Meetup talk from Claire Thornewill about sustainable web design at the GSD Meetup from 14.03.2024

2. vs.

3. It is more important to
practice sustainable habits
than favour one material over the other.

4. Claire Thornewill
Digital Strategy & Sustainability Manager
neoverv GmbH

5. Holistic Approach
to digital sustainability

6. Digitalisation = Decarbonisation

7. Digitalisation = Decarbonisation
X

8. Electricity

9. Electricity
70%

10. Energy consumption
https://theshiftproject.org/wp-content/uploads/2019/03/Lean-ICT-Report_The-Shift-Project_2019.pdf

11. 11
According to the HTTP Archive the average page weight of the top 1,000 pages
recorded over the last 3 years was 2214.4 KB
Average page weight
2.2MB
Indexed pages
55 billion
(31.07.2023)
55 billion web pages produce ca.
460 million metric tonnes of CO2e
per year.
Average page

12. 460 Million metric tonnes CO2
30 Million cars
https://www.acea.auto/files/ACEA-report-vehicles-in-use-europe-2022.pdf
x 3

13. How do we calculate?
● www.ecograder.com
● www.websitecarbon.com
● www.ecoping.earth/
● www.webpagetest.org/
● www.beta.backspace.eco/
● www.digitalbeacon.co/

14. How do we calculate?
Website Carbon Ecograder Cleaner Web

15. How do we calculate?
CO2.js Github Repository | CO2.js Docs
CO2.js is an open-source JavaScript library that enables developers to estimate
the emissions related to use of their apps, websites, and software.
15
Average grid intensity data from
Ember
Marginal intensity data from the
UNFCCC
(UN Framework Convention on Climate Change).
Historical for the latest available
year.

16. 16
Data center usage Network transfer End user device usage Production
15% 14% 52% 19%
Average grid intensity
(data from Ember)
Total CO2e emissions
Limitations
● Single pages
● Assumed page visits
● Static carbon intensity
Electricity Maps for
Germany (12 months)
399gCO2e/kWh
Hosting Green vs. Not
Green = 50gCO2e/kWh
Not Green = 442gCO2e/kWh
Sustainable Web Design
Model (SWD)
Transferred over the Wire
Pageweight = GB
CO2.js

17. 17
Lab Data: Ecograder
Average Page size MB 1.91
Total MB 28.69
Total KG CO2e 14,607
Field Data: Manual
Average Page size MB 4.49
Total MB 67.30
Total KG CO2e 2,948
● www.ecograder.com cannot calculate
the real percentage of unique visitors
vs. recurring visitors
● www.ecograder.com uses static
location gCO2e/kWh numbers based
on the SWD models locations variable
from Ember’s Data Explorer
Ecograder Limitations
A discrepancy was found in the calculated total CO2e emissions, we believe
this to be because of a number of factors:
15 same pages audited:

18. The Problem

19. Consumerism on the web
Product Bloat. Carbon heavy products.
So much content and so many
features are built that are not
used and never removed.
The more efficient the web has
become the less efficient websites
and products have become.

20. Measure the status quo

21. Estimate CO2
95.7 million annual pageviews
140,000 pages live
4.49 MB average page weight
14.7 metric tonnes of CO2e
emissions
for the whole of the website per year
14 roundtrip transatlantic flights from Zurich,
Switzerland to New York, USA.
All Pages Views
Page size - data transferred 4.49 MB
Unique Visits Factor of % 52.36%
Pageviews per month 4179819
Monthly 18753454.58 MB
Monthly 18313.92 GB
Annual 219767.05 GB
Recurring Visits (factor of 25%) Factor of % 47.64%
Pageviews per month 3802953
Monthly 17062583.21 MB
Monthly 16662.68 GB
Annual 199952.15 GB
SWD Model Fixed Factors
Annual Internet Energy / Annual End User Traffic 0.81 kWh/GB
Carbon factor Switzerland 81 Carbon Factor g/kWh
Total CO2e per year 14681.29 KG of carbon per year

22. Impact: Page Weight
● 74% of pages were bigger than
2.2 MB
● Reduce the overall page weight
to max, 2.2. M B would reduce
overall website by 50%, therefore
reduce the total CO2e
emissions by 1.8 metric
tonnes.
.
Total Page
Weight
Total CO2e
Emission
Before 67.30 MB 2939.7 KG
74% of pages reduced to
2.2 MB 31.9 MB 1117.5 KG
Savings 35.40 MB 1822.22 KG
Introducing Page Weight budget of max. 2.2 MB

23. Impact: Image Quality
Reducing the image quality by
ca. 80% would reduce the annual
CO2e emissions by 1.8 metric
tonnes.
.
Total Page
Weight
Total CO2e
Emission
Before 67.30 MB 2939.7 KG
74% of pages reduced to
2.2 MB 35.66 MB 1053.1 KG
Savings 31.64 MB 1886.57 KG
Reducing image quality to 80% and rendering as .webP

24. Impact: Image Quality

25. Asset Management
Total Assets 339,204
Total GB 204.5 GB
Used 278,354
Deactivated 9,759
Never Used 51,093
75 different asset types
1 GB costs 3 kWh =
613.5 kWh to store 204.5 GB
Switzerland’s grid produced 81gCO2e per
kWh from August 2022 - August 2023
The all asset storage produced 49 KG of CO2e emissions in 1 year.

26. Pages
Content is created and never used or taken offline and never removed.
Total Content pages 43,234 Total Article Pages 57,451
Used 38786 67.51%
Deactivated 5986 10.42%
Never Used 12771 22.23%
*The % do not add up to 100% given not 100% of the pages are
covered
Used 26726 61.82%
Deactivated 3376 7.81%
Never Used 13134 30.38%
*The % do not add up to 100% given not 100% of the pages are
covered

27. Recommendation: Remove Legacy Code
Impact: High
Reduce the amount of data users are
downloading. We estimated that it was
possible to shave 0.5 MB off every page.
Total saving of
1,495.4 KG CO2e emissions.
Actions:
● Up to date tech stack
● Reduce unused scripts
● Avoid technical debt

28. Recommendation: Create Content Guidelines
Impact: High
Content creators did not pay attention to
the final image size, therefore, increasing
overall page weight.
Incredibly large images were stored that
were Never used on a page.
Actions:
● Reduce and optimise images
● Avoid content that eats up
unnecessary data
● Make your content accessible
to everyone

29. Recommendation: Declutter
Impact: Medium
Come up with a strategy to reduce the number
of items on a content management system
that are never used.
Actions:
● Introduce Content
management strategy
● removed used unused assets
● Give your content an expiry
date

30. Digital Cleanup Day
March 16, 2024

31. For 15 pages we found that the page weight dropped by an average of 50%
less MB just by rendering a different format of images.
Most impactful and least effort.
31
Overall Results
50% reduction to the average
page weight
14.7 metric tonnes of CO2e emission is
reduced to 7.3 metric tonnes of CO2e
emissions.

32. 1 metric tonnes of CO2 emissions
Possible annual savings:

33. Shift the responsibility

34. Make it a
holistic
team effort

35. Learn more

36. Find me on LinkedIn