Main results in plain language

This page gives the main results of the ReVerDi project as text and tables. It contains the same results as the rest of the website, without charts, maps or animation. All figures are preliminary.

1. What we studied

We compared three national libraries for the year 2024: the British Library in the United Kingdom, the Koninklijke Bibliotheek (KB) in the Netherlands, and the Swiss National Library. We looked at each library as a whole organisation.

We measured three things. First, the effect on the environment. Next, the cost. Finally, the effect on people and society. Together, this method is called a Life Cycle Sustainability Assessment.

2. Environment

The British Library is by far the largest of the three, and it has the highest total emissions. But if you divide the emissions by the number of items each library keeps, the British Library has the lowest value. Large, efficient storage spreads the fixed costs over many items. The Swiss National Library is also low per item, partly because Swiss electricity causes few emissions.

Table 1. Greenhouse-gas emissions of each library in 2024

Library	Emissions per year (tonnes CO₂-eq)	Share of national emissions	Emissions per item kept (kg CO₂-eq)
British Library	17,258	about 0.0036 %	0.10
Koninklijke Bibliotheek	4,829	about 0.0033 %	1.19
Swiss National Library	1,799	about 0.0044 %	0.25

CO₂-eq means carbon dioxide equivalent. It adds up all greenhouse gases in one number.

We looked at five kinds of environmental impact. The British Library has the highest value in all five. Table 2 shows the other two libraries as a percentage of the British Library.

Table 2. Environmental impact compared with the largest library (British Library = 100 %)

Kind of impact	British Library	Koninklijke Bibliotheek	Swiss National Library
Greenhouse gas	100 %	28 %	10 %
Harm to human health (toxicity)	100 %	45 %	14 %
Land use	100 %	29 %	34 %
Use of mineral resources	100 %	9 %	4 %
Water use	100 %	22 %	26 %

Buildings and energy cause about a third to a half of all emissions. Better buildings and greener energy are the biggest levers. The library often shares these decisions with the owner of the building.

3. Cost and use

The same pattern holds for cost. The British Library spends the least for each item it keeps, and the KB the most.

Table 3. Cost for each item kept, 2024

Library	Cost per item
British Library	€1.05
Koninklijke Bibliotheek	€14.34
Swiss National Library	€5.37

The libraries create value through use. Table 4 shows how much the collections were used in 2024. Many more people visit online than in person.

Table 4. Use of the libraries in 2024

Kind of use	British Library	Koninklijke Bibliotheek	Swiss National Library
Physical items used in reading rooms	488,193	42,195	50,881
Visitors in person, including events and exhibitions	1,361,002	47,746	41,328
Visitors online	about 25 million	about 10 million	about 9 million

4. Social impact

We checked 20 social indicators for workers, users and society. Each was rated positive, neutral or negative. All three libraries score well.

• They reach a large part of their country's population, especially online.
• They run programmes for children and for users from minority groups.
• They are good employers, with fair pay, gender balance and active unions.
• Some libraries were rated neutral on accessibility, opening hours and written sustainability targets. Small changes could improve these.

5. Open heritage on Wikimedia Commons

The three libraries have shared many public-domain images on Wikimedia Commons, where anyone can use them for free. We studied 168,030 of these files. Each library shares them in its own way.

Table 5. How each library shares images on Wikimedia Commons

Library	Files	How they are shared
British Library	90,281	Large releases in 2014 and 2018, mostly uploaded by volunteers
Koninklijke Bibliotheek	30,849	A steady flow chosen by curators, with detailed descriptions
Swiss National Library	46,900	Recent and growing, uploaded through one official account in high quality

We then searched the web for 15,000 of these images, 5,000 per library. We found them 161,367 times, on stock photo sites, in news, blogs and Wikipedia, on social media and in print shops. Most of this reuse is outside the library's own country.

Table 6. Reuse of shared images found on the web

Library	Reuses found	Share of images reused at least once
British Library	76,535	76 %
Koninklijke Bibliotheek	63,062	59 %
Swiss National Library	21,770	48 %
All three	161,367	61 %

Images are reused more often when they carry a clear public-domain label and come in a common file format such as JPEG. Each extra year online raises the odds of reuse by about 31 %.

Since image generators such as ChatGPT appeared in late 2022, reuse on social media has grown, from 17 % of dated reuses in 2018 to 43 % in 2025. Appearances on stock photo sites fell from about a quarter to under 2 %.

6. The Newspaper Game as text

The Newspaper Game is a short platform game. You follow one person, Folio, who reads one newspaper at a national library: The Daily Mirror at the British Library, De Telegraaf at the KB, or the Basler Zeitung at the Swiss National Library. You make three choices:

1. Read the whole paper, or only your favourite part.
2. Read it on paper in the library, or on a screen.
3. On paper, how you travel to the library. On screen, which device you use.

At the end, the game shows the greenhouse-gas emissions of this one reading and what causes them. The main lessons are these.

• One library copy serves many readers, so each reading carries only a small share of the footprint.
• On the paper route, the trip to the library is usually the largest part. Train, bike or walking cause far less than driving alone.
• Reading only the part you need lowers the footprint on both paper and screen.
• On screen, the device matters. A phone uses far less energy than a desktop computer.

The game is a pilot. Its figures are preliminary and partly based on assumptions. The game itself works with a keyboard but cannot be read by a screen reader, so this section gives its content as text.

7. Sources and contact

• Full study: “National Libraries: An organisational Life Cycle Sustainability Assessment”, under peer review.
• Wikimedia studies: “Open by Design” (invited, special issue) and “From Digitization to Diffusion” (under review, Journal of Cultural Economics).
• Published paper on the book industry: Does the digitalization of the book industry reduce its environmental impact? (open access).
• All outputs of the project

Questions or problems with this page: Dr. Matthias Sahli, Bern University of Applied Sciences, matthias.sahli@bfh.ch.

Last updated 14 October 2026. All figures are interim results of ongoing research and may change.