Abstract for: System Dynamics Modelling of National Building Stock Decarbonisation Pathways under Climate Neutrality Targets

The buildings and construction sector is responsible for a significant share of global energy demand and greenhouse gas emissions. Achieving a net-zero-emission building stock by 2050 requires substantial scaling of renovation rates, yet current progress remains insufficient. A systemic analysis of building stock decarbonisation pathways, accounting for interdependent environmental, economic, and social variables, is necessary to identify critical leverage points and inform decision-making and policy development for building stock transition. The study integrates system dynamics modelling with life cycle assessment to analyse building stock decarbonisation pathways and the resulting environmental impacts. Lithuanian and Danish national building stocks are used as case studies, including both residential and non-residential buildings. Scenario modelling is carried out to represent the transition towards a net-zero-emission building stock through low-carbon development, implementation of retrofit and renovation measures, and the progressive decarbonisation of the energy sector. Decarbonisation outcomes at the stock level are influenced by non-linearities and feedback mechanisms related to regulation, economic incentives, financial constraints, retrofit supply-side limitations, technical capacity, willingness to change due to social norms, perceptions and values, awareness of energy efficiency and conservation benefits, and consumption behaviour. Strategies aimed at reducing operational energy use may significantly increase embodied environmental impacts, leading to trade-offs across the whole life cycle. System dynamics offers a methodological approach for addressing the dynamic complexity of building stock decarbonisation, arising from variable interdependencies, feedback loops, non-linear behaviour, and delays inherent in system processes. When designing policies and strategies for transitioning the building stock towards climate neutrality, the whole-life-cycle performance of buildings should be considered in both new construction and renovation policies to reduce environmental impacts.