Your Challenge
This challenge is about doing a digital clean-up. Similar to spring cleaning your home, take a moment to go through your phone, computer, or both, and declutter your storage. It’s easy to forget that digital files, like photos and emails, have a carbon footprint. Many of us store hundreds of photos on our phones or the cloud, forget to unsubscribe from email mailing lists and let the junk mail pile up, and rarely visit our ‘downloads’ folder to check what we have stored. All of this adds to our carbon footprint as the larger the amount of data being stored, sent, or viewed; the more energy is required.
Why you're doing this
The demand for data is rising. For example, over the past 5 years, the energy consumption from Google’s data servers has increased 27% year-on-year, to over 30 million MWh (megawatt hours) in 2024. [1] This puts pressure on global energy production to meet demand from both households and data centres. If countries do not invest in, and build, renewable energy infrastructure then this energy will come from fossil fuels and contribute to climate change.
Additionally, data centres also require water for cooling down equipment and this can put pressure on limited global water supplies. The World Economic Forum estimate that a 1MW data centre can consume up to 25.5 million litres of water for cooling per day. [2] That’s equivalent to the water used by over 180,000 people per day in the UK. [3]
How you'll make a difference
A short, text-based email has a small carbon footprint (around 0.2 grams of CO2e when read on a phone and 0.3 grams when read on a laptop) [1]. This footprint increases with the amount of time spent writing the email, the size of the pictures and files attached to it, the length of time it takes to send, and how long it takes to read. For example, an email that takes 10 minutes to write and 3 minutes to read, sent and received on a laptop, has a footprint of 17 grams of CO2e. [4] This doesn’t sound like much but if we receive hundreds of emails a day and leave them sat in our inbox without clearing them, this adds to the volume of data being stored. The larger the volume of data being stored, the more energy we need to store it. Instead, we can unsubscribe from mailing lists as much as possible.
It’s not just emails, our digital footprint consists of all the data we’re using – that includes WhatsApp messages and files, photos and files backed up to the cloud servers, files downloaded and stored on your phone, and various app data you have saved without realising it. WhatsApp have reported that users send 7 billion voice notes per day [5] – that’s a lot of data being sent and stored!
By cleaning up our devices, we increase our awareness and understanding of our digital footprint and reduce the emissions associated with it. Why not take this a step further and spread the word by asking friends and family to take a look at how much they’re storing too and do their own digital clean up?
If you want more advice on how to clean up your digital footprint, visit the Digital Clean up Day.
Track your progress
in the My Footprint App
Track your progress and discover many more challenges in the My Footprint app. Available for iOS and Android devices.
Sources
[1] Google Environmental Report (2025) https://www.gstatic.com/gumdrop/sustainability/google-2025-environmental-report.pdf
[2] World Economic Forum, Why circular water solutions are key to sustainable data centres: https://www.weforum.org/stories/2024/11/circular-water-solutions-sustainable-data-centres/
[3] Assuming each person uses 139 litres of water per day https://www.ccw.org.uk/save-money-and-water/averagewateruse/
[4] Mike Berners Lee, How Bad are Bananas? (2021) Profile Books, ISBN: 9781788163811
[5] Whatsapp, We're making voice messages even better: https://blog.whatsapp.com/making-voice-messages-better
[6] Loughborough University, World heading towards a “data doomsday” as demand outstrips energy supply: https://www.lboro.ac.uk/news-events/news/2024/november/data-doomsday/