Do you know that information and communications technologies (that includes your laptops and PCs, data centers and computing networks, mobile phones, and telecommunications networks...) is going to be, if it isn't yet, one of the biggest carbon emitters on earth?
P.S.1 If you want to know more, just register for free. And no, I don't work for McKinsey...and yes, I'm being lazy.
P.S.2 If McKinsey's advice doesn't work, you can always shelve out more cash and ask for advice from IBM's new Green Sigma Consulting.
P.S.3 Or just buy Apple's new green MacBook line, which was launched yesterday. The new MacBook line is said to meet stringent energy and environmental standards; do not contain brominated flame retardants; use only PVC-free internal cables and components; and use energy efficient LED-backlit displays that are mercury- free and made with arsenic-free glass.
A more general economy-wide McKinsey report CO2 reduction potentials, with IT-related items listed under "commercial and residential electronics" is here. It lists savings of upto 90 (2005)$/T CO2 avoided for residential and commercial electronics.