Futures of Urban Ecosystems

Abstract

Planning agencies in urbanizing regions face unprecedented challenges: Rapid environmental change places enormous pressure on their ability to support urban populations while maintaining a healthy ecosystem. Agencies must devise policies to guide urban development and to make decisions about where and how to invest in infrastructure that is economically viable while simultaneously minimizing environmental impact. In regions that are becoming urbanized, the form and pace of urbanization mediate the complex interactions between humans and ecological processes. In turn, urbanization places increasing pressures and constraints on natural resources. Planning decisions, especially those about urban growth and infrastructure, can influence the directions of urban development and determine the sustain-ability of our urban planet. To make sound decisions, it is crucial to assess the effectiveness of infrastructure choices and the robustness of urban planning strategies under alternative future scenarios. Strategic decisions about urban infrastructure and growth management are based on our assessment of the past and our expectations for the future. How we think about the future has important consequences for how we define the problems to be addressed and how we search for solutions. Traditional approaches to planning and management typically rely on predictions of probable futures extrapolated from past trends. Alternatively, planners and managers have developed participatory processes to imagine desirable futures based on a set of shared community values and goals. However, with respect to long-term trends, complexity and uncertainty in coupled human-natural systems make their future increasingly unpredictable. Planners and managers need to rely on a much broader and diverse knowledge of the past to build a view of what Stewart Brand (1999) calls the long now. Expanding on this concept, Steve Carpenter (2002, 2069), in his MacArthur lecture entitled Building an Ecology of the Long Now, noted that in many cases of environmental decision-making, what ecologists cannot predict is at least as important as what can be predicted. Thinking about the future, however, is challenging. Scientists and managers are constrained by their assumptions about how the world works and what drives change. In combination, all these conditions tend to limit planners' imagination to a default set of scenarios, and thus limit their ability to deal with surprise.