ClimateWire: If a single executive at Wal-Mart Stores Inc. deserves the lion’s share of credit for the company’s recent drift into corporate sustainability, most agree it is Lee Scott, CEO of the largest retailer on the planet from 2000 to 2009. Scott, now the chairman of Wal-Mart, has been praised by many for sparking a cultural overhaul at the big-box chain that resulted most recently in a voluntary commitment to slash 20 million metric tons of carbon emissions from its global supply chain by …