Carbon footprint labels: the latest aid for ethical shopping

Shoppers familiar with seeing fair trade, organic or rainforest labels during their weekly shop will have to get used to another logo: the carbon footprint.

Leading food brands are increasingly using the Government's black footprint logo and, according to research published today, it will become the second most common ethical label in UK shops by the end of this year.

The Centre for Retail Research forecasts that annual sales of the Carbon Reduction Label run by the publicly funded Carbon Trust would hit £2bn by the end of 2010, putting it behind only the Red Tractor farm assurance scheme (£10bn), but ahead of the Soil Association's organic mark (£1.5bn); Fairtade (£800m); RSPCA Freedom Foods (£800m), and the smaller Rainforest Alliance and Marine Stewardship Council schemes.

For shoppers, the black footprint logo shows that producers are working behind the scenes with the Carbon Trust to identify and reduce carbon emissions that cause global warming.

In some cases, the labels also display the amount of CO2 generated by each product, giving consumers a greater insight into how much unseen pollution is caused by their purchases – sometimes with surprising results. The amount of CO2 emitted generally weighs more than the product, and there can be substantial variations between different brands or types of the same product.

Tesco has been the most enthusiastic supporter of the scheme, carrying out a commitment made three years ago to carbon label all of its 70,000 food lines. It has so far put footprints on 100 own-brand products, including semi-skimmed milk (800 grams per pint); orange juice (1.1kg per litre); and toilet roll (1.1 grams per sheet).

Walkers, the UK's best-selling crisps, and baker Kingsmill, which is owned by Primark's parent company Associated British Foods, have adopted the idea too. Shoppers can already see that at 1.3kg of CO2 per 800 grams, a loaf of wholemeal bread generates 15 times more carbon dioxide than a small packet of crisps (80 grams).

However, other products have not been included, possibly because shoppers would be put off by how much pollution they generate. Meat has "astronomical" emissions according to one supermarket source, something borne out by research. A study by Japan's National Institute of Livestock and Grassland Science found three years ago that 1kg of beef released the equivalent of 36kg of CO2.

Alcohol, too, has high emissions. While a 330ml can of Coca-Cola has 170 grams, Adnams eco-bitter East Green has 432 grams per half-litre. Consumers can, however, slash the impact of their purchases by using the same products differently – washing clothes at 30C rather than 40C saves 160 grams of CO2.

Currently, these insights are interesting, but they could become more important. Two years ago the Commons Environmental Audit committee said the Government should give everyone a personal carbon allowance.

Euan Murray, the Carbon Trust's head of footprinting, said he did not know if all products would eventually be carbon labelled, but added: "We are increasingly seeing people recognise that things have a carbon footprint, and they want to do something about it."