Simone Bastianoni

Emergy use, environmental loading and sustainability. An emergy analysis of Italy

Abstract Maximizing emergy flow is the new statement (Odum, 1988a, 1991) of Lotkas maximum power principle (1992a, b): self-organizing systems which maximize emergy flow and reinforce production are sustainable, the others are displaced by those with better reinforcement of their productive basis. An emergy analysis of the Italian system of economy and nature was performed in order to study its sustainability and emergy use. Indices of thermodynamic and economic vitality of Italy were evaluated and a comparison with indices of other developed and developing countries was performed.

Emergy-based indices and ratios to evaluate the sustainable use of resources

Abstract By means of a systemic analysis of the relationships among components of an ecosystems web, the flows of energy and other resources converging to produce the output (biomass, biodiversity, assets, etc.) can be evaluated on a common basis, i.e. the content of solar equivalent energy (emergy). Indices and ratios based on the emergy flows can be calculated and used to evaluate the behaviour of the whole system. In this paper, one of these indices, the emergy yield ratio η (total yield emergy per unit of emergy invested) is evaluated and suggestions made to modify it to account for present and future environmental damages due to the use of a given resource. The meaning of this index, with and without the proposed modification, is stressed illustrating the long-term effects of environmental pollution as well as some key uncertainty factors that are very often not taken into account. Odum, 1993

Sustainability assessment of a farm in the Chianti area (Italy)

Abstract In the study of agricultural systems, where land fertility and environmental conditions are primary factors, it is essential to consider both the efficiency and the environmental sustainability of processes. Emergy analysis, introduced by H.T. Odum [Science 242 (1988) 1132], is an approach developed at the interface between thermodynamics systems ecology. It was here used to obtain sustainability indicators and to assess the efficiency of a complex agricultural system, a farm in the Chianti area. The results for different crops were compared with Italian averages to obtain an idea of the long-term sustainability of this agricultural system. The cultivation of all the crops on the farm, except grapes, was more efficient and had less impact on the environment than the Italian standards. The Chianti grapes were compared not only with the Italian average but also with grapes of similar high quality, ‘Brunello di Montalcino’ and ‘Nobile di Montepulciano’, both grown in the same region. The production of grapes in the Chianti vineyard was more efficient and had an intermediate environmental impact, in the emergy sense, with respect to the other two systems. The proportion of emergy inputs to the farm that are local or renewable is quite high. Thus the emergy analysis demonstrated that the Chianti farm has a relatively good long-term sustainability considering both the whole system, and its individual crops.

Ethanol production from biomass: Analysis of process efficiency and sustainability

Bioethanol production from agricultural raw materials can be carried out to produce liquid fuels and reduce CO2 emissions from the combustion of fossil fuels and hence its impact on climate. Crop production and transformation processes have been investigated by the traditional energy and carbon analyses and the more recent emergy analysis. The latter is able to account for, on the same basis, both renewable and non-renewable inputs, including goods and labour involved in a process. The combination of such analyses provides a deeper insight into the problems of converting biomass to fuel. In particular it is shown that emergy analysis can evaluate long-term sustainability and comparisons of emergy-based indices can be used to compare efficiency and environmental input between various production systems.

The problem of co-production in environmental accounting by emergy analysis

Abstract This paper deals with the application of emergy analysis to systems with co-productions. Emergy is a measure of how much work the biosphere has done in order to provide a product, in terms of solar energy joules. For this reason, especially by means of the emergy-based indices, emergy analysis is a one of the key functions for assessing sustainability. However the application of emergy analysis to processes with co-production can be misleading. Usually some inputs have to be added in order to obtain a ‘useful’ product from a by-product. This would lead to penalizing a co-production with respect to two (or more) independent processes, since the fact of having another output is neglected in calculations. To have a better comparison, we introduce the concept of joint transformity and the weighted average of the transformities. The same reasoning is applied to other emergy-based indices. These new indexes should be added to the set of the existing ones to enlarge the possibilities of application. A case study of a dairy farm in Puerto Rico was analyzed from this viewpoint, showing that co-production of milk and methane (or electricity) is more efficient and less impacting on the environment with respect to separate productions, while two separate processes would be more effective in using local resources.

Emergy/exergy ratio as a measure of the level of organization of systems

Abstract Emergy and exergy have been developed as complementary goal functions. By definition, emergy is the solar energy directly and indirectly required to generate a flow or a storage. Exergy is a property of a system, measuring the maximum work that can be extracted from a system when it goes towards the thermodynamic equilibrium with a reference state. The concept of emergy contains the history, the time and all the different processes involved up to the present state of the system, while exergy is a measure of the actual state, of the level of organization and of the information content. These two approaches are very suitable for describing self-organizing systems such as ecosystems. The ratio of the emergy flow to the exergy can give further information on the state of a system, showing what concentration of solar energy equivalent, space and time (emergy) is required to maintain or create a unit of organization (exergy). The proposed index is related to the efficiency with which a system organizes itself or, if steady, maintains its complexity. To test this approach we considered three coastal lagoons. Two of them are artificial, built by man to purify sewage. One is a control pond fed with estuarine water and ‘clean’ water from the local sewage treatment plant, and one is a ‘waste pond’ fed with estuarine water mixed with more ‘polluted’ (i.e. richer in nutrients) effluent. The third system is the lagoon of Caprolace (Italy) a ‘natural’ system, placed in a national park. Experimental results show that the emergy/exergy ratio has the lowest value for the ecosystem of Caprolace. The waste pond has the highest environmental cost for the production of a unit of organization. Both the control and the waste ponds show a decreasing value of the emergy/exergy ratio with time, meaning that natural selection is organizing the systems.

