"Globally, the IT industry produces about the same volume of greenhouse gasses as the world’s airlines do,” writes Jason Stamper in Standpoint. That’s somewhere in the neighborhood of two percent of the modern civilization’s CO2 emissions.
Even your Google searches have a carbon footprint:
A Google search can leak between 0.2 and 7.0 grams of CO2, depending on how many attempts are needed to get the "right" answer. At the upper end of the scale, two searches create roughly the same emissions as boiling a kettle.
To deliver results to its users quickly, Google has to maintain vast data centres around the world, packed with powerful computers. As well as producing large quantities of CO2, these computers emit a great deal of heat, so the centres need to be well air-conditioned - which uses even more energy.
So here’s something funny: According to Google’s search trends database roughly 368,000 people search “carbon footprint” every month. You get where I’m going with this, right? Even the words “carbon footprint” have a carbon footprint! Ugh.