Challenges in Urban Metabolism: Sustainability and Well-Being in Cities

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On the systemic features of urban systems. A look at material flows and cultural dimensions to address post-growth resilience and sustainability.

Urbanisation is widely recognised as a relentless trend at the global level. Nevertheless, a comprehensive assessment of urban systems able to address the future growth and decline of cities is still lacking. Urban systems today rely on abundant resources, flowing in from other regions, and their future availability and accessibility should be taken into consideration to ensure urban wellbeing and resilience in likely post-growth scenarios. A logical framework to address the challenge of urban planning and management to promote long-term urban system sustainability is proposed. Systems thinking and diagramming are applied, while comprehensively tracking the key material flows upon which cities depend back to their sources. First, the nexus among resources and urban activities is identified, and then its circularity is framed within a wider discourse on urban sustainability and resilience. Discussion is carried out within a two-fold perspective of both existing and newly built environments, while related economies are analysed in order to find possible gamechanging scenarios

Developing a procedure for the integration of Life Cycle Assessment and Emergy Accounting approaches. The Amalfi paper case study

Abstract The analysis of complex systems requires an integrated application of different assessment methods also taking into account different scales and points of view to gain a systemic understanding of the investigated case study. Life Cycle Assessment (LCA) and Emergy Accounting (EMA) are both environmental assessment methods, showing many similarities in the way they are performed, especially with respect to the inventory construction and to the interpretation of results. They also show great differences, the main residing in the different perspectives they give. LCA applies a consumer side perspective, and its space and time scales are set at a boundary capable to include all the process phases in terms of location and durability and their direct impacts on the investigated areas. On the other hand, throughout its donor side perspective, EMA expands the boundaries of the system over the entire biosphere space and time scales. Differences and similarities between LCA and EMA may gain added value by their implementation within a procedural framework which exploits the characteristics of the two methods. The present work proposes a methodological procedure based on the sequential and integrated application of LCA and EMA methods, called LEAF (LCA & EMA Applied Framework). The traditional Amalfi paper production is used as a test case study. The procedure stems include: (i) an ex-ante LCA analysis, to identify the hotspots of the investigated case study; (ii) the assessment of the environmental performance of the system through the development of different EMA-based improvement scenarios built around the chosen hotspots; and (iii) an ex-post LCA application built on each scenario results in order to detect the different environmental burdens. The application of LEAF to the traditional Amalfi paper production shows that the use of a more sustainable energy source is an effective solution (among the set of proposed options) to increase the sustainability of the investigated system

Resource use and biophysical constraints of Scottish agriculture

Agriculture is a fundamental sector of economy and society that ensures food supply, classified by the Millennium Ecosystem Assessment among the so-called “provisioning ecosystem services”. Due to the increase of food demand worldwide, farmers are shifting more and more towards intensive agriculture. This trend is connected to the unsustainable consumption of natural resources, most often exceeding the carrying capacity of natural ecosystems. In this paper, the resource use and biophysical constraints of Scottish agriculture were investigated at regional and national levels by means of the Emergy Synthesis method. The study focused on two main agroecosystems: 1) the Cairngorms National Park (CNP) and 2) the national agricultural sector of Scotland as a whole. The evolution of the agricultural sector was explored over time (years 1991, 2001, 2007), accounting for local renewable and non-renewable resources as well as imported resources. Performance and sustainability indicators were then calculated with and without including human labor and economic services (money flows). In the year 2007, the Emergy Yield Ratio (EYR) of the Scottish agricultural sector was about 46% of the same indicator calculated for the CNP (2.65 versus 5.72, respectively). A higher Environmental Loading Ratio (ELR) was calculated for the national sector than for CNP (1.25 versus 1.02, respectively). The Emergy Sustainability Index (ESI) was 2.12 for the national sector and 5.60 for CNP. Such figures were calculated without including the emergy flows supporting labor and services. If the latter are also accounted for, the ESI of the national level and CNP drop by a factor 5.6 and 3.9, respectively. Such variations suggest that larger flows of non-renewable resources strongly affect the environmental performance, increasing the dependence on non-renewable resources supporting the larger economic system in which the agricultural sectors are embedded in

Greenhouse gas emissions and non-renewable energy use profiles of bio-based succinic acid from Arundo donax L. lignocellulosic feedstock

The European Union recognizes the priority of new bio-based industrial pathways, such as bio-based succinic acid (bio-SA). This study has investigated, through a life cycle method, the cradle-to-factory gate greenhouse gas (GHG) emissions and non-renewable energy use (NREU) of bio-SA from lignocellulosic giant reed (GR) feedstock grown on marginal lands in Southern Italy (GR bio-SA). The aims were to: (1) evaluate the environmental performance of the GR bio-SA and (2) discuss the GR bio-SA profile with respect to its fossil counterparts and alternative bio-SA routes. For 1 kg of GR bio-SA, the gross GHG emissions amounted to 3.9 kg CO2 eq, while through the inclusion of the biogenic C potentially stored in SA molecule (1.47 kg CO2 eq) and soil organic matter (0.44 kg CO2 eq), the final net global warming potential would be nearly halved. Similarly to current starch-based SA supply chains, the GR bio-SA showed: (1) better gross GHG profile compared to the fossil adipic acid (GHG emissions reduced by 55%) and (2) comparable net GHG emissions in comparison with petrochemicals SA and maleic acid. The total NREU for 1 kg of GR bio-SA amounted to 26.6 MJ, with reduced energy consumption by about 55–79% relative to fossil counterparts, thanks to the on-site energetic valorization of lignin and holocellulose residues with relatively high heating values. The soy protein concentrate and the inorganic chemicals used in the co-fermentation showed up the prevailing contributions to the GHG and NREU profiles of the GR bio-SA, suggesting the need to optimize nitrogen and carbon sources of the growth medium

