Local produce consumes more energy!?!

I enjoy eating local produce whenever I can — the taste is phenomenal and it is more “Earth-friendly.” Or so I thought. A story called The Localvore’s Dilemna, which appeared in the Boston Globe on July 22, 2007, challenges the assumption that local produce has a smaller energy footprint since not all modes of transportation are created equal.

From the Boston Globe:

“All things being equal, it’s better if food only travels 10 miles,” says Peter Tyedmers, an ecological economist at Nova Scotia’s Dalhousie University. “Sometimes all things are equal; many times they aren’t.”

The American food-supply network can do certain tasks very well, and one of them is to efficiently ship things over very large distances. The costs in energy can be high: air shipping is by far the most fuel-intensive, and is the fastest growing sector of food transport. However, it still only accounts for a small minority of the food shipments into and throughout the country.

Judged by unit of weight, ship and rail transport in particular are highly energy efficient. Financial considerations force shippers to pack as much as they can into their cargo containers, whether they’re being carried by ship, rail, or truck, and to ensure that they rarely make a return trip empty. And because of their size, container ships and trains enjoy impressive economies of scale. The marginal extra energy it takes to transport a single bunch of bananas packed in with 60,000 tons of other cargo on a container ship is more than an order of magnitude less than that required to move them with a couple hundred pounds of cargo in a car or small truck.

“Local food systems are often built around small-scale logistics,” says Chris Foster, a research fellow at England’s Manchester Business School and co-author of a December 2006 study on the environmental impacts of food production and consumption commissioned for Britain’s Department for Environment, Food and Rural Affairs. “You begin to make more trips in cars. More food is shifted around in small trucks and vans, which are relatively energy-inefficient ways of moving.”

Certainly, OR types would expect some loss of efficiency in locally-grown produce, but the article doesn’t address the entire system of food purchasing from the seed to the kitchen– they mainly focus on the issue of shipping produce. Other components of local vs. non-local produce could include growing/harvesting, consumers driving too and from farmer’s markets, consumers making the lifestyle choice to eat in-season produce.

The article does mention the EPA’s Life Cycle Assessment, which calculates the environmental impact of many products, and presumably takes the entire system into account. It began in the 1960s to assess cars and appliances, but more recently has started to look at food. Apparently, they find that cows are bad for the environment because they emit so much methane!

My routine consists of going to a local farmer’s market or two, and that’s unlikely to change. The local produce tastes better, is more nutritious, and is fun to buy. Maybe locally grown produce isn’t all it’s cracked up to be, but it better than buying over-processed food from the grocery store that has a ton of trans fats and zero nutritional value (think of Twinkies or potato chips or almost anything in a box). I’m sure Twinkies are very energy efficient, but that doesn’t always tell the whole story.

For further reading:

A number of comments on this article can be found on the Marginal Revolution Blog.

More comments on a similar issue — Elizabeth Edwards habit of buying local tangerines.


2 responses to “Local produce consumes more energy!?!

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