"Organic food travels farther than industrial food, so to put 1 calorie of California organic lettuce on a plate in New York City, he said, requires 56 calories of fossil-fuel energy. Such food may be 'technically organic but not really' because the method of its production and distribution is not sustainable.

If he had to make a choice, [Michael] Pollan said, he would therefore put locally grown over organic as a priority for food."

Link.