Evaluating mitigation strategies for building stocks against absolute climate targets

With the growing urgency of addressing climate change it is increasingly important that decision makers at all levels are equipped to take efficient mitigation actions. This research evaluates the potential of four mitigation strategies to reduce greenhouse gas emissions from the building stock based on a case study, and these are further evaluated in terms of alignment with the remaining global emission budget and the planetary boundary for global warming. The results cover annual emissions from 2023 to 2050 across 18 impact categories, thus highlighting possible impact burden-shifting that may occur as a result of the mitigation strategies. The results show that decarbonisation of the electricity grid delivers a substantial reduction across impact categories. However, in absolute terms, this is counteracted by the increase in building stock. The results also show that current estimates for mitigation potentials are insufficient to comply with the remaining global emission budget. Thus, mitigation strategies should be even more ambitious: constructing 80% fewer new buildings and reducing operational energy demand by 80%. These findings highlight the urgency of taking multiple actions. The increase in demand for new buildings needs to be challenged. Present urban mitigation strategies are inadequate for meeting the stated GHG targets. To enable informed decisions it is important to quantify the effects of different strategies. Traditional life cycle assessments have static inventories and impacts can therefore not be temporarily differentiated and transparency cannot be provided on long-term potentials. This study suggests combining material flow analysis and life cycle assessment to enable integration of dynamic parameters into the life cycle inventory. This shows how the long-term effectiveness of different mitigation strategies can be evaluated. To ensure unintended burden-shifting does not occur, results cover annual emissions from 2023 to 2050 across 18 impact categories. Furthermore, this study showcases how strategies can be designed to align with global commitments such as those set by the Paris Agreement.