LONDON, United Kingdom — As a growing number of European retailers explore carbon labeling for products, a new report cautions against using confusing label messaging or sticking a label on every last product. "Check-Out Carbon," published by Forum for the Future, a sustainable development charity, found that a majority of consumers want more information about the environmental impacts of the products they buy but labeling effectiveness faces several challenges.

For instance, competing sustainability-related messages can create unintended trade-offs, such as the possibility of making a consumer choose between a product with Fair Trade label versus one with a carbon label.

"To date, carbon messaging around products has been sporadic and often tells consumers climate change impacts without making it cleat what the consumer should do with the information," the report said.

Labels need to deliver information in a way that includes context for the consumer. While the impacts of products from the items people buy and use comprise about 45 percent of the average U.K. citizen's carbon footprint, it is important to remind consumers about the larger impacts, such as driving habits or home insulation, the report said. It also advised retaielr to give consumers advice on post-checkout impacts.

The report comes in the wake of a pilot program between Tesco and the Carbon Trust that involves about 20 products with corresponding carbon labels. French retailer Casino also unveiled a carbon labeling initiative last month for some private label products.

Sweden was supposed to release its first batch of carbon-labeled products but the initaitive has been delayed because of messaging and anti-trade concerns, according to TreeHugger.