Is there that much available farm land in the world fit for agriculture? I attempted to find out via the USDA's very helpful resource but could not distinguish between low value farmland and high value farmland, low being the stuff we currently grow to feed animals.

Farming meat tends to lead to a higher land use footprint, but of lower value land which usually won't support the kinds of crops humans would eat. I'm open to the possibility that we could conceivably grow that much beans and grains as they're pretty versatile crops, but I have doubts as to the current availability of high value land and how much of this land would be needed to replace the diets of all meat eaters in the world. The ranch land lost would not be fit for agriculture in most instances.

While many vegetarian diets might be sustainable for a world level population, so are some meat inclusive diets.

All in all researching this has further opened my eyes to a few things. The first is the efficiency of land use standard agriculture has over ranching. The second is the continued absurdity of some vegan groups and their lobbying campaigns. I can't believe they honestly think that by increasing and subsidizing the supply of soy they will increase demand.

In the end I conclude that the world could not support several billion vegans. Too much whining. Not to mention, any non-vegan among the majority would surely go mad with meat lust and begin eating his or her peers.