Eat local produce, save the earth?

Not necessarily, according to author James E. McWilliams. Locally produced food doesn't have to be transported great distances, but the increased resources required to produce it can place more strain on the environment than shipping it from the other side of the world:

...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.

These life-cycle measurements are causing environmentalists worldwide to rethink the logic of food miles. New Zealand’s most prominent environmental research organization, Landcare Research-Manaaki Whenua, explains that localism “is not always the most environmentally sound solution if more emissions are generated at other stages of the product life cycle than during transport.” The British government’s 2006 Food Industry Sustainability Strategy similarly seeks to consider the environmental costs “across the life cycle of the produce,” not just in transportation.

This doesn't mean we shouldn't buy local food, but it does show that even seemingly obvious ideas can have unintended consequences.

Damian P.

Posted by damian at August 23, 2007 11:18 AM