Analysis of embodied carbon in the building life cycle considering the temporal perspectives of emissions: A case study in China

The building sector contributes substantially to worldwide greenhouse gas emissions, and efforts to meet emission reduction targets have been gaining importance. Accordingly, the present study investigates the importance of building embodied emissions to the entire life cycle and potential approaches for low-carbon development in China. Life-cycle assessment was proposed for the analysis of building emissions, dividing the life cycle into production, construction, operation, and disposal phases. The temporal perspectives of emissions were considered, including the potential improvements to energy efficiency and the weighted average impacts for delayed emissions in the operation and disposal phases. A case study of a residential building in a cold region was analyzed, and scenario analyses were conducted. The results indicated that the relative contribution of embodied emissions (10551 tCO_2e) considering the temporal perspectives could be twice that of conventional calculations. Further discussion revealed that the payback time of constructing a new building could be 45 years compared to the current regional average buildings. Hence, with respect to the high costs and technical limits of passive houses, renovating old buildings with energy saving measures might be the most appropriate approach for implementing the short-term low-carbon development target. Overall, the present study is helpful to better understand the importance of embodied emissions and for policy-making in the regional building sector.