Over on Forbes.com, I write:
…the most reasonable judgment is that flying fresh food around the planet carries an environmental cost of no more than a few cents per meal. That sounds astonishing, but perhaps it shouldn’t be. Those Chilean grapes aren’t flying first class: They’re packed tight to save money, which incidentally saves on pollution. The most wasteful part of the journey is when you and I hop in our cars and drive to the shops and back with a bag of potato chips in the trunk of the car.
You can read the whole thing here; the Forbes piece also contains links to the research.