Author(s): Ian Vázquez Rowe y otros
(Español) Background, aim, and scope: The synergistic use of life cycle assessment (LCA) and data envelopment analysis (DEA) is proposed as a new methodological approach to link environmental and socioeconomic assessments of fisheries. Therefore, the goal is to combine LCA and DEA in order to increase the assessment ability of both tools when applied to these fisheries. Specifically, the joint inclusion of economic aspects and the consideration of currently underrepresented environmental impact categories are tackled. Materials and methods: A five-step method is presented to combine LCA and DEA so that operational benchmarking and eco-efficiency verification are included together with the assessment of the environmental performance of fishing vessels. Some guidelines are also provided to orientate methodological choices in DEA. Furthermore, the applicability of the method for fisheries is discussed using a Spanish coastal trawl fishery as an example. Results: The use of the five-step LCA+DEA method for fisheries demonstrated the dependence of environmental impacts on the operational performance of the vessels. Operational inefficiencies were detected and target performance improvement values were consequently defined for the inefficient vessels. The combined method favored quantification of potential eco-efficiency gains. Optional features of DEA models allowed the inclusion of controversial impact issues such as by-catch discarding. Discussion As demonstrated by the application of the method to the trawling case study, this methodology facilitates joint consideration of the environmental impacts of the fleet together with economic issues such as operational efficiency. Moreover, the potential inclusion of “bad outputs” in DEA models makes the proposed method suitable for quantifying the potential improvements in currently underrepresented issue areas such as discarding by-catch. Conclusions: The proposed methodological approach was found as an adequate alternative to complement the mere use of LCA for fisheries. Its use avoids problems with standard deviations which usually arise when LCA practitioners work with average inventories. Moreover, the new approach facilitates the interpretation of the results for practitioners who deal with multiple individual LCAs for the same fishery. Furthermore, the joint application of LCA and DEA carry synergistic effects related to the link between operational efficiency and environmental impacts. Recommendations and perspectives: The proposed LCA+DEA approach for fisheries is recommended for its regular use. The need of multiple input/output data for multiple vessels is not seen as a limitation in the case of fisheries research.
Open linkAuthor(s): Ramzy Kahhat Abedrabbo y otros
(Español) The purpose of this study is to understand the importance of personal computers (PCs), new and used, as well as post-consumer management options in the residential sector in developing countries using Peru's capital, Lima, as a case study. Part of this study aims to understand how the growth of secondary markets for PCs satisfies demand of computer services in the residential sector. To achieve these goals a probabilistic survey was carried out in Metropolitan Lima. 600 households were interviewed in this survey. Households were divided into socio-economic levels (SEL) A–E, with A being the wealthiest and most educated and E being the least. Results show that ownership of computers in the residential sector is closely related to SEL, for example, for the highest SEL, SEL A, 93% of households owned a computer, however, only 1% of the households owned a computer in the lowest SEL, SEL E. Regarding the penetration of used computers in households, results show that for SEL A, B, C and D the ratio of used versus new computer ownership increases while SEL decreases. In addition, 68% of the households without a PC at home (HPC−) reported that economic constraint of expense is the main reason to not own one. The survey indicates that people in Lima are increasingly using computers for education, business and entertainment. In general people show a preference to buy a new computer but cost considerations have led to the diffusion of used computers in lower income groups. The penetration rate of used computers in Lima's residential sector is low at this time. People's negative perception of the reliability of used equipment and willingness to pay for new computers affects this penetration rate. Also, residents reported that landfills is the least chosen option, for end-of-life computers, monitors and electronics, with self-reuse and storage being the most selected.
Open linkAuthor(s): Ramzy Kahhat Abedrabbo y otros
(Español) This study analyzed the environmental impacts of a single-story residential building using different exterior wall systems. The environmental impacts over the complete life cycle of the residential buildings were determined and compared using the following indicators: air pollution index, energy consumption (embodied and operational), global warming potential, resource use, solid waste emissions, and water pollution index. The exterior wall systems analyzed were concrete block, poured in-place concrete, insulated concrete, traditional 0.05 m×0.1 m by 0.4 m ( 2 in.×4 in. by 16 in.) on center wood frame, traditional 0.05 m×0.15 m by 0.6 m ( 2 in.×6 in. by 24 in.) on center wood frame, and steel stud framing. Additionally, structural insulated panels were modeled for the operational energy of the building. For each scenario, the designs were based on the minimum 𝑅 value required by the International Building Code. ATHENA, a life-cycle assessment software tool, and eQuest, an energy usage modeling software tool that calculated the operational energy of the building, were used to evaluate the environmental impacts of the building, during the construction, use, and end of life phases, for each scenario. The results show that in the preuse phase, the insulated concrete buildings produce the greatest impact on the environment followed by the concrete block, poured in-place concrete, and steel stud buildings. Traditional wood frames had the fewest environmental impacts when considering only the preuse phase. In the use phase, the insulated concrete buildings had the lowest impacts to the environment because they required less operational energy, whereas concrete block, poured in-place concrete, traditional 0.05 m×0.15 m by 0.6 m ( 2 in.×6 in. by 24 in.) on center wood frame, traditional 0.05 m×0.1 m by 0.4 m ( 2 in.×4 in. by 16 in.) on center wood frame, and steel stud framing had progressively larger environmental impacts. The end of life phase was negligible with respect to the other phases. In the complete life-cycle assessment (LCA), 50-year life span, insulated concrete exterior walls used around 700 GJ (5%) less energy than traditional wood 0.05 m×0.15 m by 0.6 m ( 2 in.×6 in. by 24 in.) on center wall systems. The results also indicate the importance of exterior wall’s thermal mass for the energy performance of a building, especially for a city located in a hot climate zone such as Phoenix, Arizona, and the importance of a holistic approach, such as LCA, to properly assess the negative environmental impact of different technologies.
