Search Engine Google was singled out this morning as one of the biggest tech polluters as each Google search actually generates 7g of greenhouse gas and consumes on average 0.6w based on some calculations.
Google has disputed the figures, saying that even if the process of building the search index were to be included, each Google search would generate only 0.2g of CO2, 35x less than what Alex Wissner-Gross, the Harvard PhD student who came up with the figure, calculated.
In comparison, nearly 300 million gaming consoles have been sold during the past decade (and many of them still being used) and the most power-hungry suck in a minimum of 175w, the same as a gaming PC (ed: by comparison the Nintendo Wii consumes a tiny 18w), when in operation.
More significantly, most recent gaming consoles (and a gaming PC) still consume more than 145w even when idle and it is becoming increasingly common that users leave their computers or gaming console on to download files, updates, movies and so on.
If each of these gaming consoles has been used for only 1000 hours during their lifetime, this would amount for 52.5 gWh (1000x0.175x0.3x10^9) roughly.
A conservative estimate would put the worldwide number of web searches at more than 2 billion a day (based on August 2007 figures published by Comscore) out of which Google queries account for 1.4 billion searches.
That's 0.42 gWh (based on Google's own 0.3 watt hours calculation or 280 tons of CO2 per month.
In effect, Google would need to work for more than 10 years before equalling the amount of CO2 generated by the gaming consoles and computers.