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

Jannik Giesekam,Francesco Pomponi

doi:10.1680/jensu.17.00032

Abstract

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.

Highlights

Limiting any increase in global average temperature to ‘well below 2°C’, as outlined in the Paris Agreement (UNFCC, 2015), requires that all nations rapidly reduce greenhouse gas (GHG) emissions to achieve a balance between sources and sinks in the second half of this century
The construction industry has a critical role to play in climate change mitigation, being a significant emitter of GHGs both directly through its activities and supply chains and indirectly through operation of the assets it creates (Giesekam et al, 2016a; Müller et al 2013)
This will require substantial efforts to mitigate all GHG emissions associated with the construction of new assets and significant growth in the use of biogenic building materials

Summary

Introduction

Limiting any increase in global average temperature to ‘well below 2°C’, as outlined in the Paris Agreement (UNFCC, 2015), requires that all nations rapidly reduce greenhouse gas (GHG) emissions to achieve a balance between sources and sinks in the second half of this century. Embodied greenhouse gas emissions (‘embodied carbon’) emissions already make up as much as 90% of whole-life GHG emissions on some projects (Sturgis and Roberts, 2010), constitute a growing share across all project types (Ibn-Mohammed et al, 2013) and are responsible for almost a quarter of annual built environment emissions (see Figure 1) These embodied carbon emissions can be addressed through a wide range of mitigation strategies (Lupíšek et al 2016; Pomponi and Moncaster, 2016), such as improvement in the efficiency of structural designs (Cullen et al, 2011; Moynihan and Allwood, 2014), the use of alternative building materials (Cabeza et al, 2013; Giesekam et al, 2014; Giesekam et al, 2016c) or the adoption of circular economy approaches that encourage increased reuse and recycling of materials, components and structures (Densley Tingley and Davison, 2011; Pomponi and Moncaster, 2017). Recognising the differing approaches to carbon assessment and reporting between nations, this paper is primarily aimed at UK practitioners, many of the resources will doubtless be of use to practitioners elsewhere

Guidance on embodied carbon assessment

Gaps in knowledge and guidance

Future research priorities

Findings

Conclusions