Here's some numbers from a peer-reviewed analysis from 2018[0]:
> The new analysis shows that while meat and dairy provide just 18% of calories and 37% of protein, it uses the vast majority – 83% – of farmland and produces 60% of agriculture’s greenhouse gas emissions.
I know I was responding to a specific comment about land usage, but I probably wouldn't read that book as I also believe that we should prevent unnecessary pain and suffering, e.g. even if we hypothetically found out that the smoke from the ovens in concentration camps didn't contribute significantly to air pollution, they still wouldn't be a good idea, so of course I object to a book that describes ongoing mass killings as "benign".
But if you have the specific numbers from the book handy, I'd still like to give them a look.