A Fortune article (July 25, 2011) titled “The Trouble with Green Product Ratings” describes the challenges faced by WalMart as it tried to deliver on its stated goal, two years ago, to provide an index between 1 and 10 for all products.  The main issue was that possible measurements of a product’s supply chain were full of tradeoffs – for example, replacing recyclable packinging with cups made from plants that go into a landfill generated fewer emissions, fixing the feed for cows whose milk went into organic yoghurt was the key to reduce cow burps and the associated methane emissions, switching to organic cotton caused the amount of water used to be significant.  Thus, a recent statement from WalMart just suggests more information for customers to make choices rather than an index.  Should sustainability be described by a series of measurements (like nutrition data) rather than an index ? Should there be a national standard rather than adhoc individual standards ? Should some “bottle bill” like scheme be developed to encourage consumers to care about environmental impact by charging for end of life costs ?