Food miles is a nice concept for awareness, but a meaningless and impractical ideal to believe in for eating local. Eat local for the economy, not the environment. It doesn’t sound as “romantic”, to idealize something for money rather than for the Earth. However, you’re likely idealizing something you wouldn’t be able to prove to be true.

Why is the food miles concept meaningless?

Because it’s just 10-20% of all the greenhouse gas (GHG) emissions generated in the life cycle of the food you eat, from growth to transportation to the dinner plate, with another 10% or so for storage.

Of all the GHGgenerated from the farm food you eat (crops and livestock), 70-80% are generated before the food even leaves the farm! The exact percentage varies with a huge number of factors, from geography to what one actually eats. If someone is focusing on the 20% or 10% transportation GHG is of the whole food emissions GHG, they’ve got your priorities for the planet all wrong! We don’t need them to be leading the charge to save the planet. They’d be best saving the planet by shutting up and eating less in requiring less energy to live and “think”.

A nice summary article from the Worldwatch Institute called Is Local Food Better? is just one of many credible sources that discusses this disproportion well.

Furthermore, local food transportation GHG emissions is a lot greater than you might think. Local transportation is quite inefficient to mass transportation over long distances. Train transportation is 10X more efficient than truck. This, in turn, is more efficient than small pick-up trucks of the local farmer which have less percentage of overall mass for the food cargo. Food traveling 100 miles from a local farm could easily have the same transportation GHG as the same weight over 1200-1500 miles by train! The 100 mile diet concept isn’t so rosy in that sense, eh? What you end up with on the food transportation GHG comparison is marginal gain for local food relative to the whole amount of food GHG. If it weren’t this way, you’d never be able to afford the food from far away.

Oh, don’t forget you generate GHG in bringing your food home if you use some sort of vehicle, public or personal transportation. Your food transportation is incredibly inefficient compared to mass transportation. But we’re getting into finer details than necessary now.

With growth GHG being 80-90% of the emissions generated by food before it leaves the farm, we should worry far more about how the food was grown rather than how far it traveled to get to our plates. To worry about transportation GHG for food is like worrying about the bills of a house you’re buying rather than the price of the house, with both being the real cost of the house purchase out of your pockets. The variation in GHG generated in growing the food you eat could be staggering compared to the variation in GHG emissions from distances they traveled to get to you. A common example cited is fruits and vegetables grown in greenhouses in cold climates over winter versus the same ones grown well in naturally warm climates and shipped north. Another is local food kept frozen through the winter, or all year until next harvest. That uses more energy than transportation of the same quantity of the same food from quite a distance away.

If you care about GHG of foods, look into how they’re grown. Unfortunately, it’s not easy to find out how food from far away are grown, and don’t necessarily assume it’s more energy intensive because it’s from some less developed country. It’s even hard to convert growth methods into energy and GHG emissions for comparison. It would take an academic with some serious resources to get accurate numbers!

So given the small percentage of food transportation GHG to its growth methods, which are next to impossible to quantify accurately to compare, eating local for the environment because of less GHG for food miles is completely meaningless!

You may be saving the planet by eating local, but it would be because of how your local food is grown, not how far it travels to get to you.

Problem is, you can’t likely prove it!

Why is the food miles concept impractical?

Because it’s a complicated weighted average requiring decent math skills to do, serious research skills and pretty good resources to get all the necessary data. It’s something I would put beyond a large majority of the population (which includes me on the resources).

The research skills to get the data is a bit more obvious to illustrate. Do you know where a product of Mexico came from in Mexico? What about a product of the USA or Canada? These are big countries! Pending where you live relative to the actual place within these countries the products originated, you’re looking a huge margin of error. Then, do you know how it got to where you bought it, and how much by which method of air, train, truck, boat, etc.? Each of these have different GHG efficiencies for transportation, some of which are drastic like the 10 to 1 ratio of train to truck as mentioned previously. You can’t give the same credit for something that traveled 1000 miles by train as by truck. That would a 1000% margin of error! Don’t forget, also, the actual distance traveled is different by each method, too, since planes don’t fly on train tracks, for example!

