Wednesday, June 25, 2008

Is Everything You Read About Food Miles Wrong?

I can see the backlash. Every movement that promotes a "we eat better" philosophy is bound to provoke. Some eating directives are just a question of will power. Eating local requires time and effort and probably a bit of money too. If you don't want to do it all, maybe you decide to attack the rationales instead. No rational seems more central to eating local than the concept of food miles. Eat local advocates stress that the less food has to travel, the better it is for the environment. As Jen Maiser, one of the leaders of the locavore movement references on her blog, food miles can even outweigh other farming practices:
In a March 2005 study by the journal Food Policy, it was found that the miles that organic food often travels to our plate creates environmental damage that outweighs the benefit of buying organic.
And this concept, food miles, is where the backlashers have lashed (mostly). I'm no environmental physicist. I have not crunched the numbers, and I recognize that there are complexities in life that make just food miles simplistic. I am not convinced, however, that the concept lacks merit. published the latest salvo on food miles. Roberta Kwok, a freelance science writer and a graduate student in the Science Communication program at U.C. Santa Cruz attempts to shows that food miles really don't matter that much, that they are a misleading statistic.
But what if conventional distributors make up for the long journeys by driving big trucks packed with produce? Let's say a distributor travels 1,000 miles and carries 1,000 apples to market, while 10 local farmers each drive a pickup 100 miles and carry 100 apples each.
Seems seductive. Moreover, she finds it indeed true. She finds the visits a San Francisco farmer's market and finds it awash in small vehicles. She does the math.
But how does that translate to carbon dioxide emissions? To find out, I crunched the numbers on five types of produce -- apples, oranges, lettuce, greens and squash -- with fuel efficiency estimates from the Environmental Protection Agency and Bay Area truck dealers. Factor in carbon emission figures from Argonne National Laboratory, and I had rough carbon footprints for each farmer and wholesaler. Local farmers won one category, proving more carbon-friendly on squash. While farmers came from cities about an hour's drive from San Francisco, wholesalers had imported their squash through Arizona from Mexico. In these cases, the idea that more food miles equals more fossil fuels appeared to be true. But wholesalers beat local farmers on the four other produce items, boasting fewer average carbon dioxide emissions per pound of apples, oranges, lettuce and greens.
Count me as unconvinced.

For one thing, it's a gross case of anecdotal evidence fallacy. I mean she did a survey, c'mon.
On my Saturday visit, I found that most of them drove Ford, Isuzu or Chevrolet trucks, packing anywhere between 200 and 2,000 pounds of goods
There you go. Oddly enough, when I visit my farmer's market each week, I find most, if not all of the vendors coming to market in trucks, maybe not semi-trucks, but certainly the kinda vehicle I don't like driving. I notice the same thing at a lot of farmer's markets I visit. In other words, her experiment proves little.

For another thing, those arguing in favor of efficient transportation flat out ignore the bits and pieces of their food chain. As I like to say, who picks up their New Zealand lamb at the port? [ed., and does the New Zealand lamb graze at the port?] The author recognizes that there may be something here.
The Farmers Market's green image was beginning to look a bit tarnished. But no sooner did I finish my calculations than I started to wonder if I had missed some hidden carbon costs. For one, I'd asked the wholesalers how far their produce traveled to the terminal market -- but what about the extra leg from the terminal market to the retail store? For that matter, how much carbon dioxide was emitted while consolidating 45,000 pounds of produce from various farms into one semi-trailer truck? And how about the distance traveled by the consumers themselves, whether to the grocery store or to the Farmers Market? What kind of cars did they drive? Food researchers felt my pain. "There are so many complexities," says Holly Hill, author of a 2008 food miles review for the National Sustainable Agriculture Information Service. "Trying to make those real exact calculations is nearly impossible."
Well, there you go. It's to darn hard to think about those other factors. We already have a conclusion that smugly fits into our balloon piercing. Yet, you cannot ignore all of these other factors, and you cannot pretend that food miles are overcome via efficiency when there are inefficiencies planted throughout the industrial food chain. Likewise, a lot of fuel used efficiently is still a lot of fuel used. There's no way you can find me a calculation that says that less fuel was used transporting New Zealand lamb to Chicago markets than it takes someone like Mint Creek, an Illinois lamb farm, to bring their lamb to market.

Instead of doing the numbers taking into account all of the miles that industrial food really travels--farm to packager to distributor to regional warehouse to local warehouse, etc.; she trots out some other studies. There's a UK report that compares greenhouse grown tomatoes to imported Spanish tomatoes. And another by New Zealand researchers that tried to show that all those miles to market for their lamb don't mean a thing if the other guys use a ton of fossil fuel derived fertilizers. I find these again unconvincing, because they are cases of selective comparisons. Once more, let's stack Zealand lamb against Illinois grass fed lamb, not some historical farming practice.

A lot of the eat local backlash articles point out that food miles should not alone dissuade. The Salon author notes that reasons for eating local include freshness, taste and supporting regional economies. From my perspective, I am willing to concede that eating local is not wholly pure, that there is some energy cost associated with keeping my Michigan apples stored for my late season consumption. Nothing I have seen though makes me believe that eating local is not earth friendly. It is implicit in the eat local package that we are getting our food from vendors who practice sustainable farming. Regardless of all of that, I tend to believe there is something to this food miles thing. The less my food travels, the happier I am.

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