Fuzzy Math?

To me, the main benefit to buying local products has always been the lower carbon footprint to transport products.  Then, I read this OpEd article in the NY Times, which muddled up the issue pretty good for me…

Math Lessons for Locavores

Leesburg, Va.

IT’S 42 steps from my back door to the garden that keeps my family supplied nine months of the year with a modest cornucopia of lettuce, beets, spinach, beans, tomatoes, basil, corn, squash, brussels sprouts, the occasional celeriac and, once when I was feeling particularly energetic, a couple of small but undeniable artichokes. You’ll get no argument from me about the pleasures and advantages to the palate and the spirit of eating what’s local, fresh and in season.

But the local food movement now threatens to devolve into another one of those self-indulgent — and self-defeating — do-gooder dogmas. Arbitrary rules, without any real scientific basis, are repeated as gospel by “locavores,” celebrity chefs and mainstream environmental organizations. Words like “sustainability” and “food-miles” are thrown around without any clear understanding of the larger picture of energy and land use.

The result has been all kinds of absurdities. For instance, it is sinful in New York City to buy a tomato grown in a California field because of the energy spent to truck it across the country; it is virtuous to buy one grown in a lavishly heated greenhouse in, say, the Hudson Valley.

The statistics brandished by local-food advocates to support such doctrinaire assertions are always selective, usually misleading and often bogus. This is particularly the case with respect to the energy costs of transporting food. One popular and oft-repeated statistic is that it takes 36 (sometimes it’s 97) calories of fossil fuel energy to bring one calorie of iceberg lettuce from California to the East Coast. That’s an apples and oranges (or maybe apples and rocks) comparison to begin with, because you can’t eat petroleum or burn iceberg lettuce.

It is also an almost complete misrepresentation of reality, as those numbers reflect the entire energy cost of producing lettuce from seed to dinner table, not just transportation. Studies have shown that whether it’s grown in California or Maine, or whether it’s organic or conventional, about 5,000 calories of energy go into one pound of lettuce. Given how efficient trains and tractor-trailers are, shipping a head of lettuce across the country actually adds next to nothing to the total energy bill.

It takes about a tablespoon of diesel fuel to move one pound of freight 3,000 miles by rail; that works out to about 100 calories of energy. If it goes by truck, it’s about 300 calories, still a negligible amount in the overall picture. (For those checking the calculations at home, these are “large calories,” or kilocalories, the units used for food value.) Overall, transportation accounts for about 14 percent of the total energy consumed by the American food system.

Other favorite targets of sustainability advocates include the fertilizers and chemicals used in modern farming. But their share of the food system’s energy use is even lower, about 8 percent.

The real energy hog, it turns out, is not industrial agriculture at all, but you and me. Home preparation and storage account for 32 percent of all energy use in our food system, the largest component by far.

A single 10-mile round trip by car to the grocery store or the farmers’ market will easily eat up about 14,000 calories of fossil fuel energy. Just running your refrigerator for a week consumes 9,000 calories of energy. That assumes it’s one of the latest high-efficiency models; otherwise, you can double that figure. Cooking and running dishwashers, freezers and second or third refrigerators (more than 25 percent of American households have more than one) all add major hits. Indeed, households make up for 22 percent of all the energy expenditures in the United States.

Agriculture, on the other hand, accounts for just 2 percent of our nation’s energy usage; that energy is mainly devoted to running farm machinery and manufacturing fertilizer. In return for that quite modest energy investment, we have fed hundreds of millions of people, liberated tens of millions from backbreaking manual labor and spared hundreds of millions of acres for nature preserves, forests and parks that otherwise would have come under the plow.

Don’t forget the astonishing fact that the total land area of American farms remains almost unchanged from a century ago, at a little under a billion acres, even though those farms now feed three times as many Americans and export more than 10 times as much as they did in 1910.

The best way to make the most of these truly precious resources of land, favorable climates and human labor is to grow lettuce, oranges, wheat, peppers, bananas, whatever, in the places where they grow best and with the most efficient technologies — and then pay the relatively tiny energy cost to get them to market, as we do with every other commodity in the economy. Sometimes that means growing vegetables in your backyard. Sometimes that means buying vegetables grown in California or Costa Rica.

