The Carbon Footprint of Unwanted Emails

This post first appeared in our weekly Make Waves Mondays email series on January 25, 2021 and was updated and re-shared again on January 26, 2026..

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Hello hello, EcoWarriors!

Alright so before we get into today’s post, I want to make one thing very clear — where I and A Drop in the Ocean stand on everything happening right now:

F**k ICE.
F**k fascism.
F**k the gaslighting we’re experiencing from our leaders right now who are either telling us that what we are seeing with our own eyes isn’t actually what’s happening or simply telling us what’s happening without actually DOING ANYTHING about it.

Yes, this language is incredibly abnormal for these weekly posts, but I will not tip-toe around the atrocities that are happening and have been happening in this country.

And I can hear it now… “Focus on sustainability! Stay in your lane! Don’t involve yourself in politics!” blah blah blah

So hear me when I say this:

Sustainability is inherently political. Should it be? No. Clean air and drinkable water shouldn’t be a political debate, yet here we are.

Everything is connected. We cannot pull at the sustainability thread without tugging at the racism thread, or the feminism thread, or literally any other social justice thread. They are all connected. Full stop.

The rest of this blog post is all about unsubscribing to emails that don’t serve you, So if this upsets you, there’s no need to reach out to let me know — just stop reading the blog.

And if you agree, download the 5Calls app and call your reps. Red state, blue state, I don’t care. Call your reps and make your voice heard. Because, yes, one call won’t change policy...but thousands will.

📞 10–20 calls on an issue = noticed
📞 50+ calls = flagged as a growing concern
📞 Hundreds of calls = priority issue

And according to 5Calls, as of Monday morning, their data is showing we’re making 5 calls PER SECOND right now. Just through their app. 

Pick up the phone, give ‘em a call, and make them hear us.

Alright… now if you’re still with me, let’s get into today’s blog.

We’re bringing back a much-loved mini-series today within our regularly-scheduled Make Waves Monday series!

Say hello to Small Change, Big Impact.

As you know, the core of everything we believe and do here at A Drop in the Ocean is that small changes add up to massive impacts for the planet.

But nearly always, sustainability isn’t as black-and-white as we want it to be.

I hope that Make Waves Mondays as a whole demonstrates that while the answers aren’t always simple, there are always things that each of us can do — what we can, when we can, where we can. But sometimes we also just want those quick wins, amiright??

So the goal of the Small Change, Big Impact monthly series is to highlight one small change that can have a big impact without much thought.

First up in our revamped series…

Unsubscribe from unwanted emails.

We are all absolutely BOMBARDED with emails. All day. Every day.

And how many of them do we actually read?
How many of them do we actually value?
How many of them do we look forward to receiving?
How much time do we spend deleting emails each week?

It all. adds. up. 

What is the carbon footprint of email?

According to Mike Berners-Lee in his book How Bad Are Bananas?: The Carbon Footprint of Everything, the carbon footprint of an email can vary anywhere from 0.03g of carbon dioxide equivalent (CO2e) to 26g of CO2e.

💡 CO2 equivalent (CO2e) is the standard unit of measure for carbon footprints. It takes all the greenhouse gas emissions and standardizes them to carbon dioxide emissions, rather than breaking them out into carbon dioxide, methane, etc.

💌 The average spam email that never even reaches your inbox produces 0.03g CO2e.

💌 A short email that’s sent and received on a phone produces 0.2g CO2e.

💌 A short email that’s sent and received on a laptop produces 0.3g CO2e.

💌 A long email that takes about 10 minutes to write and about 3 minutes to read, that’s sent and received on a laptop produces 17g CO2e.

💌 An email blast that takes 10 minutes to write and is sent to 100 people, of whom 1 reads it and the other 99 glance at it for 3 seconds then decide just to ignore it produces 26g CO2e.

All of this adds up to the tune of about 40,000g (40kg) CO2e each year — for every one of us.

👆 This number assumes that about half of all emails are sent to spam and the other half are relatively useful that took about 3 minutes to write and about 1 minute to read.

