ABSTRACT
This chapter reviews influences on the health of cities looking well beyond Portland. A major factor in determining the net density of a place is the proportion of land used for streets and parking lots, rail tracks, waterways, and open spaces. Urbanism, as planning and urban design, is not a niche profession, but an aggregation of all the environmental design knowledge and invention from architecture and planning, landscape architecture, seismology, and a dozen other disciplines. The United Nations World Cities Report for 2016 states that "Cities across the world are sprawling, and as such, densities are dramatically declining. In developing countries, a one per cent decline in densities per year between 2000 and 2050 would quadruple the urban land area". A disruptive crisis can strike a city in many forms: cyberattack, extreme weather event, industrial accident, and worse.
