The Digital Carbon Detox

Want to improve your mental health and reduce your CO2 emissions? Try a Digital Carbon Detox!

July 11, 2022
3 min read

According to a study by the Boston Consulting Group, the internet is responsible for around 2% of the world’s total emissions - comparable to the aviation industry (about 2.5% of global emissions according to Our World in Data)!

We talk a lot about giving up flying for climate change, is it time we started talking about how we spend our time online, too?

Not only can changing our online habits be great for the planet, but it also has the added benefit of improving our mental health. But where are the most impactful areas to focus on? Let’s find out!

A few notes before we start

  • Almost all the estimates below come from the amazing work of Mike Berners-Lee in his book How Bad Are Bananas? The Carbon Footprint of Everything (revised in 2020).
  • He uses “CO₂e” which stands for Carbon dioxide and equivalents. This is because there are many different greenhouse gases that have differences in their effect on global warming and how long they stay in the atmosphere, therefore he and many other climate scientists typically convert them to CO₂e so it’s easier to compare the emissions of different sources.
  • There’s more to our ecological impact than just CO₂ emissions, while this piece only focuses on that element, it’s worth considering the other factors like waste, pollution, resource and land use, as well as social issues like health, and worker exploitation.

📧 Email

As of writing this blog, my inbox stands at 12,942 unread emails 😱 Aside from the horror that at least half of you are probably experiencing right now, just how much emissions is that producing?


  • 0.03g CO₂e spam email picked up by your filters
  • 0.2g CO₂e short email going from phone to phone
  • 0.3g CO₂e short email going from laptop to laptop
  • 17g CO₂e long email that takes 10 minutes to write and 3 minutes to read, sent from laptop to laptop
  • 26g CO₂e an email that takes you 10 minutes to write, sent to 100 people, 99 of whom take 3 seconds to realise they should ignore it and one who reads it
  • Our average email traffic is equivalent to driving 10-128 miles in a small petrol car

Interesting quotes

Although the majority of emails sent are spam, these messages account for only around 2% of the total footprint of your email account, because although they’re a pain, you deal with them quickly. A genuine email has a bigger carbon footprint simply because it takes more time to deal with.

So my unread emails aren’t so bad after all? 🧐

The long email sent from a laptop has 1/20th the footprint of a letter. That looks like a carbon saving unless you end up sending 20 times more emails than the number of letters you would have posted. This is a good example of the rebound effect - how a more efficient technology typically results in higher-carbon living because our usage goes up by even more than the efficiency improvement.

How Bad Are Bananas? p-16 & 17

What can we do?

Despite media stories, on a personal level, the impact is negligible. The most important thing to focus on is to make sure the email is never created in the first place.

  • Switch to a different email provider that better handles your email like or proton mail
  • Limit email sending
  • Avoid cc’ing people you don’t need to
  • Unsubscribe from newsletters - mostly to avoid distracting emails

If you really want to level up, why not persuade your company to improve its email habits? In a recent workshop I ran on this topic, one person told me that their company email signatures have a video embedded - just changing this to text only would have a massive impact on emissions.

🔍 Searching

Google claims to have been carbon neutral by 2007, but as this piece in Wired explains, that’s “only if you count the facilities it owns and not the factories that make its products and ship them.” In any case, let’s find out how much a google search emits:


  • 0.5g CO₂e one simple search
  • 5.6g CO₂e 5 minutes of web browsing from a smartphone
  • 8.2g CO₂e 5 minutes of web browsing from a laptop

Interesting quote

Google searching accounts for almost 630,000 tonnes of C02e per year. That sounds like a big number, but is less than 0.0001% of humanity’s carbon footprint.

How Bad Are Bananas? p-18 & 19

What can we do?

  • Don’t worry about it too much personally!
  • Switch to a greener alternative like Ecosia a search engine that plants trees while you search and set it as your default
  • Convince your friends, family, and even better - get your company to switch to Ecosia. Here’s a handy blog they put together to help you make the case.

