That's Great, But How Do You Feed 7 Billion People?

Sustainable agriculture in action:

Salatin, the high priest of "grass-farming," as he defines his work, hosts a field day every three years on his 550-acre spread in Swope, Virginia, in the hills of the Shenandoah Valley. Visitors have come from as far away as Florida and Iowa to trudge through the thick, soft pastures and see how Salatin raises cows, chickens, pigs, rabbits, and poultry. It is a brilliant sunny day, warm already at 8 a.m. on a Saturday.

Walking up a gentle slope, we come upon a herd of cows "mobbed" under a shady canopy, nibbling grass and depositing patties of natural fertilizer in the acre-or-so where they have been herded for the day. Tomorrow the white plastic electric fence—so thin it is hard to see in the brilliant sunlight—will be moved, the cows transferred to a new paddock so they can feast on a fresh "salad bar." Nearby, the chickens, in their big, floorless, corrugated tin-and-mesh mobile playpens are pecking at the cow patties left by the previous day's mob, picking out the fly larvae, aiding the composting process. Like so much on the farm, it is a virtuous cycle, the cows and chickens working together to create the rich soil, grass, and insect ecosystem.

I don't have a problem with low-intensity agriculture, but meat production at the scale of consumption in the United States, almost has to be industrial.  The numbers are just too big.  Then the question becomes, if oil becomes scarce, can we feed 7 billion people?