Data, cloud services, and emails
Tidy up your online data and delete unnecessary files and emails!
- Be aware of how your files are stored. Delete duplicate or unused files. Keep what you need – but not everything you’ve ever created.
- When sending emails, check whether you really need all the attachments. If several people need to access the same file or work on it together, a link to a shared online drive may be sufficient.
- Tidy up your inbox regularly. Delete emails you no longer need, especially those with large attachments, and then empty the bin.
Digital data also requires energy
The term ‘cloud’ suggests a certain lightness: data seems to be available everywhere, without us having to worry about where it is actually stored. Yet even though the cloud may seem very intangible to us, there is a very real infrastructure behind it.
And real clouds are heavier than you might think: an average cloud can contain several hundred thousand kilograms of water and ice. The situation is similar with the digital cloud: behind our emails, photos, files and backups lie data centres with servers, cooling and storage systems that require large amounts of energy, water and other resources.
The cloud is therefore not as weightless as it seems, nor is it free of environmental costs. According to the International Energy Agency, storage systems account for just under 5 % of the energy consumption of data centres worldwide (IEA, 2026). In a case study, the Umweltbundesamt estimates that storing 1 TB of data per year results in between 166 and 280 kg of CO2 (UBA, 2026). For example, based on the assumptions of a model study, each gigabyte of stored emails incurs energy costs of around 0.55 kWh per year (Siy et al, 2025).
It is therefore worth paying close attention to how, where and how often files are stored. Unused files do not need to be stored in the cloud as well. A tidy inbox, free of emails with large attachments that are no longer needed, not only keeps things organised but also helps, in a small way, to reduce the environmental impact.
Keep reading on
IEA (zuletzt abgerufen: 06.10.26), https://www.iea.org/reports/energy-and-ai/energy-demand-from-ai
UBA (zuletzt abgerufen: 06.10.26), https://www.umweltbundesamt.de/themen/digitalisierung/gruene-informationstechnik-green-it/digitale-dienste-cloud-computing?#die-wichtigste-erkenntnis-zum-fallbeispiel-online-storage
Siy et al. (2025): E-litter: Nudging Email Usage Behavior One Byte at a Time, Proceedings of the ACM on Human-Computer Interaction, 9, https://doi.org/10.1145/3744198