I know, I know, we just want to grow some good tomatoes, not necessarily change the world! But that’s the wonderfully insidious thing about food gardening. It creeps in and takes us places we didn’t expect to go. Consider garbage, for instance. You will know that you are garden-obsessed when you begin to scout your neighborhood on garbage day looking for bags of dead leaves. (You can never have too many leaves for mulching purposes, leaves for leaf-mold production, leaves for compost-making.) From there, it’s not too much of a conceptual leap to wonder: why is my city wasting this precious resource, sending leaves to the dump? Or, for those of us lucky enough to live in a city that already composts organic waste, to ask the questions: is the compost my city produces of high-enough quality to use on my food garden, and if not, why not, and does the city make this compost readily available to any gardener who wants some?
In sometimes subtle, sometimes declarative ways, the food garden takes us to politics. We may not acknowledge it as such (I am just growing tomatoes!), and there’s no imperative in the equation that says we must consider it in such terms, but politics hovers around the edges of urban food production.
And sometimes front and center. Ten years ago, one rarely heard the term “food miles.” Now, the large U.K. supermarket chain Tesco labels some of its products with carbon footprint figures, showing how many grams of carbon were emitted as a result of growing, manufacturing, transporting, and storing the product. In a relatively short time, we have begun to add greenhouse gas emissions to the mental ledger on which we do the accounting for our decisions. The focus of our guilt seems to shift regularly. One year it’s SUVs people apologize for (if they own one) or deplore (if they don’t). Another year it’s airplane travel in the shame spotlight, relegated to the status of carbon indulgence the planet can no longer afford.
While a guilty conscience is a great motivator, and awareness of the impact of our choices is always good, I wonder if we’re not in danger of missing the bigger picture when we focus exclusively on the personal. By all means consider whether or not each and every car trip is necessary, but walking or biking or taking the bus to the store won’t change the fact that the items for sale at that store got there through a system based on globalization, centralization, and concentration. As writer and food-policy expert Wayne Roberts has pointed out, so much of the current focus on “buy local” downloads the responsibility (and the guilt) to the consumer, yet the system itself—a system of government and corporate policies—does little to support, and meaningfully supply, consumer desire for the local.
Nowhere are the carbon costs of such a system more clustered and readily locatable than at the food store. According to the United Nations Food and Agriculture Organization (FAO), agriculture, along with deforestation and land-use changes related to agriculture, generates, globally, one-third of the total man-made emissions of greenhouse gases, including one-half of methane emissions and three-quarters of nitrous oxide emissions. That’s a lot of belching cows and a lot of nitrogen fertilizers. Indeed, the UN calculates that animal farming alone accounts for more greenhouse gas emissions (almost one-fifth) than all the cars, trucks, and planes in the world combined.
Well, we gotta eat. But we don’t need to eat a globalized, centralized, and corporately concentrated menu. And if we didn’t, the food-miles portion of the greenhouse-gas-emissions pie, as it relates to agriculture, would be a significantly smaller slice. There are researchers who spend their days calculating such things (Just as there are researchers who spend their days complicating the calculations with “what if’s,” “but’s,” and “have you thought of that’s”). Given that the distance food travels has been steadily increasing for the past fifty years, what they’ve found is hardly surprising, but what they’ve now calculated is how that distance translates into atmospheric emissions.
Marc Xuereb, a public health planner with the Region of Waterloo Public Health department in Ontario, conducted a study, published in 2005, that looked at fifty-eight commonly eaten imported foods, all of which could be grown or raised in Waterloo Region. The study found that the imported items traveled almost 4,500 kilometers on average to reach the dinner tables of that southern Ontario city, producing through transit 51,709 tonnes of greenhouse gas emissions annually (5.9 percent of the greenhouse gas emissions generated by households in the region). The report notes that this is equivalent to more than a quarter tonne per household, or more than 16,000 cars on the road. The study also calculated how the emissions would compare if the imported items were instead sourced locally or regionally, from within a 30-kilometer radius. Under that scenario, greenhouse gas emissions were reduced by almost 99 percent—from 51,709 tonnes for the imported items to 2,224 tonnes for the local items, a savings of 49,485 tonnes. (Even within a distance of 250 kilometers, the local items represented savings, in greenhouse gas emissions, of 96 percent.)
Other studies bring these numbers down to dinner-plate level. The Toronto nonprofit organization FoodShare, for example, went on two shopping trips in 2003 for the ingredients of a typical meal (lamb chops, sweet potatoes, Swiss chard, carrots, salad, and fruit): one trip to a farmers’ market and the other to a supermarket. Using the product labels to compare the origins of the food, they found that the supermarket items traveled, on average, eighty-one times farther than the farmers’ market items. They calculated that a year of choosing local over imported foods would save a half-tonne of greenhouse gas emissions per household.
Of course, such comparisons carry all the practical deficiencies of any ecological footprint analysis. Things are just too complicated for any straightforward calculation to take all the variables into account. And how far back in the complex chain of production can researchers—should researchers—go anyway? While it’s clear that in terms of simple tailpipe emissions trucking trumps air freight, how much would that calculation change—and how much more complicated would it become—if it included the emissions resulting from highway construction? Likewise, how does one account for the infinite variations in growing methods used across the globe? A totally non-mechanized farm in India certainly uses less energy to grow its crops than most farms in North America. So even if the food arrived here in the biggest fuel-guzzling jumbo jet there is, it could still have a lower energy footprint than its North American equivalent. As a 1997 Swedish study found, it might indeed be more energy efficient for eaters in that northern country to buy Spanish-grown tomatoes rather than local greenhouse tomatoes because Spain’s climate is conducive to heat-loving crops, whereas Swedish production requires great gobs of energy to keep greenhouse tomatoes growing.
Even principles that we might think provide certainty and comfort in this morass of complication—for example, thinking local is always more energy efficient than regional—are not straightforward. A 2001 study done by the Leopold Center for Sustainable Agriculture at Iowa State University found that a local food system can require more energy and emit more carbon dioxide than its regional counterpart when the trucks used to supply local foods are smaller than the trucks delivering regionally produced food. The smaller trucks require