What is the carbon footprint of an email?

Email has become an indispensable form of communication. We send emails for everything—from personal messages to business correspondence—and we do it almost unconsciously. But have you ever wondered what the environmental impact of sending an email is? It may seem harmless, but each email you send contributes to the global carbon footprint.

Email, like other digital activities, relies on data centres, networks, and devices, all of which consume energy. With billions of emails sent every day, the cumulative environmental impact of this seemingly trivial action is more significant than many realise. In this article, we’ll delve deep into the carbon footprint of an email, the hidden costs of digital communication, and what we can do to minimise it.

How does sending an email generate a carbon footprint?

At first glance, it might seem strange to associate email with carbon emissions. After all, there’s no physical letter being transported, no paper being wasted, and no fuel being burned to deliver your message. However, the digital infrastructure required to send, store, and receive emails is powered by energy-intensive systems that leave a carbon footprint.

Let’s break down the process:

1. Data centres: Emails are processed and stored in massive data centres. These facilities house thousands of servers that run 24/7, consuming vast amounts of electricity. Data centres not only require power for processing but also for cooling, as servers generate significant heat. Many data centres still rely on non-renewable energy sources, which contribute to greenhouse gas emissions.

2. Network infrastructure: Sending an email requires transmitting data across the internet. This involves routers, switches, and other networking equipment that also consume electricity. Every time your email moves from your device to a recipient’s inbox, it passes through multiple layers of network infrastructure, each of which uses power.

3. End-user devices: Both the sender and the recipient rely on devices like computers, smartphones, or tablets to send, receive, and store emails. These devices are powered by electricity, often sourced from fossil fuels. Even when they’re in sleep mode, your devices consume power, further adding to the carbon footprint.

4. Cloud storage: Many emails are stored in cloud-based services like Gmail or Outlook, and those emails may be archived for years. Storing vast amounts of data indefinitely requires energy, contributing to the overall carbon emissions associated with email.

Quantifying the carbon footprint of an email

So, how much energy does sending a single email consume? Estimates vary, but a simple text-only email without attachments produces roughly 0.3g of CO2e (carbon dioxide equivalent). This might seem like a tiny amount, but it increases with the size and content of the email.

• Email with attachments: Emails that include documents, images, or videos significantly increase the energy required to process and store the data. A typical email with a large attachment can generate anywhere from 10g to 50g of CO2e.
• Newsletters and bulk emails: Mass emails such as newsletters, promotions, or notifications sent to thousands of recipients can generate a much larger carbon footprint. These emails are stored on multiple servers, processed through various networks, and consumed on thousands of devices.

When you consider that more than 306 billion emails are sent worldwide every day, the environmental impact adds up quickly. It’s estimated that emails alone contribute to 2% of global carbon emissions, a figure comparable to the entire aviation industry.

The environmental cost of spam emails

A substantial portion of the emails we receive are unwanted—whether it’s spam or marketing emails we didn’t sign up for. Spam emails account for a staggering 85% of all email traffic, making them a significant contributor to email-related emissions. Despite never being read or acted upon, spam emails consume just as much energy as legitimate emails.

Some research suggests that spam emails sent in a single year could generate as much as 33 million tonnes of CO2e, which is equivalent to the annual emissions of millions of cars.

Businesses can play a vital role in reducing this burden by limiting the volume of unnecessary email traffic. For example, optimising email marketing strategies to target specific audiences can help reduce spam and cut down on emissions. Learn more about optimising email campaigns in our key features web applications should have article.

The role of data centres in email emissions

Data centres are at the heart of email carbon emissions. These facilities are responsible for processing, storing, and transferring the data required for every email sent and received. According to estimates, data centres account for 1% of global electricity consumption, and this number continues to grow as more people use digital communication tools like email, video conferencing, and cloud services.

While some data centres are transitioning to renewable energy sources, many still rely on non-renewable electricity, making them a significant contributor to global carbon emissions. Large technology companies like Google and Microsoft are investing in more energy-efficient data centres and renewable energy projects to reduce their carbon footprint.

Businesses looking to reduce their carbon footprint can also choose cloud providers that prioritise sustainability. Read more about how cloud computing affects the environment in our article on how cloud computing impacts the environment.

Practical steps to reduce the carbon footprint of emails

Reducing the carbon footprint of your emails doesn’t require a complete overhaul of your digital communication practices. Here are some simple yet effective strategies to help individuals and businesses minimise their environmental impact:

1. Unsubscribe from unnecessary mailing lists

One of the easiest ways to reduce your email carbon footprint is to unsubscribe from newsletters, promotional emails, or notifications that you don’t read or need. Every email you prevent from landing in your inbox reduces energy consumption throughout the network.

2. Be mindful of attachments

Where possible, avoid sending large attachments via email. Instead, use file-sharing services like Google Drive or Dropbox, which allow you to share a link to the file without attaching it directly to the email. Not only does this reduce the energy required to send and store the email, but it also declutters inboxes and saves storage space.

3. Delete unnecessary emails

Many people rarely delete old emails, allowing them to accumulate in inboxes and servers over time. While it may not seem like much, this stored data requires energy to maintain. By regularly clearing out your inbox and deleting unneeded emails, you can reduce the demand on data centres.

4. Use cloud providers with renewable energy

If you’re using cloud-based email services, opt for providers that are committed to using renewable energy. Many major cloud providers, including Google, Amazon Web Services (AWS), and Microsoft Azure, are working towards becoming carbon-neutral by powering their data centres with clean energy.

5. Optimise email marketing strategies

For businesses, reducing the volume of emails sent is an effective way to minimise carbon emissions. Rather than sending bulk emails to all contacts, segment your audience and send targeted campaigns to those most likely to engage with your content. This reduces unnecessary email traffic and improves marketing efficiency. Learn more about building efficient business communications in our article on how better software can grow your business.

The business case for reducing email emissions

Businesses are some of the largest contributors to email-related carbon emissions, particularly those with extensive email marketing strategies. While email remains an essential tool for communication, companies can take proactive steps to minimise their digital carbon footprint.

• Encourage sustainable communication: Businesses can encourage employees to use messaging platforms like Slack or Microsoft Teams for quick internal communication, reducing the need for email.

• Streamline marketing: Businesses can minimise the number of bulk emails they send by adopting more efficient marketing tools that target specific users. Optimising email campaigns can lead to fewer, more effective emails while reducing energy consumption.

• Partner with eco-friendly cloud providers: By choosing cloud providers that use renewable energy and eco-friendly practices, businesses can reduce the carbon footprint of their email systems.

At SmartPandas, we offer web application development services that focus on sustainability and performance, helping businesses reduce their digital carbon footprint while maintaining operational efficiency.