# Is Earth’s

Inbox Full?

You might not realise it but everything we do online has a real world environmental impact. From the emails in our inboxes to photos and videos on the cloud, our digital files are stored on physical servers that constantly use energy.

**4 minutes.**

**40 lightbulbs for an hour.**

**212 meters.**

## How You Can Help

### Managing Newsletters

Only 20% of newsletters are ever actually opened. This means that 80% are just languishing in your inbox. Of those you do open, the majority you’ll only read once, so why not delete them as you go?

Cleanfox is a handy tool that will delete your old newsletters and unsubscribe you from the ones you don't open. And it’s free!

### Reducing File Sizes

Not all emails have the same footprint — the ones with large attachments have a higher carbon cost. You can reduce the size of your emails by thinking about the type of content you send and keeping file sizes to a minimum.

SmallPDF reduces the file size of PDFs sent as attachments and helps to reduce the carbon weight of the message.

### Deleting Calendar Invites

When you receive email invitations to meetings and events, remember to delete them once you've accepted or declined the invite.

It's also possible to delete them in bulk using a keyword search for the file extension (for example search invite.ics).

### Erasing Old Accounts

Apart from the fact that unused email accounts pose a privacy and security risk, the majority just sit there amassing more spam mail. Why not get rid of them? You’ll be safer and your footprint will be instantly lighter.

## Making This Site

Every file hosted online is stored on a server that requires energy to heat, cool, power, and access. This includes emails, but also websites!

When we built this site, we made sure we considered each aspect of it from an energy consumption perspective. In fact this website is at least 97% greener than most sites. So how did we do it?

### Contrasting Colours

We used high contrast colours, which are easier to see, so you don’t have to turn up the brightness and waste battery life.

We also chose colours that use the least computing energy to display on screen.

### SVG Animation

All the animations on this site were created with scalable vector graphics (SVGs) animated through the site’s cascading style sheets (CSS). This involves only a few lines of code and no image or video files at all. Simple.

### Cloud Hosted Web Fonts

Lots of websites make use of fonts that need to be downloaded to your device and then stored in order to be visible in the browser. Instead we chose to use a font that is already hosted online. Google Fonts works in this way. You can save even more data by using system fonts, which are already installed on your computer, but choices are more limited.

### Static Web Page

On many websites each page is generated by a Content Management System (CMS) every time a visitor loads a page. Instead, we hand coded this site as a static web page which means the server uses a lot less energy.

### Green Hosting Services

We’re hosting this site with a green hosting provider that only uses renewable energy to power its servers and specialises in energy efficient architecture. We’ve chosen Krystal , but there are lots of great options available.

So, is Earth’s inbox full?

From deleting emails, to finding new sustainable ways of creating websites, this is just the beginning of a much bigger conversation. We all have a digital footprint, and if we can individually start to make small changes, we'll collectively see big results.

So go on! Start deleting and spread the word.

# Thanks In Advance

## Sources and Maths

- Hiding greenhouse gas emissions in the cloud [Accessed 6 July 2021]
- Figure of 10,222 emails was provided to us through private correspondence by a member of the CleanFox team [February 16th 2021]
- Architecting Datacenters for Sustainability: Greener Data Storage using Synthetic DNA [Accessed 16 March 2021]
- The average number of emails in an inbox in Britain is 10,222, which was provided to us through private correspondence by Louis Balladur at CleanFox [February 16th 2021]
- We calculated the average size of emails as:
- Average size of text only email is 3KB, taking into account 1-2 bytes per character, formatting, and email headers.
- Average size of a HTML newsletter is 75KB, taking into consideration that Gmail clips any message over 102KB.
- Average size of an email with a photographic attachment is 1MB.