That’s the equivalent of driving about 102 miles in an average passenger car.

Now the good news here is that when we first talked about the impact of email 5 years ago, the average year of email was estimated to be much higher — somewhere around 135kg CO2e. But today’s numbers are based on the revised edition of How Bad Are Bananas?, which apparently found that the impact is actually going down 🙌

Where does that carbon footprint come from?

Emails don’t just magically hop from my computer to your phone, even if you were sitting right next to me, even though it’s honestly so dang easy to forget that!

Emails have to travel through several servers across vast distances to get from Point A to Point B, and then actually opening your inbox, reading an email, and deleting it also requires energy.

According to How Bad Are Bananas?, when it comes to spam emails in particular, the actual footprint of sending the spam email is actually pretty small. A whopping 80% of the consumed energy from spam comes from reading, deleting, and searching through spam folders for important messages that may have gotten there by accident.

But when we’re talking about email in general, that’s where the real carbon problem comes from. Think: those emails we CC our coworker on just in case they may need the info sometime down the line. 

Those copies add up!

And, yes, the footprint of an email is about 1/60th that of a written letter. But let’s be real, how many of us send an average of 60+ more emails than we would send letters in the same time frame? 🙋♀️🙋♀️🙋♀️🙋♀️

What can we as individuals do about the carbon footprint of our emails?

This week, I want you to notice your emails.

If you’re subscribed to a bunch of email lists, notice which ones you delete immediately.

Instead of pressing the delete button first, open the email and click the Unsubscribe button. Think of how much time and energy you’ll save by never dealing with them again!

💡 Quick note: Unless the email you’re unsubscribing from really is spam, please do not report it as spam — especially if the email is coming from a small business! 

If it’s something you know you never subscribed to and you’re getting emailed anyway, that’s spam. If you never subscribed AND there’s no unsubscribe button, that’s illegal (and spam). But otherwise, marking a non-spam email as spam can actually have significant consequences for the sender. 

So if you still like the sender, just don’t need their emails in your inbox right now, unsubscribe — don’t mark as spam.

Plus, if you’re subscribed to email lists that only send you promotions, how much money will you save by not being tempted to buy??

Because we have to remember that waste comes in many forms.

Wasted time.
Wasted energy.
Wasted resources.

And if you find yourself CCing your coworkers on a bunch of emails, ask yourself if they really need to be. Is that CC worth an extra 0.3g–17g of carbon dioxide in the atmosphere?

Bonus: What does A Drop in the Ocean do about the carbon footprint of our emails?

Email is our favorite way to stay in touch with our EcoWarrior community. I’m hardly on social media anymore, pouring my energy into our Make Waves Monday email series.

But, obviously, those emails add up!

So on our end, we do two main things to keep our footprint as small as possible:

💌 Every single time we are having a sale or promotion, we ALWAYS give you the option to opt out of emails for that sale or promotion. We don’t want you to buy something you don’t need, and we don’t want to waste your time and energy, or our planet’s resources, sending you emails you don’t need and won’t read. Just look for the “Not interested in the sale? That’s cool! Click here and you won’t hear another peep about it!” block in any of our sale emails to opt out.

💌 We regularly prune our email list! Every few months I review our email list and pull a report of EcoWarriors who haven’t opened, clicked, or otherwise engaged with our emails at all in the last several months. We’ll often send them a quick “hey are you still interested?” email, and if there’s still no engagement, we unsubscribe them from our list. (I just did this last week, so YAY if you’re still receiving MWM 🥳)

So in summary…

In the grand scheme of things, email is small potatoes in the sustainability game. But hey…our name is A Drop in the Ocean. If we didn’t believe that small changes (drops in the ocean, if you will) can add up and make an impact, why would we be here at all?

Opt out of the emails you don’t value, and I will for sure be doing the same this week 💙

(And if you did find value in this post, let me know! Or if there are other seemingly small changes you want me to cover in future editions of Small Change, Big Impacts, let me know that too!)