Communication
June 20, 2024

What is the digital pollution of emails?

By
Guillaume De la Sablonnière
Content Factory Manager

We are talking more and more about digital pollution and the role that email plays in this ecosystem. Considering that nearly 1.4 billion emails are sent every day in France, it is easy to imagine that email must have a certain impact...

But what is the real ecological impact of email, and more importantly, why does sending an email cause pollution?

  • Discover what email-related digital pollution looks like in 2024 in our infographic.
  • And if you want to go further, find all our research on the subject below.

What is digital pollution?

empreinte carbone mail

Digital pollution refers to all pollutants generated by information technology. It includes energy consumption and greenhouse gas emissions associated with the manufacturing, use, and disposal of digital equipment (computers, smartphones, smart TVs, etc.). It also accounts for the infrastructures needed for these devices to function, such as data centers and communication networks, as well as the usage of digital devices themselves.

Although using digital devices contributes to pollution, the most significant ecological impact occurs during the manufacturing process. Think about the extraction of minerals, massive water usage, and long assembly chains. All of this requires a looooot of energy. And since many power plants still rely on coal or gas, large amounts of greenhouse gases are released in the process.

Does sending an email cause pollution?

The short answer: yes, it does.

But the longer answer is that the situation is a bit more complex (because nothing is ever simple, right?). In reality, sending an email—like any action performed through an internet-connected server—has a carbon footprint. The key question is to understand the scale of this pollution, how it fits into the broader digital pollution landscape, and whether solutions exist to reduce its impact.

On average, the French Agency for Ecological Transition (ADEME) estimates that each email emits around 4 gCO2e. That might seem insignificant at first glance, but when multiplied by billions of daily emails, the impact becomes far from negligible.

Let's take out a notebook and a pen: It is estimated that, on a global scale, 40.6 billion tons of CO2 are released per year (2022 figures). Of these 40.6 billion tons, 4% are generated by digital technology (and about 2.5% in France, according to ADEME). Emails account for 1% of the total share of digital pollution. So, 1% of 4%, which amounts to 0.0004% of global pollution.

How does an email cause pollution?

According to Basile Fighiera (a consultant specializing in low-carbon strategies and digital sobriety), the carbon footprint of a simple email without an attachment, sent to a single recipient, is about 0.4 gCO2e.

What contributes to email-related digital pollution?

Out of these 0.4 gCO2e, we can break down the email’s carbon footprint as follows:

  • 69% comes from the manufacturing of the computer sending the email;
  • 23% comes from the manufacturing of the computer receiving the email;
  • 5% comes from the energy consumption associated with composing the email;
  • 2% comes from the recipient reading the email;
  • 0.5% comes from the actual transmission of the email;
  • And the remaining 0.5% comes from storing the email on both the sender’s and recipient’s devices.

Looking at these numbers, we can see that:

  • 92% of the pollution comes from manufacturing the computers;
  • And out of the remaining 8%, only 5.5% corresponds to the actual process of creating and sending an email.

So, if you want to reduce your digital pollution, a great starting point is to extend the lifespan of your computer and/or smartphone.

Consider recycling them, avoiding unnecessary upgrades when new models are released, and remember that the second-hand market exists.

What is the carbon footprint of an email?

pollution informatique mail

The ecological impact of an email can vary depending on multiple factors. For example:

  • What type of device is used to send it?
  • Is it a smartphone? A computer?
  • Will it be read by one or multiple recipients?
  • Does it contain attachments?

In short, a wide range of factors can influence the carbon footprint of an email.