- Data Commons - Place Explorer - United Kingdom [Accessed 16 March 2021]
- United Nations - World Population Prospectus 2019 [Accessed 16 March 2021]
- Number Of Email Users Worldwide [Accessed 16 March 2021]
- Page 46, How Bad are Bananas?: The Carbon Footprint of Everything, Mike Berners-Lee.
- How Much Water You Use [Accessed 14 May 2021]
- Olympic Swimming Pools [Accessed 14 May 2021]
- China’s Hengqin Ocean Kingdom confirmed as world’s largest aquarium as attraction sets five world records [Accessed 14 May 2021]
- Dams and Development: An Overview [Accessed 16 March 2021. Archived from the original on 28 October 2010]
- THE FRESH-WATER LOCHS OF SCOTLAND, page 385 [Accessed 14 May 2021]
- Page 108, How Bad are Bananas?: The Carbon Footprint of Everything, Mike Berners-Lee.
- Lit Up Landmarks [Accessed 14 May 2021]
- CNBC, How many consumers does it take to design a light bulb? [Accessed 21 May 2021]
- Page 62, How Bad are Bananas?: The Carbon Footprint of Everything, Mike Berners-Lee.
- Distance to Buenos-Aires London [Accessed 21 May 2021]
- World Atlas [Accessed 21 May 2021]
- Nasa: Space Place [Accessed 21 May 2021]
- Mars Nasa [Accessed 21 May 2021]
- Nasa [Accessed 21 May 2021]
- Microsoft Word - Email Statistics Report, 2019-2023 [Accessed 27 May 2021]
- The science behind email open rates (and how to get more people to read your emails [Accessed 27 May 2021]
- Website Carbon calculator [Accessed 15 June 2021]

### Introduction

“You might not realise it but everything we do online has a real world environmental impact^{1}.”

“The average email user hoards about 10,000 emails in their account^{2}.”

### Underlying Facts

To find the average CO2eq for an email account, we took the emissions of a 1TB server^{3} and divided that by the average account size, which we found by taking the average number of emails per account^{4} and the average size of those emails^{5}.

These numbers were educated (conservative) estimates devised in-house, and proofed by an expert. If you would like some more information on how we arrived at them, please contact us.

Additional referencing from: Why Are Email Files so Large? [Accessed 14 May 2021]

The Ultimate Guide to Email File Size & Load Times [Accessed 14 May 2021]

How Many Emails Does The Average Person Receive Per Day? [Accessed 14 May 2021]

For our comparable scenarios, we have used the following numbers:

● UK’s population: 66 650 000^{6}

● Europe’s population: 741 000 000^{7}

● The world's email users: 3 900 000 000^{8}

### Hot Shower Facts

To find the comparable maths between email storage and running a hot shower, we’ve taken the CO2eq for an average email account, and divided that by the CO2eq emitted per-minute when running a hot shower.^{9}

Each figure below follows this same base maths, updated to reflect the energy output of the comparison.

“Over a year, one inbox consumes enough energy to run a hot shower for about 4 minutes.”

70 (g, CO2eq of 1 inbox) divided by 18.33 (g, CO2eq of 1 minute hot shower) equals 3.8188761593, which is the equivalent number of minutes we could run a hot shower with one inbox. Then rounded to the nearest whole unit is 4 minutes.

“200 inboxes consume enough energy to run that same shower for about 13 hours.”

14,000 (g, CO2eq of 200 inboxes) divided by 18.33 (g, CO2eq of 1 minute shower) equals 763.77523186, which is the equivalent number of minutes we could run a hot shower for with these inboxes. Then divided by 60 (minutes in an hour) and rounded to the nearest hour is 13.

“100,000 inboxes consume enough energy to run the shower for about 265 days.”

7,000,000 (g, CO2eq of 100,000 inboxes) divided by 18.33 (g, CO2eq of 1 minute shower) equals 381,887.61593, which is the equivalent number of minutes we could run a hot shower for with these inboxes. Then divided by 1440 (minutes in a day) and rounded to the nearest whole number is 265 days.

“1,000,000 inboxes consume enough energy to use the shower to fill 13.7 Olympic swimming pools.”

70,000,000 (g, CO2eq of 1,000,000 inboxes) divided by 18.33 (g, CO2eq of 1 minute shower) equals 3,818,876.1593, which is the equivalent number of minutes we could run a hot shower for with these inboxes. Multiplied by the average output-per-minute of a water-efficient showerhead^{10}, and then divided by the size of an Olympic swimming pool^{11} to give us the number of pools that could be filled.

“All the inboxes in the UK consume enough energy to use the shower to fill the world’s largest aquarium 47 times.”

