The Paris Agreement, adopted in 2015 by 194 Parties including Switzerland, mandates significant reductions in greenhouse gas (GHG) emissions to limit global temperature rise. In response, the Swiss Federal Council committed to achieving net zero emissions by 2050. To support this goal, the EPFL ENAC faculty launched the Panel Lémanique in 2022, a 5-year longitudinal study to monitors the evolution of behaviors, usages, and opinions on lifestyles in the Lake Geneva region. However, quantifying the environmental impacts associated with these behaviors raises major methodological difficulties. The aim of this work is to provide a methodology and a database of impact factors for calculating the impacts associated with the behaviours monitored by the survey.

The outputs of the projects are twofold. From a quantitative point of view, it provides a structured database tailored to the survey format, which enables the computation of behavior impacts. A critical analysis of the impact factors extracted from the literature is also carried out to ensure the robustness of the indicators.

From a methodological point of view, the work provides elements to justify the use of life cycle impact indicators to consider the possible impact transfers associated with changes in practices. The report also describes the methodological options for quantifying the impact of second-hand objects being used in the Lake Geneva region, by comparing two methods: a substitution approach and an amortization approach..