There's currently a propaganda war between multiple powerful lobbies - the animal rights lobby, the meat producers, conventional ag producers, and more - which means there is a ton of misinformation flying around about the actual environmental impacts of eating meat. Really, of all things dietary.
Meanwhile there are a bunch of people exploring alternate agriculture systems through agroecological approaches that show a lot of promise, but haven't been studied enough to really make claims about either way.
Further, you cannot just say "x amount of finished beef produces y emissions" because there are so many factors that go into it. Feedlot vs traditional range vs intensive rotational vs silvopasture are all different with completely different environmental impacts - of which carbon is only one.
> An all grass cow-calf – to – finish operation was included as a minor component in the eastern and northwestern regions
They examined a single all grass finished operation. There are studies that have found grass finishing can cut emissions in cattle by as much as 80%.
> The modeled operations were not intended to be actual operations; they were developed to represent the practices found in each region.
> Environmental footprints for all individually simulated ranch and feedlot operations were integrated into full production systems within their respective study regions using two methods
They also don't appear to be measuring actual operations, but rather modeling operations based on surveys of farmers and ranchers about the characteristics of their operations and then extrapolating from there.
Models have their place for sure, but I wouldn't make any kind of declaration of certainty based on a single model-based study. You have to average the outputs of hundreds or thousands of models, and even then, you can't be sure you have the answer.
A better approach would be one that measures the actual output of each operation at various phases and averages across them. Difficult to do, but I've seen studies that attempted it.
