How does e-mail impact your carbon footprint?



Did you know that sending an e-mail emits greenhouse gasses? It’s pretty weird to think about, but sending one e-mail emits around  4g CO2e — which means Carbon Dioxide Equivalent. An e-mail with a couple attachments could emit around 50g CO2e! (


The average American will add 300lbs of CO2 to their carbon footprint each year, simply from their e-mail ( This is equivalent of driving 200 miles in a standard car.


This is where it gets a little complicated.




According to Matthew Brander of Ecometerica, “‘CO2e’ is a term for describing different greenhouse gases in a common unit.  For any quantity and type of greenhouse gas, CO2e signifies the amount of CO2 which would have the equivalent global warming impact” (Brander, 2012).


Using this term is helpful to scientists as it allows a group of GHGs to be expressed as a single unit. These different groups are then compared in terms of their overall impact on climate change. According to Brander, “A quantity of GHG can be expressed as CO2e by multiplying the amount of the GHG by its Global Warming Potential (GWP)” (Brander, 2012).
On average, the amount of e-mail we receive in 24 hours emits 1,652g CO2e.


That’s over 1,300lbs CO2e a year! 


Spam is more than just annoying, it’s killing the planet

Screen Shot 2020-03-28 at 3.17.21 PM
No Steve, I haven’t tried your berries….
The average spam e-mail emits 0.3g C02e.


According to a report by McAfee via The Guardian,  78% of all emails flooding our inbox is spam.
Around 62,000,000,000 spam messages will be sent each year.

This amount requires the  33 billion kilowatt hours (KWh) of electricity, which creates around 20 million tons of CO2e each year!

In total, over 10% of the world’s generated electricity is used for the internet (Source)


How does deleting e-mails reduce my carbon foot print?

According to, the energy used by one email with an attachment is equivalent to 25 watts per hour.


Deleting old e-mails can save 6lbs CO2e per year.


This might not sound like a lot, but just like all zero waste habits, if everyone makes an effort, it can have a huge, positive impact!

What else can I do?



One of the easiest ways to reduce these numbers is to unsubscribe from all your unwanted subscriptions. Don’t just delete them, prevent future subscription e-mails from unnecessarily flooding your inbox.

According to the app Leave Me Alone, the average person gets 17 unwanted subscription e-mails each month.

You’re not hurting the company’s feelings. Don’t worry.

Search Wisely 

Google schmoogle. Bugle. An average search generates 0.0003 kWh of energy, which is the equivalent of  roughly 0.2g of CO2 (Source).

But what about other websites, like Ecosia, a company that plants trees to offset energy use?

In a Quora query titled, “Is Ecosia better for the environment than Google?” Ecosia Social Media Manager Trudie Carter responded with:

Google runs on clean energy, so does Ecosia. In fact, Ecosia recently built its own solar plant to power its servers with renewable energy. This is even better than buying renewable energy from existing plants, as the plant can deliver clean energy to the grid and replace electricity derived from fossil fuels.

So, why does Ecosia win over Google? Because by planting trees and offsetting its energy use with renewables, each search with Ecosia actually removes 1 kg of CO2 from the air, which makes Ecosia a carbon-negative search engine. Here’s the math: an average search generates around 0.005 € of revenue. It costs roughly 0.25 € to plant a tree, which means that Ecosia can plant one tree every 50 searches. On average, these trees will each remove 50 kg of CO2 during an expected 15 year lifetime.

This means that if Ecosia were as big as Google, it could absorb 15% of all global CO2 emissions! That’s enough to offset vehicle emissions worldwide. Just imagine how much quicker the world could solve climate change if Google invested its profits – $23 billion in 2016 – into planting trees.

Trudie Carter, Social Media Manager at Ecosia:

So if you have a moment, go through your old e-mail and try to clear your inbox, spam filter, etc.

Unsubscribe from those annoying e-mails you keep deleting

Going forward, do your best to keep that inbox tidy. It’s like virtual exfoliation that helps give us some mental clarity, and keeps our planet healthier.

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