Exploring the potentialities of emergy accounting in studying the limits to growth of urban systems

摘要

Cities are important urban productive systems whose main goal could be considered the supply of innovation to generate economic growth. However, as well as all social organization managed by scale economies, cities eventually tend to reduce or even stop growth. In this scenario, public policies are essential to avoid the potential collapse of society. The sustainability of cities has been studied through different methodological approaches, but few scientific works assessed the limits of their growth. This paper explores the potentialities of emergy accounting in contributing to the discussions about the limits of growth for urban productive systems. The cities of Araraquara, Bragança Paulista, Campinas, São Paulo and Taubaté were considered as case study due to their socio-economic importance in São Paulo State, Brazil. The time period ranges from 1999 to 2011. Results from the dynamics of “empower” (in seJ/yr) indicate that all assessed cities have the same development pattern, and differences are related to their current development degree. All assessed cities showed an efficiency increase estimated by the conversion of input materials and energy (measured in seJ) into outputs of goods and services (measured in $). However, a stabilization of efficiency was not observed along the studied period. This result suggests that the hypothesized limits to growth do not exist, were not reached, or even the time period considered was not long enough to allow for observing a stabilization pattern. The methodological approach used in this work contributes to assess urban productive systems through a macro-perspective approach using an input-output model of systems functioning.