Sometimes the obvious answer is not the right answer.

Among my favorite sources of news and perhaps among the least biased in any direction is the weekly digest of global news, The Week Magazine. I think the editor, William Falk, has a good handle on reality. the following is his brief editorial from the August 17, 2007 edition of the magazine:

"On my Saturday shopping excursions, I’ve noticed a change over at the Whole Foods. A new sign has popped up here and there amid the heirloom tomatoes, specialty cheeses and fresh roasted coffees, bearing the single virtuous word “local”. It’s a wonderful salve to the conscience: My fellow shoppers and I live amid such an embarrassment of abundance, yet simply by paying $4 for a head of local lettuce, we can do our part to save the planet from global warming. Or so it seemed, until some scientific spoilsports at Lincoln University in New Zealand ran all the numbers. To accurately calculate a products 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 in 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. Now, does this mean we can do nothing to slow global warming? No. It only means that the world is enormously complex, and that simple solutions to big problems – solutions that make us feel comforted and virtuous – are almost always illusionary."