Complexity: the Integrating Framework for Models of Urban and Regional Systems

Traditionally, science has attempted to understand urban systems using a reductionist approach in which the behaviour of a system (city or region) is represented as being an equilibrium, mechanical interaction of its components. These components are “representative agents” for the different categories of supply and demand that inhabit the system, and it is assumed that their spatial distribution reflects an optimised value of profit (supply) and utility (demand). Over recent decades many attempts have been made to introduce more dynamic approaches, in which equilibrium is not assumed, and there are many models and methods that attempt to do this. However, this still denies the essential complexity of the urban or regional system, in which activities, natural endowments, culture, skills, education, health, transport, house prices, the global economy, all combine to affect the evolution of the system. Just as in ecology, the key to the long-term structures that may emerge is the diversity, innovative and adaptive power of people and society to counter new difficulties and create new opportunities. This fluid, adaptive power is a product of the complex system, and can only be modelled and anticipated to a limited degree. However, cities and regions can limit the possibility of successful adaptation if they are too “wellorganized” or too unimaginative. New models of adaptive organisation allow us to understand better the need for integrated views linking land-use changes to environmental and socio-economic and cultural factors. These provide a new, more open way of considering the importance of adaptable, emergent networks, and the need for multiple and burgeoning accessibility to others.