A trend that has recently gained notice, despite having been around a while, is the move to increase reliance on locally grown food. In the past, the case made for the practice has largely focused on support of local farmers, the sense of knowing more about what you're eating, as well as nutritional value because the local produce is frequently also organically grown.
A more recent argument in favor of the practice relates to the transportation cost for the food we eat. If we buy local, the reasoning goes, it takes less fuel to transport the food from grower to market. This reduces energy costs and carbon footprint.
Now, I've seen other discussions that indicate the cost of transportation per unit of food (per pound, per ton, or whatever) is actually less because of the huge amounts moved and the types of transportation (not every product is transported every mile by truck), but articles have tended to be one side or the other.
This article from The Carnegie Council is one of the better ones I've run across. The article balances local issues against global issues and speaks about the opportunity cost of our choices. In fact, it is the framing of the choices that makes the article so interesting and compelling for me. It frames the choices this way:
1) Think globally, buy locally.There are, of course, other choices (although #4 includes every option, as far as I can tell). But the choices speak to the idea that each of us needs to be free to pursue our own priorities when making our choices. But as long as we're aware of the impact of our choices, both locally and globally, we can better recognize the opportunity cost. And that makes for more informed decisions.
2) Buy local when you can, import when you must
3) Buy local if you can afford to, let others buy imported food
4) Buy what you want
I think you could engage students down to the upper elementary grades in this discussion, focusing on choices, opportunity cost, and interdependence. If you did this at the middle and high school level, you could focus on interdependence, trade, economic development and world poverty. Regardless, when you put the topics into a food context, you can get attention.
I look forward to your comments.