[pclmulqdq]

Nothing said here refutes the parent comment. It turns out that a lot of land is really shitty for growing stuff that isn't a weed (without adding a ton of chemicals to the environment), and humans don't eat weeds. Cows, sheep, pigs, and chicken do.

I doubt that 86% of that 77% is truly unsuitable for farming human food, but I wouldn't be surprised if 30-50% of it was.

[bennettdams]

It is naive to believe that these 86%, assuming the numbers are true, have any impact on the food production at all.

Of all the cropland we have, 57% is used to produce human food and 43% is used to produce animal food.

https://ourworldindata.org/land-use-diets#more-plant-based-d...

The whole point is that you need way more crops in general to "produce" the same amount of calories & proteins. That's because feeding the animals with crops instead of eating them is highly inefficient in comparison to eating them directly. "As an example: beef has an energy efficiency of about 2%. This means that for every 100 kilocalories you feed a cow, you only get 2 kilocalories of beef back."

https://ourworldindata.org/land-use-diets#livestock-waste-a-...

With how much meat is eaten right now, there is just no way we have enough grazing land to produce enough meat. 99% of meat comes from factory farms. [1] These animals are always fed with crops, so there will always be land usage to product food for animals. And it is way more inefficient.

[1]: https://www.livekindly.com/99-animal-products-factory-farms/

[pclmulqdq]

The implicit assumption that you are making is that all cropland is fungible and that the 43% used for animal food can be converted directly to human food. That is almost certainly not the case. Also, the original comment's 86% doesn't imply that it is necessarily "cropland" - just that it is land that grows animal feed.

You see this with human crops too - Why do people grow corn when almonds are much higher dollar value per acre? Why not wine grapes? The reason is because not every patch of land is suitable for high-value cash crops. Going down the quality scale, not every patch of land is suitable for food for human consumption either. The reason why is that "cropland" is not fungible - soil has particular characteristics, nutrients, contaminants, and microorganisms, all of which affect which crops you can grow.