Denser cities are greener cities

South Africa’s dominant model of affordable housing delivery, where people are accommodated on the periphery of urban nodes and away from economic opportunities, is not only an extension of apartheid special planning, but bad for the environment.

It is no secret that new developments constructed to meet the housing demands of lower-income South Africans are rarely well-located, but research also shows that this segregation is resulting in higher levels of carbon emission.

Our cities are low-density and feature significant urban sprawl, and this has to change, for the betterment of our people, our country, and our environment.

Furthermore, if South Africa’s cities were to urbanise faster, there would also be significant economic growth. In fact, data shows that after the implementation of the Group Areas Act – which depopulated city centres and separated communities based on race – economic growth slowed.

Economists agree that densely populated cities are critical for growth, and the world’s highest GDP cities are very high density. Ultimately, if people live closer to their places of work, they spend less money on public transport and have more disposable income to spend on products and services.

It has also been found that denser cities are greener cities. In 2021, we at Divercity Urban Property Group conducted ground-breaking research that found the location of housing developments to be a key to significantly lowering carbon emissions.

Using a housing development in Johannesburg as a case study, we, in partnership with the Green Building Council of South Africa (GBCSA), and in conjunction with leading consulting engineering firm Arup, found that people living in the disconnected, resource-poor urban periphery generated higher carbon emission levels than those who lived in the well-connected, urban-rich core.

The gap between these levels is not only great, but growing – so much so that, should all new housing now be built on the urban periphery, the total annual carbon emissions of the entire city of Johannesburg will be ten times higher in 2050 than what it was in 2016.

The research findings reveal that, while middle- and lower-income families living on the urban periphery travel similar distances each day, mid-income families who rely on private cars generate three times the emissions of lower-income families who generally use public or shared transport. This trend was the same in urban core households. When viewed together, though, a mid-income family in the urban core still generates fewer transport emissions than a lower-income family living peripherally to the city.

This proves that the current dominant model of affordable housing delivery in South Africa results in higher carbon emissions. Therefore, urban sprawl, reliance on private car travel, and long car trips should be discouraged through spatial planning. This approach will also help connect people to economic opportunities and break apartheid spatial patterns.

According to the Intergovernmental Panel on Climate Change (IPCC), although urbanisation is a global trend often associated with increased incomes and higher consumption, the growing concentration of people and activities is actually an opportunity to increase resource efficiency and decarbonise at scale. Given the dual challenges of rising urban Greenhouse Gas emissions and future projections of more frequent extreme climate events, the IPCC also believes that there is an urgent need to integrate urban mitigation and adaptation strategies for cities to address climate change and withstand its effects. It says mitigation strategies can enhance resilience against climate change impacts while contributing to social equity, public health, and human wellbeing. Urban mitigation actions that facilitate economic decoupling can have positive impacts on employment and local economic competitiveness.

Our research report conducted with the GBCSA highlights some ways that development of well-located, good quality housing can be balanced with the need for reducing carbon emissions:

  • Public sector policies should align property development with climate goals, and manage it with regulations and standards while also encouraging compliance with incentives.
  • Property developers should commit to building better located housing that minimises lifestyle-related carbon emissions.
  • Built environment professionals can champion the low-carbon development and operation of urban spaces.
  • Town planners can design connected cities, neighbourhoods and spaces that improve equity and access to economic opportunities.
  • Urban economists can advocate for integrated thinking, including carbon emissions, air pollution, the cost of lost time during commuting, and other external costs.