At least six of the world’s largest companies have banded together to urge their suppliers to report and mitigate greenhouse-gas emissions. Joining together as the Supply Chain Leadership Coalition and partnering with the Carbon Disclosure Project — which is also working with Wal-Mart — companies including Procter & Gamble, Unilever, Tesco, Nestlé, Imperial Tobacco, and Cadbury Schweppes will pressure thousands of vendors and factories to be up front about their emissions.