Cool article!<p>I have no idea on the true scalability of it to billions of people, but Havana is a good example of low-tech high-yield food production that helped out when lots of people were going hungry in Cuba after the Soviet Union collapsed.<p>A byproduct is that it's relatively labor-intensive to get high yield out of the small urban farms, thus providing extra good jobs.<p>Would be interesting to see if these kind of low-fi solutions could contribute meaningfully to the problem of feeding 9 billion people in the coming years...