Then there’s the processed food problem. From where did all the various components come from, in what proportions, in a box of cereal or frozen dinner? How would you ever calculate that?

But let’s say you got accurate source, distance and transportation method data for everything you eat, there is still how to weight the average for what you eat. You can’t just average a can baby corns from Thailand with a 2L jug of apple juice from the farmer 100 miles away. There’s a big weight difference you have to account for. You’d then have to apply that to everything you eat in a week, at least, divided by however many meals you eat a week, to get a fair rough idea of what’s in a typical meal of yours. If you never care to compare that to any other value, you can stop there. But if you want a comparison, you’d have to divide by the weight of your average meal to get a miles per unit weight, as would someone else, to fairly compare.

But how many food mile calculations have you seen in miles per unit weight of food?

Seriously, most food mile calculations I’ve seen that gets thrown around are just bogus estimates on ridiculously over simplified models with gross margin of errors. Even if with some accuracy, what are they crying about all this for? Something like 10-20% of the problem. Good on them!

With “visionaries” like that to save the planet, we might as well extinct ourselves indulging in pleasures rather than making sacrifices to falsely save ourselves! You know, let’s die like James Dean rather than the Pope.

So should you eat local?

Of course!

Just do it for your local economy and local farming industry, and maybe for your health if the food is grown ethically, not the environment.

As said before, you might actually be saving the environment eating local, but you can’t prove it. What you can prove, though, is that your money stays local for at least that first transaction. Someone in your area got some money they could spend that they might not have gotten otherwise if they could not sell all their products before it goes bad, without your purchase. Some cash in their hands means some cash they don’t have to go looking elsewhere for, whether in another job or social transfers from the government. Where that money goes beyond the first transfer is a big debate. I’m no fan of economic multipliers, but I’d take it over food miles any day.

Did you know farmers get 8-10X as much selling directly to customers, like at farmers’ market, than to retailers that may ship it far away? In Nova Scotia, farmers at 9 cents per food dollar spent selling to retailers. They get 80 cents selling direct to customers. (The Coast, July 15 2010)

Now, what if you’re not actually saving the planet by eating local because your local farmers aren’t using as energy efficient ways of growing their food as farmers in another area better suited to grow the same food? Well, you can’t prove that so you don’t actually have to live with the thought. Beyond that, though, I would argue, who cares? The difference you make to a local farmer’s life for each batch of food purchased is far more meaningful than the difference in environmental impact of that batch of food between a local and far away source. Remember, each batch has an environmental impact. It is the difference between the two that you are “saving” in choosing one over the other, not the total impact of one or the other. But unlike the positive or negative environmental impact you can’t know for sure in choosing to buy local, your conscience can definitely see the people whose lives you are making a small difference in with each purchase of local food you buy.

Finally, if you know the farmers who grow your food do it ethically, you can also eat local for your health. “Ethically” depends on you. Maybe you want some combination of no spray, no biosolids, or whatever. But whatever you want, if you know you can get it from your local farmer, then eat local for that. It’s probably too hard for the average citizen to get trustworthy answers to all those questions from a retailer, but it isn’t hard from the local farmer. And how do you know you can trust your local farmer? Just ask another one. They usually know each others’ business. 🙂

Should you still conceptualize food miles?

Yes, but very crudely.

Just take note of where you buy all your products now and see how many you can convert after some time. No need to calculate miles, weight or anything. Just knowing you converted, say, 50% of your food once bought from international sources, to sources within your province now, or the popular 100 mile radius (161 km), should be plenty satisfying. For an example, see how I’ve used it as part of my Earth Day goals for 2010 to eat better.

So there you have it. Why food miles is such a myth, but that you could still use the concept in a basic way to help you conceptualize eating local, like I am.

Just do it for the economy, not the environment… and don’t be afraid to be honest about it!

Flesch-Kincaid Grade Reading Level: 8.8