Presenting the new green giant: Wal-mart!

Pilloried in the media, and notably in Barbara Ehrenreich's must-read Nickel and Dimed, for its low, low pay and appalling lack of benefits, Wal-mart has cleaned up its act. Okay, conditions for workers may not have improved so much, but perhaps they will: surprisingly for a company whose employees often have to supplement their incomes with welfare, the mega-retailer recently announced it's officially supporting an employer mandate on health care.

Which would be great in and of itself, but another announcement has knocked that one out of the water: Wal-mart is creating a (self-reported) scorecard for its 100,000 global suppliers detailing their impact on energy and climate, natural resources, material efficiency and people and community, which will then be converted into an index – a number, for example – to label the product in stores. With one main challenge of sustainability being the difficulty of standardizing eco-claims, this project could be a huge boon to many companies looking to go green, as well as consumers looking to compare the relative claims of various products. Wal-mart will not own the index, which it says is a collaboration with universities, NGOs, governments, suppliers, and retailers.

Meanwhile, Wal-mart isn't just regulating its suppliers – they're greening their own stores, too. Lately, they've cut their energy consumption 15% by installing a "daylight harvesting" system that dims lights when natural light streams in from windows and skylights.