👩‍💻 Video calls

Since the pandemic, we’ve spent much more of our lives on video calls instead of meeting face to face or travelling in for meetings. Aside from the dreaded zoom fatigue, what impact do all these video calls have on our emissions?


Based on a Zoom call

  • 2g CO₂e per hour on a 13-inch Macbook Pro
  • 10g CO₂e per hour on an averagely efficient laptop
  • 50g CO₂e per hour on a desktop computer with screen + embodied emissions* in the computer
  • 20 tonnes CO₂e potential saving on a meeting in Hong Kong with two people flying from Europe
  • A video call can save several commutes - or tonnes of carbon from a number of flights

Interesting quote

The chief footprint of a Zoom call is the embodied emissions* from your hardware - the actual call is pretty minimal and not much different to regular computer use. But the emissions you avoid can be of a whole different order.

How Bad Are Bananas? p-25

*Embodied emissions are the sum of greenhouse gas emissions released during the following life-cycle stages: raw material extraction, transportation, manufacturing, construction, maintenance, renovation, and end-of-life for a product or system.

What can we do?

  • Don’t worry about it! Though it can be draining, a video call is often better than commuting and it’s certainly preferable to using a high-emitting mode of transport.
  • Cancel pointless meetings (also for your own sanity 😄)
  • Switch to services that care about the planet like Whereby (they planted 1m trees in 2021, one for every three video meetings that happened on Whereby in February 2021)

📱 Using a smartphone

As Not Less But Better (a company dedicated to making learning healthy smartphone habits easy and accessible) says “it's a great feeling to have the knowledge of the world within reach, to receive a message with a picture of a loved one, or to immerse yourself in blogs or to be inspired by podcasts…but problematic smartphone use can lead to negative consequences for our mental health. From difficulties concentrating to stress, anxiety and sleeping problems to depression. Problematic smartphone use is a real problem for our health.”

Aside from the well-documented mental health benefits, what impact does smartphone use have on the planet?


  • 63g CO₂e a year if you use your phone one hour a day
  • 69g CO₂e a year’s typical usage of 195 minutes a day
  • 86g CO₂e per year if you use your phone 10 hours a day
  • 690 million tonnes CO₂e global mobile usage
  • When connected to the internet, typical mobile phone use works out at 1g per minute, about the same as a large gulp of beer. I’m not promoting alcoholism, but just saying, it’s better for your emissions to leave your phone switched off at home and go to the pub (on foot or bike of course)! 🍻

Interesting quotes

The vast majority of a smartphone’s emissions come from its manufacture and transport to the user, in particular, because of the precious metals and rare earths that need to be mined for smartphones’ chips and motherboard and because people often replace their phone much earlier than necessary.

It would take 34 years of average use for the footprint of the electricity you use to equal the footprint of the phone itself. So, if you keep the phone for twice as long, you almost halve the total annual footprint.

How Bad Are Bananas? p.116

What can we do?

Considering most of the emissions come are embodied in its manufacture and transport, for reducing our environmental impact, the primary focus should be on making it last as long as possible.

  • Get a case and set up find my iPhone (find my device on android) in case you lose it
  • Get your phone repaired if you break it and don’t replace it until you really need
  • Buy your next phone second-hand or with a company like Fairphone (a modular phone that allows you to replace single parts instead of the whole thing)
  • Set up app time limits
  • Set up downtime
  • Turn off wifi & internet when not using, or put it into airplane mode
  • Turn off at night
  • Avoid constantly charging
  • Turn off colours
  • Use services freedom app to block websites and apps

Campaign for policies like the Right to Repair Act - government legislation that would give consumers the ability to repair and modify their own consumer products (electronic, automotive devices etc.). Manufacturers often restrict access to tools and components or put up software barriers that hinder independent repair or modification.

