Getting Serious about Urban Sustainability : Eco - Footprints and the Vulnerability of 21 st Century Cities

Introduction: Framing the Analysis This chapter is concerned with the long-term sustainability of cities. My starting premise is that because of accelerating global ecological change, cities everywhere are facing unprecedented challenges to their functional integrity and even survival. Unprecedented challenges require unprecedented solutions. In keeping with this reality, I depart from most urban scholarship which assumes a humanities and social science perspective. Instead, I approach ̳the urban question‘ from a mainly biophysical point of view. Accelerating global change makes clear that society will not be able to assure the sustainability of cities without a much fuller understanding of cities as ecological entities subject to biophysical laws. With this in mind, the chapter begins with a brief consideration of the organic origins of cities and subsequent evolution of cities. Permanent settlements became possible as a result of technology-induced changes in the ecological ̳niche‘ of humans ten millennia ago. However, the subsequent alienation of urban techno-industrial society from nature has produced modern cities that are not only incomplete as human ecosystems but that exist in essentially hostile relationship to the natural ecosystems that sustain them. The next section uses ecological footprint analysis to illustrate the ecological load imposed on the natural world by people and to estimate the de facto surface area of Earth occupied ecologically by the inhabitants of modern cities to sustain their material lifestyles. Pay attention, urban planners! The eco-footprints of typical cities are hundreds of times larger than their political or built-up areas. In any functionally meaningful sense, doesn‘t this ̳hinterland‘ area constitute urban land as much as does a parking lot within the city limits? I then consider the increasing vulnerability of modern cities to global ecological change. Urbanization represents the greatest mass migration of people ever. More people will be added to the world‘s cities in the first three or four decades of the 21st Century, mostly through inmigration, that had accumulated on the entire planet by 1930! But urbanization implicitly