Supermarket chain Tesco pledged last night to revolutionise its business to become "a leader in helping to create a low-carbon economy" with a raft of new measures to help combat climate change. In the most significant step announced yesterday, the UK's biggest retailer, which produces 2m tonnes of carbon a year in the UK, said it would put new labels on every one of the 70,000 products it sells so that shoppers can compare carbon costs... [also refers to Wal-Mart, Asda (part of Wal-Mart), Sainsbury, Marks & Spencer, Morrisons, Waitrose (part of John Lewis Partnership)]