Towards indicative baseline and decarbonization pathways for embodied life cycle GHG emissions of buildings across Europe

Abstract

Buildings’ construction and operation are major contributors to global greenhouse gas (GHG) emissions, and the substantial reduction of GHG emissions across their full life cycle is required to enable meeting international climate targets. For effective climate change mitigation - as recent studies have shown - a special focus has to be put on lowering embodied GHG emissions, i.e., emissions related to construction production manufacturing and construction processes, maintenance and replacement as well as end-of-life processing. As the importance of reducing embodied GHG emissions rises, so does the need for understanding both the baseline and pathways for reduction across the full life cycle of buildings. In this paper, we offer insights into the data-driven analysis of embodied GHG emissions across the whole life cycle of buildings from recent studies. Our investigation builds on the data collection, processing and harmonisation of around 1.000 building LCA case studies. We offer an integrated perspective on GHG emissions across the life cycle of buildings, considering historical trends, current baselines and indicative reduction pathways for embodied GHG emissions in different countries across Europe. This serves to inform our current ‘decade of action’ and the transformation to a regenerative built environment by 2050.

Public buildings: Life-cycle GHG emission scenarios and reduction trajectories by 2050

“…As the definition and derivation of carbon budgets for buildings is still an ongoing research process and a consistent calculation method across countries and economic sectors does not yet exist [21], the authors of this study refer to the "carbon law" approach originally proposed by [22] to derive an indicative GHG emissions reduction pathway for building-related life-cycle emissions in line with climate goals (see [23] for a recent study supporting this approach, especially for embodied emissions). The idea of the carbon law is to halve emissions every decade, which is argued to correspond to countries' maximum achievable emission reduction according to feasibility constraints and, when proposed in 2017, was compatible with the Paris Agreement climate targets [22].…”

A comparative assessment of the development of GHG emission criteria and benchmark values for buildings in Norway

“…To meet national and international climate goals, various GHG emission criteria and benchmark values for buildings are being developed [3]. However, there is a distinct lack of harmonisation in methods and approaches making it difficult to compare construction projects or implement and apply benchmarking at a national or international level [4,5]. Norway is no exception.…”

“…More recently, the IEA EBC Annex 72 has investigated net zero emission buildings and the next generation of benchmark and calculation rules and found that there are large differences in GHG emission targets for buildings [4]. Another study has investigated indicative baseline and decarbonisation pathways for embodied life cycle GHG emissions of buildings across Europe and found that whole life cycle (WLC) embodied carbon emissions range from 400 -800 kgCO 2 e/m 2 (6.6 -13.3 kgCO 2 e/m 2 /yr), averaging at 550 kgCO 2 e/m 2 (9.2 kgCO 2 e/m 2 /yr) for residential buildings [5]. According to the EU taxonomy, new buildings over 5000 m 2 shall (amongst other criteria) calculate WLC GHG emissions to be considered sustainable [22].…”

Embodied net-zero compatible buildings? They already exist!

“…Although an important decrease of GHG in the operation of new dwellings can be observed, no trends of reduction are found for the embodied impact of buildings [4]. Multiple life cycle analysis of buildings can be found in the literature [5,6] but the urgency and exceptional situation humanity is currently in urges us to reconsider commonly accepted conclusions. Existing and new buildings need to be energy efficient today and in 100 years while also drastically reducing their embodied impact and possibly contributing to delaying emissions in the atmosphere by acting as a carbon stock.…”