Thinking about carbon “foodprints”

The February 25 issue of The New Yorker has an important article by staff writer Michael Specter about some of the economic, logistical, and moral issues related to our individual contributions to the climate crisis* (our "carbon footprints"). In his exploration of the topic, he covers product labeling for food miles, carbon emissions, offset programs, markets for carbon emission trading, and more. Although necessarily light on details in places (it's less than nine pages long), the article is a good overview of the many challenges — and some of the opportunities — we face in addressing the climate crisis.

The production and transport of food releases significant amounts of greenhouse gases (primarily carbon dioxide, methane, and nitrous oxide). A report from the Pew Center on Climate Change estimates that worldwide agricultural activities generate about 14 percent of greenhouse gases, while land use changes and forestry (e.g., land clearing for croplands and pasture lands) accounts for about 18 percent of total emissions. The report "Livestock's Long Shadow" from the Food and Agriculture Organization of the United Nations estimates that 18 percent of total greenhouse gases are caused by the livestock portion of the food system. In their calculation, they tried to include everything releated to livestock, not just the actual emissions from the animals themselves (such as cows burping methane), and so they factored in the fertilizer making activities, feed transport, land use changes to create grazing lands or farmland, and agricultural emissions resulting from feed production.

With this level of impact, it makes sense that Specter spends much of the article discussing food.

Specter begins the story with the UK grocery chain Tesco's ambitious plan to develop a system of carbon labelling for their products, with a goal of informing consumers about how their everyday choices affect their carbon footprint. "Ambitious" is probably an understatement, as illustrated by a jar of peanut butter: "Should the carbon label on a jar of peanut butter include the emissions caused by the fertilizer, calcium, and potassium applied to the original crop of peanuts? What about the energy used to boil the peanuts once they have been harvested, or to mold the jar and print the labels? Seen this way, carbon costs multiply rapidly." Having dabbled in this subject — I tried to compare the energy required to deliver a kilogram of rice from either Bangladesh and the Sacramento Valley of California to Berkeley in How Green is Your Rice?) — I know how messy and uncertain it can be to calculate energy consumption or carbon emission. (It's also easy to manipulate, as a famous "study" comparing the Prius and Hummer showed).

Specter writes that "food carries enormous symbolic power, so the concept of 'food miles' — the distance a product travels from the farm to your home — is often used as a kind of shorthand to talk about climate change in general." He notes that "American produce travels an average of nearly fifteen hundred miles before we eat it." (I'm guessing that the statistic is from a 2001 report (PDF) by the Leopold Center for Sustainable Agriculture at Iowa State University.) But he makes sure that the reader understands that local food doesn't always have a lower carbon cost. Although this might seem counterintuitive, it makes sense when you consider how many carbon-emitting steps are involved in food production and transport. You have fertilizer, irrigation, the type of animal feed, how the goods were transported, whether cold storage was required, and so on.

Unfortunately, one of Specter's examples of a supposedly low-carbon import is New Zealand lamb. He cites a study by Lincoln University that claims that New Zealand lamb shipped to England will have four times less carbon emissions than lamb raised in England. The New Yorker might be famous for fact checking, but they clearly didn't read the Lincoln study with critical eyes. A guest post here at the Ethicurean by "Small-Mart Revolution" author Michael H. Shuman took issue with many of the assumptions in the Kiwi calculation, like the failure to include “the transport of the finished product within New Zealand, the UK and any other country involved." Since the New Zealand lamb needs to be trucked from the farm to the New Zealand port (perhaps in multiple steps through a distribution chain), and then from the British port to the store, a significant source of carbon is neglected.

For those who want to think about the carbon emissions related to their wine drinking, Specter mentions a study on wine miles by Friend o' Ethicurean Tyler Coleman (a.k.a. Dr. Vino) and Pablo Paster (the man behind "Ask Pablo") in which they conclude that “the efficiencies of shipping drive a ‘green line’ all the way to Columbus, Ohio, the point where a wine from Bordeaux and Napa has the same carbon intensity.”

When considering climate change and food, it's important to also remember that cooking has a significant impact. John Murlis, the chief scientific adviser to the Carbon Neutral Company, says:

"You can feel very good about the organic potatoes you buy from a farm near your home, but half the emissions — and half the footprint — from those potatoes could come from the energy you use to cook them. If you leave the lid off, boil them at a high heat, and then mash your potatoes, from a carbon standpoint you might as well drive to McDonald's and spend your money buying an order of French fries."

