Civil Engineering nOVEMBER 2021 | Vol 29 No 10

Civil Engineering November 2021 57 A new quantitative study on the impact of the location of housing development in Johannesburg on carbon emissions – by the research partner- ship of Divercity Urban Property Fund and the Green Building Council South Africa (GBCSA) – shows that where and how housing is built in the city has a massive effect on its residents’ carbon footprints. Titled Does location matter? and conducted by consulting engineering firm Arup, the research highlights a growing gap between the lower carbon emissions generated by living in the well-connected, amenity-rich urban core and higher emissions from living on the disconnected amenity-poor urban periphery. This chasm is so vast that, should all new housing be built on the urban periphery, by 2050 it could reach 224 MtCO 2 e – a startling 10 times the total annual carbon emissions of the entire city of Johannesburg in 2016. Right now, the dominant mode of af- fordable housing delivery in South Africa confines lower-income households to the urban periphery – far from economic op- portunities and essential services such as healthcare, schools, jobs and parks. The study compared carbon emis- sions from an urban periphery housing development model to those generated by housing development in the urban core. Researchers also looked at two groups of housing residents – lower and mid-income occupants. They considered the carbon emissions of the housing’s construction and operation over a 60-year design life period, with ongoing operation accounting for 72% of the total carbon a residence will generate. The report also analysed the transport emissions of residents associated with living in each location. Mid- and lower-income families living on the urban periphery travel similar dis- tances each day, but mid-income families, who rely on private cars, generate three times the emissions of lower-income families, who typically use public or shared transport. This trend was the same in urban core households. But, viewed together, a mid-income family in the New research reveals how to build a thriving city countries around the globe. To mitigate and adapt to future climate change, we must pay special attention to the broader impacts of urban planning decisions on carbon emissions and look not only at how we can develop greener buildings but also how buildings connect to communities, ameni- ties and opportunities,” says Georgina Smit, GBCSA’s Head of Technical. So, what can we all do to make sure that we minimise carbon emissions while creating excellent places for people to live and thrive? Q Q The public sector can implement policies that align property develop- ment with climate goals, encourage this with incentives, and manage it with regulations and standards. Q Q Property developers can take care to build better located housing that minimises lifestyle-related carbon emissions. Q Q Built environment professionals can champion the low-carbon develop- ment and operation of urban spaces. Q Q Town planners can design connected cities, neighbourhoods and spaces that improve equity and access to economic opportunities. Q Q Urban economists can advocate for integrated thinking, including carbon emissions, air pollution, the cost of lost time during commuting, and other external costs. The full version of the research report is available at https://gbcsa.org.za/ wp-content/uploads/2021/09/30.09- Divercity_Carbon-Study_Final.pdf .   224 MtCO 2 e EQUATES TO... MtCO 2 e 224 56.5 The emissions of coal fired power stations in one year 10x Johannesburg’s Annual emissions in 2016 9 million m 2 The CO 2 e stored in of South African Mistbelt forest By 2050, the cumulative emissions gap between these two scenarios (development in the urban periphery vs the urban core) is 224MtCO 2 e, almost 10 times the annual total emissions of Johannesburg in 2016 (21 MtCO 2 e). urban core still generates fewer transport emissions than a lower-income family living peripherally to the city. In short, the research proves that the current dominant model of affordable housing delivery in South Africa generates significantly higher carbon emissions and counteracts the aims of Johannesburg’s Climate Action Plan and South Africa’s climate change commitments. The study shows that urban sprawl, reliance on pri- vate car travel and long car trips should be discouraged through spatial planning. In its place, urban densification, access to op- portunities, and fewer, shorter private car trips should be encouraged. This approach will help connect people to economic op- portunity, break apartheid spatial patterns and retrofit existing settlements. “This research highlights the crucial role played by spatial planning and as- sociated transport networks in shaping cities that work for their citizens and the environment. The results correspond with the findings of similar studies in other 224 MtCO 2 e EQUATES TO... MtCO 2 e 224 56.5 The emissions of coal fired power stations in one year 10x Johannesburg’s Annual emissions in 2016 9 million m 2 The CO 2 e stored in of South African Mistbelt forest By 2050, the cumulative emissions gap between these two scenarios (development in the urban periphery vs the urban core) is 224MtCO 2 e, almost 10 times the annual total emissions of Johannesburg in 2016 (21 MtCO 2 e).