This report is written on behalf of the City of Stockholm and is part of the City of Stockholm's work in CNCA´s project "Dramatically Reducing Embodied Carbon in Europe's Built Environment", which promotes a broad adoption of ambitious local, national, and regional policies that will reduce greenhouse gas emissions in the built environment of Europe. As part of this project, the City of Stockholm wants to investigate the climate effect of reusing building materials, interiors, and furniture, linked to its investigation of interim storage space. The main goal of the assignment is to provide the City of Stockholm with a basis for being able to weigh the climate aspect against other aspects such as space, economy, demand, etc. Another goal is that this report will provide a basis for further developing the city's policy documents in circularity and climate, in particular Stockholm's waste plan and Stockholm's action plan for circular construction.Two overarching, general calculation methods have been identified for assessing the climate effects of reuse. These are; 1) the calculation methods of climate savings, and 2) the climate impact of reuse. The suitable method should mainly be chosen based on the goal/objective of the climate calculation. The recommendation based on this study is to use climate savings as a calculation method to quantify climate effects from the reuse of building products, interiors and furniture during interim storage and sale of reused products.
Calculating climate savings is suitable as a foundation for decision-making and communication by enabling the user to: 1) locate the largest savings potentials, which can help to prioritize and 2) highlight the importance of reusing products instead of buying new ones. The calculation of climate impact, on the other hand, is often suitable for various reports relevant today, where, for example, an entire building is evaluated based on its climate impact. The chosen calculation method is described in detail in this report.
This study also shows that climate impacts that can occur from the three different reuse processes (storage, transport and reconditioning) are generally much lower than the climate savings from avoiding a linear scenario (a new product).