Business: U.C. Berkeley professor investigates corporate America's environmental record

During the past decade, a significant number of multinational companies have taken steps to put environmental policies in place. From BP's efforts to reduce greenhouse gases to Home Depot's decision to phase out old-growth timber, some corporations have made substantial progress. In his new book, "The Market for Virtue," author David Vogel explains some of the forces driving these companies to change, including pressure from shareholders and environmental groups. Vogel, a professor at the University of California Berkeley's Haas School of Business, also describes how some corporate environmental efforts have gone awry, and why firms need to make more progress in developing nations.