Changes to the Sustainable Web Design Model and Website Carbon

Written by Georgie Monaghan - July 2, 2024

This month sees a major update to the methodology used by a number of major website carbon calculators, including Website Carbon. Version 4 of the Sustainable Web Design Model (SWDM) is currently in a consultation phase and will go live soon. Work to integrate the new model into Website Carbon will finish shortly after the new model is approved.

Before discussing the changes in this update it is worth providing a little background on the model.

A short history of SWDM

The model is the result of a collaboration between Wholegrain, Mightybytes, Footsprint, EcoPing, and the Green Web Foundation. The original model was made available in 2020 and uses data transfer as a key input for estimations. Since release the core team of collaborators have been working to refine the model.

Studying and estimating digital emissions is still a young science. As new studies and data become available the SWDM team assess and refine the model accordingly. This research comes from organisations like:

  • UN agency the International Telecommunication Union (ITU)
  • The International Energy Agency (IEA)
  • Ericsson Research

The changes in SWDM V4

On a practical level, there are a number of calculation changes in the latest version of the model. This results in a significant change to estimated emissions.

Green hosting calculations

The model adds more granularity to the “Green Hosting” calculations. In V3 of the model Green Hosting was a binary input. You either had it or you didn’t. In the updated model, there is a more nuanced approach, allowing for an adjusted % according to the level of renewables used by a hosting provider.

Embodied emissions calculations and updated data sources

More comprehensive and accurate data is now available which changes the way estimates are now calculated. This also allows for changes in embodied emissions calculations. V3 included a “Production” system segment. This estimated embodied emissions associated with infrastructure and hardware. V4 now includes embodied emissions in the three system segments or Data Centers, Networks and User Devices.

Lower overall emissions estimates

Most significantly, for readers of this article, is what this means for the results you will receive from Website Carbon or similar services. The updated calculations and data sources will result in a significant reduction in the estimated emissions per page view.

SWDMs’ formulas divide the total energy used by the internet by the total data transferred. The updated sources show the total energy consumption of the internet reducing. This is as a result of a mix of efficiency savings, improved measurements and improved access to data.

The internet appears to be operating more efficiently (explained in this article from the Green Web Foundation), meaning that the CO2e per byte transferred has reduced.

This represents a huge change for the industry. Organisations reporting digital emissions in their ESG or impact reporting will be particularly affected – albeit in a positive way. It is important to remember that this isn’t a greenwashing campaign. The methodology changes result from updated data from trusted sources. This isn’t a push to make some sites look better than others.

What this means for users of Website Carbon

Once the consultation period for the new methodology is completed, Website Carbon will update to use the V4 of the model. CO2e estimates will reduce by around two thirds compared to the previous model.

What won’t change

Your site’s rating. The rating system will adjust in parallel with the new methodology. This means that while the CO2e estimate reduces, the equivalent rating remains the same. An efficient site, built using sustainable web design principles will still be rated more highly as a heavier site.

The advantages of a sustainably designed site. A sustainably designed site will still be a highly performant user friendly site for your users. The page speed advantages will still be popular with users and search engines alike.

How your site compares to your competitors. All sites will be subject to the same model. Results and ratings will be adjusted universally. 

In summary

This change is one that the whole industry will have to adjust to and not just Wholegrain and our clients. All the major carbon estimation services will adjust to the same model so results will remain consistent.

It’s exciting to see things move in this way as the industry as a whole improves. It’s important that we celebrate and adjust to these evolutions we are seeing but also be mindful that we can’t become complacent. Global emissions continue to increase year on year and have now overtaken that of the aviation industry. Championing sustainable web methodologies and solutions is more vital than ever. We continue to strive to create an Internet that works for both people and planet.

If you have any questions or concerns related to these changes please do not hesitate to contact me.