According to IPCC (2018),

« limiting global warming to 1.5°C would require ‘rapid and far-reaching’ transitions in land, energy, industry, buildings, transport, and cities. Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050. This means that any remaining emissions would need to be balanced by removing CO2 from the air. « 


This immense task requires the involvment of every part of the society and in particular scientists, well placed to understand the process as well as the challenge. In computer science, emissions of greenhouse gases of our community mainly come from conferences: ICALP 2022 has therefore initiated a series of measures aiming at reducing the impact of the event.

We look up

ICALP 2022 has taken several decisions aiming at reducing its carbon footprint.

TCS4F manifesto

As a testimony of our engagement, ICALP 2022 supports and has signed the TCS4F manifesto (https://tcs4f.org/).

Environmental chair

ICALP 2022 appointed an environmental chair, Hugo Férée (https://hugo.feree.fr/), in charge of assessing the carbon footprint induced by the event.

Hybrid mode

Encouraged by various experiments in recent years, and as a mean to reduce travel by plane, ICALP 2022 is a hybrid conference, both for participants _and_ speakers.


The conference [Highlights of Logic, Games and Automata 2022](https://highlights-conference.org/2022/) is taking place in Paris the week before ICALP 2022. This is an opportunity for participants to attend both conferences with only one travel.

Extended Stay Support Scheme

Participants were encouraged to extend their stay with scientific visits within train distance from Paris. More information about this on the dedicated web page (https://icalp2022.irif.fr/?page_id=50#support). This scheme was experimented simultaneously by the conference [Highlights](https://highlights-conference.org/2022/).


The footprint of food is tremendous on a global scale. Therefore we decided at ICALP 2022 to adapt the menus in order to decrease their carbon footprints.

ICALP 2022 greenhouse gas accounting


Estimating the total greenhouse gas emissions of the event is beyond our reach, since it depends on many parameters, such as participants’ accomodation, food, local transportation, or digital usage. However, we can estimate emissions due to travelling to Paris, which is actually the main carbon budget of the event.

We would like to stress that if coming with a precise carbon accounting is hard, evaluating the gain obtained from our actions is even harder. Indeed, we do not know how the covid19 has impacted the choices of participants. We do not know either if virtual participants would have attended in real if the conference were to be organised as before. And above all, we do not have an estimate of the carbon footprint of the previous editions.

For all these reasons, all numbers below have to be interpreted with great care. They should only be considered as rough estimates, or even only orders of magnitude.

These numbers correspond to greenhouse gas ([GHG](https://en.wikipedia.org/wiki/Greenhouse_gas)) emissions, and are given in [CO2-equivalent](https://en.wikipedia.org/wiki/Global_warming_potential) (CO2-e).

Total travel

All participants have been asked for their departure location and the main transportation mode used to reach Paris. We used the tools from [Labo 1.5 collective](https://labos1point5.org/) for converting these data to CO₂-equivalent quantities.

The total carbon footprint of travelling to and from ICALP 2022 is estimated at

  • for 242 ICALP participants, 172 tons of CO₂-e emitted for, i.e. about 710 kg CO₂-e per participant.
  • for 76 workshop physical participants not coming to ICALP, 30  tons of CO₂-e emitted, i.e. about 400 kg CO₂-e per participant.

Hybrid mode

There were 44 virtual participants to ICALP. The travel emissions if they would have travelled to Paris is evaluated to 43 tons of CO₂-e.

Among them, there were 31 virtual speakers to ICALP (over a total of 137 speakers = 127 regular speakers + 6 invited speakers + 4 award recipients). The travel emissions if they would have travelled to Paris is evaluated to 33 tons of CO₂-e.

Co-location with HIGHLIGHTS

There were 31 participants attending both Highlights and ICALP, or both Highlights and at least one of the workshops.

The travel emissions if they would have travelled back home in between is evaluated to 6 tons of CO₂-e.

Extended Stay Support Scheme

There were 6 participants who used the IESSS and stayed longer for collaboration. The travel emissions if they would have organise another trip to Paris is evaluated to 6 tons of CO₂-e.

The benefit of these schemes is not so much to diminish the GHG emissions, but to increase the scientific benefit of travelling to the conference.


For more information or if you have any suggestions, do not hesitate to contact us (mailto:environment-icalp2022@irif.fr).