Global construction materials database and stock analysis of residential buildings between 1970-2050

Abstract

Huge material stocks are embedded in the residential built environment. These materials have the potential to be a source of secondary materials, an important consideration for the transition towards a circular economy. Consistent information about such stocks, especially at the global level, is missing. This article attempts to fill part of that gap by compiling a material intensities database for different types of buildings and applying that data in the context of a scenario analysis, linked to the SSP scenarios as implemented in the global climate model IMAGE. The database is created on a global scale, dividing the world into 26 regions in compliance with IMAGE. The potential use of the database was tested and served as input for modelling the housing and material stock of residential buildings for the period 1970e2050, according to specifications made for the SSP2 scenario. Six construction materials in four different dwelling types in urban and rural areas are included. The material flows related to those stocks are estimated and analysed in a companion paper (also exploring commercial buildings) by Deetman et al. (2019). The results suggest a significant increase in the material stock in housing towards 2050, particularly in urban areas. The results reflect specific patterns in the material contents across the different building types. China presently dominates developments in the global level building stock. The SSP2 projections show a stock saturation towards 2050 for China. In other regions, such as India and South East Asia, stock growth is presently just taking off and can be expected to become dominant for global developments after 2050. The database is created to be used as input for resource and climate policymaking as well as assessment of environmental impact related to residential buildings and assessment of possibilities for urban mining. In the future, we hope to extend it as new data on materials in the built environment become available.

Modelling global material stocks and flows for residential and service sector buildings towards 2050

“…For Aluminium our model seems to produce slightly higher estimates for in-use construction-related stock. This is a direct result of the studies used to define the material content database (Marinova et al, 2019).…”

“…The assumptions on the material demand for service sector buildings are simpler than those for the residential stock analysis by Marinova et al (2019). Because of a lack of data, the materials in service sector buildings are not defined regionally.…”

“…The development of building stock, inflow and outflow shown in Section 3.2 translates into projections for material demand. To calculate these we used the database specifying the building materials requirement per square meter, for four different residential buildings (Marinova et al, 2019), together with the material content of the four service-related building types as described in Section 2.1. In presenting the results of the material calculations we focus on the ratio between the inflow and the outflow, which gives an indication of the recycling potential, or more specifically, the potential for closing material loops in pursuit of achieving a circular economy.…”

“…This is inevitable when compiling a model with a global scope like this. As indicated by Marinova et al (2019) this is partly due to the sensitivity of our model to assumptions based on single study or data point, which is undesirable, but currently unsurmountable, given the data availability. We emphasize that the work presented here is an initial attempt at formulating a global model, and therefore provides plenty of sensitivities and opportunities for future improvements as discussed in the following sections.…”

“…This paper documents a first attempt to achieve a more systematic coverage of material demand scenarios in buildings by building upon recent work by Marinova et al (2019). They used the available model output from the IMAGE integrated assessment model (Stehfest et al, 2014) to develop a scenario for the stock of 6 building materials in 4 different residential building types, based on the physical demand for residential floor space (in square meters) towards 2050, which was originally described by Daioglou et al (2012).…”