[telchar]

The important point is that animal agriculture is calorically inefficient, so much more land has to be used than if people could substitute plant-based food sources for animal-based. Much of plant agriculture today is only necessary to feed animals. Some animals could probably still be fed with plant agriculture byproducts if little to no land were directly used only for raising animals, but far fewer than are currently raised.

And many grasslands that cannot be sustainably be used for crops could be returned to wilderness rather than plant agriculture, if we were to increase caloric efficiency of food production. They probably should be, in fact. This doesn't preclude some animals being raised, but if we don't greatly reduce the amount of land used for raising animals, deforestation, desertification and other harms will continue to degrade ecosystems.