The Carbon Footprint Of An E-Mail

Another Reason To Reduce The Flow Of E-mail

Source: The Guardian

The carbon footprint of e-mail:

  • 0.3g CO2e: A spam email
  • 4g CO2e: A proper email
  • 50g CO2e: An email with a long and heavy attachment

(CO2e = carbon dioxide equivalent)

Of course, sending and receiving electronic message is never going to constitute the largest part of our carbon footprints. But the energy required to support our increasingly heaving and numerous inboxes does add up.

Very roughly speaking, a typical year of incoming mail for a business user – including sending, filtering and reading – creates a carbon footprint of around 135kg. That’s equivalent to driving 320 km in an average car.

According to research by McAfee, a remarkable 78% of all incoming emails are spam. Around 62 trillion spam messages are sent every year, requiring the use of 33bn kilowatt hours (KWh) of electricity and causing around 20 million tonnes of CO2e per year.

McAfee estimated that around 80% of this electricity is consumed by the reading and deleting of spam and the searching through spam folders to dig out genuine emails that ended up there by accident. Spam filters themselves account for 16%. The actual generation and sending of the spam is a very small proportion of the footprint.

Although 78% of incoming emails sent are spam, these messages account for just 22% of the total footprint of a typical email account because, although they are a pain, you deal with them quickly. Most of them you never even see. A genuine email has a bigger carbon footprint, simply because it takes time to deal with.

The average email has just one-sixtieth the footprint of a letter, according to a back-of-the-envelope comparison. That looks like a carbon saving unless you end up sending 60 times more emails than the number of letters you would have posted in days gone by. Lots of people do. This is a good example of the rebound effect – a low-carbon technology resulting in higher-carbon living simply because we use it more.

Another reason to manage our e-mail behavior…