Today, I read a great article on behavioral nudges toward sustainability. Some companies are using subtle (and not-so-subtle) cues to nudge customers toward behaviors that reduce environmental impacts. The nudge that made an impression on me was Swedish hamburger chain Max’s display of CO2 labels right on their menus, enabling CO2 comparisons at the point of sale. This made me think: could CO2 information displayed on a grocery receipt nudge people to buy food with lower lifecycle CO2 emissions?

I recognize that the relationship isn’t apples-to-apples; Max shows CO2 information before purchase, while I’m talking about CO2 information being displayed after purchase. This information would be in addition to any labels shown on products or grocery aisles themselves. The reason why I think that CO2 labels should go on a grocery receipt as well as products or grocery aisles is that anything impeding the goal of busy shoppers — “find what I want, maybe at a good price, and get out of here” — likely won’t garner much attention. Thus, I’d expect only a small percentage of shoppers to look at in-store CO2 labels. Putting CO2 information on receipts increases the chance of it being seen by people who look at their receipts afterward — though granted, I’m not sure how many people look at their receipts either. This idea isn’t new — the French retailer E. Leclerc already shows CO2 footprints of products on stores shelves and on receipts, and it even shows shoppers how their footprint compares with an average. I’m very interested to see how this has changed E. Leclerc purchasers’ behavior over time; if you’re aware of any data on this, please let me know.

Presenting CO2 footprint data in ways that will nudge behavior is only one of the challenges of CO2 labeling. Back in January of this year, the internet lit up with news of how UK supermarket chain Tesco was “reviewing its commitment” to roll out carbon footprint labels across its full product line. Of CO2 footprints, Tesco climate change director Helen Fielding commented at the time that “there is a real challenge to effectively explain this often complex message in a meaningful way.” I see lack of trust in CO2 footprint methodologies as a major challenge, relating both to the diversity and to the complexity of calculation methods. Furthermore, we must find ways to impart clearer meaning to CO2 labels. Meaning is easy with money: you know how much you spent vs. how much money you have in your account or budget. In contrast, there isn’t a universally agreed-upon CO2 account or CO2 budget for an individual or a family.

CO2 information presented smartlycan nudge people to reduce their carbon footprint, but let’s not forget the importance of trust and context.

See also:

• Context-based sustainability: what should my impact be?

Photo “Our typical shop at Morrisons” by Kai Hendry, on Flickr.