Study Comparing Local To Meat-Free Diet Is Dated and Debunked


Note date on original study, linked to in articles

All the blogs are writing about a Harvard Business Review story by Andrew Winston, titled Local Food or Less Meat? Data Tells The Real Story ; even our Rachel picked it up with New Study: Going Meat-Free One Day a Week Saves More GHG Emissions Than A 100% Local Diet.

There are are, however, a couple of problems; a) the study on which the article is based is old and tired, and was published in 2008, b) the study has been discussed, deconstructed, dismembered and debunked to death ever since, and c) it compares two things that have no relation to each other.
There has been a lot of water under the bridge in three years. Mat wrote recently in Two Simple Steps to Really Reducing Your Carbon Foodprint: Go Vegetarian + Walk or Bike to the Store:

The idea of trying to reduce the carbon footprint of your diet is almost yesterday's news in the green community, as is talking about eating locally, minimizing food miles, reducing the amount of meat you eat.

Matt noted that it is not only old news, it is a red herring; barely a quarter of the carbon footprint of our food comes from moving food; most of it comes from us getting to and from the store. He concludes with a concise roundup of why to buy local:

Which of course doesn't negate the non-carbon aspects of the benefits of eating as much local food as possible: Connection with your food producers, eating seasonal to as to be more in touch with your environment, money staying in the local economy, supporting diverse agricultural systems, etc., etc.

TreeHugger Eliza first covered this story in 2008: Study Finds Meat and Dairy Create More Emissions Than Miles, concluding:

Even more surprising, the study noted that U.S. consumers can do more to reduce greenhouse gases by eating one-seventh of a week's calories from chicken, fish or vegetables instead of red meat or dairy than buying all local foods.

Even then, people were wondering about why the authors thought that the local movement was about carbon footprints. What if the meat is local and grass-fed? Was the carbon footprint the reason we bought local, or were there other factors? Even then, commenters wrote:

I'm unclear as to the utility of comparing transportation to food; they are not alternatives to each other. It just seems like time for us all to grow up and look at the big picture, instead of leaping to assumptions based on each new infonugget dribbled out in isolation.

Of course the reflexive contrarian Freakonomics boys picked it up right away. I wrote in Freakonomists on the Merits of Local Food:

Fuel consumption is only one of the reasons that the the local food movement has taken off, and probably not the most important. Dubner compares industrial food to food grown in your garden, rather than to the food bought from local farmers through farmers markets or retailers. The "ruthlessly efficient" industrial food system delivers a lousy product--albeit efficiently.

The study quoted also notes that "the production phase contributes 83% of food's carbon footprint. I suspect that is a whole lot lower in local food then it is on a massive farm in California. For his argument to be plausible, one would have to look at the full range of energy consumption, not just getting it from the farm to the store.

The WorldWatch Institute had a shot at the study in 2009, discussed by Warren in There's Something About Dairy, Say WorldWatch, where he writes:

"food miles/kilometers don't tell the whole story. "Food miles are a good measure of how far food has traveled. But they're not a very good measure of the food's environmental impact."

There is a lot more to the local food movement than just a carbon footprint. In fact, that is just a small component of it.

Winston writes in the Harvard Business Review:

As a numbers geek, I love this kind of analysis. Now for the caveats: none of this data should dissuade anyone from eating locally also. The footprint benefits are real, even if dwarfed by food choice. And the benefits to local economies and smaller farms are very important.

As a numbers geek, one would think that he would love analysis that isn't comparing apples and oranges, eating a hamburger to buying local. Even he acknowledges there are other reasons to do so. As a weekday vegetarian and a local food geek, I wonder why he thinks one is in opposition to the other. As an english geek and pedant, I would like to complain about his headline that included "Data Tells The Real Story" and inform him that data are plural.

Winston also isn't the only one out there spouting studies about the carbon footprint of local food; as I have noted, Attacking the 100 Mile Diet is the News Meme of the Moment. I tried to do a roundup of all the debunking in Stop Eating Fossil Fuels, Start Eating Food

We recognize that you have to do a whole lot more than just simplistically look at one factor, the carbon footprint of transport, in isolation. The study, and Andrew Winston's article, are so 2008; We've moved on.

More on the Carbon Footprint of Local Food:
Meet The Food You Eat: Measuring Carbon Footprints With a Kitchen Scale
Pablo Looks at Carbon Footprint of Local Food

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Tags: 100 Mile Diet | Food Miles | Local Food

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