More than food miles

I was discussing the relative merits of buying local food vs. food that's shipped or flown in with some of the guys at work. My position, which I expressed poorly, was that often the economies of scale or comparative advantage overwhelm the carbon produced by the shipping process meaning that its often better (i.e. more environmentally friendly) to buy food that was grown overseas and flown or shipped in. Fortuitously, I stumbled across this recent NY Times article (via Cafe Hayek) which argues the point far more effectively than I did.

It all depends on how you wield the carbon calculator. Instead of measuring a product's carbon footprint through food miles alone, the Lincoln University scientists expanded their equations to include other energy-consuming aspects of production — what economists call "factor inputs and externalities" — like water use, harvesting techniques, fertilizer outlays, renewable energy applications, means of transportation (and the kind of fuel used), the amount of carbon dioxide absorbed during photosynthesis, disposal of packaging, storage procedures and dozens of other cultivation inputs.

Incorporating these measurements into their assessments, scientists reached surprising conclusions. Most notably, they found that lamb raised on New Zealand's clover-choked pastures and shipped 11,000 miles by boat to Britain produced 1,520 pounds of carbon dioxide emissions per ton while British lamb produced 6,280 pounds of carbon dioxide per ton, in part because poorer British pastures force farmers to use feed. In other words, it is four times more energy-efficient for Londoners to buy lamb imported from the other side of the world than to buy it from a producer in their backyard. Similar figures were found for dairy products and fruit.

Admittedly the research is from NZ scientists comparing NZ products to English products so there is room for bias but the point remains. Its not as simple as tallying up the carbon emitted in transporting the produce from where it was grown to where its being consumed. There are a range of other carbon emissions involved (other than transport) not to mention the fact that local small scale growers are likely to use less efficient and more carbon emission producing means of production. How clear is it that carbon emissions are really so bad anyway?