While the link between animal agriculture and environmental harm is well established, earlier studies used scientific modeling to reach those conclusions. By contrast, the Oxford research drew from the actual diets of 55,500 people — vegans, vegetarians, fish-eaters and meat-eaters — in the United Kingdom and used data from some 38,000 farms in 119 countries.
Open access Journal article published in Nature Food here: https://www.nature.com/articles/s43016-023-00795-w