Carrying capacity-based benchmarks for Belgian residential buildings

Environmental benchmarks are a means to stimulate lowering environmental impacts of buildings. These benchmarks may be based on a bottom-up or top-down approach. While bottom-up benchmarks are derived from the analysis of reference buildings and represent current building practice, staying within the Earth's carrying capacity requires top-down benchmarks representing long-term environmental goals. Top-down benchmarks are derived by allocating a share of the global carrying capacity to objects, e.g. buildings, using so-called sharing principles. Various sharing principles exist, which significantly influence benchmark values. This study applies a wide range of sharing principles, including novel principles, to define top-down benchmark values for Belgian residential buildings based on global carrying capacities. An environmental budget was first allocated to Belgium, then to households and finally to the housing function. In each step, multiple sharing principles were applied, resulting in 32 combinations of sharing principles. For a single-person household, the minimum and maximum budget resulting from the combinations differ by a factor 42. Based on data availability and quality as well as ethical considerations, the authors of this paper give preference to “right to development” for the allocation to Belgium; “household composition” for the allocation to households and “final consumption expenditures” for the allocation to the housing function. The comparison of the top-down benchmark values with bottom-up benchmarks reveals that various measures are required to remain within the Earth's carrying capacity. The top-down benchmark values presented in this paper can hence guide policymakers in establishing environmental targets and related roadmaps for residential buildings in Belgium. •32 combinations of sharing principles to allocate carrying capacities to housing.•Novel sharing principle based on the needs of different household sizes.•Budgets for housing can differ up to a factor 42 depending on the allocation method.•Housing in Belgium exceeds global carrying capacities in 4 of 11 impact categories.•Benchmarks per household are preferred over intensity metrics.