A single email can be anywhere between 0.03g CO2e to 26g CO2e.

The urgency given to how human activity affects the environment is growing with each passing year, and the figures showing how little time we have to reverse this predicament are becoming increasingly more troubling. 

Attempting to address global issues on a personal level can be intimidating, but there remain a number of ways to contribute to making a difference – and one highly unlikely option is right in your inbox. 

It is probable that another pointless email was delivered to your spam folder in the time it took you to read this, and that email is still consuming digital storage space and electricity.

While spam may be perceived as the most unnecessary email waste, the emails we write and read ourselves have a bigger impact on the environment than you may be aware of.

Understanding how to assess the greenhouse gas emissions produced by an email is the first step towards understanding the environmental impact of one.

Your laptop or phone uses electricity as you type a message. The network connection supplying your internet and the server transferring your message to its intended recipient both require electricity when you click “send” on the message. How then do we calculate an email’s overall carbon footprint?

For a broad sense, you can utilise tools like the convenient email CO2e (carbon dioxide equivalent) calculator. To get a deeper understanding, there have been several in-depth studies undertaken to help address this question, one of them is by Lancaster University professor Mike Berners-Lee.

In his book ‘How Bad Are Bananas?’, Berners-Lee determines an approximation of the carbon contribution of common items and routine activities, such as email use, using the metric CO2e, which reflects the combined carbon dioxide equivalents from every greenhouse gas the source generates.

Berners-Lee uses an average annual carbon footprint of 7 tonnes CO2e for each person as a baseline.

Did you ever think about the waste of “Thank You” emails alone? Yes, those one to two word expressions of thankfulness also produce carbon.

In late 2019, energy supply business OVO calculated that each round of “thank you” emails sent by the adult population of the UK alone produced the carbon equivalent of 81,152 flights between Heathrow and Madrid.

But just as our knowledge of the effects of emissions continues to advance, so do our techniques for assessing those effects. Because of this, Berners-Lee updated his conclusions with new information last year. As a result, we now have a better idea of how our email footprint actually appears.

Berners-Lee calculates that a single email can be anywhere between 0.03g CO2e to 26g CO2e based on latest data. Due to the various ways emails are utilised, both by individuals with good intentions and those without, the carbon emissions produced don’t know how to differentiate.

We can collectively reduce carbon emissions by ceasing cliched politeness like “thank you” emails. According to energy business OVO, if every adult in the UK sent one fewer “thank you” email a year, it could prevent 16,433 tonnes of carbon emissions, which is the same as removing 3,334 diesel vehicles from the road.

Spam, which emits only 0.03g CO2e, is the least harmful culprit. What about the sheer amount of spam that is transmitted, which is what makes it initially so annoying? According to Statista, email users exchanged more than 306 billion emails in 2020, with slightly under 50% of those being spam.

If that ratio astounds you, it means that your inbox spam filters are likely doing their job and keeping undesirable mail from even coming to your attention. Spam only makes up a small portion of the energy used by these invisible communications as they pass through your inbox.

The cause? It turns out that the quality of each email sent is just as crucial as, if not more so than, the quantity of emails sent. That’s because you consume more electricity the longer you spend writing, reading or responding to a message. Even a brief email that is prepared and read correctly emits 0.3g CO2e, which is ten times more than a spam message.

What steps can you take to reduce your email footprint?

There are a few small steps you can take that make a difference in your carbon footprint:

• Clear your inbox from emails you do not need. Keeping unwanted emails stored uses electricity and water, both of which produce greenhouse gases.
• Unsubscribe yourself from mailing lists that you don’t need. Update your own mailing lists.
• Write concisely.
• Write emails only to people who require the information you are providing.
• Do not disclose your email address to spammers or other potential sources.

In mass-blast, wordy messages, the numbers really start to soar. Berners-Lee reserves such examples for the higher end of his calculations, figuring that an email you write for 10 minutes, send to 1 person who really reads it, as well as 99 other people who scan it but don’t respond, generates 26g CO2e.

There are 4 billion active email users worldwide, so that 26g can add up rapidly.

Although people are becoming more conscious of email’s negative effects on the environment, it still appears that there may not be much of a shift in the near future; in fact, an increase in email usage is forecast.

Email usage on the rise

In Statisa’s 2021 report, it was stated that “the number of e-mails sent and received globally has increased each year since 2017. While roughly 306.4 billion e-mails were estimated to have been sent and received each day in 2020, this figure is expected to increase to over 376.4 billion daily mails by 2025.”

Traditional email systems are expected to be used more frequently, which will not only raise each of our individual carbon footprints but also have a negative impact on how we interact and coexist as a species.

According to Berners-Lee’s calculations, even if it took 4 minutes to read and write each email, there would still be 150 million tonnes of carbon dioxide produced yearly, or 0.3% of the world’s carbon footprint.

Email is typically a more effective way to convey written communications than letter mail, which emits 20 times as much CO2e. Still, it’s a drop in the bucket compared to other sources of pollution.

However, higher efficiency poses the risk of increasing carbon emissions through excessive, reckless use, just like any new technology.

Even if the minor but significant impact your inbox has on your personal emissions count doesn’t cause you to stop, the other waste products produced by an unmanageable inbox, lost time, squandered storage and irksome notifications, might.