Sustainable Construction: The Embodied Carbon Impact of Infrastructures and Landscaping

The climatic and environmental impact of construction works is well recognized, and in particular, the energy use and carbon emissions associated with both their production (embodied energy/carbon) and their lifetime operation (operational energy/carbon). However, the impact of site works, infrastructures, and landscaping has yet to be explored; most of the focus has been on the buildings rather than what is around and underneath them. Yet, these, especially in city contexts, are extensive. They are also both costly and carbon-intensive, involving mainly concrete and steel. Through intentionally simple examples, the carbon impact of the buildings themselves was compared to that of site works both on and below the surface, such as underground parking. These also represent major land use interventions often impacting the whole project site area. It is shown that these can constitute a considerable fraction of the total carbon footprint of construction projects. Further, this fraction is likely to increase as future buildings achieve much lower operational as well as embodied energy/carbon. This paper employs life cycle analysis tools to calculate the embodied carbon in specific case studies, with comparative evidence from the literature and a discussion of pertinent issues. Some broader issues were noted relating to building typologies, materials, and the varying significance of the infrastructures and site works in different climates. The carbon impacts of the site work need to be addressed more sustainably, irrespective of varying contexts. This perspective has implications for sustainable design as well as for urban planning.