Sustainability in the digital world

Simone Viani
6 min readFeb 29, 2024

We are all well aware of the constantly growing importance of technology in our lives and today, with AI being all the rage, we’re seeing amazing steps forward in various fields with definitely a huge social impact. I myself am very excited on what the future holds for us for that matter.

But, honestly, let’s stop for a moment and think: do we ever ask ourselves what the real cost behind this technological sprint is? Do we ever ask ourselves how our planet is actually going to reach that bright future, considering the harm we bring to it on a daily basis — and in some cases not even consciously?

Now, since we were kids we’ve come to learn that factors like industrial activities, transportation and even agriculture have an environmental impact, but what we probably don’t actively consider is that many of our daily digital activities have an impact too, even though it’s physically intangible.

Ordering a pizza through a mobile app, sending an email, listening to music, watching a movie on Netflix or simply surfing the web (reading articles on Medium, lol) are just a few of the actions that countless individuals around the world perform on a daily basis. Like it or not, all of these apparently “harmless” activities actually take a toll on our planet, especially if you consider there are over 5.3 billion Internet users in the world. It’s not just you.

Surprisingly enough the Internet accounts for around 5% of global carbon emissions, a value that is comparable to the output of all air travel put together! The use of any Internet-based platform leaves a carbon footprint into the atmosphere.

/ Carbon Footprint /

A measurement that expresses the amount of greenhouse
gasses emissions that are generated during the lifetime of a product, service,
organization, event or individual, usually expressed in tons of
CO2 equivalent.

Here are a few numbers to chew on:

  • 28–63 g CO2 emissions produced per gigabyte on the Internet.
  • 50 g CO2 emissions produced sending an email with attachments.
  • 55 g CO2e (grams of carbon dioxide equivalents) is the average carbon footprint of one hour of streaming in Europe.
  • 0.15g CO2 emissions produced posting a photo on Instagram.
  • 1–5 tons C02 annual emissions of a server.
  • 150 g CO2 per km estimated emissions of a petrol car.

It should be therefore clear that we should all start to acknowledge that our digital lifestyles actually have an environmental impact and that the Web Industry has an important part to play with designers and developers that can contribute to more sustainable practices.

This step, this first step, is crucial and it’s something we should all be aware of because, after all, the first step in solving a problem is recognizing there is one, isn’t it?

An important starting point in this sustainability journey has actually been made by the W3C (World Wide Web Consortium) that recently put out a draft of the Web Sustainability Guidelines (WSG) 1.0, a series of recommendations for making websites and digital products in general more sustainable, with a reduced ecological footprint. These guidelines are based on ESG (environment, social, and governance) principles focusing on user-centered design, sustainable business strategy, renewable infrastructure and performant web development.

So now that we know we have a sustainability problem, let’s try to better understand what the current challenges that we designers and developers have to face to move towards digital sustainability.

Reduce Carbon Emissions

Let’s start from the aforementioned carbon emissions generated by web-related activities: these are primarily due to electricity use, which today is still often sourced from fossil fuels — that once burnt produce carbon dioxide (CO2).

In the digital industry, electricity has many applications, the main three being:

  • powering devices (phones, computers, etc.)
  • enabling data storage and transfer across networks
  • enabling the manufacturing of hardware

Finding ways of limiting power consumption is therefore crucial for reducing carbon emissions.

Let’s cut to the chase and see where we can take action to reduce power consumption.


Believe it or not, but we can have a positive impact on power consumption starting from the design phase of a digital product. Starting from the color palette we choose: light blue colors use more energy than red or green do, while “dark mode” can save energy because black pixels are actually off, so they don’t contribute to energy consumption.

The user journey also plays an important part: How much time are users spending clicking around on your site, loading more resources than they need because they can’t find what they’re looking for?


Turns out there is a direct correlation between performance and sustainability.

Optimized and faster digital products usually have a lower-carbon footprint, while also ensuring a more enjoyable user browsing experience. This is because the optimization can help reduce the amount of data stored and transferred thus reducing the amount of power consumed by the user’s device.

Here are some practical performance optimizations:

  • reduce image size: nearly half of data transfer on the web comes from images, therefore reducing and optimizing these assets is crucial.
  • serve the most appropriate image for a user’s device.
  • leverage optimization tools to find areas for improvements.
  • optimize fonts/css: these files can significantly affect page weight. Forn instance limiting the number of web fonts used is key, just like serving modern font formats (like WOFF2) are all actions we can take to help reduce the payload. Also, removing unused css rules and compressing files once in production reduces overall page weight.
  • reduce javascript usage: always consider whether you really need a JavaScript framework (e.g. Jquery) for your project and limit the use of external plugins.

Digital Waste

Every media we consume, from videos, to photos, e-books, emails, online music, or podcasts are, at the core, data. Once consumed, this data is collected and stored. This process, as you can guess, consumes an important amount of energy.

Reducing the number of media exposed on a digital product has therefore a positive impact.

Internet Connection

Turns out that the way your device connects to the Internet affects power usage. Connections like 4G or 5G require more power than WiFi, and WiFi uses more energy than an ethernet connection. If you always use the same workstation you should therefore prefer a cable connection over WiFi.

Device Life-span

Always try to extend the life-span of your devices, and repair over replace whenever you can. A big part of the environmental impact in the digital world comes from manufacturing the technology in the first place, as we’ll see in the next paragraph.

Reduce Water Usage

Unfortunately carbon emissions is only one of the aspects to take into account in making our web applications more sustainable. Other factors should be considered, one of them being related to our probably biggest asset on Earth: water.

The continually increasing generation and consumption of data, as discussed earlier, requires the establishment of a growing number of data centers. These centers, known for their high energy consumption, also demand substantial amounts of water for cooling. Even the manufacturing process of silicon chips involves significant water usage. The escalating global issue of water scarcity is becoming a growing concern and must be limited, just like carbon emissions.

Green Hosting

Another important aspect to take into account is the distance from the host. The closer the data centers are, the fewer devices will the data need to pass through, thus lowering the environmental impact.

Similarly, it is crucial to rely on energy-efficient servers and in general on a hosting company that uses data centers powered solely by renewable sources or at least to a rather high percentage.

There are of course many other considerations to be made, and there’s no “one solution fits all”, but as we’ve seen many concrete actions can be taken to start addressing the (big) sustainability problem we’re facing. Nonetheless, probably the first and most important step we must all take is to really start considering technological innovation and environmental protection as two interconnected and interdependent worlds.

It’s hard and challenging because in some cases it means questioning those daily habits that are today part of our lives and that seem so natural.

But it must be done.



Simone Viani

Creative Digital Program Manager @ SDA Bocconi School of Management — Interface and Interaction Developer —