Reduce CO2 emissions of your website

We had the great opportunity to speak with Torsten Beyer, author and expert on "Sustainable Websites".

Torsten has been working on the subject for several years and has attracted attention with specialist articles in renowned trade journals and, most recently, with the publication of his book, "Sustainable Websites". We are therefore particularly pleased to have secured him for an interview.

Hello Torsten, could you briefly introduce yourself?
My name is Torsten Beyer and I hold a PhD in chemistry. In 1998 I founded Dr. Beyer Internet Consulting to combine my passion for the internet with chemistry. Designing and optimising websites with regard to page loading speed and search engine rankings has been a central part of our offering from the start. Without this specialist knowledge it would have been impossible to found and establish our advertising-funded online lab magazine Analytik NEWS in competition with well-funded publishers. I have remained true to chemistry to this day and use the site to test sustainable optimisations and their effectiveness. This year we have expanded our portfolio to include sustainability audits for websites. We support companies in optimising existing sites and in the strategic planning of new, more sustainable sites. We also produce CO₂-assessments of websites, including metrics to document the status quo and to evaluate optimisation measures.

In your view, is hosting in Germany sensible or rather problematic because of climate change, and do we need to look for long-term alternatives in Northern Europe?
You can't make a blanket statement. At present hosting is concentrated in the Rhine-Main region because of the internet hub in Frankfurt, which is problematic due to water scarcity, a warmer climate and the limited locally available green electricity.
In the north and the south some hosts produce renewable energy or purchase it locally. In general we need stronger environmental requirements for new builds and transparency when using the "Green Hosted" label. Buying climate certificates (guarantees of origin), for example purchased in Scandinavia, is qualitatively different from using renewable energy on site.

There are four points where electricity is consumed that CO₂-emissions are caused to load web pages. Could you briefly present these and which is the most relevant?
Besides the data centres, the entire network infrastructure, all internet-enabled end devices and the whole hardware sector including recycling must be considered. All common tools calculate the CO₂-emissions based on the so-called "Sustainable Web Design Model". They rely on the transferred data volume for the homepage and simplified assumptions about the electricity mix. The accuracy of these values is, however, limited, because a precise determination of the transferred data volume and a correct accounting is only possible by analysing server log files.

Dr Torsten Beyer in an interview

Photo: Torsten Beyer

Do you have an approximate figure, compared with road or air traffic, for what percentage web browsing is responsible for of global CO₂-emissions?
For years the figure of 3.7 percent has been circulating, which would correspond to global air traffic. Other studies already place us in the 6–7 percent range. I would treat such figures with caution, because it is unclear what is being counted (for example cryptocurrencies, the dark web, IPTV, autonomous driving, AI applications) and how reliable data from Russia, China or Africa are. I would rather argue that we should focus on specific areas and identify optimisation potential.

Can you show our readers how they can, with little effort, reduce the CO₂ e on their website? CO₂ e?
The biggest potentials lie in video content. Are they really necessary and how are they embedded in web pages? For example, they should not autoplay. Next comes optimisation of image assets. This involves using modern formats (e.g. webp), lazy loading and correct scaling. Custom fonts and PDF files should also be reviewed. Avoiding unnecessary JavaScript and CSS frameworks, as well as implementing a responsive design, is usually a task for the next relaunch, since changes to existing pages can be very time-consuming or even impossible.

Which testing tools can you recommend to see how much saving potential remains on your own website?
A helpful tool for a first rough estimate is the Website Carbon Calculator. It lets you assess the data volume of the homepage compared with other sites and check whether an environmentally friendly hosting provider is used. For a more detailed analysis of other subpages based on the data formats used, the tool Beacon is suitable. Technically proficient users can also read the transferred data volume directly from the browser console. The professional tool Ecograder uses, among other things, all checks from Google Lighthouse and lists concrete optimisation suggestions.

If someone now wants to delve deeper into the subject, can you tell us how that is possible?
A good introduction is provided by my freely accessible feature article in the magazine WebSite Boosting from August 2022. For a deeper insight with background information and numerous practical tips, my book "Nachhaltige Websites" (Springer Gabler Verlag) was published at the end of May 2023. In addition, I have been a guest on several podcasts about the topic and regularly share interesting news and practical tips on LinkedIn.

Thank you for your time!

The interview was conducted by Marco Keul, founder and operator of hosttest.

Profile of Dr. Torsten Beyer

Company: Dr. Beyer Internet-Beratung
Name: Dr. Torsten Beyer
Position: Founder and Owner
Company founded: April 1998
Services offered:

• Sustainable website optimisation
• CO₂ accounting for websites
• Online magazine Analytik NEWS