An analytical framework of quantifying carbon emission impacts of construction and demolition waste circularity and trading: A case study of the UK

Developing a circular economy (CE) for construction and demolition waste (CDW) presents a promising pathway to decarbonize the construction industry by reducing reliance on carbon-intensive primary material production. However, most existing studies rely on life cycle assessment (LCA) approaches and treat CDW flows as isolated processes, overlooking the broader economy-wide emission consequences and distributional effects arising from complex inter-sectoral and inter-regional material and energy flows. This limitation risks underestimating the full carbon mitigation potential of CDW circularity, thereby hindering progress toward the Net-Zero targets pledged by most global economies. This study introduces a novel analytical framework integrating LCA with environmentally extended input-output (EEIO) analysis to quantify the environmental impacts of CDW circularity, explicitly accounting for sectoral and regional trading linkages. Applying the framework to the United Kingdom (UK), this study estimates carbon emissions and potential savings under multiple CDW circularity scenarios for the year 2018. The results indicate that material use for domestic final demand and exports generates approximately 159 and 170 million tonnes of CO₂, respectively, while CDW circularity achieves only modest emission savings of 2–3 million tonnes (<1%). Reuse scenarios deliver greater reductions than recycling, with the most significant benefits observed in secondary and tertiary industries, particularly from the circular use of metallic and wood materials. Despite the UK's high CDW recovery rate, inefficient treatment pathways and weak alignment between recovered-material supply and industrial demand constrain the net-zero potential of CDW circularity. Enhancing recovery efficiency, advancing cleaner technologies, and improving material productivity are therefore critical for supporting the UK's net-zero transition. This study is novel in pioneering one of the first LCA–EEIO analytical frameworks for evaluating the economy-wide environmental impacts of CDW circularity, providing a scalable methodological foundation and system-level evidence for global economies seeking to accelerate their pathways toward Net-Zero targets. • Developed a framework to assess carbon impacts of CDW circularity and trading. • Integrated environmentally extended input–output (EEIO) analysis and LCA. • The UK was used as a case to offer policy implications and validate the framework. • Carbon savings from CDW circularity and trading are rather limited in UK (<1%). • Greater carbon savings from reuse than recycling, and from metals than others.