We would need to expand the cropland growing food for humans, yes. But there is a lot of cropland currently growing types of corn and hay that we as humans can’t eat, just so we can feed animals and get a less than 20% return on calories from the ‘food’ we get when we eat animal muscle and organs.

Which is why our total crop land use would go down if we didn’t eat animals: we need less space to grow calories and nutrients for us that we do to feed the animals we eat. So much gets wasted with the current process that it is unsustainable, and we need to start shifting this now to avoid running into severe land and water deficiencies with the changing climate.

Or we can use it as compost, which we should be moving towards producing and using instead of manure as fertilizer for a lot of our agriculture. That way it doesn’t go to waste even if it does get ‘thrown out’.