Solar Energy Demand (SED) of Commodity Life Cycles

The solar energy demand (SED) of the extraction of 232 atmospheric, biotic, fossil, land, metal, mineral, nuclear, and water resources was quantified and compared with other energy- and exergy-based indicators. SED represents the direct and indirect solar energy required by a product or service during its life cycle. SED scores were calculated for 3865 processes, as implemented in the Ecoinvent database, version 2.1. The results showed that nonrenewable resources, and in particular minerals, formed the dominant contribution to SED. This large share is due to the indirect solar energy required to produce these resource inputs. Compared with other energy- and exergy-based indicators, SED assigns higher impact factors to minerals and metals and smaller impact factors to fossil energetic resources, land use, and nuclear energy. The highest differences were observed for biobased and renewable energy generation processes, whose relative contribution of renewable resources such as water, biomass, and land occupation was much lower in SED than in energy- and exergy-based indicators.

Environmental heterogeneity patterns and assessment of trophic levels in two Mediterranean lagoons: Orbetello and Varano, Italy

The management of coastal lagoons is of particular interest due to their high economical importance. In spite of their great productivity, coastal lagoons are often impacted by human pressure which produces water eutrophication. The aim of this paper is to assess the trophic state of the two Mediterranean lagoons taking into account chemical-physical parameters, nutrient concentrations and biological parameters. Two Italian lagoons, Orbetello and Varano (respectively located in Tyrrhenian and Adriatic coast, Italy) were studied between May 2003 and April 2005. Both these systems receive treated urban outflows, agricultural effluents and rivers freshwater inputs. Field collected data showed that studied lagoons were characterized by different human and natural pressures. Orbetello showed the highest water eutrophication, highlighted by the trophic index values, while Varano showed lower eutrophication levels except for the summertime. The values of physical, chemical and biological parameters measured in Orbetello and Varano lagoons indicate that a wide spatial and seasonal gradient of the water characteristics was established during the study period, but in particular in winter. This gradient, typical of estuarine systems, was essentially due to the mixing of freshwater, seawater and anthropogenic inputs. Orbetello lagoon seemed much more affected by the urban impact and the fish-farming activities than Varano lagoon, but the latter showed a greater agriculture activities impact as showed by the remote sensing images.

Tourism and Climate Change: Two-Way Street, or Vicious/Virtuous Circle?

This paper presents the approach and reasoning behind two central conceptual diagrams relating tourism and climate change. The first diagram describes a typical polarisation in tourism and climate change knowledge management. It is argued that this polarisation restricts the collective body of knowledge and obscures important causal links between tourism and climate change phenomena. Developments are proposed in a second conceptual model which counters the tendency of scientists, policymakers, the tourism industry and NGOs to polarise along two research interests by discussing climate’s influence on tourism vs. tourism’s influence on climate; either of which could be interpreted as a primary limitation to the sustainability of tourism. The paper places into context key perspectives in the tourism–climate change discussions, addresses the difficulty of including system feedbacks between human activity and climate interactions, and draws attention to the underlying drivers of unsustainable trends. New strategic conceptual models are advocated to support long-term non-territorial collaboration, to incorporate adaptation and mitigation in ways which are not mutually exclusive, and to address the following paradox: that the cross-section of the global population driving the demand for tourism resources threatened by climate change are also disproportionately responsible for increased radiative forcing.

CH 4 and N 2 O emissions embodied in international trade of meat

Although previous studies have quantified carbon dioxide emissions embodied in products traded internationally, there has been limited attention to other greenhouse gases such as methane (CH4) and nitrous oxide (N2O). Following IPCC guidelines, we estimate non-CO2 emissions from beef, pork and chicken produced in 237 countries over the period 1990–2010, and assign these emissions to the country where the meat is ultimately consumed. We find that, between 1990 and 2010, an average of 32.8 Mt CO2-eq emissions (using 100 year global warming potentials) are embodied in beef, pork and chicken traded internationally. Further, over the 20 year period, the quantity of CO2-eq emissions embodied in traded meat increased by 19%. The largest trade flows of emissions embodied in meat were from Brazil and Argentina to Russia (2.8 and 1.4 Mt of CO2-eq, respectively). Trade flows within the European region are also substantial: beef and pork exported from France embodied 3.3 Mt and 0.4 Mt of CO2-eq, respectively. Emissions factor of meat production (i.e. CO2-eq emissions per kg of meat) produced depend on ambient temperature, development level, livestock category (e.g. cattle, pork, and chicken) and livestock management practices. Thus, trade may result in an overall increase of GHG emissions when meat-consuming countries import meat from countries with a greater emissions intensity of meat production rather than producing the meat domestically. Comparing the emissions intensity of meat production of trading partners, we assess trade flows according to whether they tend to reduce or increase global emissions from meat production. S Online supplementary data available from stacks.iop.org/ERL/9/114005/mmedia