💻 Computers (and using them)

Just like smartphones, we spend huge chunks of time on our laptops. Last week I spent an average of 6hrs 54mins per day on my laptop


The computer itself

  • 326kg CO₂e 13-inch MacBook Pro, 128gb storage
  • 329kg CO₂e low-cost 14-inch HP Chromebook 14g5
  • 620kg CO₂e 13-inch MacBook Pro, 1tb storage

Using it

  • 2g CO₂e per hour on 13-inch MacBook Pro, with 128gb storage
  • 6g CO₂e per hour on 14-inch HP Chromebook 14g5
  • 50g CO₂e per hour on a desktop computer with a screen
  • 68g CO₂e per hour on gaming PC with screen + 22g CO₂e per hour for use of servers and networks

Interesting quotes

A new laptop has the footprint of a flight from London to Rome — but its use is low-carbon.
If a laptop were just a lump of plastic, steel and semiconductor, you could get its footprint to something like 10kg CO2e. The problem is that microprocessors come in at around 5kg CO2e for a 2g chip.

How Bad Are Bananas? p.129 & 130

What can we do?

Similar to smartphones most of the emissions are embodied, so again, let’s make it last as long as possible!

  • Buy a case to make it last longer
  • Get it repaired if you break it
  • Don’t replace it until you really need
  • Buy second-hand
  • Turn off wifi & internet when not using
  • Set up app limits and downtime (if on a mac)
  • Turn off at night
  • Avoid constantly charging
  • Dim your monitor display

If you’re using a company laptop, encourage them to help you repair and maintain it, and buy second-hand if you need a replacement. It will save money for them too - so it’s a win-win!

💱 Cryptocurrencies

This is a huge topic so I won’t get into the weeds, but if this is an area of interest for you and you’re actively investing, it’s worthwhile to understand the impacts because they are huge and growing rapidly.


  • 46 million tonnes of CO₂e Bitcoin in 2019
  • 68 million tonnes of CO₂e all cryptocurrencies in 2019

Interesting quotes

In just a decade, cryptocurrencies have eaten up 0.12% of the world’s carbon footprint.
Currently, a whopping 0.3% of global electricity is used for Bitcoin alone, and 0.5% for all cryptocurrencies.

How Bad Are Bananas? p.164 & 165

What can we do?

  • If you’re investing in cryptos, pick ones that use proof of stake (instead of proof of work). In these systems, there’s no incentive to use energy-consuming hardware because your chance of winning depends on how much wealth you have rather than how much computation power. Currencies like Ethereum 2.0 utilise proof of stake - here’s an article about Ethereum’s initiative to reduce its carbon emissions by switching to this system.
  • If you’re interested you can check out the Regenerative Finance movement (ReFi for short), this podcast and the folks at Regen Network are exploring how to redirect this form of currency for the planet.

☁️ Cloud storage and data centres


160 million tonnes of CO₂e in 2020

Interesting quote

Data centres use about 1% of global electricity and 0.25% of its footprint

How Bad Are Bananas? p.166 & 167

What can we do?

  • Don’t store files you don’t need and delete the large ones
  • If you run a website, try this website carbon calculator to see how it performs and get tips on how to improve!
  • Advocate for GDPR laws. This encourages companies to only collect the data they need and to clearly state to their users what they’re using it for. This will avoid data you’re not using just sitting around taking space. Usually, companies pay for storage - so they’ll save money if they store less.
  • Convince your company to switch to a greener hosting provider - The Green Web Foundation has a directory listing over 500 hosting providers around the world that have a tangible commitment to using green energy in their data centres. This is a useful blog to help you choose.

Time to detox 💆‍♀️

I hope that you feel empowered to take action and can direct you're energy to the most impactful online habits and feel less guilty about the low-impact ones.

I ran a digital carbon detox session with the Climate Action Community in Berlin, here are just a few of the actions we took together - we deleted old email accounts, unsubscribed from newsletters, set up app limits and downtime on our devices, changed our default search engines to Ecosia, opened a business bank account with an ethical and sustainable bank, and started preparing cases to make changes in our companies.

Why not get a group of friends together and make a fun session out of it?