4,665,500,000 (g, CO2eq of 66,650,000 inboxes^{4}) divided by 18.33 (g, CO2eq of 1 minute shower) equals 254,528,096.017, which is the equivalent number of minutes we could run a hot shower for with these inboxes. Multiplied by the average output-per-minute of a water-efficient showerhead^{10}, and then divided by the capacity of the world’s largest aquarium^{12} to give us the number of aquariums that could be filled.

“All the inboxes in Europe consume enough energy to use the shower to fill up 8 large dams.”

51,870,000,000 (g, CO2eq of 741,000,000 inboxes^{5}) divided by 18.33 (g, CO2eq of 1 minute shower) equals 2,829,787,234.04, which is the equivalent number of minutes we could run a hot shower for with these inboxes. Multiplied by the average output-per-minute of a water-efficient showerhead^{10}, and then divided by the average reservoir capacity of a large dam^{13} - according to the World Commission on Dams - gives us the number of dams that could be filled.

“All the inboxes in the world consume enough energy to use the shower to fill up Loch Ness 18 times.”

273,000,000,000 (CO2eq of 3,900,000,000 inboxes^{6}) divided by 18.33 (CO2eq of 1 minute shower) equals 14,893,617,021.3, which is the equivalent number of minutes we could run a hot shower for with these inboxes. Multiplied by the average output-per-minute of a water-efficient showerhead^{10}, and then divided by the capacity of a Loch Ness^{14}, to give us the number of lochs.

### Light Bulb Facts

To find the comparable maths between email storage and leaving the light on, we’ve taken our CO2eq amount for an email account, and divided that by the CO2eq emitted by a light bulb left on for one year^{15}, and then divided that to find the emissions for one hour.

Each figure below follows this same base maths, updated to reflect the energy output of the comparable.

“Over a year, one inbox consumes enough energy to illuminate 40 lightbulbs for an hour.”

70 (g, CO2eq of 1 inbox) divided by 1.71232876699999981 (g, CO2eq of a lightbulb being on for 1 hour) equals 40.88, which is the equivalent number of lightbulbs left on for an hour with one inbox. Then rounded to the nearest whole unit gives us 41 lightbulbs left on.

“200 inboxes consume enough energy to illuminate 8,176 lightbulbs for an hour.”

14,000 (g, CO2eq of 200 inboxes) divided by 1.71232876699999981 (g, CO2eq of a lightbulb being on for 1 hour) equals 8176, which is the equivalent number of lightbulbs left on for an hour with these inboxes.

“100,000 inboxes consume enough energy to light up the Sydney Opera House for 11 days.”

7,000,000 (g, CO2eq of 100,000 inboxes) divided by 1.71232876699999981 (g, CO2eq of a lightbulb being on for 1 hour) equals 4,088,000, which is the equivalent number of lightbulbs left on for an hour with these inboxes. Then divided by the number of lightbulbs in the Sydney Opera House^{16} gives us 263.741935, which is divided by 24 (hours in a day), and rounded to the nearest whole number gives the number of days.

“1,000,000 inboxes consume enough energy to light up the Eiffel Tower for 12 weeks.”

70,000,000 (g, CO2eq of 1,000,000 inboxes) divided by 1.71232876699999981 (g, CO2eq of a lightbulb being on for 1 hour) equals 40,880,000 which is the equivalent number of lightbulbs left on for an hour with these inboxes. Then divided by the number of lightbulbs in the Eiffel Tower^{16} gives us 2,044, which is divided by 168 (hours in a week), and rounded to the nearest week gives the number of weeks.

“All the inboxes in the UK consume enough energy to light up the whole of London for 40 days.”

4,665,500,000 (g, CO2eq of 66,650,000 inboxes^{4}) divided by 1.71232876699999981 (g, CO2eq of a lightbulb being on for 1 hour) equals 2,724,652,000.20 which is the equivalent number of lightbulbs left on for an hour with these inboxes. Then divided by the number of lightbulbs in the City of London^{16} gives us 973.09, which is divided by 24 (hours in a day), and rounded to the nearest whole number gives the number of days.

“All the inboxes in Europe consume enough energy to light up Las Vegas for 14 months.”

