For almost twenty years, digital technology has often been described as one of the levers of the ecological transition. It allows, among other things, the establishment of carpooling platforms, teleworking, the optimization of the energy consumption of buildings or the monitoring of forest fires, etc. But digital uses also come with a certain number of environmental impacts. How to reconcile them with transition issues? To answer this question, the notion of “frugal digital” is often invoked. But what exactly do we mean by that?

Let us first remember that there is nothing virtual about digital. French people are equipped with numerous digital devices – smartphones, connected televisions, tablets and computers, speakers and connected objects, etc. – whose uses are based on hardware infrastructure – sensors, 4G-5G antennas, wifi terminals, data centers, buried cables, etc. All this equipment is necessary for the deployment and use of digital services, whether within mobile applications, state or community services.

By 2030, if the sector continues to progress at the current rate, the carbon footprint of digital technology on French territory (excluding, for example, the use of data centers located abroad) will increase by approximately 45% compared to 2020 , and the consumption of abiotic resources (metals and minerals) will increase by 14%.

To this environmental cost linked to the manufacture, use and end of life of digital equipment, it is appropriate to add the impacts in the sectors of application, with for example the consequences of changes in user behavior (distance from home to work in the case of teleworking or anticipated replacement of a smartphone after deployment of 5G) and transformations in society, with an acceleration in the consumption of goods and services, for example.

Faced with the environmental cost of digital technology, it is necessary to consider how to limit it. Two complementary approaches can be undertaken: efficiency and sobriety, or frugality.

• The first aims to optimize the resources used once the service has been designed, or even deployed. It is then a question of producing a more efficient tool, that is to say one which offers the same service using fewer resources.
• The second approach, of sobriety or frugality, aims to seek sufficiency. It aims to globally reduce the use of material and energy resources by questioning the uses, the organization of society, the needs and the underlying values. It opens the possibility of not deploying certain services, and of questioning certain business models.

Tackling the frugality of a digital service requires taking the measure of the implications of this notion. The frequent shortcut of reducing frugal digital to a simple search for energy efficiency and, sometimes, material efficiency of the service itself, opens the door to “greenwashing” discourses .

Evaluating the frugality of a digital service therefore requires questioning uses and needs, in relation to planetary limits and evaluating the efficiency of the system.

This evaluation can only be relative (by comparing two equivalent systems) and not absolute. It must rely on established methodologies to quantitatively and qualitatively gauge environmental impacts, for example the general eco-design framework for digital services or the ISO standards for Life Cycle Analysis and digital impacts , and be consideration of the service provided to society and the environment. Let us also point out the general framework for frugal AI in Spec AFNOR 2314.

Defining a service as having a “positive impact” would require carrying out this full environmental assessment and deciding on a trade-off between different impact indicators (water and soil pollution, destruction of abiotic resources, greenhouse gas emissions, etc.). This goes well beyond the observation of a simple efficiency gain.

Author Bios: Denis Trystram is University Professor of Computer Science at the University of Grenoble Alpes (UGA), Aurélie Bugeau is University Professor of Computer Science at the University of Bordeaux, is Emmanuelle Frenoux is a Lecturer in Computer science at Paris-Saclay University, Gael Guennebaud is a Researcher at Inria and Ligozat Anne-Laure is a University Professor of Computer Science at Paris-Saclay University