Livestock mostly lives on soy and corn, things that humans can eat too (or, growing on lands that could produce human food). Some meat can be had in a sustainable way, animals are part of a sustainable agriculture as they can eat food waste or graze on low productivity (or recovering) lands, while naturally adding fertilizer to the soil. The current level of industrial meat production is quite far from that.
The idea that animals only eat food that humans can't consume is very strange. The animals get fed whatever is cheapest on the market, even if that involves burning the rainforest and depleting its soil permanently or feeding them skittles.
Our baseline should be what is required for a healthy body and brain. We can go up from there.
Going down from the current level is farcical. We're in a crisis.
I like me an avocado as much as the next person, but if they need a 500% tax (invented, I don't actually know) to incorporate externalities, they need it. End of.
Like, seriously. It doesn't matter what we "want" at this point. Carbon needs pricing or we are totally fucked.
