Carbon labels will be tested on Tesco-brand products next month, The Guardian reports.

The retailer will put carbon labels on varieties of orange juice, potatoes, energy-efficient light bulbs and washing detergent, stating the quantity in grammes of CO2 equivalent put into the atmosphere by their manufacture and distribution and the category average.

Tesco announced its intention to put carbon counts on up to 70,000 products some 15 months ago. It has since been working with the Carbon Trust to find an accurate method of labeling.

There’s a lot of controversy surrounding carbon labels – as most readers know. To start with, carbon labeling is incredibly complex.

Unilever, a top supplier of household products to Tesco, operates 260 factories in 70 countries and works with more than 10,000 subcontractors. Trying to measure the carbon from all the various parts is hard enough, but what happens when Unilever moves production of a product, which Unilever says might be as often as once a week? Tesco might ask for a new carbon label, something Unilever says it just couldn’t do.

Still, more than half of UK consumers want information about the carbon footprint of the products they purchase and nearly half would switch to brands with smaller carbon footprints.

More on carbon labels here.