Friday, March 17, 2006

"Food miles don't go the distance"

That is the title of a BBC guest column by agriculture and land use professor Gareth Edwards-Jones. Edwards-Jones asks us to rethink the assumption that buying locally benefits the environment by reducing the number of food miles, measured in the distance that food travels from its production source to your mouth, that we consume.

The assumption is that by decreasing the distance that the food they buy is transported - try apples from a local orchard rather than ones shipped by train, plane, boat, and automobile all the way from another continent - consumers could do their own small part to help the environment through greenhouse gas reduction.
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That, says Edwards-Jones, is a nice thought, but one which we have very little evidence to back up.
Unfortunately though, simply getting consumers to target food miles when making their purchasing decisions may not necessarily bring about a reduction in greenhouse gas emissions, as these are emitted from many more places within food systems than just trucks, planes and automobiles.

For example, the production of fertiliser, pesticides, machinery and packaging all use energy - the generation of which will undoubtedly have contributed some greenhouse gases to the atmosphere.

In addition, storing and cooking food also consumes energy.

Indeed, our research suggests that when considering UK grown potatoes, 48% of all energy used during the potato's life cycle is expended in the kitchen (the life cycle encompasses the sowing, growing, harvesting, packaging, storage, transport and consumption of potatoes).

One disadvantage to buying locally is that it is frequently, although not always, a more expensive option. I typically buy from the local farmer's cooperative but the premium that I pay for doing so is not insignificant given the overall size of my budget.

In choosing to buy local the perceived benefit to the environment is not the only motivating factor - a reality that Edwards-Jones recognizes. But, at least for me, it is certainly a motivation, and one that I'd heretofore taken for granted.

Edwards-Jones doesn't suggest that it's a mistaken assumption that a reduction in food miles produces environmentally beneficial results, he simply argues that it's an unsupported one. It may be correct, and it certainly seems to satisfy a common sense test in that it sounds like it should be correct. But common sense is no substitute for science, and sounding like a good idea is hardly enough to justify avoiding an actual empirical investigation.

Sounds reasonable enough to me.


4 Comments:

Blogger Potentilla said...

And I suppose that non-perishable goods (rice? coffee?) are more likely to have been shipped by sea with a very low marginal consumption of resources, as opposed to very perishable goods which probably consume a lot of resources to ship even quite short distances (in vans).

Tue Mar 21, 06:40:00 PM EST  
Blogger Tim Kanwar said...

I don't know if that's the case, although it seems like a plausible hypothesis. Then again, the main thrust of this article, at least for me, is that a very plausible hypothesis may not be so right on the money after all.

This is an area I know little about, and I'd like to learn more...

Wed Mar 22, 10:23:00 PM EST  
Blogger Potentilla said...

http://www.newscientist.com/channel/earth/mg18524895.400.html

I seem to recall reading something more recent than this, but I can't find it on a cursory search. Anyhow, this is quite an interesting starting-point. (I don't know much about it either. My original comment was sparked by something I'd read, which might have been the article above but it seems rather a long time ago, um, I might track it down).

Thu Mar 23, 01:11:00 PM EST  
Blogger Tim Kanwar said...

Thanks for the link, although this still doesn't address the fundamental underlying assumption that it is food-miles that create the greatest environmental impact with respect to the food we eat.

Whether those food miles are accumulated by producers driving the food to the grocery store, or by you and me driving it home from the store, they're still food-miles.

What I still want to know is, where do food-miles really rank among the list of environmental harms produced as a byproduct of food consumption? Is buying local (and walking to the store, which I do, by the way. One of the benefits of living in an actual city) the best way to eat green, or are there other more time- and/or cost-efficient ways to do so?

Thu Mar 23, 02:27:00 PM EST  

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