Selected Aspects of Urban Complexity

Abstract: As cities represent an emergent phenomenon themselves, they are a prime example of complex systems. Most striking is their regular organization across many scales. Scaling appears in at least three respects, (i) city size distributions, (ii) fractality, and (iii) urban scaling. The discovery of regular city size distributions goes back to Auerbach in the beginning of the 20th century. Today they are best known as Zipf's law for cities. While empirically well studied, there is no consensus on the processes behind them. Since Mike Batty's “Fractal Cities” (1994) became well known, new data permits more detailed and systematic analysis. Urban scaling, i.e. the nonlinear scaling of urban indicators with city size, is being studied since the last two decades and is intriguing due to its simplicity and robustness. In this presentation, he will introduce the three themes and draw connections to climate, sustainability, and urban transition.

About the Speaker

Dr. Diego Rybski leads the Urban Complexity Group at IOER (Dresden), is external faculty at the Complexity Science Hub (Vienna), and section editor at PLoS One (Urban Studies). He holds a PhD in Physics (Justus-Liebig-Universität Gießen), was admitted to the Heisenberg Program (DFG), and was a Feodor Lynen Fellow (Alexander von Humboldt Foundation, 2019–2021) at UC Berkeley; he has also been a postdoc at CCNY and visiting scholar at Bar-Ilan University. Since 2025, he is one of three speakers of the Physics of Socio-Economic Systems Division of the German Physical Society. He edited the Compendium of Urban Complexity (Springer, 2025). His research focuses on cities as complex systems, urban sustainability, urban climate, and the urban heat island effect.