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Highlights • A method for quantifying the limits to growth of cities is proposed. • Emergy accounting is introduced to assess the limits to growth. • Results claim for more studies considering larger time-period under analysis. • The proposed approach offers a new perspective to assess the limits of urban growth. Abstract 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. [ABSTRACT FROM AUTHOR]

Abstract: Environmental aspects have been acknowledged as an important issue in decision making at any field during the last two decades. There are several available methodologies able to assess the environmental burden, among which the Ecological Footprint has been widely used due to its easy-to-understand final indicator. However, its theoretical base has been target of some criticisms about the inadequate representation of the sustainability concept by its final indicator. In a parallel way, efforts have been made to use the theoretical strength of the Emergy Accounting to obtain an index similar to that supplied by the Ecological Footprint. Focusing on these aspects, this work assesses the support area (SA) index for Brazilian sugarcane and American corn crop through four different approaches: Embodied Energy Analysis (SAEE), Ecological Footprint (SAEF), Renewable Empower Density (SAR), and Emergy Net Primary Productivity (SANPP). Results indicate that the load on environment varies accordingly to the methodology considered for its calculation, in which emergy approach showed the higher values. Focusing on crops comparison, the load by producing both crops are similar with an average of 0.04ha obtained by SAEE, 1.86ha by SAEF, 4.24ha by SAR, and 4.32ha by SANPP. Discussion indicates that support area calculated using Emergy Accounting is more eligible to represent the load on the environment due to its global scale view. Nevertheless, each methodology has its contribution depending of the study objectives, but it is important to consider the real meaning and the scope of each one. [Copyright &y& Elsevier]

Abstract: Society needs urgently good tools to understand the biosphere dynamics, become aware of Earth''s biophysical limits and make appraisals of environmental performance of human dominated systems. In this context, the Ecological Footprint (EF) was suggested as one of the most important tools. But, according to calculations based on Emergy Analysis, the indicators of EF could underestimate the problem of human carrying support. EF does not consider the work of untouched nature in productivity and ecosystems services. In order to improve the EF results, the present study suggests: (a) to include the ecosystems not considered in conventional EF i.e. tundra, deserts and areas covered by ice; (b) to consider the value of Net Primary Production (NPP) in Emergy units (seJm−2 year−1) as the base for the calculation of Equivalent Factors (EQF); (c) to account for the consumption of fossil energy used in collection, treatment and distribution of water for domestic use, for this the carbon emissions data (in tonCm−3 of water) were used. Introducing these changes to the conventional EF calculation and considering the Peruvian economy (in 2004) as the study case, the Biocapacity obtained was 14.31ghacapita−1 and the footprint was 6.68ghacapita−1. These values mean that Peru can support 2.14 times its population if the current life style is maintained, as opposed to the 4.0 times ratio obtained with a conventional EF calculation. [Copyright &y& Elsevier]

Highlights • We assess the stocks of three urban systems using emergy synthesis. • Materials and energy stored increase the size and complexity of the urban systems. • ABC developed and grown relying mainly on economic and social capitals. • Emergy Synthesis provides insight into the reliance of economic activity on natural capital. • Emergy Synthesis may guide the development of effective policies for urban systems. Abstract Environmental assessments of urban systems intend to help city managers to identify feasible measures towards the reduction of urban vulnerability and to the understanding on how cities are dependent on available resources. Through the emergy approach, city managers may recognize subcomponents from each building block that individually and collectively influence the municipalities' environmental performance. Internal stocks of the urban systems play an important role on cities functioning, and the interactions among economic, social and natural capital influence the municipal performance. This paper uses emergy synthesis to account for the internal stocks of the multi-urban system called ABC Paulista, the role of stocks in ABC development and growth. Three forms of capital (economic, social and environmental) were accounted for, which allowed describing the urban settlements according to their nature (such as service provider or industrial cluster). Results may assist policy makers in regard to urban aggregates sustainability and also in formulating policies for particular cities. [ABSTRACT FROM AUTHOR]