Achieving a Net Zero Built Environment: The Need to Focus on Urban Green Footprint

Abstract

Urbanisation is growing rapidly with global population and economic growth. Significant action is required to find possible solutions to reduce greenhouse gas (GHG) emissions from new physical structures and supporting infrastructure, such as transport, water and energy networks, enabling urban planners and engineers to decarbonise the built environment to achieve a net zero emission (NZE) target by 2050. Life cycle assessment (LCA) plays a pivotal role in decarbonising the built environment as it helps identify materials, construction processes, design, and end use energy technologies significantly increasing the carbon footprint of the built environment and extending the influence of urban heat island (UHI) impacts. This paper will present a comprehensive LCA framework to calculate the GHG emissions associated with a modern central business district (CBD), including trade, commerce, and service industries, to help identify the hotspots contributing significantly to GHG emissions in a city and the possible decarbonising pathways to encourage NZE development. This framework could then be used to assess the potential for emissions management in city development and urban planning. The system boundary of the LCA will consider all stages from raw materials procurement up to the delivery of the aforementioned services. All the main urban infrastructure systems, including the transportation system, construction, energy and water supply networks and waste management systems, will be considered in the life cycle assessment process. Traffic congestion, population mobility, the urban heat island effect and landscape issues will be considered as these are also factors accelerating the increase of GHG emissions. In using this suggested LCA framework, we can then develop the green engineering solutions required to help the urban planning process develop a potential decarbonisation roadmap towards NZE targets for our cities.