ICT4S 2023
Mon 5 - Sat 10 June 2023 RENNES, France


As with most human activities, a scientific conference will have some negative impact on the environment, regardless of how it is organized. The “most sustainable” way to organize a conference is therefore to not have a conference at all − even though in this scenario we obviously lose all the social benefits that a conference brings.

Since we did decide to organize a conference, what remains is a matter of making choices, by considering the tradeoff of each decision, hoping that the social benefits of our choices will outweigh the environmental costs. We also have to remain humble and honest, as the range of action to improve the sustainability of an in-person conference is limited, given that air travel represents by far the biggest cause of environmental impact.

This page aims to explain what actions we endorsed to make ICT4S 2023 more sustainable, and what actions we considered and did not endorse. In the appendices, we also present what data and studies we used to make our decisions.

Actions endorsed for ICT4S 2023

Using the studies presented at the end of this page, we selected a set of target actions to make ICT4S 2023 more sustainable. We also considered a few additional actions that we believe can be beneficial, despite being not directly considered in said studies.


  • Free access to public transports in Rennes for all conference participants,
  • Providing detailed information about ground travel to reach the conference.

Food & Catering

  • Provide high-quality vegetarian/vegan choices for all meals,
  • Reducing the amount of animal-based products in all meals,
  • Managing leftovers efficiently – giving these away to a student organization and composting whatever remains,
  • Rely on local food sources when possible and relevant.
  • Judicious waste management:
    • Avoiding waste (including cutlery and containers) that is not compostable,
    • Eliminating single-use cutlery,
    • When there is no alternative, prefer waste with the lowest footprint (eg. aluminum over plastic),

Conference Material

  • No printed t-shirts will be given to organizers and student volunteers. Instead they will visible with with colorful conference badges (eg. colored paper and/or colored lanyards) and personal clothes of a specific color.
  • A reduced amount of gifts available: there will be no “gift bags” by default, instead all goodies will be freely available in limited quantities for all participants to take when and if they want.
  • No printed signposts to guide attendees inside the campus, replaced by arrows and text written directly on the ground using chalk.

Digital Communication

  • Low-impact website − no JS, no bloating, small images.

This list may evolve until the start of the conference.

Actions not endorsed for ICT4S 2023

Going online? (hybrid or fully virtual)

By far, most of the negative impact of a conference comes from air travel. An additional small negative impact also comes from hotel stays, which are not environmentally friendly. Due to the pandemic, we are now more technically and mentally prepared to meet and discuss online instead of in-person. This opens the possibility to cut between 40% and 80% of the carbon footprint of the conference by deciding to organize a hybrid conference (mixing both online participants and participants coming to a venue) or a fully virtual conference (all participants online with no venue) respectively.

Yet, even though it cannot be easily measured, we believe that the cost of going online outweighs the environmental benefits that this format would bring. Here we quote the authors of the main study we considered for our decision making [1]:

“ Further measures of environmental optimization could be identified, e.g. digital meetings. It is however unlikely that those will totally replace physical meetings. The social benefits of direct personal and globally-oriented exchange can probably not be outweighed by environmental savings. Future conference planning should thus relate the sustainability benefits with the detrimental impacts. ”

For this reason, ICT4S 2023 will not be an online conference. Instead, we provide online access only for exceptional situations, and we will strongly encourage train travel to reach the venue. We hope that making the community meet in-person will contribute to bringing exciting and outstanding research results, in order to help on a grander scale to drive our digitalized society into a more sustainable future.

Vegetarian and/or plant-based meals?

The second most negative impact of a scientific conference is the food and catering. Most impactful are animal-based products (meat, fish, dairy, etc.), which for manifold reasons require much more energy and land use than plant-based products. One possibility to significantly reduce the environmental footprint of a conference would therefore be to only provide vegetarian and/or plant-based meals.

Yet, food is not only a required input for human bodies. It is also a very important cultural aspect of our lives and history. ICT4S 2023 will be organized in France, a country with a strong relationship with food, and with a cooking style that relies heavily on animal-based products. In this context, going fully vegetarian would not only force caterers to perform an incredible (and possibly disappointing) sidestep, but also prevent participants from discovering what is part of the country’s heritage.

For these reasons, ICT4S will not be a strictly vegetarian conference. Instead, we aim to have vegetarian choices of the highest quality, and to reduce the amount of animal products used overall in all meals.

Outside the conference schedule, you can find a few restaurants in Rennes that are specialized in plant-based cuisine — currently only Symbiozh, Les Enfants Terribles and Petite Nature, all mostly serving during lunch hours but unfortunately not in the evenings. More typical French restaurants rarely offer a wide range of vegetarian choices, but it is possible to find more vegetarian-friendly cuisine in Lebanese, Tibetan, or Indian restaurants. Happycow is also a good source for vegetarian-friendly restaurants.

Appendices: Data and Studies Considered

Environmental impacts of conferences

There is a rising academic interest (eg. [1-7]) on measuring the environmental impacts of science or of conferences. To drive our decisions for ICT4S 2023, we focused on a study from 2020 [1] that provides what appears to be the first complete life-cycle analysis (LCA) of a scientific conference. More precisely, the authors measured the holistic environmental impact (carbon footprint, natural resources consumed, acidification, eutrophication, etc.) of a complete conference series in the field of sustainability research. The study also includes some “what-if” scenarios to help identify possible efficient levers to reduce the footprint of a conference.

