Conversation Among Friends

To accurately calculate a product’s carbon impact, they found, you have to go beyond “food miles”—the distance that kiwi or artichoke-flecked sausage traveled before reaching your table—and figure in how much fertilizer, transported water, electricity, and other energy was used to produce it. Lamb raised on New Zealand’s sunnier, grassier hills and shipped 11,000 miles to Britain, the study found, produced a mere 1,520 pounds of carbon emissions per ton. “Local” British lamb, which requires more intensive care, produced 6,280 pounds—four times as much. As if that heresy were not upsetting enough, a British scientist has calculated that walking to the store contributes more to global warming than driving a car. Walking, it seems, burns calories, which have to be replaced by eating food. And producing food—especially beef and dairy products—is more carbon-intensive than burning a smidgen of gasoline, particularly since ruminating cattle emit so much methane.