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Purpose: Adequate and affordable housing is essential in tackling poverty and improving living and indoor health conditions for lower and medium-income families, in both developed and developing nations. However, there is a lack of affordable housing which directly causes homelessness and formation of slum-dwellings. Sub-Saharan Africa has the most urban slum dwellers with an estimated 53.6% of the urban population in sub-Saharan Africa dwelling in urban slums. Additionally, the housing deficit in South Africa currently stands at about 2.2 million units, with a projected housing demand of 500,000 housing units over 20 years. Given the climate crisis and need for affordable housing in South Africa, low-cost and low-carbon solutions are essential. Sandbag building technology (SBT) is one such promising solution, consuming less energy during construction and operation than conventional technologies as well as regulating the internal temperature of the building through thermal mass. However, there is still a need to assess how this simpler construction style and locally sourced building materials perform from a whole life cycle perspective. Thus, this paper presents a life cycle assessment (LCA) determining the holistic sustainability of a vernacular, sandbag house design in South Africa. Methods: The environmental LCA analysed the SBT under two scenarios: manual and automated, based on extraction of sand. The life cycle cost (LCC) analysis evaluated the SBT house from the different life cycle stages: design, production and operation, and disposal. The findings show that the carbon dioxide equivalent (CO2e) emissions depend largely on the availability of locally sourced sand and whether the process is manual, automated, or both. Results: Upfront embodied CO2e emissions total 189 and 174 kgCO2e/m2 for the automated and manual scenarios, respectively. Assuming no decarbonisation, the operational emissions equal 7966 kgCO2e/m2, but could be as low as 1444 kgCO2e/m2 (achieving net zero by 2050). Whole life embodied CO2e impacts, i.e. stages A and C, total 262 and 247 kgCO2e/m2 for the automated and manual scenarios, respectively. The difference between the manual and automated scenarios can be significant at 15 kgCO2e/m2, equating to an additional 1125 kgCO2e for a 75m2 house. The estimated LCC for a 75 m2 building constructed with SBT is R 533,898.01 (US $31,167) or R 7118/m2. Conclusions: The sandbag method remains challenging for multi-storey construction due to the weight; however, it can contribute to low carbon, affordable housing in South Africa as a sandbag house does not need highly skilled labour or expensive materials. [ABSTRACT FROM AUTHOR]

Purpose: Dynamic LCIA has been developed in the past 12 years almost exclusively for climate change impact assessment, and especially the Global Warming Potential (GWP) indicator. Recently, discussions have taken place in France on the issue of integrating, a dynamic GWP indicator in the 2020 regulation (noted RE2020) on new buildings. This regulation uses a combination of static and dynamic indicators. Discussions to produce a standard on a dynamic GWP indicator could be soon launched at European level. This close perspective of using dynamic indicator into regulation recalls the importance using scientifically sound indicators. Therefore, this article re-examines the fundamentals concepts of the dynamic GWP indicator on which the future regulation is based. Method: Three basic principles of LCA are recalled: (i) no inventory flow should be omitted from an assessment, (ii) all impacts of all substances contributing to an impact category should have the same Time Horizon of the Impact (THI) in the indicator used for that impact category, and (iii) the time horizon of the impact has no reason to change as a function of time. It is then shown that the current and common version of the dynamic GWP (Levasseur et al. 2010) does not respect these principles. A new expression of dynamic GWP is provided in order to respect the three basic principles. Results: Both dynamic GWP indicators are compared according to their meaning and according to the decrease that they quantify compared to static GWP. The initial dynamic GWP indicator (Levasseur et al. 2010) sets a fixed Time of Observation Duration (TOD), chosen subjectively, after which nor flows nor impacts on climate change are assessed. The new dynamic GWP sets a TOD according to the life cycle duration (LCD) and the THI that avoids any flow omission and guarantees the full account of the impact of all flows. THI and LCD have independent values, but both time entities are related chronologically: THI has to be considered to account for the full effect for the very last emission of the product's life cycle. Thus, the total observation duration (TOD) to consider for any dynamic approach is TOD = LCD + THI. The initial dynamic indicator overestimates the effect of temporary carbon storage of around 25% at the time 50 years. The raised issue is not only an implementation issue due to the choice of TOD, it is a conceptual issue, because even in the case of TOD > LCD, the value of THI would still be variable according to the moment of emissions. Finally, the notation between dynamic and static GWP is not harmonised which can lead to confusion. Conclusion: The initial GWP indicator (Levasseur et al. 2010) represents an assessment of the impact within a subjectively chosen observation period and neither the flows nor the effects of these flows on climate change are taken into account beyond this limit. The new equation provided for the dynamic indicator takes into account the totality of the flows and the entireness of their impact according to the value of THI; it thus represents only and exclusively the effect of delaying emissions compared to the static GWP. This new method is totally applicable for the regulation, as only new FRE2020(t) coefficients, produced in this paper, have to be changed. At a time when the dynamic GWP indicator is being considered as a regulatory tool on a French or even European scale, it seems crucial to consider its scientific relevance, because using the wrong method could lead to an overestimation of the possible beneficial effects of temporary carbon storage in the construction sector as a whole. [ABSTRACT FROM AUTHOR]

