What is the carbon footprint of an email?

12 June 2023 | digital pollution


In the world in 2022, 6% of greenhouse gasses are caused by digital. Among the digital uses, we usually send emails, for our own uses and for the professional. Indeed, according to Statista, nearly 319.6 billion emails have been sent and received every day in 2021. So, what is the impact of emails on our environment?

What is the carbon footprint of an email?

A study of the Carbon Literacy Project shows that emails can emit between 4 to 50 grams of CO2. Yes, 4 grams for an email with no attached files, 11 grams for an email with attached files of 1Mb and up to 50 grams for a long email with several attached files.

The ADEME estimates thus that sent professional emails by salaries of a company of 100 persons generate every year 13 tons of CO2. This represents 13 round-trip flights between Paris and New York.

The email isn’t the single emitting source of CO2. Send emails, it’s also sending them to data centers, which have an important impact on the digital carbon footprint. Indeed, they work 24h/24 and need to be cooled.

The majority of emails in France run on average 15 000 km. Once the emails are received, they are generally stored. A stored email in a data center for a year emits on average 10 grams of CO2.

The carbon footprint of emails is also linked to its terminal. Indeed, a sent email on a phone won’t have the same impact as on a computer, because the phone will use less energy than a computer with a big screen.

How to reduce the carbon footprint of his own box mail?

  • Sort regularly your box mail

You can sometimes clean your box mail. Don’t forget to delete all the emails that go in your spam box. Also delete the read emails that are no longer useful. Once your box is sorted, don’t forget to empty your bin.

  • Unsubscribe you from useless newsletters

We all do it, we generally sign in to the newsletter to have the promo code of the inscription but after, do we really read this newsletter?

Useless to keep in your spams or your box mail newsletter that you don’t read anymore or even never read at all. To seriously reduce these emails, unsubscribe you of these newsletters. A tool such as CleanFox can help you automate some of these tasks.

  • Delete your other boxes

Don’t keep your old email address in which unread emails pile up. Privilege a single and same personal box mail and categorize its content to help you understand.

  • Lighten your emails

Avoid attached files per mail or think about compressing them before including them in your email. If you have many attached files to transfer, favor compression as a folder and don’t forget to merge PDFs that have the same information.

If you send attached files to several persons at the same time, of which some of them are simply in copy for information, you can use the document delivery services with a finite life.

You can for example use the tool FileVert, that allows you to send documents more responsibly.

  • Favor another share mode

If you want to transfer heavy files, don’t forget your good old USB drive.

How to reduce the carbon footprint of his professional box mail?

The applicable tips of your personal box mail also can be done on your professional box mail. But moreover, other tips can reduce the carbon footprint of emails in a company.

In a company, on average, every salary sends 33 emails of 1Mo per day. In the world, 188 million emails are sent every day. Here’s few advice to help:

  • Avoid talking by email

Avoid talking with your colleague by email if the exchange can be done orally. Favor spaces of dedicated exchange. You can use messaging platforms or use the chats in the box mails. *

Think to invite your collaborators to target the recipients: avoid clicking on “answer all” and to multiply copies.

  • Lighten your electronic signatures

You can reduce the weight of your emails, by lightening your signature. For the external messages (clients, suppliers, providers, etc. …), rather a signature, with a light image, of some ko.

For the intern communications, (between colleagues) you can create a signature with no logo and minimalist. (name, first name, work).

Be also careful with the beautiful animated signatures. They are generally more heavy than classic signatures. Concerning the animation for wishes, the company’s birthday, or other special operations, favor the messages in text, with a light image, rather than an animation.

  • Send targeted newsletters

You can regularly clean your list of diffusion by deleting the invalid emails addresses. You can analyze your sendings and thus see among your recipients/subscribers who doesn’t open your emails.

 How to reduce the pollution of email marketing strategy?

It’s tough to limit when we use strategies like emailing for his marketing operations. To respect the environment and reduce the carbon footprint, you can use automation marketing.

  • Segment your targets

You can segment your targets, to send emails only to the people concerned by your marketing operation. With good targeting, you reduce your carbon impact and you increase the commitment of your readers.

  • Avoid the reminded emails

It’s not necessary to send reminder emails to people that have already made the action that you put in place. Put in place solutions, tools to stop you when your objective is reached.

  • Send targeted newsletters

You can clean your diffusion list regularly by deleting the invalid email addresses. You can analyze your sending and thus among your recipients/ subscribers who don’t open your emails.

  • Optimize the content of your emails, particularly the images

Your marketing email includes images? If images aren’t optimized properly, they will weigh heavier, and will pollute more. By using the good practices to optimize images for the web, you reduce the pollution of your emailing marketing campaigns operations, while optimizing their deliverability rate.

These techniques of better targeting will increase your opening rate, and to reduce the cost of sending emails platforms, generally billed by volume.

What solutions to manage his emails and his carbon footprint?

On average, French people keep between 10 000 to 50 000 emails unread in their box mail. We remind you, a stored email is emitting 10 grams of CO2.

You don’t have the time to manage your emails? Did you know that there exist several solutions that help you clean your box mail and thus reduce your carbon footprint!

CleanFox: a service that automatically deletes emails that you don’t want anymore by unsubscribing you from these newsletters.

FileVert: Favor this French software, secured, responsible and very simple to use for your heavy sending.


To go furthermore into the digital carbon footprint reduction, you can also reduce the carbon footprint of your website. How?

Greenoco can calculate the carbon footprint of your website but also to reduce its emissions by identifying the optimizations to realize.

Greenoco is made as well for companies, communities and institutions, as for web agencies and developers, it will make digital sobriety accessible.

You want to measure and reduce the carbon footprint of your site? Contact-us, for more information!

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