The Locavore's Dilemma
Page 12
As is now obvious, although much damage was done in some areas, the global catastrophe predicted by past activists never materialized because of the adoption of a number of tools and strategies, from contour plowing, windbreaks, legume fallow crops, mulching and alley cropping to deferred and rotational grazing, drip irrigation, re-vegetation and no-till agriculture. Unfortunately, one of the greatest advances in combating erosion in the last decades—“no-till” agriculture, which leaves the root systems of previous crops undisturbed, thereby retaining organic matter and greatly discouraging erosion—is decried by many activists because of its reliance on rDNA-modified plants and synthetic herbicides.
Be that as it may, the key point is that by concentrating the growing of crops in ever more suitable locations, long distance trade not only maximized output and drastically lowered prices, but also significantly reduced the environmental impact of agriculture. For instance, the agricultural economist Dennis Avery observes that with the rise of the American corn and wheat belts in the 19th century, grain growers in Virginia’s Shenandoah Valley could no longer compete with producers whose yields were three times higher than theirs and whose farm machinery didn’t get damaged by buried rocks. In short order they had no choice but to switch to cattle grazing and wood production for which their land was better suited. As a result, in today’s Shenandoah Valley wildlife is more common than in colonial and pre-colonial times, the area has gained beauty and the “huge soil erosion losses that cropping inflicted on its steep, rocky slopes” has long ended. True, the ecosystems of grain producing states from Indiana to Montana have been profoundly altered, but because their land is more productive and less prone to erosion, more grain is now being produced on fewer acres and, overall, more habitat is available for wildlife. Avery further argues that, because of similar land use changes in many other locations, severe erosion problems are now largely confined “to poor countries extending low-yield farming onto fragile soils.”20
Of course, Avery was far from being the first agricultural analyst to observe this phenomenon.21 To quote but one other writer, the Marxist theorist Karl Kautsky observed in 1899 that “as long as any rural economy is self-sufficient it has to produce everything which it needs, irrespective of whether the soil is suitable or not. Grain has to be cultivated on infertile, stony and steeply sloping ground as well as on rich soils.” In time, however, the emergence of commodity production and overseas competition meant that “it was no longer necessary to carry on producing grain on unsuitable soils, and where circumstances were favorable it was taken off the land and replaced by other types of agricultural production,” such as orchards, cattle, and dairy farming.22
International trade is also beneficial in terms of overall water usage, as exporting food from locations where it is abundant to regions where it isn’t reduces the need to drain surface waters and aquifers in these less-productive areas. For instance, a country that imports one ton of wheat instead of producing it domestically is said to save about 1,300 cubic meters of local (or “indigenous”) water. As food production represents approximately 70% of human water use, the issue is not insignificant. Trading agricultural products grown in water-rich regions to drier ones is now often subsumed under the labels of “virtual,” “embedded,” “embodied,” or “hidden” water23 to describe the environmental benefits of the practice, but it has long been a reality because of simple economic incentives.
Perhaps the least heralded triumph of high-yield agriculture and international trade is that, along with urbanization, they have played a crucial role in the expansion of forested areas in significant parts of the Earth in the last two centuries. Contrary to the common belief that massive deforestation is a recent occurrence (with the bulk of it taking place in the tropical regions of the world during the last five decades), it is now acknowledged by specialists that perhaps as much as nine-tenths of all deforestation caused by human beings since the emergence of civilization occurred before 1950 as people needed to clear vast tracts of forested land in order to provide themselves with shelter, food, warmth, and a multitude of implements.24 A reversal of these trends (not attributable to wars, epidemics, or collapse of civilizations) began in the early decades of the 19th century in certain European countries through a process since labeled “forest transitions.” In France, the forest area expanded by one-third between 1830 and 1960, and by a further quarter since 1960. Similar processes, although of varying intensity and scope, have been occurring in all major temperate and boreal forests and in every country with a per capita Gross Domestic Product (GDP) now exceeding U.S. $4,600 (roughly equal to the GDP of Chile) and in some developing economies, most notably China and India.25
While in some cases this outcome can be traced back to aggressive governmental policies,26 these efforts would have been unthinkable without drastically improved agricultural and forestry productivity (including the development of tree or “fiber farms”) that reduced harvesting pressures in other locations. Of course, this transition also owed much to the more efficient transformation of wood into various products and to carbon-fuels that were the basis of substitutes for organic fibers, dyes, and animal feed (when automobiles, tractors, and trucks became substitutes for horses).27
Turning our back on the global food supply chain, and, in the process, reducing the quantity of food produced in the most suitable locations will inevitably result in larger amounts of inferior land being put under cultivation, the outcome of which can only be less output and greater environmental damage. Such problems would obviously be made worse by the locavores’ rejection of technology-based approaches such as no-till farming. Unfortunately, these considerations are never addressed by locavores, whose primary focus is on reducing the distance that foodstuff travels between producers and final consumers.
