Analysis of carbon emission trends and mitigation benefits throughout the residential building lifecycle: A case study of Jiangxi Province

The building sector is a primary contributor to global carbon emissions and resource consumption, necessitating a shift from incremental, high-carbon growth to a managed, low-carbon development model. This study investigates the interactions among decarbonization, circular economy principles, and cost-effectiveness within the urban residential building stock of Jiangxi Province. Adopting a dynamic life-cycle perspective spanning 2000-2060, a stock-driven model simulates building flows and associated carbon emissions. Three integrated strategies are quantitatively assessed. First, retrofitting existing buildings through envelope optimization and service life extension curbs new construction demand and operational energy use, achieving a 4.13% carbon reduction alongside 15.2-22.8% cost savings. Second, implementing classified management of demolition waste according to the 3R principle lowers embodied carbon through secondary material utilization, resulting in 1.65% emission abatement. Third, adopting low-energy design standards for new constructions demonstrates the most substantial operational carbon reduction, yielding a 14.02% decrease. The synergistic implementation of these strategies achieves cumulative carbon reductions of 945 Mt of CO2 between 2025 and 2060, enabling the provincial building sector to peak emissions by 2035. Notably, an inhibitory interaction is identified wherein retrofitting reduces both recyclable waste availability and new low-energy building area, thereby moderating the standalone potential of circular and efficiency measures. This study highlights the value of a systemic, life-cycle approach that concurrently addresses building stock dynamics, material circularity, and energy efficiency to foster a sustainable and resource-aware built environment.