Addressing the challenges of reducing greenhouse gas emissions in the construction industry: a multi-perspective approach
Jackson, David John
With average global temperatures rising and more extreme weather events recorded year on year, several counties have now declared a climate emergency. To address this emergency, 195 nations came together to sign the Paris Agreement, setting an ambitious target to keep the increase in global average temperature to well-below 2 oC, whist actively pursuing efforts to minimise the increase to 1.5 oC. Each nation was to determine its contributions to this target, stating how they would reduce carbon emissions within their control. Governments have in turn called for industry to significantly reduce their carbon emissions. Although the direct footprint of the construction industry is relatively small (for example, approximately 2.5% of the United Kingdom’s (UK) annual emissions), these numbers rise drastically when the carbon embodied in the materials, the operation and use of the assets are also included. As an example, just over half the UK’s emissions are directly or indirectly related to the construction and use of infrastructure assets. Given these figures, it is imperative that the construction industry takes steps to make deep cuts in its carbon emissions. To help the industry along the carbon management journey, the CITT (Carbon Infrastructure Transformation Tool) Project has developed an embodied carbon calculation tool to aid decision makers in developing low-carbon solutions to reduce emissions on large infrastructure projects. The tool accounts for emissions from materials, transportation and construction of an asset. This scope was selected as it is what the contractor would have direct control over and is easier to gather accurate data for embodied emissions as opposed to the operation and use phases. However, the uptake of tools such as the CIT tool has been relatively slow in the industry. This thesis takes a multi-perspective approach to understand the technological and social implications of developing and adopting an embodied carbon calculator within the construction industry. This is done first by assessing the risk of burden shifting where the use of an embodied carbon calculator may suggest emission reductions during the construction of an asset at the expense of increasing emissions elsewhere in the life cycle. Second, the thesis explores the barriers to the tool’s adoption within the industry and provides recommendations for how to enable change within organisations to increase the use of carbon calculation tools. Finally, the thesis shows how collaboration can be improved to successfully reduce carbon emissions through the infrastructure supply chain. Using a portfolio of papers, this thesis makes several important contributions. Although the risk of burden shifting has been discussed in the literature, there is little empirical evidence to support this. Paper 1 provides this evidence by studying four decision cases from a rail project. Paper 2 contributes to practice by developing a framework highlighting the steps required to overcome the barriers to the adoption of carbon calculators in the construction industry. Finally, Paper 3 brings together the literature on low-carbon supply chain management and collaboration success factors to understand how the industry can collaborate to reduce emissions through the infrastructure supply chain. Taken together, this thesis provides novel insights into the challenges of using carbon calculation tools, and advises policy and decision makers in how to improve carbon management practices within the construction industry.