Food Politics

I liked the idea in MPs article that foods could have a bar code that would tell you more about their environmental impact when you scanned it with a reader in your cell phone (or something like that). I would really like to have a way to compare all of the ways I could be helping the world (eating local, vs. organic, vs. lower on the food chain, etc.) so when I make choices, they are informed by the whole ‘cost’ of the items involved. I think this is impossible, but hope we can get closer. If there is a source of such comparisons, please post a link.