Without accounting for all possible variables, Basile Fighiera attempted to estimate the carbon footprint of an email in different scenarios. Here are his results:

```html
Length Attachment? Email Size Connection Number of Recipients Carbon Footprint
LengthShort Attachment?No Email Size10 KB Connection4G Number of Recipients1 Carbon Footprint0.4 gCO2e
LengthShort Attachment?Yes Email Size1 MB Connection4G Number of Recipients1 Carbon Footprint1.8 gCO2e
LengthShort Attachment?Yes Email Size1 MB ConnectionWi-Fi Number of Recipients1 Carbon Footprint3.3 gCO2e
LengthShort Attachment?No Email Size10 KB ConnectionWi-Fi Number of Recipients10 Carbon Footprint4.9 gCO2e
```

Environmental impact of emails based on type

Depending on the type of email sent (or received), the carbon footprint will not be the same. Here is the average amount of carbon dioxide emitted per email type (according to Carbon Literacy Project):

  • Email without attachments: 4 gCO2e;
  • Email with large attachments: 50 gCO2e;
  • Spam email: 0.3 gCO2e;
  • Newsletter: 10 gCO2e.

And what about email signatures?

Determining the exact carbon footprint of an email signature is challenging, as it depends on many factors. For instance, a signature with an oversized image and excessive information will naturally be more polluting than a minimal, optimized signature.

However, to give you a general idea, we conducted some internal calculations, and here is our estimate:

Signature sent to external recipients

pollution signature externe

  • Code weight: 23.97 KB
  • Image weight: 86 KB
  • Total signature weight: 109.97 KB
  • Equivalent to 0.36 gCO2e

Signature sent to internal recipients (with fewer details)

Signature interne poids

  • Code weight: 11.96 KB
  • Image weight: 86 KB
  • Total weight: 97.96 KB
  • Equivalent to 0.32 gCO2e

Signature in a reply or forwarded email (minimalist signature)

Signature mail minimaliste Guillaume

  • Code weight: 8.93 KB
  • Image weight: 6 KB
  • Total weight: 14.93 KB
  • Equivalent to 0.05 gCO2e

The example of Tootbus

A strong commitment to reducing its ecological footprint

Tootbus, a company specializing in tourist transport in multiple European cities (Paris, London, Brussels, Bath), has committed to reducing its greenhouse gas emissions by 50% by 2030.

This goal involves concrete actions, such as electrifying its fleet of buses, using biofuels, and minimizing data storage on its servers.

Reducing its digital pollution

Regarding digital data, the company has also pledged to minimize its impact. It has implemented a policy of deleting customer data from its servers after a defined period and actively encourages customers to uninstall the Tootbus app from their smartphones after their trip. As for email signatures, Tootbus has chosen to use an email signature management tool (in this case, Letsignit) to standardize signatures and reduce the amount of data needed for their display.

What is the biggest source of digital pollution?

As mentioned earlier, the most polluting process is the manufacturing of devices (computers, smartphones, tablets). If you want to combat digital pollution, the first step is to rethink your consumption of electronic devices.

Saviez-vous que : il faut environ 500kg de matière pour produire un ordinateur portable ? C'est environ 250 fois son poids final ! Il est aussi calculé que celui-ci relâche 246 kg de CO2 en moyenne pendant les différentes phases de sa vie.

The next major contributor is pollution caused by using digital devices. They consume energy throughout their lifecycle—during daily use, maintenance, and recycling. The environmental impact depends largely on the source of this energy, which is often non-renewable, leading to greenhouse gas emissions. Additionally, frequent software updates and the need to stay constantly connected further increase energy consumption. Thus, it is essential to prioritize renewable energy sources and adopt digital sobriety practices to minimize this impact.

What Are the Three Main Sources of Digital Pollution?

Pollution numérique chiffres

  1. Manufacturing Digital Devices: Just think about all the computers, smartphones, tablets, and other connected devices that people around you own. For example: manufacturing a computer requires an average of 500 kg of materials (240 kg of fossil fuels, 1.5 tons of water, 22 kg of various chemicals, rare metals necessary for production, etc.) and generates 246 kg of CO2.
  2. The Creation of Ever-Larger and More Energy-Consuming Data Centers: Today, the combined energy consumption of all these centers accounts for 3% of global energy. With the growing presence of the cloud, this energy consumption continues to rise.
  3. Internet Usage! Watching videos is the leading cause of bandwidth consumption. It is estimated that video streaming represents at least 60% (source: greenpeace.fr) of the data consumed on the web. Other online tools and activities follow.

