Once again SM solves the world's biggest issues
To be fair... there is evidence out there to prove it would.
At this point, I'm going to say that I'm a meat eater!
In summary, for the pollution side of things:
Cows produce methane, which is bad.
Transporting feed to cows also produces pollution, which is bad.
On the hunger side of things:
Breeding cows to feed to people involves growing more than enough crops to feed every human on the planet.
You can't get more out than you put in though, so the cows get fed 9x as much food as they produce (become...) basically meaning people are starving elsewhere because there isn't enough food, because people want to eat meat.
Add to this that the population is growing, and we aren't freeing up more cow fields...
Much like the oil industry, the farming industry is worth rather a lot, and employs a massive amount of people. In the same way we won't see electric cars (or whatever the alternative ends up being) taking over overnight, something will happen eventually.