Quantifying Australia's life cycle greenhouse gas emissions for new homes

Abstract

Australia is going through a significant housing boom with approximately 200,000 new homes built each year; and significantly more are required on an annual basis to accommodate the estimated population growth of almost 36 million by 2050. The effects of climate change are increasingly being felt and responsive action is required for mitigation and adaption, which must include the greenhouse gas (GHG) emission implications of this new residential stock. Mitigation strategies have been predominantly focused on decreasing the operational GHG emissions associated with buildings, leaving the other life cycle stages, such as construction, largely ignored. To achieve national targets, such as zero net emissions by 2050, it is imperative to address GHG emissions mitigation from a life cycle perspective. This study found that based on current building practices one new detached dwelling built today will be responsible for roughly 545 tCO2e by 2050. This translates to the need to plant over 8,000 trees to offset these emissions, a figure it is safe to say, most homeowners will not achieve. This study modelled life cycle GHG emissions of all new detached dwellings constructed in Australia for a single year (2019) estimating 39 MtCO2e, which increases to 883 MtCO2e by 2030 and 3,654 MtCO2e by 2050. This is much higher than the current projections for Australia's total emissions by 2030 of 563 MtCO2e if a business as usual approach is followed, and the optimum target of 441 MtCO2e to meet emissions targets of 26% less than 2005. The results of this study suggest that housing-related GHG emission are underestimated by 60%, because of the absence of embodied GHG emissions being counted in emission projections. This emphasises that firstly, target and current GHG emission projections fail to consider emissions from a life cycle perspective, and primarily report findings based on operational data, which as this study has shown can lead to a misrepresentation of almost 96% of total life cycle GHG emissions.