When scientists take all the complex factors into account and do the sums it turns out that in general plant-based foods are still far more sustainable than livestock, e.g. https://theconversation.com/climate-explained-how-the-climat...
Simplest example: Beyond meat is 2-4x the price of meat.
It seems pretty clear that switching away from protein sources like lamb and cows in favor of pork and chicken is carbon-positive.
There's likely an optimal level of meat consumption. Unfortunately most of our information comes from either an industry and farmers dependent on our continued meat consumption, or dishonest vegan evangelists.
Being a small share of the population doesn't mean they're invisible or silent. Here on the UK my leftist self that far too often reads the Guardian, one of the biggest newspaper in the nation, there's many times a week an article advocating the vegan diet. One of the two resident recipe writers only prints vegan recipes. I'm pretty sure it's newspaper policy never to print any diet related news that's not vegan-favourable, I guess it's their way of "changing the world". It's conquered a large part of the popular opinion, even though as you suggest the percentage of actual vegans might be very small.
As a meat eater that is non indifferent to the ecological issues we're facing, and believes the vegan diet NOT to be the answer, I would appreciate a more educated and reasoned approach to a hairy question than the constant evangelizing and ignorant repetition of meat bad, vegan good.
We developed a vaccine against Covid in less than two years, which we previously thought to be impossible to do.
If we really tried, the problems you mentioned would have a sizable chance of being solved.
Michellin apparently already makes "vegan" tyres. Even for cat food, there are already vegan supplements and the science will improve. Beyond Meat being only 2x the price of killed meat is I think quite impressive when you consider how long each industry has had to optimise.
Yes switching from cows to chickens is better with regards to carbon but the problem is it's much worse with regards to animal welfare since many more animals need to be killed per kilo of meat..
There could be an optimal level of meat consumption if you just consider the environment, but it's far below what we're doing now, and given the urgent climate action that's recommended by expert scientists, it seems wise to reduce this consumption as much as possible. We're _far_ more likely to reduce too slowly than too quickly..
Just going to go out on a limb and say the optimal level is probably less than the typical North American or European diet... Societies that are more resource constrained eat a lot less meat.
They also lag the life expectancy curve by about 10 years. There are a lot of factors at play obviously, but the universal trend is richer countries have better medical care, education, and more complete diets.