Are building embodied emissions aligned with future climate pathways? A method for measuring building-sector performance and defining science-based targets

Research has made huge progress in measuring and benchmarking embodied emissions at the building level. But gaps remain in our understanding of how changes in technologies, socioeconomic pathways and construction trends could influence future embodied emission trajectories at a national and regional level. This research presents a novel methodology to measure whole of life greenhouse gas emissions of building sectors using prospective life cycle analysis. The method provides a comparison with emissions pathways to limit global warming and establish science-based embodied emission targets to meet these pathways at the national level. This is demonstrated on the office building sector in Australia, from 2024-2049. Results show total emissions of 137.8 Mt CO 2 e by the end of 2049, with 45% of this from embodied emissions. A gap of 79.7 Mt CO 2 e is found with a < 1.5°C emissions pathway, and 56.9 Mt CO 2 e to a < 2.0°C pathway with an equal per capita allocation. Technological (reduced tall buildings, low carbon concrete, biomaterials, longer lifespan of materials) and sufficiency strategies (refurbishment, reduced construction) were able to close these gaps by up to 47.1 Mt CO 2 e, but not completely. Upfront embodied emissions would need to reduce 37% annually to meet the 2.0°C pathway, requiring targets of < 10 kg CO 2 e/m 2 by 2032. If new office construction activity is halved, such drastic targets would not be required until 2046. This study shows widespread use of low carbon technologies such as mass timber are not enough to adequately reduce emissions in the Australian office sector, and sufficiency measures such as mass refurbishment and reducing new construction are essential.