The Basic Problems with Food Miles
The locavores’ only original addition to the rhetoric of past generations of food and environmental activists is the concept of “food miles”—the distance food items travel from farms to consumers—which they use as a proxy for greenhouse gas emissions. In short, the more distance traveled, the more greenhouse gases emitted and the more overall environmental damage. Despite its popularity, the concept and its underlying rationale have been convincingly debunked in numerous Life Cycle Assessment (LCA) studies, a methodology that examines the environmental impact associated with all the stages of a product’s life cycle, from raw material extraction to disposal of the finished product. Not surprisingly, it turns out that food miles can only be taken at face value in the case of identical items produced simultaneously in the exact same physical conditions but in different locations—in other words, if everything else is equal, which is obviously never the case in the real world.28 What follows is a brief summary of the most relevant findings of LCA researchers.
Production vs. Transportation
The fact that retailers are able to sell profitably food items that have traveled long distances clearly indicates that they can be produced more economically elsewhere for reasons that range from better growing conditions to cheaper labor costs. If this were not the case, transportation costs would act as an insurmountable trade barrier.
In the most comprehensive literature review to date, in 2007 New Zealand researchers Caroline Saunders and Peter Hayes29 surveyed 27 studies (17 of which were funded by U.K. sponsors) that all unambiguously demonstrated the relatively insignificant carbon dioxide emission impact of transporting food. For instance, in 2005, researchers associated with the U.K. Department of Environment, Food and Rural Affairs (DEFRA) published30 a comparison of U.K. and Spanish tomatoes sold in the U.K. that factored in both the production and delivery by land transportation of Spanish tomatoes to British consumers. According to their estimates, U.K. tomato producers emitted 2,394 kilograms of carbon dioxide per ton compared to 630 kilograms per ton for their Spanish competitors. This huge gap could be traced back to differences in the climate between the two locations. Because they live in a much coo
ler and overcast part of Europe, producers in the United Kingdom had no choice but to use heated greenhouses. Their Spanish competitors, by contrast, are located along the much warmer Mediterranean coast and can obtain much higher yields in non-heated greenhouses, which emitted much less carbon dioxide, thanks to nature providing the heat free of charge.
Tomato production is but one instance of a much larger phenomenon. As American researchers have documented, in their country the “food miles” segment (from producer to retailer) contributes only about 4% of total emissions related to what Americans take home in their grocery bags, while 83% of households’ carbon dioxide footprint for food consumption can be traced back to the production stages.31 Again, these credible LCA studies document the commonsensical notion that producing food requires a lot more energy than moving it around. This is especially the case for food that requires significant heating and/or cold protection technologies when the same items can be produced elsewhere in much more favorable climates. A schematic overview of the globalized food supply chain can also help put the relative (un)importance of transportation in broader perspective:
LCA SCOPE AND INPUT IN FOOD MILE ANALYSIS
Transportation Mode/Load
Another general conclusion of the LCA studies is that the distance traveled matters less than the mode of transportation employed, whether boat, railroad car, truck, or individual car. Using 2002 data, the authors of the aforementioned 2005 DEFRA study developed two different types of measurements for food transport. The first was vehicle kilometers—the distance traveled by vehicles carrying food and drink regardless of the amount being transported. The second was ton kilometers—the distance multiplied by load, which gives a better sense of the amount of energy required for each item transported.32 The researchers observed that 82% of the estimated 30 billion food miles associated with U.K.-consumed food are generated within the country, with car transport from shop to home accounting for 48% and tractor-trailers (what they call HGVs—heavy goods vehicles) representing 31% of food miles. Remarkably, air transport amounted to less than 1% of total food miles. The large share accounted for by cars was the result of individual families making numerous trips to the supermarket. By contrast, delivering these goods to stores using much more efficient means required much less energy per item. In other words, transporting a large volume of broccoli in a refrigerated container that had been moved around on a boat, a railroad car, and a truck to a distribution point required a lot less energy than a few thousand consumers bringing the same volume of broccoli back to their homes.