Like one of those computer programs that uses idle CPU time to search for extraterrestrials, I have been spending the lulls in my day thinking about the article, generally with a good bit of frustration. Take the issue of carbon labels on foods. I would certainly factor a carbon rating into my rather complicated purchasing algorithm, but how many others would care? And would they use the labels to compare the carbon emissions of Cool Ranch Doritos and Fritos, or would they take the much more dramatic step of determining the carbon savings from one meatless day per week?

But on the other hand, anything that makes people think more about their food is a good thing. And perhaps labels will inspire people to run one of those carbon footprint calculators and discover how much carbon comes from the different sectors of their lifestyle (driving, eating, heating, flying, etc.).

Thinking about this subject inspired me to do the calculation (using the link above, which goes to the Nature Conservancy). It said that my driving and flying habits accounted for 59 percent of my emissions, home energy 35 percent, waste and recycling 4 percent, and food 4 percent. When I changed from a no meat diet to a diet that includes meat at most meals, the food portion of my footprint increased from 4 percent to 20 percent and increased the number of tons that I would emit by over 20 percent. The calculation, to be sure, is somewhat crude — it never asked me how much I eat, whether I choose strictly grass-fed meat, or whether I consume dairy — but clearly shifts in dietary habits can have a significant impact.

As a final thought, it seems that whenever the topics of food and the climate crisis are combined, the knives come out to slash at the local foods movement. "It's just a bunch of hype," the critics say gleefully. "Did you hear that Australian beef has lower carbon emissions than that grass fed stuff from 50 miles away?" they ask. "Those locavores drive their SUVs to the farmers market and think they're saving the planet!" And so on.

With this in mind, it's worth repeating that the choice to eat local is about much more than reducing carbon emissions. Eating local is about building a robust and resilient food system. It's also about building community, eating seasonally, experiencing peak flavor, respecting the cycles of nature, protecting culinary diversity, and preserving local farmland. It's likely that the coming energy and climate crises will require a "relocalization," and the shock of the transition will be much less painful if we have already started strengthening our local economies and building a more resilient food system.


* The more common terms are global warming and climate change. I'm not crazy about these terms because they don't directly convey the negative consequences that we face. In last week's Living on Earth radio program, they listed some additional suggestions — climate disruption, global weirding, and human induced global catastrophe — and asked for additional suggestions from their listeners.

5 Responsesto “Thinking about carbon “foodprints””

  1. Dr. Vino says:

    Hey Marc -

    Thanks for the shout out! And don't forget Mark Bittman's great term: the "meat guzzler."

  2. tasterspoon says:

    Thanks for critiquing this article. I came away from reading it last week very uncertain. I didn't get the sense that Specter was taking delight in bursting locavores' bubbles; I think he was making really interesting points about how difficult these things are to think about, or to summarize on the back of a package in any meaningful way.

    I did come away with a sense of, "You're kidding yourself if you think food miles matters." I appreciate your last paragraph, which points out that trying to eat locally may have a slightly different/wider focus than just 'saving the planet,' and may be worth doing for other reasons.

    One quibble with the article I had was, he talked about the energy costs of imported produce vs. locally (i.e. U.K.) grown produce - I forget what it was, maybe a tomato - and found the locally grown one required more energy to produce. Yet his calculation, I believe, was factoring in heated greenhouses for the local food and did seem to assume that anyone should be able to eat anything at any time of year. I felt this was a critical assumption. As you mentioned, and one thing I don't think locavores get credit for, is that (I think) locavores instead assume a certain amount of self-deprivation out of season, rather than insisting on (local) hothouse tomatoes.

    Maybe the calculations are tricky only when everyone wants everything, in large quantities and cheaply, all the time.

  3. Andy2 says:


    I think that is a really good point. Eating in season foods or not certainly sounds like it has an affect on the energy needed to grow foods. The problem then is certainly getting people to not buy out of season foods. Having had such access for a long time now, I think it will/would be really hard to get people to give up that variety.

  4. George says:

    I'm curious - how do you think changing diets in the developing world are going to affect the planet? There have been several articles lately that blame ethanol for rising food costs (particularly corn and wheat). But, as China, India, and other developing countries start to eat more meat, wont that put pressure on feedstocks and increase the amount of GHG produced?

  5. George -- Increasing prosperity in China and India are certainly having an effect on the world-wide food markets.  The higher demand from those places as well as other factors like the Australian drought and U.S. ethanol policy are removing slack from the system, leading to higher prices.  The higher prices, in turn, push farmers to plant on marginal lands or lands that are currently in conservation programs.  The overall effect on the planet will be and the change in GHG is hard to predict, but there is certainly a high probability of negative consequences.