Protect every e-mail inbox with a top-notch spam filter, and the result would save 25 terawatt hours of electricity and reduce greenhouse gases as much as taking 2.3 million cars off the road.
That's one of the conclusions of a new report out Wednesday from ICF International and McAfee. The report details the energy effect of the enormous spam tide that has engulfed the world's e-mail -- an estimated 62 trillion spam e-mails in 2008 alone.
ICF is a global professional services firm that works with government and corporate clients on climate change, energy, environment and other areas. McAfee is a leading provider of security and spam-catching software.
62 Trillion Spams
Although spam involves no postage or actual paper envelopes tossed into the garbage, it does use up energy and create pollution. The report, one of the first to look at spam from this point of view, set the "annual spam energy" for the planet at about 22 billion kilowatt hours, which it said is equivalent to the electricity use of 2.4 million homes in the U.S. or the same greenhouse gas emissions of 3.1 million passenger cars using two billion gallons of gas.
Current spam-fighting efforts do help, with filtering saving 135 terawatt hours, equal to taking 13 million cars off the road. According to the report, a typical medium-sized business uses 50,000 kWh to handle e-mail, of which more than 20 percent can be spam-related.
The report associates 0.3 grams of carbon dioxide to each spam message. It admits that the "average legitimate e-mail" also results indirectly in carbon dioxide, almost four grams worth, but notes that 80 percent of all e-mail messages -- consumer and business -- are spam.
'Lots of Grains of Sand'
Of course, spam filtering itself consumes energy, but the report put it at only 16 percent of spam-connected energy use. The largest use of energy comes from simply deleting spam and looking for real e-mail -- 52 percent of spam-related energy.
McAfee commissioned ICF to study the environmental impact of spam, noting that most of the reporting thus far has been on the financial impact. McAfee said it hopes the report will "aid the decision makers who are working to stem the tide of spam e-mail and open a timely conversation on the costs of e-mail spam to the planet."
Laura DiDio, an analyst with industry research firm Information Technology Intelligence Corp., said she expects the report could have an impact on companies that have set reducing their carbon footprint as a goal. She noted that these include such household names as Intel, Dell, Hewlett-Packard, IBM, Apple and Microsoft.
IDC's Chris Christensen agrees that this energy-conscious view of spam "just makes sense." People tend to look at an individual e-mail spam as "a grain of sand," he said, but when "you add together lots and lots of grains of sand, you've got a weighty matter."