Building on the Paris Agreement: making the case for embodied carbon intensity targets in construction

Progressive clients are targeting embodied carbon reduction through the introduction of carbon intensity targets (CITs). CITs challenge design teams to deliver buildings with supply chain carbon emissions below a set level per functional unit. Despite CITs acting as catalysts for innovation, there are few drivers for their use and substantial variations in their implementation. There is also no means for ensuring consistency between project CITs and national mitigation targets, nor a mechanism for ratcheting up ambitions as anticipated by the Paris Agreement on climate change. This paper discusses these concerns and suggests how CITs could in future be determined, implemented and enforced

Scenario analysis of embodied greenhouse gas emissions in UK construction

Motivated by national greenhouse gas (GHG) emissions budgets, the UK construction industry is pursuing reductions in emissions embodied in buildings and infrastructure. The current embodied GHG emissions benchmarks allow design teams to make a relative comparison between buildings and infrastructure but are not linked to sector or national GHG emissions reduction targets. This paper describes a novel model that links sector-level embodied GHG emissions estimates with project calculations. This provides a framework to consistently translate international, national and sector reduction targets into project targets. The required level of long-term GHG emissions reduction from improvements in building design and material manufacture is heavily dependent on external factors that the industry does not control, such as demand for new stock and the rate of electrical grid ‘decarbonisation’. A scenario analysis using the model suggests that, even if external factors progress along the better end of UK government projections, current practices will be insufficient to meet sector targets

Aligning carbon targets for construction with (inter)national climate change mitigation commitments

In the face of a changing climate, a growing number of construction firms are adopting carbon reduction targets on individual projects and across their portfolios. In the wake of the Paris Agreement, some firms are seeking a means of aligning their targets with sectoral, national and international mitigation commitments. There are numerous ways by which such an alignment can be achieved, each requiring different assumptions. Using data from the UK construction industry, this paper reviews current company commitments and progress in carbon mitigation; analyses the unique challenges in aligning construction targets, and presents a series of possible sectoral decarbonisation trajectories. The results highlight the disparity between current company targets and the range of possible trajectories. It is clear that a cross-industry dialogue is urgently required to establish an appropriate response that delivers both a widely-accepted target trajectory and a plan for its delivery. This paper is intended to stimulate and support this necessary debate by illustrating the impact of different methodological assumptions and highlighting the critical features of an appropriate response

The contribution to UK climate mitigation targets from reducing embodied carbon in the construction sector

The UK construction industry faces the daunting task of expanding output whilst achieving substantial greenhouse gas emission reductions. Recent building life cycle assessments show that embodied carbon constitutes a growing proportion of whole life emissions. However, the precise distribution of embodied carbon along sector supply chains; the range of mitigation options available to practitioners and the potential policy responses have received little attention. This thesis addresses a number of these outstanding issues. The thesis commences with an analysis of the distribution of emissions along construction sector supply chains using Multi-Region Input Output modelling. The results of this analysis are combined with a large database of building carbon assessments to form a hybrid UK Buildings and Infrastructure Embodied Carbon model. This novel combination of bottom up project data and top down sector data provides a much needed link between sector carbon mitigation targets and project carbon intensity targets. A scenario analysis using the model suggests that, if external factors progress within the range of Government projections, current practices will be insufficient to meet sector targets. Therefore additional embodied carbon mitigation strategies must be implemented. One such mitigation strategy is increasing the use of alternative building materials with lower embodied carbon. This thesis presents a comprehensive overview of the barriers to uptake, based upon a literature review, survey of construction professionals and interviews with industry leaders. This research highlights the current lack of drivers for embodied carbon assessment and mitigation. In response, the thesis presents possible policy responses and industry led actions as a series of dynamic adaptive policy pathways developed through a participatory approach with key stakeholders. Collectively this thesis depicts the sizeable contribution embodied carbon abatement could make to the achievement of long-term UK climate mitigation targets and the interim response required from industry practitioners, institutions and policy makers

Briefing: Embodied carbon dioxide assessment in buildings: guidance and gaps

The construction industry, through its activities and supply chains as well as the operation of the assets that it creates, is a major contributor to global greenhouse gas emissions. Embodied carbon dioxide emissions associated with the construction of new assets constitute a growing share of whole-life emissions across all project types and make up nearly a quarter of all annual emissions from the UK built environment. Yet these embodied emissions are still rarely assessed in practice, owing to the perceived difficulty and lack of supporting guidance for practitioners conducting an assessment. This briefing paper retraces recent advances in the field of embodied carbon dioxide assessment and highlights existing and forthcoming practical guidance that could support more widespread assessment. The paper constitutes a where-to rather than a how-to, directing assessors towards appropriate resources, of which there are many. Although the paper does highlight some remaining gaps in the field and identifies corresponding research priorities, recent additions to the body of guidance are generally sufficient to support more widespread assessment. Now, the industry must demonstrate its commitment to tackling climate change by using this guidance to drive deeper carbon dioxide reduction

