Everywhere you go these days there seems to be a vendor talking about the virtues of green computing. The most recent example of this trend was Microsoft CEO Steve Ballmer last week promising to reduce the amount of energy that Microsoft products consume by a factor of five.
Ballmer wasn't very specific about how this would be accomplished, but you could take it as a tacit admission that a lot of bloated code that has built up over the years is a major contributor to the problem.
The basic pitch from all these vendors is that IT organizations should upgrade their computer infrastructure in the name of saving energy costs. That in turn will have a positive impact on the environment because there will be less harmful carbons produced.