Gauthier Roussilhe

Exploring digital ecosystems in a world stabilized at +2°C

Current path for 2100 (2021 data): +2.7°C

We must make unprecedented choices to adapt to the environmental crisis in the mid and long term. We are therefore compelled to reduce our material and energy footprint, and all sectors are concerned. Faced with this transformation effort, the place of the digital sector is yet to be determined.

From State-wide scale to that of rural territories, I am exploring and implementing digital services that are consistent with transition pathways, even if it means not digitalizing if that is the most relevant choice.


  1. Researcher specialized on the environmental challenges of digitisation

  2. Digital sustainability specialist

  3. Providing advice to public actors

  4. Team training

  5. Learning Life Cycle Assessment (LCA) of digital services

Ongoing projects

  1. Supporting the state-owned start-up Labels Transition Écologique on sustainable digital design / digital sobriety, for the ADEME (French Environment and Energy Management Agency)

  2. Coordinating Plateaux Numériques, a service to create accessible and sustainable websites for rural town halls, with Timothée Goguely

Ongoing research

  1. Methodology for estimating the environmental footprint of the digital sector on a territorial scale

  2. Impacts of the semiconductor industry on water management in Taiwan and medium / long-term climate and industrial perspectives

  3. Review of assessment methods for positive climate impact of digital technology

I provide independent expertise for public actors who wish to be informed in their digital and technological choices to be in line with ecological transition policies. I base my studies, as much as possible, on verified scientific literature and local field surveys to formulate recommendations without any conflict of interest.


Tableau du peintre Alejandro Ferrant

Environmental challenges of digital systems at a local scale (French) (1,8 Mo)

Chaire "Villes et Numérique" Sciences Po Paris, November 2021

Deux marins observent la mer avec un sextant.

What can digital technologies do for the ecological transition? (French) (2,2 Mb)

Review of the positive impacts of the digital sector on the ecological transition, March 2021

Une balance d'apothicaire pèse des circuits imprimés

4G to 5G smartphones evolution (French) (0,8 Mb)

How to assess the situation and the environmental footprint, September 2020

L'inscription NO 5G est taggée sur un panneau dans les rues de Genève.

The 5G Controversy (French) (1,2 Mb)

Understanding and deciding together on the deployment of the new mobile generation, April 2020

Digital designer, consultant and PhD student for the Design Research Centre (ENS Saclay, ENSCI), I study how the environmental crisis modifies the design and maintenance of digital systems. In a commitment to open education, my lectures are compiled in the form of a free textbook that can be consulted here : Situer le numérique [FR].

Recent talks

  1. The question of sustainability in digital design education and practice

    Médiations sémiotiques, XXXIXe Colloque Albi-Nîmes

  2. Analyse des affirmations d'impacts positifs de la numérisation sur le climat

    Séminaire des doctorant⋅e⋅s en informatique 2021, Société Informatique de France

  3. Clair-obscur : enjeux du calcul des impacts environnementaux du numérique

    Séminaire doctoral : Le visible et l’invisible sur les plateformes 2021, CEMTI Paris 8

  4. Best environmental practices across the Internet value-chain

    Internet Governance Forum 2020, United Nations

  5. Repenser le numérique dans les limites planétaires

    CNAM Pays de la Loire

  6. Framing digital industry into planetary limits

    36th Chaos Communication Congress 2019

Recent publications

  1. Nicolas Nova et Gauthier Roussilhe, "Du low-tech numérique aux numériques situés"

    Sciences du Design 11, no. 1 (mai 2020): 91-101. (revue à comité de lecture)

  2. Situer le numérique

    Introduire et comprendre les enjeux environnementaux du numérique, novembre 2020 (manuel pédagogique)


  1. ENS Saclay

  2. Sciences Po Paris

  3. Sciences Po Grenoble

  4. ESC Clermont-ferrand

  5. Strate École de Design Lyon

  6. INSA Lyon

  7. HETIC

To ensure consistency, my business model is based on the transparency of my activities and limited annual revenues. This model aims to explore new ways of working and not to reproduce potentially toxic or unsuitable logics. This transparency is a foundation for creating a framework of trust with the organizations and people I work with. In addition, I reserve the right to refuse to work with organizations with direct links to the fossil fuel industry.

2019 / 2020 Financial report can be consulted here [FR], this model evolves every year.

Selection of recent sustainable projects

  1. Managing digital sustainability for Commown's website

    with Timothée Goguely and Derek Salmon, 2021

  2. Managing digital sustainability for the Low-tech Lab's website

    with Sylvain Julé and Derek Salmon, 2019-2020

  3. Managing digital sustainability for the Kaïros-Jourdain's website

    with Les Raisonné·e·s and Addviso, 2019-2020

  4. Managing digital sustainability for the Master Strategy & Design in the Anthropocene's website

    with Fairness and Collectif Bam, 2020


  1. Expert for Halte à l'Obsolescence Programmée (Stop Planned Obsolescence)

  2. Advisor for The Billion Seconds Institute