We made the assumption that the results from this study [1] can be transposed to a conference such as ICT4S. Here are some important takeaways that we took into consideration:

  • The largest portion of the overall ecological footprint (~80% of the carbon footprint) of studied conferences comes from the means of transportation used to reach the conference, air travel in particular. The remaining share comes from the conference preparation (~2% of the carbon footprint) and from the conference execution (~18% of the carbon footprint).
  • During the conference execution, by decreasing order of importance, the main environmental impacts come from:
    • Food and catering − due to non-vegetarian meals, alcohol, coffee and waste,
    • Hotel overnight stays − due to heating, air conditioning, water, electricity, waste,
    • Conference materials − due to the tote bags, printed programs, printed proceedings,
    • Energy consumption of venue rooms − due to electricity, heating, air conditioning
  • Based on their results, the authors identified the following actions that can efficiently reduce the footprint of a conference:
    • Going online,
    • Train travel instead of air travel,
    • Vegetarian meals,
    • Reduction of conference material.

Environmental impacts of transportation

As explained above, because of the sheer amount of kilometers that must be covered by each attendee to reach the conference venue, transport is usually the biggest environmental footprint of a conference. To better understand why this is the case, we can look at the main available options:

  • Train travel is a quite CO2-efficient choice for mid- to long-distance land travel (between 6 and 41 gCO2e/km on average [8]). It is however not always practical or available, and rather slow compared to air travel.
  • Car travel can also be used for land travel, yet less CO2-efficient with a factor of ten (around 53 gCO2e/km with an electric car and around 192 gCO2e/km with a gasoline car [8]), but this factor can be significantly reduced by car pooling.
  • Air travel is often the only valid option for long-distance travel, with the same order of magnitude as private car travel when it comes to CO2-efficiency (between 150 and 255 gCO2e/km on average [8]).

Of course the possibilities depend significantly on the distance to be travelled, on the means of transport available, and on time or organizational constraints— in the end, air travel is often the only possibility!

Environmental impacts of food

As explained above, the second largest portion of a conference’s environmental footprint usually lies in the food eaten by its participants. Here are two important facts that made us aim for local and vegetarian options during the conference:

  • Local products yield on average 5% less greenhouse emissions than non-local food [9,11,12].
  • Most plant-based products yield between 90% and 98% less greenhouse emissions than most animal-based products [9,10].

Environmental impacts of beverage packaging

In some rare cases we might not be able to eliminate waste caused by beverage packaging during conference events. Looking at a recent Life-Cycle Assesment (LCA) focusing on beverage packaging [13], we learned the following:

  • 100% recycled glass bottles are more impactful than plastic bottles,
  • 100% recycled aluminium cans are less impactful than plastic bottles,
  • Tetra Pak containers and cartons are the least impactful − but not always available, eg. pressurised beverages require either plastic or aluminium.


[1] Sabrina Neugebauer, Maren Bolz, Rose Mankaa, Marzia Traverso, How sustainable are sustainability conferences? – Comprehensive Life Cycle Assessment of an international conference series in Europe, Journal of Cleaner Production, Volume 242, 2020, 118516, ISSN 0959-6526, https://doi.org/10.1016/j.jclepro.2019.118516

[2] Wouter M.J. Achten, Joana Almeida, Bart Muys, Carbon footprint of science: More than flying, Ecological Indicators, Volume 34, 2013, Pages 352-355, ISSN 1470-160X, https://doi.org/10.1016/j.ecolind.2013.05.025.

[3] Tao, Y., Steckel, D., Klemeš, J.J. et al. Trend towards virtual and hybrid conferences may be an effective climate change mitigation strategy. Nat Commun 12, 7324 (2021). https://doi.org/10.1038/s41467-021-27251-2

[4] M.H. Holden, N. Butt, A. Chauvenet, M. Plein, M. Stringer, I. Chadès. Academic conferences urgently need environmental policies. Nat. Ecol. Evol., 1 (2017), pp. 1211-1212. https://doi.org/10.1038/s41559-017-0296-2

[5] R. Hischier, L. Hilty. Environmental impacts of an international conference. Environ. Impact Assess. Rev., 22 (2002), pp. 543-557. https://doi.org/10.1016/S0195-9255(02)00027-6

[6] S. Desiere. The carbon footprint of academic conferences: evidence from the 14thEAAE congress in Slovenia. EuroChoices, 15 (2016), pp. 56-61. https://doi.org/10.1111/1746-692X.12106

[7] D. Spinellis, P. Louridas. The carbon footprint of conference papers. PLoS One, 8 (2013), pp. 6-13, https://doi.org/10.1371/journal.pone.0066508

[8] Hannah Ritchie. “Which form of transport has the smallest carbon footprint?”. Our World in Data. https://ourworldindata.org/travel-carbon-footprint (accessed on 08/03/2023)

[9] Hannah Ritchie. “You want to reduce the carbon footprint of your food? Focus on what you eat, not whether your food is local”. Our World in Data. https://ourworldindata.org/food-choice-vs-eating-local (accessed on 08/03/2023)

[10] Poore, Joseph, and Thomas Nemecek. “Reducing food’s environmental impacts through producers and consumers.” Science 360.6392 (2018): 987-992. https://doi.org/10.1126/science.aaq0216

[11] Christopher L. Weber and H. Scott Matthews. “Food-Miles and the Relative Climate Impacts of Food Choices in the United States”. Environmental Science & Technology 2008 42 (10), 3508-3513, https://doi.org/10.1021/es702969f

[12] Vilma Sandström, Hugo Valin, Tamás Krisztin, Petr Havlík, Mario Herrero, Thomas Kastner. “The role of trade in the greenhouse gas footprints of EU diets”. Global Food Security, Volume 19, 2018, Pages 48-55, ISSN 2211-9124, https://doi.org/10.1016/j.gfs.2018.08.007

[13] Brock, Alice, and Ian Williams. “Life cycle assessment and beverage packaging.” Detritus 13 (2020): 47-61. https://doi.org/10.31025/2611-4135/2020.14025