51,870,000,000 (g, CO2eq of 741,000,000 inboxes^{5}) divided by 1.71232876699999981 (g, CO2eq of a lightbulb being on for 1 hour) equals 30,308,432,002.18 which is the equivalent number of lightbulbs left on for an hour with these inboxes. Then divided by the number of lightbulbs in Las Vegas^{16} gives us 10,824.44, which is divided by 730 (average number of hours in a month), and rounded to the near whole number gives us the number of months.

“All the inboxes in the world consume enough energy to light the whole of the US for 28 hours.”

273,000,000,000 (g, CO2eq of 3,900,000,000 inboxes^{6}) divided by 1.71232876699999981 (g, CO2eq of a lightbulb being on for 1 hour) equals 155,344,000,011.18, which is the equivalent number of lightbulbs left on for an hour with these inboxes. Then divided by the number of residential lightbulbs in the U.S^{17} gives us 27.74, and rounded to the nearest whole number gives us the number of hours.

### Driving Fact

To find the comparable maths between email storage and driving a car, we’ve taken our CO2eq amount for an email account, and divided that by the CO2eq emitted per mile by an average UK car^{18}.

Each figure below follows this same base maths, updated to reflect the energy output of the comparable.

“Your inbox: is like driving 212 meters.Over a year, one inbox consumes enough energy to drive 212 meters.”

70 (g, CO2eq of 1 inbox) divided by 329.327550424397579 (g, CO2eq of driving 1km) equals 0.2125721227, which is the equivalent number of kilometers that could be driven with one inbox. Then multiplying by 100 and rounded to the nearest whole unit gives the distance in meters.

“200 inboxes consume enough energy to drive 42.5 km.”

14,000 (g, CO2eq of 200 inboxes) divided by 329.327550424397579 (g, CO2eq of driving 1km) equals 42.51442454, which is the equivalent number of kilometers that could be driven with these inboxes. Then rounded to the nearest unit gives the distance in kilometers.

“100,000 inboxes consume enough energy to drive from London to Buenos Aires and back.”

7,000,000 (g, CO2eq of 100,000 inboxes) divided by 329.327550424397579 (g, CO2eq of driving 1km) equals 21257.21227, which is the equivalent number of kilometers that could be driven with these inboxes. Then divided by the distance between London and Buenos Aires^{19}, and rounded to the nearest whole number gives us the number of journeys

“1,000,000 inboxes consume enough energy to drive around the Earth 5 times.”

70,000,000 (g, CO2eq of 1,000,000 inboxes) divided by 329.327550424397579 (g, CO2eq of driving 1km) equals 212,572.1227, which is the equivalent number of kilometers that could be driven with these inboxes. Then divided by the circumference of the Earth^{20}, and rounded to the nearest whole number gives us the number of circumnavigations.

“All the inboxes in the UK consume enough energy to drive to the Moon and back 18 times.”

4,665,500,000 (g, CO2eq of 66,650,000 inboxes) divided by 329.327550424397579 (g, CO2eq of driving 1km) equals 14,167,931.98, which is the equivalent number of kilometers that could be driven with these inboxes. Then divided by distance between Earth and the Moon when they are at their closest^{21}, and rounded to the nearest whole number gives us the number of journeys there and back.

“All the inboxes in Europe consume enough energy to drive to Mars 3 times.”

51,870,000,000 (g CO2eq of 741,000,000 inboxes) divided by 329.327550424397579 (g, CO2eq of driving 1km) equals 157,515,942.9, which is the equivalent number of kilometers that could be driven with these inboxes. Then divided by distance between Earth and Mars when they are at their closest^{22}, and rounded to the nearest whole number gives us the number of journeys there and back.

“All the inboxes in the world consume enough energy to drive to the Sun 5 times.”

273,000,000,000 (g CO2eq of 3,900,000,000 inboxes) divided by 329.327550424397579 (g, CO2eq of driving 1km) equals 829031278.5, which is the equivalent number of kilometers that could be driven with these inboxes. Then divided by distance between Earth and the Sun when they are at their closest^{23}, and rounded to the nearest whole number gives us the number of journeys.

### How You Can Help

By 2023, it’s projected that over 347 billion emails will be sent and received globally every day^{24}.”

“Only 20% of newsletters are ever actually opened^{25}”

“In fact this website is at least 97% greener than most sites^{26}”