The latest forecasts for urbanisation rates make for a shocking read. Cities around the world are growing due to high birth rates and due to the greater economic opportunities that cities seem to give to their inhabitants. Citizens around the world are giving up rural life and heading to the cities in search of easier living and greater access to education and healthcare and who can blame them? The reality, however, may be tougher than they imagine. Can cement and concrete help in making future cities more ‘liveable’?
Global population is forecast at 11.2bn in 2100, up from 7.2bn in 2017, according to the latest UN projections1. Africa and Asia will make up approximately 40% each of the world’s population, or 80% overall in 2100 (while Europe’s population will have dropped from 742m to 653m in the same time span). Using population growth rates and urbanisation trends, and admitting to large uncertainties in the data and forecasts, researchers2,3 have suggested that Lagos could become the world’s largest metropolis, with 85-100m inhabitants by 2100. Similarly, Niamey, little-known capital of Niger and home to around 1m people today, could count 46m denizens by the end of the century, catapulting it into the top 15 of cities globally, by population size. The list goes on: Kinshasa in the DRC from an already-alarming 12m to an eye-popping 83m; Dar Es Salaam will have 73m inhabitants, Mumbai 67m, Delhi 57m, Khartoum 56m, Dhaka 54m, Kolkata 52m and Kabul 50m. Karachi will have 49m burghers, while Nairobi will have 46m. These cities will have no similarity to the seemingly paradisiacal Wakanda4.
A number of the world’s largest cement companies have recently come together to form a new association, called the Global Cement and Concrete Association5. The association represents over 1Bnt/yr of cement production capacity, so it has some real heft behind it. Membership of the association is also open to other cement companies and other organisations that share in the association’s aims. As the GCCA states, ‘The association will focus on driving advancements in sustainable construction, working to enhance the cement and concrete industry’s contribution to a variety of global social and developmental challenges. To this end, the GCCA will promote the development of durable, resilient and environmentally-sensitive buildings and infrastructure at a global level. With concrete now representing the world’s second most consumed product after water, issues at the forefront of the organisation’s agenda include sustainable development and urbanisation, as well as climate change mitigation and adaptation.’ If the GCCA can really make a difference to city living (and Lafarge Africa’s ‘motto,’ incorporated into its logo, is ‘Building better cities’6) then it will have made the world a better place.
How can cement and concrete make a city more ‘livable’? From my own experience, I would suggest that the most important possible use of concrete in a city is the provision of sanitation services. When a significant proportion of a city has no access to clean water and no access to toilet facilities, not only is a large part of the day spent in collecting water from central water distribution points, but there is also a strong possibility in slipping over in something nasty during the journey. The elimination of illnesses due to faecal contamination of water and food is surely a basic requirement of civilisation - and it’s something that cement and concrete are perfectly suited for, in terms of water pipes, sewage channels and water treatment facilities.
Much of the growth in cities worldwide will come in the form of sprawling shanty towns, essentially without access to services, but it need not be like this. Forward thinking and town planning, along with the supply of basic concrete-based housing will save everyone a lot of grief in the long run. It’s been shown7 that the provision of a home with a US$150 concrete floor compared to a house with a dirt-based floor can lead to a 78% reduction in parasitic infestations, 49% reduction in diarrhoea, 81% reduction in anaemia and a 36 - 96% improvement in cognitive development in children.
Houses built of concrete (and there are many different designs that are suitable for different regions of the world, incorporating various other materials to make them energy-efficient, insulated or even energy-generating) are also robust, and can generally withstand natural disasters better than homes built of flimsier building materials. The message is clear: build these future cities of concrete!
1 https://esa.un.org/unpd/wpp/Publications/Files/WPP2017_KeyFindings.pdf
2 http://journals.sagepub.com/doi/abs/10.1177/0956247816663557
4 https://en.wikipedia.org/wiki/Wakanda_(comics)
5 http://www.globalcement.com/news/item/7032-global-cement-concrete-association-launches