The Open Compute Project is working hard to generate and develop a leadership stance on environmental stewardship. Facebook, one of the founders of Open Compute, has made significant accomplishments by establishing industry leading Power Usage Effectiveness (PUE) metrics (the ratio of the power delivered to a facility that is available for servers to consume).
A perfect 1.0 PUE would mean that all the power delivered to the facility is available for servers to consume. Typically, power is lost in conversion, transport and delivery from a power utility to a server system. A common PUE you will see in the industry ranges between 1.2 and 1.5. Facebook has been able to achieve a PUE that is sub 1.1. As noted this is an impressive accomplishment.
Another area to which we look for advancements in sustainability is simplification of the servers themselves. Focusing on things like material selection and sheet yield, reduction in component count and optimization of the overall assembly process can yield real environmental benefits. All of these things play into a very effective environmental envelope meant to deliver solutions optimized for environmental stewardship from the inside out.