EDIT, with a relevant source for context:
Since 1940, an estimated 50% of zoonotic disease emergence has been associated with agriculture (1–3). This estimate, however, is necessarily conservative because only direct agricultural drivers are considered in the epidemiological literature, i.e., within the farm gat
[…]
The intensification of animal agriculture through confinement and industrialization has directly led to the emergence of viruses including Nipah and H5N1 influenza (“swine flu”) (18) and antibiotic-resistant infectious bacteria including methicillin-resistant Staphylococcus aureus and Escherichia coli (19, 20).
Hmm well for one thing you can pollute more to make up for your smaller environmental footprint on a vegan diet, maybe get some trash fires going in the backyard, throw plastic in the ocean, that sort of thing, and then maybe watch dog fights and buy stocks in animal ag companies to help them lobby to subsidize torturing unimaginable numbers of animals?