Implications of circular strategies on energy, water, and GHG emissions in housing of the Global North and Global South

As urbanization continues to surge, building materials are poised to become a dominant contributor to global emissions. Traditionally, the building sector has focused on mitigating "operational carbon" linked to a building's day-to-day energy needs, such as heating, cooling, lighting, and equipment usage. However, there has been a paucity of studies on the environmental impacts associated with building materials across a building life cycle. This paper addresses this gap by conducting a life cycle assessment of housing stocks in two diverse case studies: Montreal (Canada) and Lima (Peru). These cities offer a North/South perspective, highlighting the challenges, opportunities, and potential solutions for decarbonizing the housing sector. The study investigates the potential of circular strategies and investigates three scenarios: selective deconstruction (allowing for reuse and recycling), recycling, and landfilling. The results underscore the potential of selective deconstruction in significantly reducing the overall environmental footprint of residential buildings. In Lima, for instance, selective deconstruction, when compared to landfilling, can cut greenhouse gas emissions, water consumption, and fossil resource usage by a substantial 70%, 67%, and 69%, respectively. These findings offer valuable insights for decision-makers in construction materials and waste management, encouraging the adoption of circular economy practices through informed guidelines and recommendations.