The environmental impact of spam

McAfee announced new research findings that reveal spam e-mail is not only a nuisance, but is damaging to the environment and substantially contributes to green house gas (GHG) emissions.

In McAfee’s “Carbon Footprint of Spam” study, climate-change researchers ICF and spam experts calculated globally the annual energy used to transmit, process and filter spam totals 33 billion kilowatt-hours (kWh), or 33 terawatt hours (TWh). That’s equivalent to the electricity used in 2.4 million homes, with the same GHG emissions as 3.1 million passenger cars using 2 billion gallons of gasoline.

A day without spam

In late 2008, McColo, a major source of online spam, was taken offline and global spam volume dropped 70 percent. The energy saved in the ensuing lull before spammers rebuilt their sending capacity, equated to taking 2.2 million cars off the road that day, proving the impact of the 62 trillion spam e-mails that are sent each year.

Research findings

The “Carbon Footprint of Spam” study looked at global energy expended to create, store, view and filter spam across 11 countries, including Australia, Brazil, Canada, China, France, Germany, Japan, India, Mexico, Spain, the United States and the United Kingdom. It correlated the electricity spent on spam with its carbon footprint, since fossil fuels are by far the largest source of electricity in the world today. Since emissions cannot be isolated to one country, it averaged its findings to arrive at the global impact. Key findings of the “Carbon Footprint of Spam” study included:

  • The average GHG emission associated with a single spam message is 0.3 grams of CO2. That’s like driving three feet (one meter); but when multiplied by the yearly volume of spam, it is equivalent to driving around the earth 1.6 million times.
  • Much of the energy consumption associated with spam (nearly 80 percent) comes from end-users deleting spam and searching for legitimate e-mail (false positives). Spam filtering accounts for just 16 percent of spam-related energy use.

    Spam filtering saves 135 TWh of electricity per year. That is equivalent to taking 13 million cars off the road.

    If every inbox were protected by a state-of-the-art spam filter, organizations and individuals could reduce today’s spam energy by 75 percent or 25 TWh per year, the equivalent of taking 2.3 million cars off the road.

    Countries with greater Internet connectivity and users, such as the United States and India, tended to have proportionately higher emissions per e-mail users. The United States for example, had emissions that were 38 times that of Spain.

    While Canada, China, Brazil, India, the United States and the United Kingdom had similar energy use for spam by country, Australia, Germany, France, Mexico and Spain tended to come in about 10 percent lower. Spain came in at the lowest, with both the smallest amount of e-mail that was received as spam and the smallest amount of energy use for spam per e-mail user.

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