared to artificial fertilizers? Looking at the devastation caused by run-off from farms in the baltic ocean, there is a man made underwater desert that is constantly growing with the current size of approximately 100,000 km2. Those dead zones (as they are called), lead to massive death of all aquatic organisms.

If we talking about fairness, food should be sustainable and not causing massive harm to the environment. That seems however to be outside the ballpark of what people consider possible. The question is then where we should start.