Just a quick note: The "Cowspiracy" movie unfortunately presents its case by cherry picking scientific evidence and presenting much higher numbers than what is reasonable. Wikipedia has something about it: https://en.wikipedia.org/wiki/Cowspiracy#Criticism
I recently saw that movie. Basically what the movie maker did was taking the highest number he could find and repeating it over and over again.
This is unfortunate, because the overall message is still very much true: Meat production causes a lot of greenhouse gas emissions and cutting them is a great opportunity. And NGOs are very reluctant to talk about it.