Significant differences also exist between transportation modes. By far the most efficient is maritime transportation, as modern container ships float on water and are powered by highly efficient diesel engines that can cover huge distances using very little fuel. According to the authors of the DEFRA study, in the U.K. sea transport accounted for 65% of food miles—the actual distance traveled by numerous food items that were imported from distant locations—but overall maritime food miles accounted for less than 1% of the total vehicle kilometers of the country. So moving New Zealand apples to the U.K. using highly efficient container ships consumed very little energy per apple, when compared to moving the fruit by car and in very small volumes from a supermarket to relatively close residences. Distance may be important, but in truth the transportation mode is typically a much more significant issue.
Seasonality and Storage
Advances in transportation have historically been associated with the increased outsourcing of perishable food items at the expense of local production and storage. Not only were imported items fresher than stored local produce, but they also reduced the costs associated with storage, especially in terms of energy (refrigeration) and spoilage. As we have already discussed, the timing of local harvests has long influenced the geographical distribution of food production. This consideration is lost on food activists, but was tackled head-on in a study published in 2006 by New Zealand researchers Caroline Saunders, Andrew Barber and Greg Taylor. Their work took into account the energy required for out-of-season cold storage as well as the related carbon dioxide emissions equivalent for U.K. apples and assumed that they would be kept in this state for an average of 6 months.33 According to their scenario, the amount of energy needed to store these apples was 2,069 megajoule per ton (MJ/ton), and emissions for production was 85.5 kilograms of carbon dioxide per ton (CO2/ton). These amounts are comparable to the energy consumption required to ship New Zealand apples to the U.K. (2,030 MJ/ton), but far exceed those required to produce New Zealand apples (60.1 kg of CO2/ton). In other words, because New Zealand is located in the Southern Hemisphere where the growing season coincides with the Northern Hemisphere’s winter, shipping freshly picked New Zealand apples and quickly selling them to U.K. consumers during their late winter season results in less greenhouse gas emissions than the purchase by U.K. consumers of U.K. apples that have been in storage for several months. Another study published by Llorenc Milà i Canals et al. in 2007 factored in seasonal storage and storage losses and reached a similar conclusion. 34 In this scenario, local apples stored between 5 and 9 months with normal storage loss rates increased the energy used by 8–16%. What these studies show is that the smart thing to do is also the most economical: avoid cold storage as much as possible and purchase produce grown in different latitudes instead.
Consumer Behavior
The LCA and other studies have also highlighted additional considerations that, while less crucial to our argument, help put the food miles rhetoric in broader perspective. For one thing, consumers’ transportation choices, such as walking, biking, or taking a crowded bus (as opposed to driving) can obviously reduce the total carbon dioxide emissions associated with food purchases. The authors of the DEFRA study showed that, in the worst-case scenario, a U.K. consumer driving 6 miles to buy Kenyan green beans emits more carbon dioxide per bean than does flying the vegetables from Kenya to the U.K. There are, however, good reasons why most of us use a car to shop. Among other things, when we drive to the store we are able to buy more groceries and thus reduce the number of shopping trips and amount of time devoted to this activity.
Another largely overlooked issue is the amount of food that is wasted. According to some estimates, between 30 to 40% of raw food materials and ingredients are lost between the points of production and consumption.35 In less advanced economies, food losses in the production, harvesting, and on-farm storage stages are primarily attributable to the lack of infrastructure, knowledge, or investment in the means to protect agricultural products from damage and spoilage due to rodents, insects, molds, and other microorganisms. (Postharvest losses as a result of these factors are believed to account for at least 30% of the harvested crop in some parts of the world, a dramatic waste of seeds, water, fertilizer, and labor.) By contrast, in industrialized countries, food losses are more significant in retail and food service establishments and in homes.36 For instance, a 2008 British study conducted by the Waste & Resources Action Programme analyzed the trash of 2,138 households and estimated that more than 6.7 million tons of food—roughly a third of the food bought by consumers—was thrown out every year. According to its authors, 61% of this food waste (consisting mostly of fresh fruits, vegetables, and salads, and amounting to approximately 70 kilograms per person annually) could have been avoided with more care and planning. The costs involved were estimated to be about £10.2 billion (about $19.5 billion USD) and the cause of 18 million tons of carbon dioxide emissions per year in the U.K.—an amount equivalent to the emissions of one fifth of the British car fleet during this time period.37
We have already documented in chapter 2 how locavore initiatives such as Community Supported Agriculture result in more waste of fresh produce than is the case when people shop at supermarkets. Another misconception promoted by activists is that the absence (or much smaller volume) of packaging material at farmers’ markets has significant environmental benefits, a notion that conveniently ignores the fact tha
t food packaging has the dual advantage of protecting food from microbes and greatly prolonging shelf life. These advantages, in turn, significantly increase the probability of the food being consumed instead of ending in a landfill or incinerator.38