Video: The Biggest Polluter in the Digital World

In the realm of "internet usage that generates pollution," video is unfortunately the worst offender. It accounts for 60% of all data transmitted on the web. A staggering 700,000 hours of videos are watched every minute worldwide! And you thought your annual Lord of the Rings movie marathon was long...

Given the amount of data used when watching a video, this medium is far more polluting than all the others. For one person, just 1 hour of streaming emits 400 g of CO2!

Email Pollution in 5 Key Figures

  1. Email accounts for 0.0004% of global pollution.
  2. 92% of this 0.0004% is caused by the manufacturing of computing devices (computers, tablets, smartphones) themselves.
  3. The average carbon footprint of an email is 4 gCO2e (this figure includes pollution generated by manufacturing the digital devices used).
  4. Email signatures generate an average of 0.24 gCO2 per email sent.
  5. 60% of digital pollution linked to internet usage comes from video consumption (mainly on YouTube and other video streaming services).

What Solutions Exist to Combat Digital Pollution?

Contrer pollution numérique conseils

The good news is that you can take concrete actions to reduce your consumption and, therefore, your environmental impact. The key idea? Digital sobriety!

Some Tips to Reduce Your Digital Pollution

  1. Start by avoiding over-equipping yourself (do you really need that second phone for talking to your secret lover?). In the end, the fewer new devices are in demand, the fewer will be produced. And a device that isn’t manufactured is a device that doesn’t pollute.
  2. Make sure to repair your equipment whenever possible. Computer and phone repair specialists can help extend the lifespan of your devices significantly.
  3. Stop watching TV over the internet by switching back to DTT (Digital Terrestrial Television) and its good old coaxial cable.
  4. Set your computer to energy-saving mode. This will slightly reduce its performance but will also lower its energy consumption.
  5. Limit your use of cloud storage and store your data on your computer’s hard drive or an external hard drive. Also, consider cleaning up your photos and emails. Delete duplicates or unnecessary items. Do you really need to keep all 60 variations of your selfie with The Little Mermaid at Disneyland Paris?
  6. Reduce your social media consumption and the amount of content you share. Also, visit websites directly instead of searching for them through a search engine—this avoids unnecessary requests to servers and reduces data processing.
  7. Avoid connected objects. These continuously consume data and—let’s be honest—aren’t always essential to your daily life. Try to own as few as possible.
  8. Use Wi-Fi instead of 4G or 5G (for comparison: 4G consumes 20 times more energy than standard Wi-Fi).
  9. Use optimized data centers that run on renewable energy sources.
  10. Turn off your devices before bed. While you sleep, why not let your internet-connected devices sleep too (internet access box, router, etc.)? Instead of consuming data continuously in the background, a little rest will allow them to use less data.

How to Reduce the Carbon Footprint of Emails?

If you want to take your efforts even further and reduce email-related pollution, here are some solutions:

  1. Clean out your inbox. Your old or archived emails can probably be deleted. Also, erase emails in the "sent items" folder. By decluttering your inbox, you limit unnecessary data usage.
  2. Delete spam emails that take up unnecessary space. If needed, install an anti-spam software or extension. A tool like Cleanfox can be very useful for this digital spring cleaning.
  3. Unsubscribe from newsletters you don’t actually read. If every time you receive a newsletter you think, "I’ll read it later or tomorrow," you probably aren’t really interested. No need to increase your carbon footprint for emails you’ll never read—unsubscribe!
  4. Limit email attachments. Instead of attaching files directly, use WeTransfer, File Vert, or proximity transfers (via USB stick, external hard drive, or Bluetooth). Also, delete attachments in email replies when they’re no longer needed.
  5. Target your recipients carefully. Minimize the number of people in CC and avoid using the "Reply All" function unless absolutely necessary. It may seem minor, but reducing unnecessary emails to colleagues could save 1 ton of CO2 per year for a company with 100 employees.
  6. Think before you send an email to avoid unnecessary messages. A simple “thank you” email might not really be essential.
  7. For short messages, opt for SMS instead—it emits 200 times less greenhouse gas than an email.

