What‘s the carbon footprint of an email?

Nowadays we are all asking ourselves “How can I reduce my carbon footprint?” And many of us are spending more and more time online – working remotely as well as streaming our favorite series and listening to music. In many cases business travel has also been replaced by chats, video calls, and, of course, emails.
Email’s carbon footprint depends on the energy used in the data center
Email’s carbon footprint depends on the energy used in the data center
Each of these online activities still cause carbon emissions, even if only a few grams.

This is because energy needs to be generated to power our devices and Wi-Fi – and, more significantly, the data centers and servers needed to store all that content and keep the internet running. So how do our emailing habits impact on the environment?

  1. What’s the footprint of an email?
  2. Data centers and our carbon footprint
  3. mail.com and green energy
  4. Reduce your email carbon footprint
  5. Email vs. text vs. snail mail

Email carbon footprint: Calculations vary

The footprint of an individual email can vary dramatically. In 2010,  Mike Berners-Lee, a researcher at Lancaster University (and brother of the man who invented the World Wide Web), crunched some numbers and came up with figures ranging from 0.3 g CO2e (carbon dioxide equivalent) for a spam email to 50g CO2e for an email with a “long and tiresome attachment.” These figures not only account for the IT infrastructure you need to receive, read, write and send emails in your home or office, but also the power used by the servers and data centers that process and store them. Based on these numbers, he estimated that receiving emails adds 300 pounds of emissions to the average person’s carbon footprint in a typical year.

A more recent figure comes from Germany, where in 2019 an expert in the Bavarian consumer protection agency estimated that a normal email without an attachment is responsible for 10g CO2e – about the same amount as a plastic bag – and that the amount is doubled by adding a one-megabyte attachment. A another study performed in 2019 by UK power company Ovo Energy tackled the problem from the other end, calculating how much we can reduce our carbon footprint by cutting down on emailing. Their conclusion: if every email user in that country were to send one fewer email per day, it would lead to a total annual reduction of 16,433 metric tons CO2e – the equivalent of 81,152 flights between London Heathrow and Madrid.

Data centers – the key to our digital carbon footprint

The two factors contributing to our email carbon footprint are the energy used at home or work to write the emails, and the energy it takes to store and transmit them through servers and data centers. The energy efficiency of data centers has been improving by leaps and bounds, but in the United States they are still responsible for two percent of the country’s electricity use. Everywhere you look nowadays, however, electricity is being generated by cleaner methods, which means that the energy powering servers and data centers is greener as well.

Climate-friendly email from mail.com

In the case of mail.com, our data center in Kansas – which has an annual power consumption of 13 GWh – has been using 100 percent wind energy since 2020. We also do carbon offsets for the footprint of our headquarters in Pennsylvania in the form of renewable energy certificates. So we can proudly affirm that mail.com is an extremely climate-friendly email service. This helps all mail.com users shrink their personal carbon footprint through the reduced environmental impact of sending or receiving email.

How you can reduce your email carbon footprint at home

Besides signing up with a green email provider, there are other steps individuals can take to bring the climate impact of each email down to zero. The most important is choosing the right home energy supplier to make sure the inbox on your screens is being powered by green energy. In addition, environmental experts suggest reducing the size of emails and the amount of email data you save to cut the amount of power it takes to store them. Here are a few tricks that can help:
  • Send links to files instead of attachments (our free Cloud file sharing feature is great for this!)
  • Unsubscribe from newsletters you no longer read
  • Reduce email size by compressing images and avoiding large HTML elements
  • Regularly update your mailing lists so no messages are sent to invalid addresses
  • Delete old, unnecessary emails from your custom folders, and empty your Trash and Spam folders regularly (check your folder settings)
  • Turn off social media email notifications – usually they just duplicate information you already see online

Carbon footprint of email vs. text or letter

You may also have wondered what is the most climate-friendly way to keep in touch – if a text message or a good old-fashioned letter might have a lower carbon footprint than your email. In a 2016 interview, Berners-Lee estimated that a regular text message is only about 0.014g CO2e, which is only a tiny fraction of the average person’s daily carbon footprint of 30 kg per day – about 700 times less than the average email. These calculations vary extensively, however, with French IT expert Frederic Bordage putting the number much lower at 0.00215 g. It is clear, however, that a text has a lower carbon footprint than an email. Snail mail, however, has a much larger environmental impact: A 10-gram letter averages 140g CO2e, or 14 times more than an email.This larger number makes sense, since it includes the carbon emissions of the vehicles used to transport the letter from sender to recipient.

If you’d like to find out what your personal email carbon footprint is, check out the email carbon footprint calculator from 8 Billion Trees. And if you'd like to read more about our company's commitment to environmental sustainability, the 2021 sustainability report (PDF) is now online.

Did you learn something about your carbon footprint today? Please give us a thumbs-up below!

This article first appeared on April 22, 2021 and was updated on April 21, 2022

Images: 1&1/Getty Images

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