I am quite suspicious of any movement that decrees itself as the answer to a region's entire set of problems, and as a food activist, I am on record as being uneasy with terms like "urban ag" as I believe in regional ag which includes existing farmers and includes our hinterlands and waterways which also need to supply food for our beloved cities!
However, I love these quotes from the article linked below about Detroit's agricultural movement:
I asked her whether the city government would support large-scale urban agriculture. “City government is irrelevant,” she answered. “Positive change, leaps forward in the evolution of humankind do not start with governments. They start right here in our living rooms and kitchens. We are the leaders we are looking for.”
Detroit: Farming Paradise?