The McKinsey / Uptime Institute report Revolutionizing Data Center Efficiency, available as both a PowerPoint and a podcast, contains a wealth of current and projected data on energy utilization and GHG (greenhouse gas) emissions, including information about what various enterprises are doing. Among its findings:

"[One of] the primary drivers of poor efficiency [is] significant failings in asset management (6% average server utilization, 56% facility utilization)"

"Improving efficiency is the best near term means to solving the twin challenges of rising spend and GHC emmissions"

"Enterprises and their equipment providers will face increased scrutiny given the projected quadrupling of their data center GHG emissions by 2020"