Sent with Carbon

Or, why you maybe don’t need to reply to those unactionable emails after all.

They say that the more fixated you are on an idea, the more you’re bound to attract like-minded people. I can still vividly recall a conversation I had with a friend about reducing carbon footprints. This was weeks after I’d tried switching my lighting preferences  in the hope of saving some money and reducing my carbon footprint. I’d even written a piece about the process and experience in doing so.

Besides the nice catchup session with my friend, I will always remember a titbit that he shared about reducing carbon footprints as a heavy computer user.

In one way or another, we are all probably leaving carbon footprints as we go through the day: for transportation, ventilation, lighting, and, of course reading through this article. But have you ever heard about carbon footprints from sending emails?


Email can be fun, but these days, many find it overwhelming. Those who attain Inbox Zero are looked upon with respect and envy, while we lesser mortals struggle to deal with our own overflowing inboxes.

Inboxes have everything these days. Promotions and offers, notifications and receipts, and the occasional stranger with a rich deceased uncle and a fortune they inexplicably want to share with you. And then, of course, the emails you’re actually supposed to read and respond to; the ones which you have to actually spend time reading and responding to.

These days, most business have gone digital, using emails and online documents in an effort to save paper — because paper uses trees and cutting trees is bad for the environment, right?

Be that as it may, digital setups aren’t as ‘clean’ as they may seem. Unbeknownst to a lot of people (or to me, at least) sending email does leave carbon traces into the environment.


Have you ever wondered where our emails go after we click that ‘send’ button? Every file, photo, and email zips through your wireless or wired connection, and eventually lands up in  this space called a ‘data centre’ — which collects and stores them indefinitely.

Data centres are basically large arrays of computers with overgrown hand-drives, built to collect and send out whatever data is requested at a high speed. In practical terms, you could think of them as large communal hard-drives, except of course with restricted access to different parts: you probably can’t access the data from my emails for example — at least, I hope not!

Ultimately, data centres are computers, and, like all computers, they need electricity. There’s such a humongous amount of data around these days that, put together, 2% of the world’s electricity usage goes into keeping them running — and that share is estimated to go up to 8% by 2030. Of course, that demand of power supply will only increase from there onward, especially in a age that is witnessing rise of Artificial Intelligence and Internet-of-Things technology, where lots and lots of data are needed, not to mention the fact that we’re working to make Internet accessible to everyone, and, in the days of the virus, we depend on large amounts of videocall data just to stay in touch.

Even today, the cost of maintaining these data centres is about the same as that of the airline industry.

But do we really need to store that much data? An article from Bloomberg shows that, of the 33 trillion gigabytes of data stored all over the world, only a small percentage is in active use. This amounts to 31 trillion gigabytes worth of data just lying around and releasing carbon into the atmosphere.


Every time you click ‘send’ on an email, the electricity used to produce it and the energy used to store it, they go into work. And yes, those amounts are significant. Storing a “thank you” email by itself produces around 0.00001 tonnes of carbon, which is close to unnoticeable…until you consider the thousands of thank you messages being sent every day in just a single country.

It’s not easy to make the connection when you can’t see smoke coming out of your computer, but there power plants are likely being made to generate electricity to store those ‘thank you’ messages that you send.

Vincent de Rul, director of energy solutions at EDF Energy agrees, but adds that it’s not just a sustainability challenge that data centres present the IT sector with: it’s also a strategic one.

“Energy costs can make up as much as 70 to 80 percent of operational expenses for a data centres, and simply put it, power supply is a business-critical issue for data centres,” says de Rul. “One provider was recently fined over one million pounds for an outage of only 12 minutes, caused by an issue in their local power distribution grid.”


Have you ever noticed how your laptop heats up if you use it for a long time? Especially when you’re doing heavy work such as video editing, hi-res gaming, or, apparently, badly configured Zoom meetings.

This heating happens when you’re using your laptop for a while. Now, take the same principle and apply it to data centres which have to keep their systems going all the time. This generates a lot of heat, and, to prevent them from overheating, it’s important to have a effective cooling system. Of course, that  requires its own source of energy too, thus releasing even more greenhouse gases into the atmosphere. A 2017 study showed that around 40 percent of data centres’ total energy usage was going into cooling IT equipment.

That’s why companies like to run their data centres in places like Iceland and Sweden.

That’s a bit harder these days with government policies like “the need to require citizen data to be stored on servers located domestically”. Either way, the questions still stands: is there a way to reduce the power consumption of data centres?

A simple answer would be ‘yes’, but it’s not that easy.


Unactionable emails are emails that one doesn’t take any action on. Messages like “thank you”, “I received your documents”, or “noted for next time”. People who receive them don’t actually do anything with them. It’s just an email for them to read and delete.

In which case, how many of those emails actually need to be sent?

An estimation by Statista claims that if everyone in UK reduces one unactionable email, it would account to 16,433 tonnes of carbon — equivalent to 81,152 flights to Madrid! However, the plain assumption that everyone in UK sends email on an everyday basis isn’t right to begin with, so they had also come with a better assumption.

After only including people who are employed, as well excluding those whose job doesn’t involve sending emails, this still lead to half of the original amount; 8,760 tonnes of carbon. (That’s 43, 260 flights to Madrid, if you’re keeping score).

If you think about it, we can play a part in reducing carbon emission by simply not sending these e-mails! If this idea is spread in a positive manner, no doubt people would be more than happy not-receiving these thank you messages, in an effort to reduce carbon footprints

Organization such as OVO energy have looked into this problems as well. They helped in creating a Chrome extension to monitor the amount of emails you sent in per day, taking in account factors like word count and attachment size, so you know where to trim down.


We can reduce our email, but will it be enough? This is where it gets tricky. The idea of lessening carbon waste by reducing the amount of email we sent isn’t actually a new idea. It’s been proposed by people from time to time but whether or not corporate choose to enforce that culture is a different story.

However, if you were to compare that to the greenhouse emission over the span of a year which is close to 500 million tonnes of gas, those unactionable emails only comes to 0.0037% of the total share.

Mike Berners-Lee, a respected professor on the topic whose research was used in the Ovo Energy work, described it as “back-of-the-envelope” maths from 2010. Evidently there are more drastic problem to deal with for governments than monitoring the amount of emails people send each day.

So, what do we do?

When it comes to solving this kind of energy issues, there are three main way to go about it: use less, improve efficiency of the electricity supply, or bring in a more environment-friendly energy source.

As consumers, our only way of supporting the effort is to actually reduce our consumption as much as we can. We could reduce our electricity usage at home or put more effort into carpooling — you know, the usual stuff. But if you think about it, those are tiny amounts too. Most people have the mentality that because they don’t have much trouble paying the bills they can afford to spend extra unused electricity — but if you truly want the next generation to live in a better Earth then we all should be using less.

Every small change, as they so often say, makes a difference.


Returning to emails, the idea of reducing 0.0037 percent is undoubtedly a small percentage no matter how you look at it. That’s far from a fraction of 1 percent, considering it’s the combined effort of everyone in the United Kingdom. But if you ask me, a pebble’s worth of influence is always better than zero.

Personally, I’m not a frequent email user. As a post graduate student, I send about 2–3 emails per day on average, most of them related to the daily progress in my research. These could be thought of as ‘essential’; they’re not something that I can simply reduce. But then, every once in a while, I send email asking for a favour or simply requesting confirmation. And that’s where I can avoid sending another email later, by just adding the line: thanks in advance.

Who’d say no to a few minutes less in the inbox?