The sending, sorting and filtering of spam email alone accounts for 33bn units of electricity each year
Spam
The carbon footprint of spam:
0.3g CO2e: A spam email
4g CO2e: A proper email
50g CO2e: An email with long and tiresome attachment
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 (remember that all complex carbon footprints are really best guesses), a typical year of incoming mail for a business user – including sending, filtering and reading – creates a carbon footprint of around 135kg. That's over 1% of of a relatively green 10-tonne lifestyle and equivalent to driving 200 miles 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.
If the great quest is for ways in which we can improve our lives while cutting carbon, surely spam and unnecessary email have to be very high on the hitlist along with old-fashioned junk paper post. But what can be done?
Here's one radical idea: a tax of a penny or cent per message sent. Obviously this wouldn't be ideal from the perspective of digital access, and it might be impossible to implement. And no-one likes an extra tax. But it would surely kill all spam instantly. The funds could go to tackling world poverty, say, or to help unlock a global emissions deal by supporting adaptation and technology transfer payments. The world's carbon footprint would go down by a substantial 20 million tonnes even if genuine users didn't change their habits at all. The average user would be saved a couple of minutes of their time every day and an annual fund of up to £170bn would be made available.
