One of the sustainability axioms that I don't believe has been thoroughly unpacked is the question of densification. In every conversation about sustainable cities, the need to densify our cities is an early point of discussion. On the surface it seems to have merit but there are some fundamental concerns with a vision of densification as the silver bullet. And especially so in Africa.
The stat that is often trotted out to support densification is that people living in Manhattan have a lower carbon footprint than those living in Brooklyn. The high rentals lead to smaller dwellings and the good public transport, proximity to work and play and exorbitant cost of parking all play a role in reducing transport emissions. However, this highlights my first concern - that dense urban settlements are typically compared to urban sprawl. Because this supposes a false polarity - we are not faced with just two options. Human settlements have come in a variety of sizes and shapes and some have been more functional than others. We could be interrogating the strengths and weaknesses of many more models than just the dominant two in our search for solution to how we structure our cities.
It also supposes that carbon intensity is the only measure of environmental impact - another common position, if not an accurate one. Some of the critical sustainability considerations in modern cities relate to ecological function within cities - forests, parks, green belts and rivers connected to each other and the wider surrounding areas.
With respect to resource efficiency, there are many arguments for densification: smaller properties and shorter commutes being chief amongst them. However as a whole, they fly in the face of one key principle: denser urban spaces result in concentrated environmental impacts, and nowhere in my engineering career have I come across a point load that has a lower impact than a distributed load.
The environmental footprint of dense spaces extends far beyond their physical boundaries, and the feedback loops from these much wider systems being impacted are often difficult to isolate and pick up. It is said that the environmental footprint of London is larger than the whole United Kingdom. In a globalised world, such astounding concentrations of consumption are possible. But they mean that often the externalities associated with consumption are experienced by faceless, nameless communities in far-off places the residents will never see. Until we have an agreed, and accurate mechanism for assessing the true costs of dense urban spaces on those natural and societal systems that support them, to claim the resource-efficiency of densified areas is shortsighted.
Another concern I have with the Manhattan-Brooklyn comparison is how idealised the comparison is. But most dense urban spaces are not Manhattan; Central Park is often absent from urban densification models. And not many people want to live in the cities of Judge Dredd without a blade of grass or green leaf for miles regardless of how modern, hip or cool it may be shown to be in the adverts.
The urban dream is great at building self-esteem through achievement; the shiny apartment, new tv, smart car, access to the newest, coolest restaurants and bars. But it is only through deep human interaction, not just the transient collitions at the coffee shop, that our sense of community and attendant empathy is realised . While these things are not exclusive to less dense areas, they seem to me to be far more prevalent in neighbourhoods than apartment blocks. Density works best when one's raison d'etre is work and the trappings of wealth but when the rest of real life rears it's head, suddenly that shiny apartment isn't quite so appealing.
However the productivity of cities is evident. So how do we get the benefits of high-intensity interaction that comes with densification (and has driven successful cities) without compromising livability, ecology and resource efficiency. How do we have resist both the temptation of high density high impact centres and that of McMansions and strip malls? Well, I think a part of the answer might lie in one form of urban settlement that predates most others: the village.
Villages are remarkable from a sustainability perspective. They are typically quite self-sufficient; i.e. their ecological footprint does not extend too far beyond the boundaries of the community. Approaching cities and urban density as groups of villages side-by-side might offer us some potential to address densification in a manner that results in neither urban sprawl or packed apartment buildings.
The advances of telecoms tech have allowed us to work in a more distributed manner, so moving people to a central location can be mitigated. Satellite centres could replace the modern CBD and be linked together primarily by public transport and rely on pedestrian movement within their "villages". Many decentralized infrastructure approaches would be optimal in a village context as opposed to our current city thinking; including distributed electrical and thermal energy distribution and village scale water management (with nutrient recovery and water re-use).
And while it would be terribly naive to believe that villages would cure all society's ills, at least at a social level they may realise greater participation of business with that messy, frustrating and absolutely essential mish-mash called community. And participation of civil society and community in the function of business is one of the massive missing elements of current cities on the front of sustainability.
And so why is this so particularly relevant in Africa? Well, firstly, Africa is one of the regions where mega-cities are becoming dominant; Cairo, Lagos and Johannesburg; immense cities which pull people from vast areas into tightly packed centres, cities often typified by huge disparities between rich and poor and often surrounded and permeated by slums. Secondly, Africa is culturally still much closer to village living than many more developed regions. The potential to unlock the benefits of smaller scale design in the context of cities is still very much an option here. And finally, because the face of Africa's cities are still to be shaped. The opportunities for re-imagining planning, infrastructure, transport, communications and our preconceptions of success are abundant here precisely because we are less developed. And this opportunity for applying new thinking to cities might just give Africa the edge as we move into a resource-constrained future.