• by Staff Writers , April 15, 2008

Google's braintrust won't tell. Sure they make a commitment to reducing the company's carbon footprint, but they aren't sharing its current output (out of fear that competitors will use that information to calculate how many servers they have). But there are ways of finding this information - at least roughly. And with the help of ERM, a UK-based environmental consultancy, we attempt to do just that.

The misleadingly named server farms suck enough kilowatt hours to light Las Vegas. Based on Ask.com operations vice president Dayne Sampson's estimate to Wired mazine that the five leading search companies together have some 2 million servers, Simon Foster, a consultant with ERM, has estimated the amount of CO2 they produce combined.

ERM estimates that each server uses around 200 watts per hour, which over a year comes out to: 2,000,000 x 200 watts x 24 hours x 365 days = 3,504,000 x 106 watts.  = 3,504,000,000 kilowatts each year.

"Now if we assume that each kilowatt hour = 0.6kg of CO2 in the U.S. (and this is a conservative estimate) then the five top servers produce 2,102,400 tons of CO2?," concludes Foster.

Google's share of searches run on the top five engines comes to about 59.5 percent according to comScore statistics. Our rough estimate of the search giant's giant carbon footprint (for search alone) is 1,240,416 tons of CO2 a year. How do you send an e-condolence card to the planet?

*Calculations courtesy of ERM (erm.com); for more info on carbon footprinting contact   Charles Alison, partner, (charles.allison@erm.com) †Media magazine estimate