How much CO₂ does an email produce? Emails also have an environmental impact: sending 20 emails a day for a year can be equivalent to driving 1,000 km by car. Here’s how to reduce your digital footprint.
Every day, we send dozens of emails without giving it much thought, but our digital lives also have an impact on the environment. Discover how much energy a simple email requires and which small actions can help you reduce the environmental footprint of your inbox.
How Much CO₂ Does an Email Produce?
Sending an email is a simple and immediate action: just press the “Send” button and the message reaches its recipient within seconds. But email also has an environmental impact.
Every email requires energy to be written, sent, transmitted through the network, processed by servers, stored and displayed on the recipient’s devices. According to some of the most widely cited estimates, a simple email can produce around 4 grams of CO₂ equivalent, while a message with a large attachment can generate several dozen grams.
The figure varies greatly depending on the size of the message, the number of recipients, how long it is stored and the energy used by data centers and networks. This makes it difficult to assign a single value to the carbon footprint of an email.
One thing, however, is certain: reducing unnecessary digital communications and making the files we send smaller can contribute to greater digital sustainability.
Emails and the Environment: Why Does Email Use Energy?
When we send a message, an email does not simply travel from one computer to another.
Energy is used by:
- the device we use to write and send the message;
- the network that transmits the data;
- the servers that process and store emails;
- the recipient’s device, which downloads and displays the message;
- data centers, which need to be powered and cooled.
Fewer Emails, Fewer Attachments: Better for the Planet — Here Are Some Facts
Attachments also play an important role: the larger a file is, the more data needs to be transferred and stored.
According to data from the EWWR (European Week for Waste Reduction), more than 12 billion emails are sent worldwide every 60 minutes. An email with a 1-megabyte attachment is equivalent to the energy consumption of a traditional 60-watt light bulb left on for 25 minutes.
Consider a company with around one hundred employees, each sending approximately 30 emails a day: this can amount to 13.6 tonnes of carbon dioxide over 12 months.
This does not mean that we should stop using email. On the contrary, email is an extremely useful communication tool and, in many cases, can reduce the need for paper and other materials. The point is to use it more consciously and avoid digital waste.
10 Good Practices to Reduce the Environmental Impact of Emails
1. Send an Email Only When It Is Truly Necessary
Before writing a message, ask yourself: is this email really necessary?
Sometimes we send messages out of habit, simply to say thank you or to share information that could be communicated in another way. Reducing even a small proportion of unnecessary emails can help decrease data traffic and the energy required to process them.
Of course, this does not mean avoiding all digital communication, but taking a small step towards using technology more consciously.
2. Limit the Number of Recipients
Sending a message to many people often means multiplying the amount of data transferred and stored.
It is therefore better to:
- include only the people who genuinely need the information among the recipients;
- avoid using “Reply All” when it is not necessary;
- avoid adding people in copy simply out of habit.
More targeted communication is often more effective too.
3. Avoid Carrying Entire Conversations Forward
How often does a new email contain a long chain of previous messages, perhaps with attachments that are no longer needed?
Whenever possible, avoid unnecessarily keeping entire conversations and large attachments in the email thread. A shorter, lighter message requires less data to be transferred and stored.
4. Regularly Clean Up Your Inbox
An inbox full of unnecessary messages, unread newsletters and forgotten attachments represents a large amount of data stored over time.
You can therefore:
- delete emails you no longer need;
- empty the trash regularly;
- delete unwanted messages;
- remove old, large attachments.
Deleting emails does not automatically eliminate every environmental impact, but it can help reduce the amount of data stored unnecessarily, especially when done regularly.
5. Unsubscribe from Newsletters You No Longer Read
How many newsletters arrive in your inbox every day and go straight into the trash?
If you are no longer interested in a newsletter, the best solution is not simply to delete it every time, but to unsubscribe.
This way, you avoid receiving, transferring, storing and eventually deleting messages you will never read.
6. Disable Unnecessary Email Notifications
Many services automatically send notifications for every new activity.
Social media updates, reminders, promotions and automatic notifications can quickly multiply. Disabling those you do not need helps keep your inbox more organized and reduce unnecessary digital communications.
7. Reduce the Size of Attachments
Large attachments are among the elements that can significantly increase the environmental impact of an email.
Before sending a document or image, you can:
- compress the file;
- reduce the resolution of images when high quality is not necessary;
- use lighter file formats;
- share a link to the document instead of attaching very large files.
This allows the recipient to access the document without necessarily having to receive another copy of the file via email.
8. Use a Simple Email Signature
An email signature with large images, heavy logos, banners and animations is downloaded and transferred every time the message is sent.
A simple signature consisting mainly of text and essential information is often the more sustainable choice.
9. Group Your Communications
Do you need to send several messages to the same person throughout the day?
Whenever possible, try to group the information into a single email. One more complete communication can be more effective than a long series of short messages sent just a few minutes apart.
Of course, in this case too, clarity of communication should remain the priority: there is no point in creating endlessly long emails simply to reduce the number of messages.
10. Before Writing, Search Online for the Answer
Sometimes we send an email to ask for information that is already available on the website of the company, organization or service we are interested in.
Before pressing “Send”, it can therefore be useful to check whether the answer is already available online, in the FAQ section or in the support area.
A quick search can prevent an unnecessary communication.
Spam Also Has an Environmental Impact
Spam is not just annoying and, in some cases, dangerous.
Unwanted messages also require resources to be sent, filtered, processed and, at least in some cases, stored. Some estimates have calculated an impact of around 0.3 g of CO₂e per spam message, although the figure varies depending on how the message is handled by email systems.
For this reason, it is important not only to delete spam, but also to use reporting and unsubscribe options whenever possible.
Email or SMS: Which Has a Lower Environmental Impact?
The most widely cited estimates indicate that an SMS has a much smaller environmental footprint than an email, mainly because it normally contains a much smaller amount of data. One estimate reported by several sources indicates around 0.014 g of CO₂e per SMS, although this figure can also vary depending on the methodology used.
This does not mean that we should always replace emails with SMS messages: they are different tools with different functions. But it reminds us that the amount of data we send also plays a role in the environmental impact of our digital lives.
Sustainability Also Depends on Our Digital Habits
Email is now a fundamental part of our daily and professional lives. We cannot completely eliminate email, but we can learn to use it more consciously.
Sending fewer unnecessary messages, reducing the size of attachments, limiting recipients, deleting content we no longer need, and unsubscribing from unwanted newsletters are small actions that, multiplied by millions of people, can help reduce digital waste.
Sustainability, in fact, is not only about what we buy, eat or transport. The way we use technology also has an impact on the environment.
And you? How many emails could you avoid sending today?
Cover photo source: Canva Pro