Open linkAuthor(s): Ramzy Kahhat Abedrabbo y otros
(Español) This paper considers the importation of used personal computers (PCs) in Peru and domestic practices in their production, reuse, and end-of-life processing. The empirical pillars of this study are analysis of government data describing trade in used and new computers and surveys and interviews of computer sellers, refurbishers, and recyclers. The United States is the primary source of used PCs imported to Peru. Analysis of shipment value (as measured by trade statistics) shows that 87−88% of imported used computers had a price higher than the ideal recycle value of constituent materials. The official trade in end-of-life computers is thus driven by reuse as opposed to recycling. The domestic reverse supply chain of PCs is well developed with extensive collection, reuse, and recycling. Environmental problems identified include open burning of copper-bearing wires to remove insulation and landfilling of CRT glass. Distinct from informal recycling in China and India, printed circuit boards are usually not recycled domestically but exported to Europe for advanced recycling or to China for (presumably) informal recycling. It is notable that purely economic considerations lead to circuit boards being exported to Europe where environmental standards are stringent, presumably due to higher recovery of precious metals.
Open linkAuthor(s): Ramzy Kahhat Abedrabbo y otros
(Español) Product lifespan is a fundamental variable in understanding the environmental impacts associated with the life cycle of products. Existing life cycle and materials flow studies of products, almost without exception, consider lifespan to be constant over time. To determine the validity of this assumption, this study provides an empirical documentation of the long-term evolution of personal computer lifespan, using a major U.S. university as a case study. Results indicate that over the period 1985−2000, computer lifespan (purchase to “disposal”) decreased steadily from a mean of 10.7 years in 1985 to 5.5 years in 2000. The distribution of lifespan also evolved, becoming narrower over time. Overall, however, lifespan distribution was broader than normally considered in life cycle assessments or materials flow forecasts of electronic waste management for policy. We argue that these results suggest that, at least for computers, the assumption of constant lifespan is problematic and that it is important to work toward understanding the dynamics of use patterns. We modify an age-structured model of population dynamics from biology as a modeling approach to describe product life cycles. Lastly, the purchase share and generation of obsolete computers from the higher education sector is estimated using different scenarios for the dynamics of product lifespan.
Open linkAuthor(s): Ramzy Kahhat Abedrabbo y otros
(Español) The dynamics of an e-commerce market and the associated environmental impacts from a bottom-up perspective using an agent-based model is explored. A conceptual meta-theory from psychology is adopted to form the behavioral rules of artificial consumers choosing different methods of buying a book, including conventional bookstores, e-commerce, and a proposed self-pick-up option. Given the energy and emissions savings that result from a shift to e-commerce from bookstore purchase, it appears that reductions in environmental impacts are relatively probable. Additionally, our results suggest that the shift to e-commerce is mainly due to the growth of Internet users, which ties energy and emissions savings to Internet penetration. Moreover, under any scenario, the energy and emissions savings will be provided by the introduction of the proposed self-pick-up option. Our model thus provides insights into market behaviors and related environmental impacts of the growing use of e-commerce systems at the retail level, and provides a basis for the development and implementation of more sustainable policies and practices.
Open linkAuthor(s): Ramzy Kahhat Abedrabbo y otros
(Español) We attempted to design and assess an example of a sustainable networked delivery (SND) system: a hybrid business-to-consumer book delivery system. This system is intended to reduce costs, achieve significant reductions in energy consumption, and reduce environmental emissions of critical local pollutants and greenhouse gases. The energy consumption and concomitant emissions of this delivery system compared with existing alternative delivery systems were estimated. We found that regarding energy consumption, an emerging hybrid delivery system which is a sustainable networked delivery system (SND) would consume 47 and 7 times less than the traditional networked delivery system (TND) and e-commerce networked delivery system (END). Regarding concomitant emissions, in the case of CO2, the SND system produced 32 and 7 times fewer emissions than the TND and END systems. Also the SND system offer meaningful economic benefit such as the costs of delivery and packaging, to the online retailer, grocery, and consumer. Our research results show that the SND system has a lot of possibilities to save local transportation energy consumption and delivery costs, and reduce environmental emissions in delivery system.
Open linkAuthor(s): Ramzy Kahhat Abedrabbo y otros
(Español) Reverse supply chains for the reuse, recycling, and disposal of goods are globalizing. This article critically reviews the environmental, economic, and social issues associated with international reuse and recycling of personal computers. Computers and other e-waste are often exported for reuse and recycling abroad. On the environmental side, our analysis suggests that the risk of leaching of toxic materials in computers from well-managed sanitary landfills is very small. On the other hand, there is an increasing body of scientific evidence that the environmental impacts of informal recycling in developing countries are serious. On the basis of existing evidence informal recycling is the most pressing environmental issue associated with e-waste. Socially, used markets abroad improve access to information technology by making low-priced computers available. Economically, the reuse and recycling sector provides employment. Existing policies efforts to manage e-waste focus on mandating domestic recycling systems and reducing toxic content of processes. We argue that existing policy directions will mitigate but not solve the problem of the environmental impacts of informal recycling. There are many opportunities yet to be explored to develop policies and technologies for reuse/recycling systems which are environmentally safe, encourage reuse of computers, and provide jobs.
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