Wal-Mart Stores, Inc.'s just-announced labeling plan to require suppliers to disclose the full greenhouse gas (GHG) and “environmental footprint” of their products illustrates -- once again -- the growing power of the retail giant to drive environmental decisions. Wal-Mart CEO Mike Duke July 16 unveiled a “Sustainability Index” program that will focus on reducing energy consumption and waste, as well as introducing more sustainable products, according to a July 16 presentation . According to the presentation, the program, which could...