Life cycle assessment of wheat straw lignocellulosic bio-ethanol fuel in a local biorefinery prospective

A ″cradle-to-wheel” life cycle analysis was carried out to investigate the environmental profile of bioethanol (EtOH) production from lignocellulosic wheat straw (WS) and its use as transport fuel in E10 (10% of EtOH and 90% of gasoline) and E85 (85% of EtOH and 15% of gasoline) vehicles. The aims of this study were: (i) to evaluate the environmental performance of the whole WS-EtOH supply chain and (ii) to identify the best performing feedstock for a prospective bio-refinery network in Campania Region (Southern Italy). A comparison of WS-EtOH system against the fossil counterpart (gasoline passenger car) and similar bio-based production-use chains was conducted to fulfil one of the main goals of EnerBiochem and BioPoliS projects: investigating the environmental profitability of a bio-refinery system in Campania Region. Starting from the use of residual feedstock (wheat straw) or the revaluation of marginal lands (cultivation of dedicated perennial giant reed or annul fiber sorghum), through the investigation of an advanced lignocellulosic conversion processes, this work assesses the environmental feasibility of bio-energy production in Campania Region. The WS-E10 environmental profile was driven by the gasoline input in the blend, whilst the WS-E85 results showed the relevance of the crop phase. The comparison of the different blends and the gasoline-fuelled car highlighted for E10-blends similar profiles for almost all the impact categories, nearly overlapping with the conventional vehicle. Differently, for E85 vehicles, the differences between the bio-based systems appeared amplified according to the specific impacts of the feedstock supply and the conversion steps. On the whole, Fiber Sorghum-E85 system showed the worst environmental profile whilst WS-E85 entailed the best performance

Towards an energy efficient chemistry. Switching from fossil to bio-based products in a life cycle perspective

The reduction of energy demand and greenhouse gases (GHG) emissions is a main target of the chemical industry. By implementing Best Practice Technologies (BPTs) (i.e. the most advanced technologies currently in use at industrial scale) as well as by implementing recycling and energy recovery strategies through cogeneration and process intensification, consistent energy savings and CO 2 emissions reduction can be achieved in the short to medium term. Long-term additional cuts may arise from development and deployment of “game changer” technologies, that re-invent the way some large-volume chemicals are made. Although still far from commercial maturity and still facing high economic and technical hurdles, switching to the use of non-food biomass as fuel and feedstock in the chemical industry may represent a suitable option. During the transition towards a more energy efficient chemistry, the environmental performance of bio-based products need to be carefully evaluated on a case-by-case basis. In this study, an overview of energy improvement options is provided and the different patterns of bioethanol as fuel to generate energy or as platform chemical to generate chemical derivatives are compared as a case study within a life cycle perspective. The consequences on the environmental sustainability of the chemical industry are envisaged

Circular patterns of waste prevention and recovery

The growth of modern societies with their scientific, economic and social achievements was made possible by the cheap availability of fossil fuels. Side effects of fossil energy resources were the development of unsustainable production and consumption patterns, the degradation of natural capital, and the release of airborne, waterborne and solid waste. Consumption and environmental loading are not only related to fuels, but also to other material resources, such as minerals in general and rare earths in particular. The increasing shortage of crucial resources affects and constrains important economic sectors (e.g., electronic sectors, renewable energies, food production), thus placing a limit on further development and wellbeing. Concepts of sustainable economies and communities, with focus on the social dimension of development and also on the ecological and economic aspects at the same time, are gaining the attention of policy makers, managers, and investors, as well as local stakeholders (organisations, small and medium enterprises, individual citizens) and encouraging new development and business models globally referred to as the “circular economy”. The circular economy (CE) is a production and consumption system that is restorative by intention and design. Although there has been a relative decoupling of economic growth from resource use in recent decades, the gains made so far have been eaten up by a combination of economic growth and the rebound effect. There are two questions: (i) why has it been so hard to move from theory(most often from rhetoric) to practice and implementation, and (ii) how is it possible to promote an innovative and effective CE strategy in urban systems where 60% of world population is concentrated. This shift (design, networking, organisation, implementation, community planning) and related monitoring tools constitute the skeletonof the transition that needs to occur within both urban systems and economies. The point we make is that a society without waste is not only desirable, but also possible and necessary. We cannot wait longer and we cannot just accept small adjustments, increased end-of-pipe technologies and the usual interplay of promises and conflicts. The time for a massive and successful effort towards a radical change of lifestyles and production/consumptionpatterns is now, where the term "waste" itself is considered a symptom of societal illness, an indicator of immature economies, poor science and old-fashioned technology