One of your typical long-haulers.

Is long-distance better than local?

Attention farmers’ market shoppers: Put that heirloom tomato down and rush to the nearest supermarket.

By seeking local food, you’re wantonly spewing carbon into the atmosphere.

That’s the message of a budding backlash against the eat-local movement. The Economist fired a shotgun-style opening salvo last December, peppering what it called the “ethical foods movement” with a broad-spectrum critique.

Among the claims: organic agriculture consumes more energy than conventional, and food bought from nearby sources often creates more greenhouse-gas emissions than food hauled in from long distances. (Here was my response to that influential piece).

More recently, in a New York Times op-ed piece, the historian James E. McWilliams sought to debunk the idea that choosing locally produced food automatically decreases one’s carbon footprint. He warns that efforts to reduce “food-miles” — the distance between farm and plate — might actually support higher carbon emissions at the source. And in Britain, a debate over whether to withdraw organic certification from African imports based on their transportation impact has spurred coverage of the issue as well.

In a sense, these high-profile rebukes are good news: they herald the arrival of the sustainable-food movement as a pop-culture phenomenon. Just as you’re not really famous until you’ve been rumored to be gay or on drugs, a movement hasn’t come into its own until it’s drawn a formidable entourage of detractors.

A decade ago, few would have thought to analyze the efforts of eat-local zealots. But now, farmers’ markets are booming, celebrity chefs are proudly decorating their menus with the names of nearby farms, and a steady stream of best-sellers is urging us to “come home to eat” (to paraphrase the title of Gary Paul Nabhan’s popular 2001 book).

That surge has earned attention both positive and negative, and landed local-food advocates in a valuable position. By sniffing out easy sloganeering, a movement’s critics can help it hone and deepen its analysis — and reach the next level of acceptance.

Farm-to-Plate Tectonics

So how to respond to these critiques?

First of all, it’s important to understand the context in which they come. The sustainable-food movement’s achievements have thus far been largely cultural. In other words, despite all the attention from celebrity chefs, best-selling authors, and, ahem, environmental webzine columnists, the vast bulk of food consumed in this country still travels gargantuan distances, consumes unspeakable amounts of fossil fuel in its production and distribution, and leans heavily on poisons and water-polluting artificial fertilizers.

Way back in 1969, the U.S. Department of Defense performed what remains the only comprehensive nationwide study of the average distance food travels from farm to plate. The study’s estimate, 1,200 miles, probably falls well short of the current mark.

Why? Because food imports are rising at a stunning pace. According to the USDA, the dollar value of U.S. food imports doubled [Excel] between 1999 and 2006. Over the same period, exports rose nearly as fast.

In short, while we “locavores” strive to minimize food-miles, and critics chide us for the effort, food continues to zip across the U.S. borders, gushing in from, and flowing out to, points all across the globe.

And while the sustainable-food movement’s power may be causing vapors within the pages of the Economist and the New York Times op-ed page, Wall Street hasn’t gotten the memo. In the stock exchanges, shares in agribiz powerhouses Monsanto, Archer Daniels Midland, John Deere, Smithfield, and Tyson are all trading at or near all-time highs. That means that the “smart money” isn’t quite as impressed by the rise of buy-local campaigns as commentators on either side of the food-miles debate are. For unsentimental investors, the profit prospects for industrialized agriculture, geared for long-haul distribution, are rosier than ever.

Miles to Go

So food-miles are likely adding up at an accelerating rate, and may well continue to do so. Is that so bad? Not in the eyes of some. McWilliams makes the case that we should forget food-miles and focus instead on lifecycle analysis — accounting for not just distribution, but also for energy burned in growing food.

This eminently reasonable insight leads him to a startling claim: that locally grown food under certain conditions burns more energy, and leads to higher greenhouse-gas emissions, than food produced thousands of miles away. Echoing The Economist, McWilliams trots out a recent study claiming to show that green-minded U.K. consumers should spurn locally grown lamb in favor of lamb grown in distant New Zealand.

Why? Because according to the study, “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.”

To McWilliams, the message is clear: U.K. residents should buy more New Zealand lamb, and reject local product. But over on Ethicurean, Small-Mart Revolution author Michael Shuman raises a key point about the study: it compares conventionally grown, feed-reliant U.K. lamb with lamb raised in New Zealand, where all lamb is grown on pasture.

But pasture-based organic U.K. lamb exists and is available. Wouldn’t buying that be the greener option for U.K. consumers? The study doesn’t comment on this option — perhaps because, as Shuman points out, its authors are funded by New Zealand agribusiness interests that rely on export markets.

Act Locally, Think Regionally

What often arises in the food-miles debate, I think, is a false dichotomy: local vs. long distance. But the most attractive model might be a regional one. McWilliams touches on it, albeit vaguely, with a mention of a “hub-and-spoke system of food production and distribution.” Crucially, he clings to the notion that Western consumers can continue to commandeer the globe’s bounty perpetually, season be damned.

“Consumers living in developed nations will, for better or worse, always demand choices beyond what the season has to offer,” he declares confidently, even though such choices have existed all of, say, 40 years.

At any rate, what could such a robust regional system look like?

Take North Carolina, where I live and help run a farm. The state stretches nearly 400 miles east to west, encompassing relatively cool Appalachian highlands and blistering-hot eastern lowlands. Orthodox “locavores” in either region commit themselves to various year-round privations: many vegetables wilt (or require heavy irrigation) in the eastern summers, and can’t survive cold highland winters. But I like any idea that pushes local-food advocates beyond arbitrary constructions such as “100-mile” diets.

Currently, most supermarkets across the state tap into global production networks that rely on long-haul travel. But ideally, North Carolinians could eat regionally year-round if we organized to leverage these regional differences. What if the west provided the bulk of the state’s food production in the summer months, and the east did so in the cold months?

To do so with any reasonable amount of environmental responsibility, we’d have to reject the temptation to transport food up and down the mountains in diesel-guzzling, highway-hogging 18-wheelers. Rather, as Rich Pirog of Iowa State University’s Leopold Center for Sustainable Agriculture recently told me, “If we want regional food systems to be energy-efficient, we have to reinvest in rail infrastructure.”

Pirog, who probably counts as the nation’s most rigorous analyst of food-miles, told me that as recently as 1980, trains accounted for fully half of food transport in the United States. By 1997, following a period of low petroleum prices and steady decay of rail systems, just 13 percent of food traveled on trains. Trucks hauled the other 87 percent.

Thus rebuilding regional food networks — presumably what McWilliams means by “strengthen[ing] comparative geographical advantages” — requires something that critics of the eat-local movement rarely advocate: reinvestment in food-production and distribution infrastructure designed for something beyond maximizing agribusiness profit.

Such a regional conception requires not a rejection of the eat-local ethic, but rather a broadening of it.

Contra industrial-agriculture dogma — implicitly echoed by McWilliams and other eat-local critics — we’d still have to relearn the skill of thriving within the physical limits of relatively nearby landscapes. And we’d still have to think seriously about hard questions posed by Wendell Berry: “What will nature permit me to do here without damage to herself or to me? What will nature help me to do here?”