Walmart's Sustainable Product Initiative is an ambitious, multi-year project aimed at determining the environmental and social footprint of all of the products on Walmart shelves.

The project will be rolled out in three phases, beginning with survey of all of Walmart's suppliers around the globe. The survey consists of 15 questions in four categories: energy and climate, material efficiency, natural resources and people and community. Suppliers will be asked to fill out the questionnaire by October 1.

The second phase of the project involves the development of a Sustainability Index Consortium, a coalition of universities and suppliers, retailers, NGOs and government entities working together to build a global product-lifecycle database, measuring the impact and resource use of products from raw materials through to end of life.

Walmart said it intends to make the database open to the world rather than proprietary information, although the company has yet to choose a partner to work on the development of the database.

Finally, once all the lifecycle data has been compiled and analyzed, Walmart and its partners will develop a customer-facing rating system to enable shoppers to make choices based on the environmental impact of their purchases.