I've been in Moscow and Paris this week and urban agriculture is on my mind.

In the neighborhood of Montmartre, the street fronts are jammed with tiny fresh vegetables stands, fruit stores, butchers, cheese stores ... you get the picture.

(It's one of the small perks of a travel schedule that has me spending far too many nights on airplanes.)

The thing that's striking about all of these little shops is how local they are. I have often paraphrased former House Speaker Tip O'Neill: "All sustainability is local" -- and we can see it here in spades. But even here in France, the home of the artisanal cheese maker, drives for standardization and industrialization in the food industry provide countervailing pressures on the also growing locavore and slow food trends.

During my undergraduate studies, I was taking extensive courses in urban studies as well as environmental studies, which, at the time, seemed a bit contradictory. My thinking was and continues to be that we need a lot less urban in the environment and a lot more environment in the urban.

There is a hot new term in the local sustainability vocabulary, "terroir," which is a French term that essentially means "local bioregion." As urban areas spread out, covering the surrounding terroir, it seems to me that the terroir needs to cover back, of course, with the help of a few friends. Clearly, designers' treatment of roofs has received far less attention than the vertical surfaces so far. However, I am seeing strong signs that this is changing rapidly.

We are seeing an explosion of urban gardening both indoor and outdoor, horizontal and vertical, in the last couple of years. Innovative projects like the integrated fish and vegetable farm complex run by Sweet Water Organics, which took over an abandoned factory in Milwaukee and now supplies organic vegetables and seafood to the Milwaukee area. Rooftop farms like The Grange in Brooklyn and the indoor "Green Machine" wall, developed by Bronx Discovery High School teacher Steve Ritz  and Boston's Green Living Technologies' George Irwin as a way for students to not only learn about their own food, but also to empower themselves through the earning power of vegetable sales -- I was surprised to see how much money the fresh vegetables from these classroom walls could earn over the course of a year.