Tech as dirty as aviation - IT Director - Breaking Business and Technology News at silicon.com: "The global IT industry accounts for two per cent of the world's carbon dioxide emissions - the same amount the world's aviation industry churns out, according to analyst house Gartner.
The estimate is based on the amount of energy PCs, servers, cooling, fixed and mobile phone systems, LANs, office telecommunications and printers all use within the world's offices."
So IT can make a difference here too. (But in the winter, IT energy probably reduces heating expenditures.)