The objective of this chapter is to more fully explore how urban environmental change takes place. The role and significance of economic development and normative planning efforts are explored. These conditions further help refine understanding of how different drivers and social and economic forces influence how cities both create and respond to the environmental crises and how transitions are manifested. Several different narratives of urban transitions are defined. These include urban transitions as sequence, collapse, advance, futures, and just sustainability. An integrated framework that links the different elements of urban environmental transitions is presented and discussed. The framework includes four steps – stress, crisis, transition, and transformation – with coupled components and elements such as drivers, spheres of action, and process and product outcomes. A review of the application areas and specific cases are presented as an introduction to the next section of the book.

Urbanization and the concentration of population and activity traditionally have brought cities an array of environmental quality and pollution issues. The process through which cities have responded to their air pollution problems are equally varied. This application chapter focuses on the narratives of three cities and an urbanized region: London, UK; Los Angeles, US; Rhine-Ruhr River Valley, Germany; and Tokyo, Japan. In all cases, worsening air pollution began to have clear and often immediate economic consequences and human health impacts. While different, several important similarities were present among the crisis-to-transformation processes for each city. These include an extended history of ever-worsening air quality conditions, often punctuated or accelerated through large-scale social or environmental trauma, the emergence and rapid application of new science and technology, and the concomitant innovation in public policy and governance capacity to address the problem of urban air pollution. The desire to address urban air pollution became both an economic imperative and an ambition to protect the well-being of the cities’ residents and to restore the sentiment that the communities were pleasant and healthy places in which to live.

The growth and impact of urban environmental problems can manifest as significant stress and eventual crises for cities and their residents. The focus of this chapter is on how and why these stressors and crises are addressed in cities and the conditions under which the crises can eventually result in significant environmental policy transitions and follow-on transformations. Several different types of documented urban crises (including ecological-resource, urban spatial development, socio-economic, and extreme events) are discussed and analyzed in the chapter. Social, environmental/ecological, and infrastructural/technological drivers influence the connection between urban environmental stress, crisis, transition, and transformation. The actual mechanisms that set up and orchestrate the transition process reflect the resilience of the existing environmental and policy management regime and the magnitude of the stress and crisis. The chapter focuses on describing each of the steps in the transition and the mechanisms that connect each step, as well as the key terms and concepts associated with the process. The importance of policy system tipping points or regime shifts is illustrated.

Natural resource scarcities are fundamental challenges for cities – and water is an especially critical resource. The chapter examines how maintaining adequate water supply is a constant challenge for cities. More specifically, this application chapter focuses on how urban water supply can be maintained, and when and why threats to supply emerge and can grow. How urban water supply stress and crisis can lead to significant environmental policy transitions is the focus of four specific city case studies. These include Atlanta, US; Cairo, Egypt; New York, US; and Tel Aviv, Israel. While droughts were relevant proximate drivers of the transitions, the cases illustrate how a range of root drivers (e.g., lack of governance capacity, transboundary conflicts) and context drivers (e.g., competing economic interests, legal precedents, inequity) played significant roles in the policy transitions and resulting transformation. The social conditions, ecological constraints, and technology access all took on important functions. Built infrastructure, including water supply infrastructure (e.g., dams, reservoirs, aqueducts) as massive, fixed assets representing the legacy of past actions, was especially important in the articulation of the transition process.