Their results show that transportation accounts for only 11 percent of the carbon emissions caused by food production. Of that amount, so-called upstream transportation of inputs to the farm (or to farm suppliers) accounts for some seven percent of overall food-related transportation emissions. Most notably, perhaps, final delivery—the trip from the farm to the supermarket—accounts for just 4 percent of total food emissions on average. By comparison, production of the food accounts for 83 percent of the carbon emissions, with warehousing and wholesale and retail operations making up the small remainder.

An extreme example of this effect can be seen in farm products shipped to Europe or the United States from New Zealand. Several New Zealand researchers crunched the numbers to show that the carbon emissions from producing and delivering lamb, apples, and dairy products from New Zealand to the United Kingdom were actually lower than the emissions from the same foods produced locally in the United Kingdom. Why? The study no doubt sought to put New Zealand goods in the best possible light, but the numbers are still compelling: As these researchers demonstrated, not only do New Zealand farmers use less chemical fertilizer than their British counterparts, but also more than half of New Zealand's electricity derives from hydropower, which produces no carbon emissions. Those two differences, as it turns out, are enough to offset the emissions from 11,000 miles of ocean shipping.