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The Carbon Cost of an Email

February 2018 by Emma Charlotte Richards

It is likely that you have sent or received one email so far today, or even 10 or more! When writing, sending or receiving emails the last thing you’re probably thinking about is the carbon footprint – but should you be?

After all, once an email has been sent it’s out there forever, somewhere…

Carbon Literacy is ‘an awareness of the carbon dioxide costs and impacts of everyday activities, and the ability and motivation to reduce emissions on an individual, community, and organisational basis’.

So it’s no surprise that once Carbon Literate, it becomes apparent that everything and every aspect of life has a carbon footprint – no matter how small or seemingly insignificant. This includes the email you just sent.

Below are the average carbon footprints of different emails:

An average spam email:  0.3 g CO2e (carbon dioxide equivalent)

A standard email: 4 g CO2e

An email with “long and tiresome attachments”: 50 g CO2e

This information is taken from the book by Mike Berners-Lee: “How Bad are Bananas?: The Carbon Footprint of Everything“. Mike Burners-Lee is the brother of Tim Burners-Lee, (the guy who invented the internet) two pretty smart guys if you ask me.

This might not initially seem like a lot, but when you consider the number of emails sent and received, it’s easy to see how this can add up. Let’s take a look –

It is estimated that the average office worker receives 121 emails per day, and that half of these will be spam (Global News). Based on my own emails, the remaining half is almost equally comprised of those with and without attachments (those with attachments predominantly have more than one). So…

60.5 spam emails  x   0.3 g CO2e  =  18.5 g CO2e
30.25 standard emails  x  4 g CO2e  =  121 g CO2e
30.25 emails with attachments  x  50 g CO2e  =  1512.5 g CO2e

This means that a days’ worth of emails received is equal to  1,652 g CO2e

And that one years’ worth of emails received equals  603,393 g CO2e  =  0.603393 tonnes CO2e

To put this into perspective, the total yearly carbon footprint of the average person living in India is approx 1.5 tonnes CO2e(Climate Outreach).

By this account, it takes just three average office workers’ yearly received emails to surpass that of another human’s carbon footprint for all their activity for a whole year.

I bet your emails don’t seem quite so insignificant now?

Given the scale of what before seemed a minor impact on climate change, it is encouraging to learn that “ICT solutions have the potential to enable a reduction in global greenhouse gas emissions of up to 15.3% by 2030″ (Policy Connect).  But what can you do as an individual?

1. Reduce the size of emails by lowering the resolution and compressing images and avoid large HTML elements.

2. Regularly clean and maintain mailing lists.

3. Remove any contacts that unsubscribe, and update changed email address immediately.

4. Check your emails thoroughly before sending to ensure they contain all the necessary (and correct) information, to avoid the need for a follow-up email.

5. Link to files or information online rather than adding an attachment.

Some of the advice listed above has been adapted from Mail Jet.





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