Wolves that eat deer don't also breed them to the point where they contribute to climate change. Hunter gatherer folk don't breed them to a point where they are a significant factor in climate change.
As carnivores wolves don't really have a choice to not eat meat. You do, though. With a couple of different choices at the supermarket or simply ordering different choices on the menu, you can help cut down our global emissions.
It's now illegal in USA.
https://www.usatoday.com/story/news/politics/2018/09/13/eati...
Though I don't think it should be illegal unless slaughtering other animals is illegal too. I think our disgust with the idea of slaughtering dogs highlights our arbitrary ethical inconsistencies when it comes to eating meat.
Hunter gatherers ended up doing that once they figured it out. Civilization didn't magical come about. Hunter gatherers decided to start animal husbandry as a way to keep a surplus food supply. Then they became "civilized".
I heard that choice arguement before. No. I've done the vegan diet for about 1.5 years. That's when depression, anxiety, bone and muscle problems popped up. My bloodwork was shit and I felt like doom and gloom. I snuck off from my girlfriend, who forced me into it, with a friend and he peer pressured me to drink a glass of milk and eat a steak. I did shit myself silly that night, but it felt like I was actually awake and the brain fog was gone. We broke up a few months later because I made a lovely red thai curry with murdered chicken instead of tofu.
By the way, look up how many ground nesting birds and rabbits die during grain and soybean harvesting. Those combines are just pure murder.
Don't you think the current age of high depression and high anxiety is oddly correlated to the recent rise of "meat bad, tofu good", is a bit interesting? So no, I don't have a choice. From personal experience. Difference is, I never made existential excuses for the depression, anxiety, fatigue and brain fog. I did it for tail...which really wasn't worth it.
Most soybeans grown are consumed by livestock [0]. A lot of wheat is also fed to livestock [1]. We'd need a lot less if we as humans ate it directly instead of eating the animals that eat it.
I don't know what your diet was like, but this is not my experience (7 years in), and it is the position of the American Dietetic Association that vegan diets, when planned well, are healthy [2].
Now, let's say that even with good planning, you are still unhealthy on a vegan diet. That does not mean you couldn't be healthy on a vegetarian diet, or a diet that has drastically reduced meat consumption. The less meat we eat, the better for the environment.
[0] https://www.drovers.com/article/usb-promotes-us-soybean-meal...
[1] https://news.cornell.edu/stories/1997/08/us-could-feed-800-m...