In 2005, Wal-Mart's CEO announced a corporation-wide environmental sustainability initiative to go green. The company would take drastic measures to cut down on waste, energy consumption, and greenhouse gas emissions, thus generating savings that would be passed on to the customer. Andrew Ruben, who spearheads the effort supported by consultant Jib Ellison, explains to a Stanford MBA audience in this University podcast why Wal-Mart is engaging in sustainability.