This article looks into how bad emails are. Is it possible that this seemingly harmless activity, when repeated by billions of people every day is having an outsized impact on the environment?


The data that I am basing this article on is largely from Mike Berners-Lee’s 2010 book How Bad are Bananas: The Carbon Footprint of Everything. I really enjoyed reading this book and it is one of my all-time favourite books on sustainability.

His research revealed that the average spam email has a footprint equivalent to 0.3g of carbon dioxide emissions (CO2e).

That is lower than the carbon intensity of the average email. According to Mike an average email, has a footprint of 4g of CO2e. This is created because of the power drawn for data centres and computers when sending, filtering and reading messages.

There are emails with a carbon intensity significantly higher than average. Emails with large attachments and high-resolution images have a carbon footprint of 50g CO2e. Significantly higher than average.

According to Mike Berners-Lee’s estimates, a typical year of incoming emails adds 136kg of emissions to a person’s carbon footprint. This is the equivalent of driving 200 miles in an average car. Whilst each individual email may only be responsible for a small quantity of carbon emissions, when repeated often by many people, these emissions add up.

At a global scale, the world’s data centres account for three percent of electricity consumption and about two percent of total greenhouse gas emissions. This gives data centres around the same carbon footprint as the aviation industry, when the impact of radiative forcing is not taken into account.

What you need to know

This article looked into how bad emails are for the environment.

We looked into the wide variety of carbon intensities associated with emails.

We looked into how these small releases of carbon emissions multiply over time. This is not helped by the seemingly endless proliferation of emailing in society.

We looked into how data centres are on par with the aviation industry in terms of carbon emissions. It seems strange that there is not more public focus on these emissions. I think the public struggle to make the link between their clicks online and the carbon emissions associated with that online activity.

Thank you for reading,

By Barnaby Nash

Please share your thoughts in the comments section below, or reach out to me on social media. What do you think needs to be done to help make the connection between emails and carbon emissions from data centres?

 Let’s stay connected

I can be reached on LinkedIn and on Twitter @FollowBarnaby

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