Climate Change: Implications for the Assumptions, Goals and Methods of Urban Environmental Planning

As a result of increasing awareness of the implications of global climate change, shifts are becoming necessary and apparent in the assumptions, concepts, goals and methods of urban environmental planning. This review will present the argument that these changes represent a genuine paradigm shift in urban environmental planning. Reflection and action to develop this paradigm shift is critical now and in the next decades, because environmental planning for cities will only become more urgent as we enter a new climate period. The concepts, methods and assumptions that urban environmental planners have relied on in previous decades to protect people, ecosystems and physical structures are inadequate if they do not explicitly account for a rapidly changing regional climate context, specifically from a hydrological and ecological perspective. The over-arching concept of spatial suitability that guided planning in most of the 20th century has already given way to concepts that address sustainability, recognizing the importance of temporality. Quite rapidly, the concept of sustainability has been replaced in many planning contexts by the priority of establishing resilience in the face of extreme disturbance events. Now even this concept of resilience is being incorporated into a novel concept of urban planning as a process of adaptation to permanent, incremental environmental changes. This adaptation concept recognizes the necessity for continued resilience to extreme events, while acknowledging that permanent changes are also occurring as a result of trends that have a clear direction over time, such as rising sea levels. Similarly, the methods of urban environmental planning have relied on statistical data about hydrological and ecological systems that will not adequately describe these systems under a new climate regime. These methods are beginning to be replaced by methods that make use of early warning systems for regime shifts, and process-based quantitative models of regional system behavior that may soon be used to determine acceptable land uses. Finally, the philosophical assumptions that underlie urban environmental planning are changing to address new epistemological, ontological and ethical assumptions that support new methods and goals. The inability to use the past as a guide to the future, new prioritizations of values for adaptation, and renewed efforts to focus on intergenerational justice are provided as examples. In order to represent a genuine paradigm shift, this review argues that changes must begin to be evident across the underlying assumptions, conceptual frameworks, and methods of urban environmental planning, and be attributable to the same root cause. The examples presented here represent the early stages of a change in the overall paradigm of the discipline.