| How much food per hectare can you get out of ruminants sustainably grazing on grassland? The table here indicates that beef yields 2.2 g/m^2 of protein, soybeans 40 g/m^2: https://en.wikipedia.org/wiki/Edible_protein_per_unit_area_o... Perhaps animal protein should get a quality factor bonus over vegetable protein. But even if it's twice as good as vegetable protein, that's still a much lower yield of effective-protein-per-acre. Is it enough for everyone? If people should be eating 60 grams of animal protein per day[1], and beef yields 2.2 grams/m^2/year, that's 60 * 365 / 2.2 = 9954 m^2 per person, or almost exactly one hectare. 0.9954 ha * 7.4 billion people = 74 million km^2 of pasture land required. According to the FAO, as of 2011 the world's total land used for agriculture was 49 million km^2. It looks like feeding everyone from beef grazing on grassland would require claiming significantly more of the planet's surface for agriculture. That makes intuitive sense too -- if grazing animals produced as much food per unit area as fertilized and irrigated plants tended with machines, farmers wouldn't have bought the fertilizers, irrigation, or machines in the first place. [1] You might set this number higher, since in other comments you have supported a low-carb, high-meat diet. |