How to Reduce the Carbon Footprint of Your Email Signature?

While it’s impossible to reduce the environmental impact of your email signature to zero, the good news is that it can be significantly minimized. All it takes is adopting a few good habits and applying them consistently. And why not encourage those around you to do the same?

So, to reduce the carbon footprint of your email signature and those of your colleagues:

  1. Start by reducing the file size of the images in your email signatures: Images are often poorly optimized and consume unnecessary data. Be sure to:
    1. Resize them according to their actual display size. There’s no need to use a 1200 x 1200 profile picture if the display size is 150 x 150 pixels (we know you want everyone to admire your beautiful face, but still). For more information, refer to our article on the correct format for email signatures.
    2. Reduce their weight. Compression tools (e.g., squoosh.app) can help minimize the file size of your images. A smaller image will consume less data when sent and received.
  2. Optimize the HTML code of your signature: Any HTML-coded element can contain unnecessary information (such as excessive spaces, line breaks, or overly complex hexadecimal codes). Minification simplifies the HTML code, optimizing it to be as lightweight as possible. Ultimately, this reduces the server space required and the energy consumption of sending emails. Tools like HTML Minifier (Minify HTML Online) can help you minify your code easily.
  3. Reduce the amount of displayed information: If certain elements in your signature don’t add real value, consider removing them. Limit banner displays to relevant messages. Your beloved cat Grisou (third of his name) might not be essential to the good reception of your emails. We know you love him dearly, but that’s not the point...
  4. Use a lighter signature for replies, reply-alls, and forwarded emails: There’s no need to load your full signature with every response. Once your recipient has received your complete signature, you can switch to a more minimalist version for subsequent exchanges.
  5. For businesses: Use an email signature management solution. By standardizing and compressing your employees' emails, you can reduce the carbon footprint of email signatures. No more Martine from accounting attaching a 4K photo of her dog Pixou to every single email!

Advice for Companies Looking to Reduce Their Carbon Footprint

  • Establish clear policies and rules for digital sobriety: Define guidelines for email sending, limit mass emails, reduce the use of attachments, encourage file transfer links, and set best practices for email signatures, etc.
  • Organize training and awareness sessions: Educate employees on best practices and useful tools. Guide them in developing habits that minimize their digital footprint. Workshops, webinars, or even online training modules can be useful.
  • Encourage better digital practices daily: Employees should be reminded to turn off their computers after work, use power-saving modes, and prefer physical meetings or audio-only calls (without video) when possible.
  • Choose greener cloud technologies: Many cloud service providers now use renewable energy and optimized infrastructures. Work with companies that have a strong environmental record and clear CSR commitments. Look for certifications such as ISO 14001.
  • Optimize cloud resource usage and avoid content duplication: Implement clear strategies to limit cloud use to essential needs. Regularly delete obsolete files, consolidate data to avoid duplicates, and use efficient content management tools.
  • Equip employees with tools to manage emails and cloud usage efficiently: Anti-spam software, automated sorting tools, and messaging services that reduce the number of emails sent daily can make a difference.

Regulations and Government Initiatives

To contribute to the reduction of digital pollution, the European government has introduced various initiatives aimed at curbing digital pollution. These include:

  • Regulations on data center energy efficiency (such as the "tertiary decree," which mandates a 60% reduction in energy consumption by 2050).
  • A circular economy action plan, aimed at limiting electronic waste and promoting the reuse of electronic devices through the "right to repair" policy.
  • Recommendations for a reward system to encourage electronic device recycling.
  • Mandates for sellers to repair damaged products, unless replacement is more cost-effective.

Nordic countries like Sweden and Norway have chosen to power their IT infrastructures with renewable energy. In Japan, national programs have been introduced for the collection and recycling of electronic devices.

