For the methane issue. Apparently adding seaweed to their feed reduces that by up to 82%:

https://caes.ucdavis.edu/news/feeding-cattle-seaweed-reduces-their-greenhouse-gas-emissions-82-percent

people have lots of different reasons. some don't like the idea of killing a big animal with feelings and expressiveness. some because of how farms abuse or torture animals in some countries. some think Anibal farming is worse for the environment. some have religious prohibitions. some think it's bad for your health. some people don't like the taste or can't afford it but don't want people to think they are weird so they tell people they have a principled argument for it.

I guess my only follow up would be that if we reduce our meat consumption to a more sustainable level, that would mean that we would have to replace our protein source with something more sustainable.

Seafood maybe out of the question as I hear concerns about overfishing as it is.

I would assume that would leave plant protein, like Peanuts or something similar. Are there other sources of protein that are in development (Also major assumption that Beyond and those other meats are also based on the plant protein)

Thanks everyone for the answers, I will update the post to add in the answer.

Different vegetarians have different motives. Some of the more common ones include:

• Moral concerns, e.g. about animals suffering or being killed. This is common among Buddhist vegetarians, animal-rights vegetarians, and utilitarian vegetarians.
• Health concerns; belief that a vegetarian diet is better for one's health, whether due to substances naturally in meat (e.g. saturated fat) or introduced by industrial meat production.
• Environment and climate concerns; that raising animals for meat is bad for the environment, contributes to climate change, is unsustainable, etc.