We send a lot of email. As a marketing agency, it’s hard for us to imagine ever doing business without it. Everyday, we send emails to our clients, amongst our team, and to people that have asked us for marketing advice and information. In fact, if you’re one of our newsletter subscribers you may be reading this article because we just sent you a link to it… with an email.

Hitting that send button is effortless. It feels so natural and easy, you may never think about all the work that goes on behind the scenes: the servers, power plants, and other infrastructure that make email possible.

But all that infrastructure comes with an environmental cost. How much? We’re glad you asked…

How is carbon footprint calculated?

If you found this article by searching, ‘what is the carbon footprint of an email,’ then we’ll save you some time and just answer your question right now…

The carbon footprint of a spam email:
0.3g CO2e

The carbon footprint of regular emails: 4g CO2e

The carbon footprint of an email with an attachment: 50g CO2e

Source: BERNERS-LEE, MIKE. HOW BAD ARE BANANAS?: the Carbon Footprint of Everything. PROFILE BOOKS LTD, 2010.

Hopefully that helps you settle the debate you’re having with your friend.

However, if you’re here because you want to know why email has a carbon footprint or you’re wondering exactly how those numbers are calculated, we appreciate the curiosity and we’ve got you covered.

Carbon footprint is calculated by figuring out how much of the following greenhouse gasses are emitted during any activity: Carbon dioxide, Methane, Nitrous oxide, Hydrofluorocarbons, Perfluorocarbons, and Sulphur hexafluoride. Then, using math that’s honestly too complicated for this writer to understand, they’re all worked out into a single measurement: CO2e.

What’s important to understand is that the measurement takes into account all the legwork involved in an activity, not just the activity itself. For example, burning gas in your car produces a specific and measurable amount of C02. However, the carbon footprint would include all the emissions required to extract the oil from the ground, refine it, and deliver it to the gas station.

Complicated. Yeah.

When calculating the carbon footprint of a single email, the equation includes the cost of running servers, your laptop, and a fraction of the energy required to read, send, and delete it. On the surface it doesn’t look like much. At 4g C02e, that’s more than sending a text (0.014g), but far less than say, taking a shower (1kg). So what’s the issue?

The daily carbon footprint of email

Every day, the world sends more than 293 billion (with a freaking ‘B’!) emails. If 55% of those emails are spam, that means you’re looking at the following daily carbon cost of email:

186 billion regular emails: 744,000 metric tons CO2e

107 billion spam emails: 32,100 metric tons CO2e

Total daily carbon footprint: 776,100 metric tons CO2e

That’s an extremely conservative estimate though, because we aren’t factoring in attachments. In reality, the cost would be much higher due to all the PDFs, spreadsheets, and cute cat photos that the human race sends every day.

Reducing your carbon footprint

So what can be done? Well, when it comes to email there’s a few easy steps you can take to reduce your own carbon footprint:

  • Don’t CC people unless absolutely necessary.Every person that receives, reads, and takes action on an email contributes to the total carbon cost. Unless someone truly needs to be part of the conversation, resist the urge to CC them.

  • Include all necessary details.If you leave out important information then your conversation partner will have to follow up. That means more email and more carbon. Try to include as much information as necessary to avoid prompting a reply.

  • Be careful with attachments.

Sending fewer attachments is just the start. Also be careful to ensure you’re not forwarding attachments when you reply to an email. Often, hitting the reply button will send a recap of the previous email, attachments and all. Watch out for this, and remove any extra weight from your reply before you hit send.

Keep in mind that email is just one, small part of your total carbon footprint. If you’d like to learn more, try one of the many carbon footprint calculators available online (our favorite) to find out how much your day to day existence is contributing to global warming.

January 29, 2021

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