The Guardian reports that debate has been raging on the net over claims that the amount of carbon emitted as a result of two Google searches is almost equivilent to the quantity released by boiling a kettle. According to research published by US physicist Alex Wissner-Gross, a Google search produces about 7g of CO2.
However, Google has fought back, arguing that "in fact, in the time it takes to do a Google search, your own personal computer will use more energy than Google uses to answer your query."
Ultimately, is there anything that we can do that doesn't create carbon emissions? As the Guardian notes, one commentator says that breathing generates about 6g of Carbon every 10 minutes. I suppose the key is to avoid unnecessary carbon emission. It's arguable whether Google searches falls into this category, but presumably taking the car on a five-minute journey when it's almost as handy to walk would fit the bill.