How big is your carbon footprint? The U.K. wants to know

Do supply chains contribute to global warming? Consumers in the United Kingdom are starting to learn the answer to that question—and they will be among the first to choose products based on which supply chains have the least environmental impact.

The U.K. government has launched an initiative that could eventually lead to carbon-footprint labeling for all retail and grocery products. The labels would tell consumers how many grams of carbon dioxide are emitted during sourcing, manufacture, distribution, and packaging of those products. The U.K.'s Department of Environment, Food and Rural Affairs and BSI British Standards, the national standards organization, teamed up on the project with the Carbon Trust, a company funded by U.K. government agencies and counterparts in Scotland, Wales, and Northern Ireland. The Carbon Trust's mission is to work with business and the public sector to promote a low-carbon economy.

The project aims to develop a way to measure the amount of greenhouse gases expended in bringing a product to the store shelf. This would allow manufacturers to label their products with a "carbon point" score in much the same way that electrical appliances have energy-efficiency scores. Some U.K. retailers and manufacturers are already starting to implement such a labeling system. For example, Walkers Snacks Ltd. now puts carbon labels on its line of snack crisps and plans to extend labeling to all of its products. Marks & Spencer has also started working with the Carbon Trust to calculate the carbon footprints for its food products. And the United Kingdom's biggest retailer, Tesco, has said it would place carbonpoint labels on its products.

Despite its acceptance by these and other companies, the carbon-labeling scheme has generated both controversy and confusion. Critics have noted that a vegetable grown in Africa and shipped to the United Kingdom could—despite the air travel involved—have a smaller carbon footprint than the same vegetable grown in a local greenhouse that required heating. The Soil Association, a group that promotes and certifies organic food, has also raised concerns about the carbon-footprint plan, arguing that there's no scientifically proven method for determining a product's environmental impact.

Accurately assessing a supply chain's carbon footprint is also vexing the retailers involved in the pilot program. The Daily Telegraph newspaper reported that Marks & Spencer was finding it challenging to calculate the greenhouse gases created in the final stage of a product's life, when it is transported to a home, cooked, eaten, and disposed of. Ironically, although one of the goals of carbonfootprint labeling is to educate the consumer, U.K. newspapers report that many consumers don't understand the labeling scheme.

In spite of the criticism and confusion, the U.K. government may still move ahead with its carbon- footprint labeling program. If that happens, international manufacturers that sell products in the United Kingdom will need to begin a fullscale assessment of the carbon content of their supply chains.

[For more information, visit Carbon Trust's web site: www.carbontrust.co.uk.]