In sub-Saharan Africa, where roughly 60% of people still live in rural areas urbanisation is occurring faster than anywhere else in the world. The temptation to build new cities on greenfield sites, away from existing city centres is enormous.
Alison Groves, director: discipline lead: built ecology and WSP in Africa and Hlologelo Manthose, built ecology: sustainability consultant at WSP in Africa, are advocates for retrofitting buildings to make them more sustainable – environmentally, socially and economically – across Africa’s cityscapes.
“Given the available land, it’s far simpler to develop new, state of the art urban environments from scratch,” Groves notes. These can be designed to achieve NetZero and meet all the criteria for supporting human health and happiness, biodiversity, and climate resilience as building from scratch is much easier than trying to retrofit and refurbish old, run down city centres.
“And, while rapid urbanisation certainly implies that we need more urbanised space, overlooking the critical importance of retrofitting existing urban centres could inadvertently have a negative impact on climate change effort, and further entrench the social inequalities that so many African countries are working hard to correct.”
Climate and social impact
WSP’s Retrofitting+ paper points out that retrofitting will be the global property and building sector’s greatest contribution to avoiding catastrophic climate change and transforming cities into healthier, happier, more resilient places.
The built environment is responsible for just under 40% of global energy-related emissions. In 2022, operating buildings generated nearly 10 billion tonnes of carbon, and construction a further 2.5 billion of embodied carbon.
“Africa faces the challenge of balancing emissions generated from new construction against the demand to accommodate the ongoing influx of people from rural areas to cities,” explains Manthose. “Retrofitting serves a dual purpose. It not only improves the energy efficiency of existing buildings and incorporates key sustainable practices like water efficiency, it also repurposes underutilised or redundant buildings to serve a new purpose – such as converting old office buildings into housing.”
WSP’s Built Ecology team believes that making adaptive reuse of existing buildings the default for meeting new demand – rather than demolition – is just as important in the African context as it is internationally. The embodied carbon of the materials that were used to build existing building stock has already been realised. It is worth it to know that for every cubic meter of concrete that is NOT poured, one saves approximately 474 kgCO2e. That means for every 1 000sqm of concrete floor plate that is reused, one saves 156,65 tonnes of CO2e.
“We all need to remain within hard limits on resource consumption to avoid catastrophic climate change,” Groves says. “This global retrofitting movement is an opportunity to reflect on and re-envision how and where we want to live, and to shape our urban reality to match this vision. It’s a chance to transform cities into healthier, happier, more resilient places, even as we adapt them to accommodate a rapidly growing urban population. Perhaps even more importantly in our African social and economic context, retrofitting represents an opportunity to overturn entrenched inequities that stifle economic and human potential.”
Bringing central business districts back to life
In the global context, this means giving people a reason to return to urban centres, especially with return to office full time being more the exception than the rule. A post pandemic impact that has resulted from the remote and hybrid work approach is the appreciation for the reduction of the daily commute. For commercial buildings, the continuing hybrid work style means smaller office footprints, which also opens avenues for possibly redundant office space to be reconfigured and retrofitted into residential spaces and other amenities.
“This could be a catalyst for realising the 15-minute city vision,” says Groves. “A 15-minute city is an urban planning concept that emphasises the role of neighbourhoods in promoting climate, social and economic resilience. Like the notion of a smart city, the 15-minute neighbourhood approach aims to decentralise cities and to guide the development of lively, low-carbon, safe communities. It centres on the principle that people would have access to the essential services they need – workplaces, schools, affordable food shops, public transport, healthcare and green space – within a 15-minute radius of where they live.”
In the African context, this means an opportunity to incorporate affordable housing near existing infrastructure, services, workplaces and amenities to accommodate more people in safer, more sustainable buildings.
“It’s not solely about the building itself,” Manthose says. “It’s about meeting the growing demand for housing without compacting existing social and economic inequalities, while ensuring environmentally sustainability. This is why we need to think about retrofitting buildings in terms of their broader impact on the surrounding precinct, and society as a whole. We should think about these projects in terms of the context and the lifestyle of people who inhabit and engage with the area. These could encompass everything from environmental quality, to how walkable or well-connected a neighbourhood is, to the amenities or economic opportunities in the local area.”
In the African context, retrofitting to achieve NetZero could present opportunities to address social and economic inequality. It could also help to prevent biodiversity collapse, address the housing crisis, and influence social determinants of health for the better.
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Quelle/Source: IT-Online, 12.11.2024
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