What About Digital Pollution from Emails?

Diminuer pollution numérique mail

The pollution caused by emails and email signatures does not represent the majority of digital pollution globally.

However, while each email sent has a relatively small impact, the accumulation of all emails sent and received can become significant on a global scale, particularly when considering large enterprises' email activity. By adopting more responsible digital practices and optimizing communication tools, we can all contribute to a more sustainable future.

  • For individuals: Encourage colleagues and contacts to adopt more eco-friendly digital habits. Simple actions like regularly cleaning out your inbox, optimizing email signatures, limiting daily email volume, and reducing large attachments can make a difference.
  • For businesses: Companies play a crucial role. They can establish clear digital sobriety policies, raise employee awareness, work with eco-responsible partners, and use the right tools. Today, businesses have the opportunity to improve their environmental footprint while setting an example and inspiring others to follow suit.

Remember, every small action counts in reducing digital pollution. The fight against digital pollution and climate change is a collective responsibility that requires action at all levels—from individuals to large corporations and governments. Together, we can transform our digital habits and minimize our environmental impact. There’s no longer any excuse not to take concrete steps to reduce the pollution caused by emails and, more broadly, the digital sector.

Sources :

https://www.sami.eco/blog/empreinte-carbone-email

https://www.sami.eco/blog/greenit-pollution-numerique

https://www.iea.org/commentaries/the-carbon-footprint-of-streaming-video-fact-checking-the-headlines

https://pisrt.org/psr-press/journals/easl-vol-3-issue-2-2020/new-perspectives-on-internet-electricity-use-in-2030/

https://www.umweltbundesamt.de/sites/default/files/medien/5750/publikationen/2021-06-17_texte_94-2021_green-cloud-computing.pdf

https://www.hellocarbo.com/blog/calculer/empreinte-carbone-mail/

https://www.greenit.fr/2011/07/11/19-grammes-de-co2-l-empreinte-carbone-d-un-e-mail-selon-l-ademe/

https://www.greenit.fr/impacts-environnementaux-du-numerique-en-france/

https://institutnr.org/mooc-numerique-responsable-complet

https://climate.selectra.com/fr/empreinte-carbone/pays-pollueurs

https://climat.be/changements-climatiques/changements-observes/rapports-du-giec/2023-rapport-de-synthese

https://archives.qqf.fr/infographie/69/pollution-numerique-du-clic-au-declic

https://www.europarl.europa.eu/

https://www.hellio.com/

https://www.data.gouv.fr/fr/reuses/quelle-est-lempreinte-carbone-dun-ordinateur-portable/

About the author
Guillaume is a Content Factory Manager at Letsignit! Using words, he creates various types of content (text, videos, and in the most extreme cases, telepathic messages) to boost Letsignit's visibility on the web. Legend has it that at the age of three, Guillaume built his first multichannel web marketing strategy using a dictionary, a baby bottle, and a bit of Chinese ink. Whether this is true or not remains a mystery, but that's what they say...
About Letsignit
Letsignit is an email signature management solution that enables organizations to turn their employees' email signatures into a powerful 1:1 engagement channel for their brands and campaigns.

Questions
Fréquentes

1

Is it possible to track the number of clicks on email signatures?

Yes, with the 'Campaigns' offer, it is possible to track the number of clicks on the email signatures of all your employees in the 'Statistics' area of the platform.

You can then access a detailed or global view of the number of clicks on the email signatures of each employee. You can use the search option to target a specific signature or a given period. Finally, you have the possibility to export all statistics to an Excel document.

If you launch campaigns with banners inserted in your email signatures, you can also access their performance via this same space.

2

Can we add links to social networks, our website, and appointment-setting applications such as Calendly?

With Letsignit, you can easily add social network icons in your collaborators' email signatures and link to your company pages. Also, our "attributes" feature allows you to manage personalized URLs for each of your collaborators such as their individual LinkedIn profile.

