there's also dead oceans by 2048 which is the most pessimistic estimate.
but some numbers are fine.
the amount of land that is used for livestock is incomparable. water pollution, dead ocean zones, all caused by animal agriculture.
the amount of environmental destruction and pollution is incomparable. more than 90% of destroyed Amazon rainforest was for the sole reason of raising more livestock.
yeah, CO2 equivalent footprint might not be 51% but the oil industry does less environmental damage than animal agriculture. highest CO2 footprint isn't even cars and transport but heating and cooling.
(now whether this number is 51% or something else is another debate)
Also 51% because equivalent calculations are not done over the span of 100 years, but shorter (methane becomes more dominant) and deforestation is also accounted for - (which is both fine).
So it is somewhere in between the results of renovated studies that say it is around 31% (e.g. Tukker et al) and the 51% worldwatch report.
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.