Eating locally grown produce is a fine thing in many ways. But it is not an end in itself, nor is it a virtue in itself. The relative pittance of our energy budget that we spend on modern farming is one of the wisest energy investments we can make, when we honestly look at what it returns to our land, our economy, our environment and our well-being.

Stephen Budiansky is the author of the blog liberalcurmudgeon.com.

A version of this op-ed appeared in print on August 20, 2010, on page A21 of the New York Times

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14 Responses to Fuzzy Math?

  1. This is really interesting and definitely food for thought. I’ve often wondered about that – the amount of gas consumers and farmers use up driving to and from the market. But I think there’s more to it than just food miles – like how connected people feel to their food, the farmers, and therefore the environment in general, the benefits of diversified farms vs. giant industrial monoculture, the local communities surrounding these farms, the fact that many of our large industrial operations are just producing stuff like corn syrup or CAFO beef, the idea that a farmer who meets you face to face is far more likely to treat his/her land well or treat the animals humanely … so I still want to buy local.
    I’m really looking forward to following your blog!

  2. AmznGrace_SC says:

    Hi Scott! I found your blog and have subscribed to your feeds. I look forward to reading more of your thoughts as well as learning from others’ comments. While I’m not a eco-warrior (yet), we are becoming more and more environmentally aware and do our best to, in the words of Jack Johnson, “reduce, reuse and recyle.” I’ve already gleaned a few good tips on here.

  3. charis says:

    Sure it is possible to grow something closer to home and take up more energy than purchasing a product that’s been transported across the country—but these are extreme examples of locavores gone loco.

    The real issue here is eating local AND seasonal (at least in regards to Mr. Budiansky’s argument). Sure, we all love tomatoes or strawberries in the dead of winter, but maybe we should preserve them like they did way back when or dare I say do without them. Not to punish ourselves or feel high and mighty for such sacrifices, but to practice what you preach. The way Barbara Kingsolver describes eating a strawberry in “Animal, Vegetable, Miracle” for the first time in nine months almost makes me want to abstain for a while…

    • Scott says:

      I do agree with you, Ms. Charis- in the general sense- but you know I can’t give up my daily dose of blueberries…

  4. Nick says:

    I also think the op-ed you point out is a great argument for sustainable communities more than sustainable food. Personal transportation is extremely low impact if you live near a farmers market and grocery store… not to mention restaurants, shops, public transit, etc.

    The other point is if you buy local, you’re usually buying something picked in the last day or so – especially true of farmers markets. The longer it’s off the vine, out of the soil, etc, the more nutrients the food loses and sugars it converts to starch, etc (this is why canned food isn’t so bad if it started with a good, fresh product). Local food tends to be (not always) fresher, healthier, and tastier. Not to mention that industrial farms tend to employ methods to make their food look ripe before it actually is ripe. I admit this is more hearsay, but I’ve bitten into some beautiful *looking*, flavorless fruit from large grocery chains.

    • Scott says:

      Nick- that is the 2nd most important reason that I purchase local produce- because it’s more fresh. The only caveat to that is that some of the smaller local guys don’t have very good handling procedures. IOW, they don’t have the proper refrigeration/cooling (or pick at the hottest time of day), so the product loses shelf life (freshness).

      Overall though, I think it’s safe to assume that locally grown produce is usually going to be more fresh than non-local.

      Interesting point on sustainable communities, btw.

  5. alyssabdh says:

    I have to confess I am more attracted to local products. The more I’ve thought about this, and talked with my friends about this issue, I’ve accepted that it’s true for many of us. I don’t know if it really goes much further than that, though. There doesn’t seem to be a real, quantifiable argument in favor of my attraction. I’ll start with this: I don’t intrinsically care more about the farmer down the street than the farmer in Iowa or Latin America. And then there’s this: If your product is local but isn’t organic, then I don’t want to pay you to use chemicals in my “backyard”. And finally: What should be important is diverse, efficient certified organic farms of varying sizes all over the place (including urban backyards!). This may be the only way to sustain us during future food safety or supply threats, and ensure energy usage is continually reduced.

