Scale, or the secret life of urban waste
I’ve been reading the book Scale: The Universal Laws of Life and Death in Organisms, Cities and Companies by Geoffrey West.
Actually, reading implies something quite civilised. I have been devouring this book, tearing it limb from limb, covering it in digital highlighter marker to the point where it is white space strung together with line upon line of market.
I feel this book is extremely important.
Its creation of a “science of cities” is important, its formation of a quantitative framework around how cities scale is important, its close analogy to biological metabolism is important.
In short, as cities increase in size, the amount of infrastructure per capita goes down, whereas wages and innovation go up. The fascinating point about West’s book is the observation that these trends shift uniformly, across all cities of all sizes, and that the trend is built around two power laws.
The first power law relates to infrastructure. For every doubling of a city’s size, the amount of infrastructure needed per capita REDUCES by 15%. That is, it increases sublinearly.
The second relates to wages, GDP and innovation (and disease and crime), where every doubling of a city’s size leads to a 15% INCREASE per capita, or superlinearly.
And these trends can be explained by the principles underlying complex systems.
Waste appears to straddle both sublinear and superlinear trends.
The infrastructure bit (number of landfills, transfer stations, MRFs etc) increases sublinearly. It is not common for new waste facilities to be built as cities grow, instead existing facilities just get bigger. Less facilities per capita.
As for the amount of waste being generated, West makes the comment (without a chart to demonstrate, but presumably based on previous analysis) that garbage generation is superlinear. The amount per capita goes up as cities grow.
I think this is a fertile piece of research.What does the data for Australia show? If waste is superlinear, is it total waste generation that is superlinear? Waste for disposal? How does recycling behave? Percentage of waste diverted from landfill?
Because if we get a sense of this, we get a sense of what increases in waste are invariant, just a part of the growing pains of a city, and what are opportunities for policy makers to improve (ie where the growth is faster than expected using West’s model).
Of course, the frightening point that is made clearly in the book is that a superlinear power law for generation of waste (and other pollution) is clearly not sustainable. It leads to waste generation rapidly spiralling out of control, after a long time of seeming all ok. That’s what happens with power laws.
West makes the point that there needs to be a radical shift to prevent this exponential overwhelm from happening. Perhaps the shift will be a deep form of the circular economy such as described in A Good Disruption, with materials banks and materials leasing. That is worth thinking about too.
Finally, there is something deeply satisfying in the book, and that is this wonderfully rich metaphor that connects cities back into animal metabolism. After all, waste is produced in all biological systems, including cities. The city takes in information, resources and energy and converts it into wealth and waste.
What happens in our cities determines what happens with our waste. Understanding cities is vitally important: how they function and how they scale, how they live, breathe and evolve.
I will return to the question of waste, cities and scale in later writing, but for now want to mark this book as important.
Very important and essential reading for the thoughtful materials manager.
