There are few pieces of office equipment as ubiquitous or as necessary as the personal computer. While the number of PCs in use worldwide is nearly impossible to estimate, their prevalence as a basic tool may be obscuring their role as energy consuming devices.
Because PCs, along with the servers that support them, are estimated to be responsible for 2 percent of all global carbon dioxide emissions, a figure equivalent to all emissions of the gas that have resulted from global airline travel.
Several factors are driving this surprising figure. Corporations and institutions, for example, are increasingly relying on massive data centers where hundreds of servers may be housed in a single complex. Google is estimated to have as many as 450,000 servers housed in 25 locations around the world, while Microsoft has as many as 200,000 and plans to raise that to 800,000 by 2011.