The study, commissioned by anti-virus software maker, McAfee, and produced by the consulting firm ICF International, found that spam emails worldwide wasted 33 billion kilowatt-hours of electricity in 2008, an amount equivalent to the electricity used in 2.4 million American homes.
At the individual level, a single spam email emits only 0.3 grams of carbon dioxide into the atmosphere, but with an estimated 62 trillion spam emails sent worldwide in 2008, the cumulative emissions of spam are approximately 17 million metric tons of CO2 — a number equivalent to the emissions from approximately 1.5 million American homes.
The report attributes the vast majority of spam’s greenhouse gas emissions to energy used in the process of viewing and deleting spam or searching for legitimate email erroneously trapped in spam filters.
Even anti-spam developers admit their programs drain roughly 16% of a computer’s power devoted to handling spam. Granted, it’s not an ideal solution, but I think we’d all agree it’s a necessary evil.