2019 - Embodied GHG emissions of buildings - the hidden challenge for effective climate change mitigation

Type document : Thèse, mémoire, article scientifique, etc.

Buildings are major sources of greenhouse gas (GHG) emissions and contributors to the climate crisis. To meet
climate-change mitigation needs, one must go beyond operational energy consumption and related GHG
emissions of buildings and address their full life cycle. This study investigates the global trends of GHG emissions
arising across the life cycle of buildings by systematically compiling and analysing more than 650 life cycle
assessment (LCA) case studies. The results, presented for different energy performance classes based on a final
sample of 238 cases, show a clear reduction trend in life cycle GHG emissions due to improved operational
energy performance. However, the analysis reveals an increase in relative and absolute contributions of so‐called ‘embodied’ GHG emissions, i.e., emissions arising from manufacturing and processing of building materials.
While the average share of embodied GHG emissions from buildings following current energy performance
regulations is approximately 20–25% of life cycle GHG emissions, this figure escalates to 45–50% for highly
energy-efficient buildings and surpasses 90% in extreme cases. Furthermore, this study analyses GHG emissions at time of occurrence, highlighting the ‘carbon spike’ from building production. Relating the results to existing
benchmarks for buildings’ GHG emissions in the Swiss SIA energy efficiency path shows that most cases exceed
the target of 11.0 kgCO2eq/m2a. Considering global GHG reduction targets, these results emphasize the urgent
need to reduce GHG emissions of buildings by optimizing both operational and embodied impacts. The analysis
further confirmed a need for improving transparency and comparability of LCA studies.

2019 - Embodied GHG emissions of buildings - the hidden challenge for effective climate change mitigation

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