I'm gonna go out on a limb and bet the study grossly underestimates how much more fertilizer would be required to turn pasture into cropland, as pasture is norm

I'm gonna go out on a limb and bet the study grossly underestimates how much more fertilizer would be required to turn pasture into cropland, as pasture is normally far less suitable to cropland, and thus is used as pasture. Not that there is a need to convert very much of that land to cropland - corn and wheat produce far more food per acre than livestock. Most or all of that land would turn back into wilderness and we'd all die in car wrecks from the millions more deer crossing the roads.