How Big's Your Foot?

Become a locavore. Put a carbon rating on food labels. Sell carbon emissions futures. These are some of the solutions to our ever-increasing carbon footprint discussed by Michael Specter in an article in this week's New Yorker. However, as Specter points out, the more feel-good a solution might be, the less quantifiable it probably is.

Let's start with consuming only food grown locally, or only food grown or produced within a certain radius of your home. This sounds incredibly good - no bananas flown up from South America, no beef from New Zealand, no green beans from Africa. It sounds so good I've spent the past year going more and more local myself. As it turns out, even when factoring in the environmental impact of shipping goods by air, local foods might have the greater carbon footprint.

Factors other than air shipping that need to be considered include water use, type of fertilizer, harvesting methods, packaging, growing seasons, land use, and storage and transportation method. Something boat shipped, for example, uses far less fossil fuel than a product produced domestically but shipped by refrigerated truck. And New Zealand has more sunny days than the United States, and more renewable sources for electricity, making the New Zealand beef a viable option against beef from cattle raised here in the Northeast.

In the UK, Tesco supermarkets are attempting to have all of their products come with a "carbon label" letting consumers know the environmental impact of their choices. Walkers crisps was the first product on the shelves to carry this label. How do you figure out the carbon dioxide emissions associated with potato chips? According to Specter, the company had to take into account the energy required to plant seeds for the ingredients and make the fertilizers and pesticides needed for growing; the energy required to harvest the potatoes (diesel tractors); the carbon effects of cleaning, chopping, storing, and bagging the potatoes; the energy needed for the production and printing of the chip bags; the petroleum needed to deliver the chips to stores; and finally the impact of disposing of the packaging once the chips have been consumed. In other words, a carbon footprint is never an easy calculation, and the results might not be as expected.

On Friday I told everyone to go out and buy a print publication, so let's think about publishing in print versus publishing online. You'd think online would easily leave the smaller footprint, since print involves growing and harvesting trees, manufacturing ink, content production, the printing process, distribution by truck, and finally recycling of the printed product after consumption. On the other hand, each of us right now is on a computer that is not easily recyclable, looking at a monitor that contains arsenic and mercury, running on electricity. This blog is stored on the equivalent of a monster computer somewhere, in a climate-controlled room. You are accessing the blog utilizing not only electrical power but also phone or cable lines which had to be manufactured and installed and which also need to be powered. There's this to consider as well: the print publication has centralized distribution, and can be shared among readers. In the next issue of my magazine (printed on recycled paper), content by six contributors will be consumed by 25,000 readers, with a press run of only half that. Each of you is reading this blog individually, so to really think about this we'd need to take into account each and every factor and look at energy required not only to produce each post but for each of you to read it. It's not at all as simple as it would at first appear.

Specter's article does make clear one easy way for us to reduce our carbon footprint: stop deforestation. Trees absorb carbon dioxide, maintain our ecosystem, absorb groundwater, cool the planet. It might be more important to plant a tree than to drive to the farmers' market for some local winter potatoes.