Former Walmart environmental policy consultant and current Saatchi & Saatchi sustainability chief Adam Werbach has a different approach to dealing with environmental woes from most greenies.
The 39-year-old, who once spearheaded the United States' environmental movement as the youngest president of the Sierra Club - the largest environmental grassroots organisation in America - made the shift into the corporate world in 2006.
Since then he has worked with some of the world's biggest companies towards creating sustainable business practices, including Procter & Gamble and Sony BMG.
Working with these corporations has come at a price for Werbach. When he signed on with Walmart he was labelled a sell-out by many of his colleagues and friends, some of whom still don't speak to him today.
But for Werbach, the offer to work towards greening one of America's largest companies was too good to turn down.