Évaluation de la mesure de l’empreinte environnementale urbaine en fonction de la capacité de charge de la Terre

Abstract

Our global demand for resources currently exceeds the Earth’s carrying capacity (ECC), defined as the limit of anthropogenic pressure that our ecosystem can withstand within its regenerative and assimilative capacities. Representing a significant share of global environmental degradation, cities are seen as having the potential to catalyze a transition to a truly sustainable state in compliance with ECC. However, in order to do so, urban decision-makers must rely on robust measurement tools representing the complex dynamics or urban systems to guide their actions. This paper asks what tools exist to bridge this gap between theory and practice, what role urban planners are now giving to the ECC, and what the sustainability status of high-income reductionleading cities is in relation to the ECC. Ten assessment frameworks and four sustainability indicators were identified as compatible with the One Planet goal and adapted to measure key urban flows. Sustainability is primarily considered through the lens of climate at the urban scale, and existing assessment standards lack comprehensibility, leading to an overall underestimation of cities’ total environmental footprint. To select and analyze the leading cities in impact reduction, we used the following criteria : achievement of an absolute GHG emission reduction greater than 15 % over the period 1990-2020, and intentionality/commitment to sustainability through active membership in specific environmental knowledge transfer groups. Twenty-four cities were identified whose GHG reductions since 1990 range from 24-49 %, which is between 2-4 times lower than what is required by high-income cities by 2050 to reach the goal of living within ECC. To achieve a "one-planet life", cities must address their overconsumption using systemic tools that incorporate the notion of ECC and consider indirect emissions related to urban consumption. Various obstacles to this approach have been identified, of a practical, economic, cultural and geopolitical nature, and must be taken into account in order to promote the wider use of ECC as the ultimate goal of sustainability. Achieving a global state that respects ECC is everyone’s concern. Hence, the establishment of specific reduction targets, based on collaboration and effort-sharing approaches, must be promoted to ensure an environmentally efficient and socially just transition.

Date	2 May 2022
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Claudiane Ouellet-Plamondon (Supervisor)