Arguably, Al Gore's greatest contribution to America has been his commitment to bring awareness to the potential environmental threat of global warming.

Nearly three years later, are Americans any wiser right now about their carbon footprint (the amount of carbon dioxide produced by a business, organization or human being over a given time)? Most Americans still don't think much about footprints, other than the muddy ones they track through their homes.

This interesting article from OPEN Forum, however, explains how folks can have a greater impact on the environment -- more than owning a hybrid car or replacing incandescent light bulbs with energy-saving bulbs in their homes -- just by rethinking how and where they get their food as well as disposing of it through sustainable food systems.

But that's the huge quandary: How does America create the space, particularly in urban areas, for sustainable food production? Perhaps, the blueprints being formulated by one entrepreneur hoping to revitalize Detroit (considered the American poster child for shrinking postindustrial cities) to create the world's largest urban farm offer a possible solution.

While you're mulling over the idea of an apple orchard growing next to your home, determine your own carbon footprint with the help of this awesome calculator sponsored by The Nature Conservancy.

Assignment Detroit/CNNMoney.com December 29, 2009

OPEN Forum December 18, 2009