From browsing websites to using devices, our online interactions have a hidden impact on the planet that we often overlook. Join me as I explore these environmental costs during my internship with the Web and Communications team.

Ever stopped to think about what happens every time you turn your computer on, access websites, click on links or even while you are reading this blog post? No, I’m not talking about possible eye strain from staring at screens for too long. I’m talking about the environmental cost of all those seemingly harmless digital activities. Because when we use our devices and visit websites, we rarely consider the environmental toll of our actions. In our minds, digital activities are often associated with the cloud and the imaginary, we put it in a place that is virtual, and unreal. A place where its environmental impacts do not exist, because out of sight, out of mind right? But the truth is that the effects of our digital lifestyles are very real and substantial.  

Consider this: every google search, every website accessed, every click- all of these require electricity. And where does most of the electricity come from? Mostly fossil fuels. The energy needed to create digital products and handle our ever-increasing data demands results in a significant carbon footprint. However, it is not just about carbon, the maintenance of our digital life requires substantial usage of resources such as water, minerals and space at various supply levels- from mining rare minerals and manufacturing devices to distributing them and running massive data centers. Then there’s the issue of e-waste. Each year, we produce an almost unbelievable amount of hazardous electronic waste. This non-recycled junk often ends up in landfills creating toxic environments that could fill approximately 1.55 million 40-tonne trucks, enough to form a line that could encircle the equator. All these impacts add up, even if we don’t see and think about them.  

Being aware of the environmental impact of your digital life is the first step towards becoming more sustainable and that is what my role as a Green Web Estate intern is all about. Hi! My name is Catalina, and I joined the Web and Communication (WAC) team to explore this environmental dilemma. I am working alongside Osh, and we are collaborating with Chris, the Green Digital Design Intern. We are more than halfway in our internship, and I will share the biggest challenge we encounter.  

Measuring the Digital Environment Impact: 

In the first five hours of our internship, we came face to face with our biggest challenge for the next 12 weeks: measuring the environmental impact of the web estate. Ironically, this was also one of the main goals of our internship! This task is difficult due to the lack of an established, universally agreed, accurate, and easily accessible method. While the environmental impact includes more than just carbon emissions—like the fact that the average data center uses 300,000 gallons of water a day to stay cool, equivalent to the water use of 100,000 homes—current approaches only measure carbon emissions. 

We learned about the Sustainable Web Design Model, which is the most widely accepted and used model for estimating website emissions. It uses data transfer, the process of moving data from the web server to the user’s browser, as a key foundation to estimate carbon emissions. 

 This model breaks down energy consumption into several components:  

• Datacenters: Data centers are like the engine rooms of the internet. They store and serve up all the content we access online. Running these data centers and keeping them cool uses up a significant amount of electricity—about 15% of the total energy figure. 

• Network transfer: This is the energy used to transfer data across core networks, mobile networks, on-premises Wi-Fi, and wired routers. Every time we access online content, data must travel through various networks, consuming around 14% of the total energy. 

• End user’s device usage: This refers to the electricity used by our devices—like laptops, workstations, smartphones, and tablets—when we access digital content. It’s the biggest chunk of energy consumption, making up about 52% of the total. 

• Production: This includes the energy used in making our devices. From processing silicon and other raw materials to creating integrated circuits, batteries, and metal casings, this production phase accounts for 19% of the total energy figure. 

There are online carbon calculator tools that use this model as a foundation like Eco Grader, Website Carbon Calculator, and Beacon. We use these tools to measure the CO2 emissions of different web pages across the university. Not only does this give us the CO2 Emissions per page, but also other important data such as page weight and page assets such as images, scripts, HTML/CSS and others.  

From the data collected using these tools, we found that:  

• Homepages are 1.6 to 7.2 times larger than other university web pages, making them the highest emitters within the University’s web estate. 

• Images are the largest source of emissions on average, responsible for 67.34% of total CO2 emissions, significantly higher than documents (18.81%), style sheets (6.66%), scripts (5.26%), fonts (1.75%), and media (0.26%).  

• Effective caching can significantly reduce data transfer and carbon emissions for returning visitors. The average data transfer for return visits is about 95.59% smaller compared to first visits. 

Truth, Debates, Accuracy and the Sustainable Web Design Model 

There is an ongoing debate regarding the right way to measure digital carbon emissions. The Sustainable Web Design Model is severely critiqued for giving inaccurate measurements. This is because it uses page weight measurements and assumes CO2 emissions grow proportionally with page weight. However, many believe that page weight is not a useful predictor of the greenhouse gas emissions generated by a website.  

Other methodologies such as the Power Model and DImpact have been suggested to provide more accurate measurements. However, these models can be less user-friendly and adaptable, as they require more resources, data, and time to implement. 

The power behind the numbers 

While the Sustainable Web Design Model has faced criticism for its reliance on data transfer as a foundation—oversimplifying the complex nature of networks —its simplicity is also its strength. It enables quick, user-friendly assessments that a wide audience can understand and act upon. 

The reality is that our focus isn’t solely on achieving exact and accurate measurements—at least not for now. The true power lies in the insights and trends these measurements provide. The real value behind the numbers is their ability to identify major contributors to carbon emissions, highlight areas for improvement, and drive meaningful conversations about sustainability. This allows us to recommend practical changes that can have a significant positive effect. It’s not about the absolute accuracy of the numbers, but about the truths they reveal and the actions they can inspire.