By now you’re probably aware of Wal-Mart’s efforts to green its business practices and its image. If you haven’t, you probably will soon. The company that a business professor I recently met called the 13th largest economy in the world has launched an advertising onslaught tied to Earth Month. According to Wal-Mart’s news release, its national advertising campaign includes print, television, radio and online ads and a 16-page insert in May issues of several consumer magazines. Brandweek says the company calls it “the most comprehensive environmental sustainability campaign” in its history.

No less of an environmentalist than Paul Hawken, speaking at his book-tour event in Portland last year, said Wal-Mart was indeed serious and sincere about sustainability. The professor I mentioned supports Hawken’s assessment. She is among a group of academics taking part in Wal-Mart’s green initiatives and is a regular visitor to Wal-Mart’s home in Bentonville, Ark. The company’s new-found green zeal is apparent on its website:

Wal-Mart’s environmental goals are simple and straightforward: to be supplied 100 percent by renewable energy; to create zero waste; and to sell products that sustain our natural resources and the environment.

What to make of all this? This is Wal-Mart we’re talking about, the company so many, including me, have good reasons to despise. I’m on the board of a Portland nonprofit that actively supports locally owned, independent businesses and encourages people within our community to do the same. This in the face of out-of-town big-box retailers — Wal-Mart being the poster child — that have decimated so many local independent businesses and left their communities poorer for it.

Still, if Wal-Mart — given its staggering size — is successful in using only renewable energy, producing zero waste and greening its supply chain and the products it sells, it would have an enormously positive impact on the global environment. Or so it would seem.

Something, however, doesn’t add up for me. Green or no, Wal-Mart hasn’t backed off using low prices to beat its competition (including the Mom & Pops in your town). The message it’s sending is you can have it all. “Save Money. Live Better.” — it’s new slogan promises. Wal-Mart will drive its suppliers to go greener, but it will still expect the lowest possible prices from them. That protects its profit margins and enables its customers (in theory) to save money. But someone or something has to pay for Wal-Mart’s margins and our low prices — as has always been the case.

What do you think? If Wal-Mart achieves its environmental sustainability goals, will it have earned your admiration, maybe even turned you into a customer? Is going green enough? Or do you, like me, view sustainability as far more than going green? What about the matters of social and economic equity? Wal-Mart’s lower prices and business practices mean lower wages, loss of independent businesses and the community diversity they bring and the leakage of dollars out of local communities and into the coffers of Wal-Mart headquarters. Should we just chalk that up to the free market doing its thing?