LAUSR

In order to meet the mid-century carbon reduction targets and to mitigate climate change and global warming it is imperative that embodied carbon in the built environment receives immediate attention from policy, industry and academia. To shed light on how to accelerate a wider uptake of embodied carbon assessments in buildings, an industry academia collaboration was funded by Innovate UK and the Engineering and Physical Sciences Research Council (EPSRC). Implementing Whole Life Carbon in Buildings (IWLCiB) has been the resulting project, a cooperative endeavour led by key academics and practitioners in the UK. Over the course of the project, three independent environmental consultants have produced a total of fifteen embodied carbon assessments across various building types, all starting from the same information including building specification and bill of quantities. These assessments have then been reviewed and analysed in detail by the academic team to establish similarities, differences, and common challenges and pitfalls. This paper reports on the project’s numerical findings by life cycle stages and building type. Detailed results are presented for each of the five case studies, showing elements of agreement and, most often, of variation. Additionally, each of the life cycle stages as defined by the TC350 standards is analysed both numerically and in terms of its contribution towards the whole life embodied carbon. The results show that significant discrepancies consistently exist even when the initial information available to the assessors is the same. The many assumptions that are necessary throughout the assessments inevitably present a barrier to consistency and convergence of the outputs. The numerical analysis also reveals that all life cycle stages account for important shares of the whole life carbon, and that therefore partial assessments – e.g. cradle-to-gate - are not sufficient if carbon reductions are to be realistically achieved. Yet, life cycle assessment remains the best tool for environmentally informed decision making. Future research in the field should continue to address the challenges identified in this article and work towards greater understanding and reliability of the numbers produced.