I'd imagine that you are all aware of the tremendous decreases in energy use, water pollution and carbon emissions that go along with vegetarian and vegan eating patterns. However, I am curious about whether your choices to be vegetarian or vegan are tied to a moral objection to imprisoning and killing animals - or only to human health and pollution concerns.
In my case, one of my motivations is the sense that other animals have a right to live according to their nature and that humans don't have the moral right to interfere with that - absent an overwhelming necessity. For example, there are people who live in harsh environments where it may not be feasible to grow plants. However, in our current culture, meat production is destroying our environment and our health - and is obviously not only unnecessary, but destructive.
Since we all have a strong interest in the cessation of factory farming and the insane cruelty of practices such as hatching millions of baby chicks only to have the male chicks tossed into chippers (grinding machines) because they aren't as valuable as potential hens - who will be debeaked and forced to lay eggs under barbaric conditions, etc. More than that, however, is another moral outrage. When we treat other animals without compassion or humanity, we distort our own moral compasses.
For example, chimpanzees and other human cousins are very much like us. They are motivated by essentially the same things that motivate humans - love and security, group acceptance and compassion. Can we not say the same about any other animal? Are we really so different? Perhaps, if we truly understood our tremendous similarity to apes, we would finally protect them from exploitation and cruelty by humans. And this compassion could spread to the ways in which we see other species - as our relatives - rather than disposable goods.
If you'd like to interact further on this topic, please respond here, and join the "Human Primates" group on Ode.
Peace,
Earon