Enviromental Assessment of Increased Use of Wood in the Building Sector: Towards more Effective Life Cycle Assessment to Support Environmental Impact Mitigating Implementation of Biobased Materials

Global warming and mitigation of greenhouse gases (GHG) are of great focus globally. Buildings’ constitute 38% of global greenhouse gases and the absolute amount has reached the highest number in history in 2019. 28% of the GHG-releases from buildings are from operational energy consumption and 10% from activities in the production of building materials (embodied emissions). Thus, it is necessary to reduce impact related to buildings to comply with the Paris Agreement of limiting global temperature increase to well below 2.0 °C and preferably to 1.5 °C compared to pre-industrial era. The building sector is as well a significant player for Denmark to reduce climate impact and meeting the target of 70% reduction of national GHG-emissions in 2030 compared to 1990 levels.

New buildings in Denmark have higher climate impact from embodied emissions than from operational energy. Therefore, strategies for improving building carbon footprint should centre on reducing impact related to building materials. Wood as a building material is promoted as carbon neutral, however, the carbon flows of wood products induce complexities that need nuances to evaluate if or when wood materials can mitigate the environmental impacts from buildings. Further, increasing use of wood in buildings might change demand for other building materials such as concrete, steel and bricks. Finally, it will be important to know the contribution increased use of wood has for buildings to be within a so called safe operating space where GHG-emissions no longer compromise global warming targets.

Evaluating environmental impacts from the entire life cycle of a building is often completed using the methodology of life cycle assessment (LCA). The method accounts all the resources, transportation and energy that goes into production of building materials, construction processes, operational and maintenance activities and demolition and disposal related buildings along their life cycle and assess the environmental impacts from these inputs. Noteworthy, the LCA-approach has methodological choices and aspects that needs to be addressed when it comes to increased use of wood in buildings.

These methodological issues of LCA in relation to wood in buildings is what this project has as focus. It targets to provide knowledge to the industry of using wood in different residential housing typologies. This will also include the degree of improvement the increase of wood in residential buildings has in the green transition of the industry. Further, it wants to form an extended foundation of the knowledge and understanding in academia of wood in residential buildings and the influence on market mechanism consequences and which impact in might have on the environment.