Integrating embodied carbon into transport infrastructure scenarios

This report summarizes the aims, objectives and results of a DecarboN8 Seedcorn funded project completed in 2021. The project sought to develop resources that could support greater incorporation of capital (embodied) carbon emissions into transportation models and scenarios. Owing to a number of challenges related to data access, data quality and processing resource requirements, the project failed to deliver the primary intended outcome – an open and extendable prototype web resource on capital carbon emissions in transportation projects. However, the project did develop a large novel dataset and successfully delivered a number of the intended secondary outcomes. Subsequently, the links forged and insights gained throughout the project ultimately resulted in a successful funding bid to support further development in collaboration with key stakeholders. Datasets compiled under the project were incorporated into development of a new database and spatial tool under the Department for Transport’s Shared Digital Carbon Architecture (SDCA) programme, in turn informing strategic decision making within Government departments and Arm's-Length Bodies. The opportunity to deliver this subsequent high-impact project would not have arisen without stakeholder engagement supported by the DecarboN8 Seedcorn fund and the Centre for Research into Energy Demand Solutions (CREDS)

Thermodynamic insights and assessment of the ‘circular economy’

This study analyses the effect on energy use of applying a wide range of circular economy approaches. By collating evidence on specific quantifiable approaches and then calculating and analyzing their combined full supply chain impacts through input-output analysis, it provides a more complete assessment of the overall potential scope for energy savings that these approaches might deliver than provided elsewhere. Assessment is conducted globally, across the EU-27 and in the UK. Overall, the identified opportunities have the potential to save 6%–11% of energy used to support economic activity, worldwide and in the EU, and 5%–8% in the UK. Their potential is equivalent to the total scope for other industrial energy efficiency savings. The potential savings are further divided into those due to sets of approaches relating to food waste, steel production, other materials production, product refurbishment, vehicle provision, construction and other equipment manufacture. Each of these sets of approaches can make a key contribution to the total savings that are possible. Complementary use of energy and exergy metrics illustrates the way in which energy use might change and for the first time provides indication that in most cases other energy efficiency measures are unlikely to be adversely affected by the circular economy approaches. Potential for savings in the energy embodied in each key product input to each major sector is assessed, enabling prioritization of the areas in which the circular economy approaches have the greatest scope for impact and identification of supply chains for which they are underrepresented

Thermodynamic insights and assessment of the ‘circular economy’

This study analyses the effect on energy use of applying a wide range of circular economy approaches. By collating evidence on specific quantifiable approaches and then calculating and analyzing their combined full supply chain impacts through input-output analysis, it provides a more complete assessment of the overall potential scope for energy savings that these approaches might deliver than provided elsewhere. Assessment is conducted globally, across the EU-27 and in the UK. Overall, the identified opportunities have the potential to save 6%–11% of energy used to support economic activity, worldwide and in the EU, and 5%–8% in the UK. Their potential is equivalent to the total scope for other industrial energy efficiency savings. The potential savings are further divided into those due to sets of approaches relating to food waste, steel production, other materials production, product refurbishment, vehicle provision, construction and other equipment manufacture. Each of these sets of approaches can make a key contribution to the total savings that are possible. Complementary use of energy and exergy metrics illustrates the way in which energy use might change and for the first time provides indication that in most cases other energy efficiency measures are unlikely to be adversely affected by the circular economy approaches. Potential for savings in the energy embodied in each key product input to each major sector is assessed, enabling prioritization of the areas in which the circular economy approaches have the greatest scope for impact and identification of supply chains for which they are underrepresented

Bridging the climate mitigation gap with economy-wide material productivity

Projections of UK greenhouse gas emissions estimate a shortfall in existing and planned climate policies meeting UK climate targets: the UK’s mitigation gap. Material and product demand is driving industrial greenhouse gas emissions at a rate greater than carbon intensity improvements in the economy. Evidence shows that products can be produced with less carbon intensive inputs and demand for new products can be reduced. The economy-wide contribution of material productivity and lifestyles changes to bridging the UK’s mitigation gap is under studied. We integrate an input-output framework with econometric analysis and case study evidence to analyse the potential of material productivity to help the UK bridge its anticipated emissions deficits, and the additional effort required to achieve transformative change aligned with 2 and 1.5°C temperature targets. We estimate that the emissions savings from material productivity measures are comparable to those from the Government’s planned climate policy package. These additional measures could reduce the UK’s anticipated emissions deficit up to 73%. The results demonstrate that material productivity deserves greater consideration in climate policy

Science-Based Targets: On Target?

Companies are increasingly seeking to align their actions with the goals of the Paris Agreement. Over 1000 such companies have committed to the science-based targets initiative which seeks to align corporate carbon reduction targets with global decarbonisation trajectories. These ‘science-based targets’ are developed using a common set of resources and target-setting methodologies, then independently assessed and approved by a technical advisory group. Despite the initiative’s rapid rise to public prominence, it has received little attention to date in the academic literature. This paper discusses development of the initiative based upon a quantitative assessment of progress against each component of the science-based targets set by 81 early adopters, using information gathered from company annual reports, corporate social responsibility websites and Carbon Disclosure Project (CDP) responses. The analysis reveals a mixed picture of progress. Though the majority of targets assessed were on track and, in some cases, had already been achieved, just under half of the companies assessed were falling behind on one or more of their targets. Progress varied significantly by target scope, with more limited progress against targets focused on Scope 3 emissions. Company reporting practices were highly variable and often of poor quality. This paper concludes with a range of recommendations to improve the transparency, consistency and comparability of targets within this key agenda-setting initiative