Starvation history

In my neighborhood and book club crowd, a hot topic is food production. Everyone is all for local, organic, chemical-free food production and, accordingly, is anti-Cargill, anti-factory-farms, etc. (The StarTrib has been running a series on Cargill that I haven't read yet, but will.) I've read Michael Pollan's book, Omnivore's Dilemma, that advances the same philosophy towards food. The arguments are that our health and environment, perhaps even our souls, are compromised by "factory" food. I accept that that's true.

Nevertheless, the thing that's missing from Pollan's book and all the discussions I run into, is a quantitative analysis of whether the world's population could get its nutritional needs met without factory food. How many people would be starving either due to the absence of food or because it would be too expensive? Is there enough arable land on the planet for us each to grow the food we need in our backyard? Can Minnesotans each nothing but local food without getting scurvy?

Does anyone have any info you could point me to about the history of starvation and malnutrition, or a quantitative look at the feasibility of more holistic food production?