There is an unexpected and sinister link between two apparently very distant realities: large metropolises and cancer. To unite them, according to a recent study (that I link to you here), is the way in which they grow and expand, following dynamics so similar that they leave you speechless.
London, Sydney and other metropolises behave like malignant tumors, feeding on infrastructure and population to always invade new spaces. A discovery that could revolutionize the approach to urban planning, paving the way for solutions inspired by medicine. Ready to explore the dark side of urban growth?
London's growth under the magnifying glass
A team of researchers from University College London (UCL) analyzed the evolution of the British capital over the last 180 years, using mathematical models. The results are surprising: London has grown remarkably like a malignant tumor.
The original London, the one that existed during the Middle Ages, was known as the “square mile”. Today, modern London is a metropolis over 600 times larger than that historic nucleus.
Before the advent of the rail network, London's population was concentrated in a small central area. Long-distance travel to the suburbs was expensive and difficult.
The use of trains, however, enabled a shift towards suburban living, allowing residents to live further and further from the centre. This seems to be a trend in other cities around the world too: people tend to prefer to live in low-density areas if transportation to the center is available.
The key role of transport in the growth of metropolises
The growth dynamics of metropolises, argue international researchers, are comparable to the way blood vessels in tumors sprout and divide, forging new "roads" in the emerging tissue.
This process, called angiogenesis, allows the cancer to grow more than a few millimeters in size; blood vessels deliver oxygen and nutrients to cells further away than diffusion could.
The same principle seems to apply to many large metropolises around the world such as London, Washington DC, Paris and Sydney, and to several public transport systems beyond trains.
Sydney follows in London's footsteps
When UCL scientists teamed up with researchers from the University of Sydney, they found that the Australian port city has grown similarly to London. Using data from 1851 to 2011, Sydney's rail system and its urban population evolved side by side in the models.
Like London, the two most important factors that seemed to govern the growth of the Australian city were the mass of its population and its interconnectedness. These are the same factors that govern the growth of cancerous tissue.
Towards a new approach to urban planning
Today, the world is experiencing an acceleration of urbanization and digitalization, where cities are generally treated as large machines or logistics systems that can be controlled by top-down interventions.
But in reality, the study authors argue, cities behave like complex adaptive systems that evolve – to some extent – like living organisms.
This isn't a new analogy – architects and scientists have made this comparison in the past – but the new study provides quantitative comparisons between urban and biological growth that could prove useful.
The team hopes that urban planners will look to the field of biology for future solutions.
For example, policies aimed at regulating the development of road, subway and rail networks can constrain future urban growth patterns in a similar way to how strategies aimed at controlling vasculature and cell-cell interactions can mitigate cancer growth.
A lesson for the future of our metropolises
The discovery of this disturbing similarity between cities and tumors opens up new scenarios for the urban planning of the future. If we want to prevent our metropolises from turning into gigantic uncontrolled masses, devouring resources and territory, we will have to take inspiration from medicine.
Understanding the biological mechanisms that govern tumor growth could provide us with the tools to plan more sustainable, balanced and human-scale cities. Because, after all, a healthy city should grow in harmony with the environment that surrounds it, do not invade and suffocate it.
It is up to us now to grasp this lesson and rethink the way we build and develop our urban centers. Only in this way can we guarantee a future in which cities are living and vital organisms, and not malignant tumors that threaten our very existence.
