I know a person who refuses to eat any food that is not sourced within 150 miles of where she lives, in Northern California. That's hard-core "slow food" radicalism, a natural outgrowth of the organic farming movement that has put down such deep roots in the region.
She might have a hard time with a comprehensive new research report compiled by the Manchester School of Business for the United Kingdom's Department for Environment, Food, and Rural Affairs, "Environmental Impacts of Food Production and Consumption." Rhett Butler's Mongabay environmental news service alerted me to it this morning, posting a news release with the inflammatory headline: "Organic food may not be sustainable says U.K.-report."
The report is a collection of life-cycle assessment studies that attempt to understand the environmental impacts of the production, transport and packaging of 150 different popular grocery items. What do we know about their contributions to global warming, their energy and water consumption, their effects on local ecosystems? The report's authors go to great pains to stress what they don't know: "The data on environmental impacts of the supply and consumption of the range of common foods consumed in the U.K.... and from which we could draw policy-relevant evidence are patchy, to say the least." But they still provide quite a bit to chew on.
Some conclusions seem obvious, upon reflection. Locally grown isn't always the best answer. Tomatoes grown organically in a greenhouse next door to you may consume more fossil fuel energy than tomatoes shipped from hundreds of miles of away, if you take into account the energy used to produce the aluminum and glass that the greenhouse is built from. Organically grown tomatoes cut down on pesticide use, but may also require more land and water than "conventional" tomatoes, depending on where they are grown.
Some observations are somewhat more subtle. Worried about the global warming impact of the fossil fuel consumed by the trucks that bring your tomatoes from hundreds of miles away to your local supermarket? In a life-cycle analysis, the couple of miles that you drive in your car to get to the supermarket and back does proportionally signficantly greater damage. This raises the possibility that it might be better for the world if you biked to the supermarket to pick up tomatoes grown far away, than drive to the nearest farmer's market to get tomatoes grown on the other side of the hill.
This may seem like splitting hairs, and the number of variables that are not accounted for in the life-cycle assessments that have been conducted to date are legion. But the report doesn't really declare that organic agriculture is not sustainable. What the report says is that the production of goods breaks down to no simple definitive statement as to what is best, and that to make sound decisions we need more information and should evaluate things on a case-by-case basis.
So, while organic farming advocates might be aggravated by the following summation:
There is no doubt that, for many foods, the environmental impacts of organic agriculture are lower than for the equivalent conventionally-grown food. This would be especially the case if those impacts not well handled by [life-cycle assessment] methods (e.g. biodiversity or landscape aesthetics) were to be taken into consideration. However, it is not true for all foods and appears seldom to be true for all classes of environmental impact. There is certainly insufficient evidence available to state that organic agriculture overall would have less of an environmental impact than conventional agriculture. In particular, from the data we have identified, organic agriculture poses its own environmental problems in the production of some foods, either in terms of nutrient release to water or in terms of climate-change burdens.
It is nonetheless difficult to argue with the following:
So, whilst there are no grounds from the available data to argue "local good -- global bad" as a general statement, this could be true for certain foods, as could be the reverse. This prompts us to suggest that supermarkets and food processors could make environmental improvements by being more discriminating about the locations from which they source their goods by taking account of some environmental impacts in their purchasing systems.
It's easy to believe in unilateral, all-encompassing world views. Organic is the One True Way. Or, the price mechanism of the free market will solve all our problems without government intervention. It's much harder to try and figure out which tomato of the nine differently sourced varieties available at my local grocery store is most pleasing to my palate and least damaging to the global ecosystem. It makes me yearn for the realization of my panopticonic dream of of a perfectly labeled future in which the properly vetted results of a comprehensive life-cycle assessments are available to me with the wave of my magic RFID wand, any time I want.
I don't know if the experts at the Manchester School of Business are correct in their various conclusions about any of the foodstuffs that they investigate. But I'm sure we need more of this kind of research.