A characteristic feature of complex systems is that when they double in size, many of their parts do not. Typically, some aspects will grow by only about 80 percent, others by about 120 percent. The astonishing uniformity of these two growth rates is known as “scaling laws.” Scaling laws are observed everywhere in the world, from biology to physical systems—and in cities. Yet, while a multitude of examples show their presence, reasons for their emergence are still a matter of debate.
A new publication in the Journal of The Royal Society Interface now provides a simple explanation for urban scaling laws: Carlos Molinero, a researcher at the Hub until last September, and CSH President Stefan Thurner, derive them from the geometry of a city.
SCALING LAWS IN CITIES
One example of an urban scaling law is the number of gas stations: If a city with 20 gas stations doubles its population say, from 100,000 to 200,000, the number of gas stations does not increase to 40, but only to 36. This growth rate of about 0.80 per doubling – it will always be between 0.75 and 0.85 – applies to much of the infrastructure of a city.
For example, the energy consumption per person or the land coverage of a town rises by only 80 percent with each doubling. Since this growth is slower than what is expected from doubling, it is called sub-linear growth.
Read more at Complexity Science Hub Vienna
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