    I don’t think I can break my attraction to local products, and I don’t think there’s a good reason to, but I will start paying more attention to just exactly where it is in my priorities.

  6. elaine says:

    wow. we should really use trains more than tracktor trailers. it makes more sense. although
    there’s probably some PAC, union or government agency helping the trucking companies.

  7. Ann M says:

    I was attracted to farmer’s markets because I assumed they were like the ones we have in Tennessee. Not so for many around here in PG and Monty Cty. Some of the vendors had the same boxes and cartons of veggies I saw the produce guys in Giant and Shopper’s unloading. So, I ask now, where the produce is grown and how.
    In our local farmer’s market in Tennessee, there was only local farm grown produce. In the winter there is very little to purchase except some diary products, canned fruit and vegetables and root vegetables grown by the local Amish population. We need to go back to eating seasonally or at least freezing those things we just can’t do without. But then use of the freezer comes into play. Oh, well…

    • Scott says:

      Ann- farm stands in this area can be very sketchy. So many times have I seen things for sale like cantaloupes and tomatoes for sale in May/June. There is no way that stuff is being grown locally. They’re likely picking the products up at the wholesaler in Jessup.

      Some farm stands are differentiating themselves by hanging a sign up saying “We grow our own produce.” You don’t see many of those signs around, though…

  8. Kate says:

    I think the point of the local foods movement has gotten diluted. The whole purpose is to buy local foods that are in season.

  9. Marc says:

    This piece is certainly challenging. But without seeing the plus and minus signs on the author’s scratch paper, I am skeptical of the numbers here.

    Mr. Budiansky writes:
    “Given how efficient trains and tractor-trailers are, shipping a head of lettuce across the country actually adds next to nothing to the total energy bill.”
    It costs next to nothing because these trains and trailers are already making those trips to bring other goods across country. Because they are shipping large amounts of whatever, they save money by packing the trucks full. Why wouldn’t they? It makes good sense. But that ignores how much fuel these vehicles use in the first place just to DO that. Why not bring our food system to the local level and reduce emissions across the board? Am I oversimplifying?

    I agree with Kate: the local food movement has left in the dust its major sustainable component which is “in season.” Maybe I will start a business to retrofit homes and yards with root cellars. Then, Scott you can still have your blueberries in the winter, and we can begin to reduce the energy consumption from our freezers and fridges.
    By the way, an excellent and enjoyable book on that topic is, “Root Cellaring: Natural Cold Storage of Fruits & Vegetables” by Mike and Nancy Bubel.

    And if we want bananas and oranges but live in Maryland – tough luck! Have grandma in Florida order a crate for you when you come to visit her each year and pig out on oranges. Thats your treat. But we do not “deserve” these things just because its currently possible to have them here, 1,000 miles away.

    I’m trying to get my dad to tend his small garden without Miracle-Grow and think about planting fruit trees in the yard. (I dream that the wonderful, tasty and native to the mid-atlantic paw-paw could enjoy a resurgence in people’s backyards!) I find that his resistance arises from two things 1) ignorance of why he shouldn’t use artificial fertilizers and 2) a perceived lack of time to think about and tend to these things, aka “priorities”.

    I love this blog! Thanks, Scott.

  10. Scott says:

    Marc- I just saw your post on here- after already replying to you on the “lawns” post. You make a good point regarding “seeing the plus or minus signs on the author’s scratch paper”.

    It’s all very complicated. I think it’s going to be near impossible to convince 100’s of millions of people to eat only in-season to their region. It will probably be easier to convince people to switch to renewable energy.

    The culinary food craze in as strong as ever- and given the masses of people in certain regions like the NorthEast (1/3 of the country’s population(?) in an area with a 4 month harvest season?), I think shipping food in from far away is approaching an issue of survial. And if you think about it, compact/urban living has an environmental benefit which could more than offset the drawbacks of shipping food from afar.

    Like I said- a complicated issue…

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