Friday, April 18, 2008


NEW SCIENTIST An analysis of the environmental toll of food production concludes that transportation is a mere drop in the carbon bucket. Foods such as beef and dairy make a far deeper impression on a consumer's carbon footprint. "If you have a certain type of diet that’s indicative of the American average, you're not going to do that much for climate while eating locally," says Christopher Weber, a researcher at Carnegie Mellon University in Pittsburgh who led a comprehensive audit of the greenhouse gas emissions of our meals.

His analysis included emissions such as transporting and producing fertilizer for crops, methane gas emitted by livestock, and food's journey to market. All told, that final step added up to just 4% of a food's greenhouse emissions, on average. But some items, particularly red meat, spewed out far more greenhouse gases than other foods, Weber and his colleague Scott Matthews found.

"It seems much easier to shift one day of my beef consumption a week to chicken or vegetables, than going through and eating only Jerusalem artichokes for three months in the winter," says Weber, a "vegetarian bordering on vegan." . . .

Food traveled an average of 1640 km in its final trip to the grocery store, out of total of 6760 km on the road for the raw ingredients. But some foods log more kilometers than others. Red meat averaged 20,400 km – just 1800 of those from final delivery.

Accounting for greenhouse gas emissions made those contrasts even starker. Final delivery "food-miles" make up just 1% of the greenhouse emissions of red meat, and 11% for fruits and vegetables.