Jannik Giesekam

Construction sector views on low carbon building materials

As is the case in a number of countries, the UK construction industry faces the challenge of expanding production whilst making ambitious greenhouse gas emission reductions. Embodied carbon constitutes a growing proportion of whole-life carbon emissions and accounts for a significant share of total UK emissions. A key mitigation strategy is increasing the use of alternative materials with lower embodied carbon. The economic, technical, practical and cultural barriers to the uptake of these alternatives are explored through a survey of construction professionals and interviews with industry leaders. Perceptions of high cost, ineffective allocation of responsibility, industry culture, and the poor availability of product and building-level carbon data and benchmarks constitute significant barriers. Opportunities to overcome these barriers include earlier engagement of professionals along the supply chain, effective use of whole-life costing, and changes to contract and tender documents. A mounting business case exists for addressing embodied carbon, but has yet to be effectively disseminated. In the meantime, the moral convictions of individual clients and practitioners have driven early progress. However, this research underscores the need for new regulatory drivers to complement changing attitudes if embodied carbon is to be established as a mainstream construction industry concern.

Applying Circular Economic Principles to Reduce Embodied Carbon

This chapter explores the connections between the circular economy and the reduction of embodied carbon. Circular economic approaches focus on maintaining the value of materials for as long as possible. A circular economy seeks to keep materials in circulation, removing the concept of waste from the system and the need for material extraction from primary sources. In a completely circular economy, all ‘waste’ outputs would equal system inputs. If the built environment is thought about in this way, as a system, then the inputs are construction materials, and these materials accumulate in buildings, which can also be thought of as the stock. Demolition waste is the output flow of materials in this system. This concept can also be extended to embodied carbon. Construction materials are input flows of embodied carbon. These emissions are new to the system. The adoption of circular economic design approaches that facilitate longer building lifetimes, greater component and material reuse can reduce the input flow of embodied emissions and ensure already expended embodied carbon remains in stock. This chapter commences with a review of the key literature on the circular economy in construction in general terms and provides an overview of four related design strategies: building reuse, material reuse, design for deconstruction and design for adaptability. A series of ‘good practice’ case studies illustrate the respective strategies across a range of structural types. Each case study is used to provide practical insights on project processes, drivers, enabling conditions and the perceived benefits and challenges of adopting circular economic approaches. These insights are drawn from semi-structured interviews with members of each design team, supplemented by supporting literature. The chapter concludes by drawing out common lessons of how circular economic approaches can contribute to the delivery of a low carbon built environment.

Decision making under uncertainty in climate change mitigation: introducing multiple actor motivations, agency and influence

ABSTRACT Climate change mitigation has two main characteristics that interact to make it an extremely demanding challenge of governance: the complexity of the socio-technical systems that must be transformed to avoid climate change and the presence of profound uncertainties. A number of tools and approaches exist, which aim to help manage these challenges and support long-term decision making. However, most tools and approaches assume that there is one decision maker with clearly defined objectives. The interaction between decision makers with differing perspectives and agency is an additional uncertainty that is rarely addressed, despite the wide recognition that action is required at multiple scales and by multiple actors. This article draws inspiration from dynamic adaptive policy pathways to build on current decision support methods, extending analysis to include the perspectives and agency of multiple actors through a case study of the UK construction sector. The findings demonstrate the importance of considering alignment between perspectives, agency and potential actions when developing plans; the need for mobilizing and advocacy actions to build momentum for radical change; and the crucial influence of interaction between actors. The decision support approach presented could improve decision making by reflecting the diversity and interaction of actors; identifying short-term actions that connect to long-term goals and keeping future options open. Key policy insights Multiple actors, with differing motivations, agency and influence, must engage with climate change mitigation, but may not do so, if proposed actions do not align with their motivations or if they do not have agency to undertake specific actions. Current roadmaps, which assume there is one decision maker with control over a whole system, might overstate how effective proposed actions could be. Decision making under deep uncertainty needs to account for the motivations and agency of diverse decision makers and the interaction between these decision makers. This could increase the implementation and effectiveness of mitigation activities.