Over at our brother blog Digital Nirvana, Phil Riebel has an excellent post in which he identifies the difference between “green” and “sustainable”:
Sustainability includes three elements, or three “pillars”: environmental responsibility, social responsibility and financial responsibility.  Sustainability takes into account the realities of our economy and our society.  In other words, it means that organizations or individuals should operate in a financially sound framework but also be socially and financially responsible in their activities and operations. Think of the “environment” or being “green” as just one of the three pillars, and don’t dismiss the other two.
It’s common to conflate “environmental sustainability” with general “sustainability,” and while here at Going Green we tend to focus on that one pillar, we (the royal we) should make a conscious effort not to ignore 2/3 of the definition of sustainability.