And that's not all: you can add links to an appointment-setting application, allow your customers to leave reviews easily, and integrate our 'Chat on Teams' widget to let anyone start a discussion via Microsoft Teams chat.

3

Can employees update their signature information themselves (number, function, etc.)?

It’s up to you! As an administrator of the Letsignit platform, you choose whether or not to grant modification rights to your employees. These permissions are managed on an attribute-by-attribute basis, which means that you can decide to allow the employee to change their phone number, but not the address of your premises, for example.

This feature applies to all attributes in your directory, including custom attributes created on Letsignit. When your employees change one or more attributes, your directory is obviously not affected.

4

Why it is important to standardize our email signatures on a large scale to ensure our identity and brand image?

It often happens that employees make their email signature their own: custom format, bad fonts, colors inconsistent with the brand standards... all of this has an impact on your brand!

A consistent visual identity is considered authentic and outperforms a perceived weak one by 20%. And, your customers are 2.4 times more likely to buy your products.

With Letsignit, take back control over your brand identity by standardizing all your email signatures. Our tool has many features that allow you to customize your signatures by department, by audience or by subsidiary. Not to mention the possibility of carrying out campaigns within your email signatures thanks to our Campaign offer.

5

What is the user experience like for our employees?

What is the user experience like for our employees?

  • If you opt for the Letsignit Add-in for Outlook, they will have a dedicated space in their Outlook account where they will be able to view the signatures and campaigns assigned to them.
  • If you opt for the Letsignit Desktop APP, they will be able to preview all their signatures and campaigns in this space. If they want to change their default signature to another one when sending an email, this will be done in their signature library in Outlook.

In both cases:

  • They preview their signature before sending an email and choose from signatures assigned to them.
  • Based on the permissions granted, they will also be able to modify their personal information such as their name, position, or address in these spaces.

In short, they have autonomy in their email signature, but you keep control on the field, signatures, and banners they can edit or use.

6

Can my employees have multiple signatures available to them?

With our "multi-signature" feature, your employees can benefit from multiple email signatures. No technical manipulation is required. Thanks to our Add-in for Outlook or the desktop app, they can change their email signatures as they wish with just a few clicks.

Regarding the creation of email signatures, you can make several variations such as:

Everything has been thought of to go further in the personalization process based on the recipient of your emails.

7

Regarding “Green IT,” have you implemented measures to limit the digital footprint of email signatures?

If sending emails has an impact, non-optimized email signatures also have an impact. An unsuitable format or an image that is too heavy considerably increases the size of your signatures... and therefore, your emails.

As a responsible economic actor, we contribute to reducing our CO2 emissions and those of our customers in several ways:

  • Optimization of the weight of signatures and campaigns in emails.
  • Green features: lightening of signatures during response/transfer emails, possibility of not embedding images, implementation of lighter signatures for internal exchanges.
  • Integration of a 'Switch to Teams' widget to encourage your employees to continue their exchanges via chat, rather than email.

As we are increasingly involved in sustainability initiatives, our priority in 2023 is to develop even more green IT functionality.

8

Regarding “Green IT,” have you implemented measures to limit the digital footprint of email signatures?

If sending emails has an impact, non-optimized email signatures also have an impact. An unsuitable format or an image that is too heavy considerably increases the size of your signatures... and therefore, your emails.

As a responsible economic actor, we contribute to reducing our CO2 emissions and those of our customers in several ways:

  • Optimization of the weight of signatures and campaigns in emails.
  • Green features: lightening of signatures during response/transfer emails, possibility of not embedding images, implementation of lighter signatures for internal exchanges.
  • Integration of a 'Switch to Teams' widget to encourage your employees to continue their exchanges via chat, rather than email.

As we are increasingly involved in sustainability initiatives, our priority in 2023 is to develop even more green IT functionality.

Questions
Fréquentes

1

2

3

4

5

6

7
8

Looking for a tool to manage your email signatures?

Letsignit allows you to create, manage, and deploy email signatures for all your employees in just a few clicks.
Discover Letsignit