Purpose: Climate change, environmental concerns, and economic problems pose challenges to the construction sector in Iran, which must provide affordable solutions while addressing environmental issues. Hence, natural earthen building materials are critically needed to reduce energy-intensive and costly construction practices dramatically. The purpose of this paper is to provide a framework for comparing life cycle assessments (LCA) and life cycle costs (LCC), for load-bearing walls of an single-family affordable housing unit in a desert part of Iran, Ardakan City. Methods: To do so, both LCA and LCC for the unit were performed, considering a cradle-to-site perspective. For this purpose, 22 load bearing wall systems are assessed, including 18 stabilized and unstabilized earthen construction techniques, such as adobe, rammed earth (RE), and compressed earth block (CEB), in addition to four conventional wall assemblies of fired brick (FB), autoclaved aerated concrete block (AAC), ceramic block (CB), and concrete masonry unit (CMU). As well as assessing the environmental impact and life cycle costs associated with the life cycle of each wall, the optimal assembly of the wall is also examined. Results: Results show that unstabilized earthen walling alternatives have significantly lower environmental impacts than conventional materials. Conclusions: Sensitivity analysis indicates that by utilizing local materials to the maximum extent possible, impacts can be further minimized. Considering the results, transportation may even account for a greater proportion of EI than wall components. [ABSTRACT FROM AUTHOR]

Purpose: The Peruvian coast is known for its low water availability and high water demand, which is mainly satisfied by groundwater sources. The current study develops regionalized water scarcity characterization factors (CFs) based on the available water remaining (AWARE) method for eight selected watersheds located along the hyper-arid Peruvian coast. Furthermore, the paper proposes water scarcity CFs for groundwater in six watersheds, which are not available in current methods. Methods: The regionalization of water scarcity CFs along the Peruvian coast was based on the following: (i) national delineation of hydrological units (HUs), (b) use of primary data on water availability and demand provided by official water balance reports and national databases, (c) use of the ecological flow values recommended by national authorities, and (d) proposal of specific water scarcity CFs for groundwater. Moreover, the results of the updated CFs were compared to those from the original CFs from AWARE. A sensitivity analysis, including recalculated CFs based on future climate change scenarios, was also provided. Thereafter, water scarcity impacts for grape and avocado production available in the scientific literature were recalculated based on previous studies with the new CFs. Results and discussion: Results revealed significant differences between updated and original water scarcity CFs in both geographical and temporal (i.e., monthly) terms. Hence, updated CFs showed that all watersheds selected experience high levels of water scarcity, especially from June to October, a more realistic scenario than that showed with original water scarcity CFs when confronted to water availability values. Meanwhile, water scarcity CFs for groundwater showed intense pressure all year round for the three main sources of groundwater (i.e., Chillon, Rimac, and Lurin aquifers) that provide water to the city of Lima, whereas only one groundwater watershed showed low water scarcity (i.e., Mala-Omas aquifer). Conclusions: Updated water scarcity CFs provide a watershed-based quantification of water scarcity in the hyper-arid Peruvian coast, which we consider more realistic as compared to the original CFs. Moreover, the water scarcity CFs proposed for groundwater allow estimating the pressure over aquifers in a higher level of disaggregation, which can be used to monitor the overexploitation of groundwater sources in an area that is highly dependent on these water sources. [ABSTRACT FROM AUTHOR]

Purpose: Plastics generate more than 500 tons of waste in Ecuador each year, according to statistics from 2016. Therefore, the Ecuadorian Congress has approved a law to ban single-use plastics to deal with their high volumes contaminating the environment. Furthermore, researchers and policymakers have been concerned about finding possible solutions to replace single-use plastics. Hence, the production of polylactic acid (PLA) in Ecuador and its environmental impact analysis and potential use as the replacement material for petroleum-based polymers is the aim of this study. Methods: An environmental performance analysis is carried out for the potential production of polylactic acid (PLA) in Guayaquil, Ecuador. For this purpose, the life cycle assessment (LCA) methodology has been used. Therefore, the LCA was considered in three steps: production of PLA, transformation to film product, and end-of-life scenario. The LCA was performed to analyze the potential environmental impact of 1 m2 PLA film production. The International Life Cycle Data System (ILCD) 2011 Midpoint + method, which exists in SimaPro software, was used for the impact analysis. Results and discussion: The production of biodegradable PLA film causes a climate change impact of 0.85 kg CO2 eq for the established functional unit and several positive environmental impacts. Due to the natural raw material used for its production, the PLA production process significantly contributes to the impacts. The process contribution order was calculated starting with PLA production (74.32%), then electricity (20.41%), polyethylene glycol (PEG) (5.05%), and finally transport (0.21%). An increase in PLA production requires more land, machinery, fuel, and fertilizers. These increases mean higher environmental impacts. PLA production in Ecuador showed a 14% higher climate change indicator than its production in the USA. Optimization of the process could lower the indicator. The landfill scenario was the most pollutant, but recycling shows great promise as the option for end-of-life. Conclusion: Despite being a bio-solution, all the parameters must be considered when analyzing a shift from plastics to PLA biopolymer. According to the sensitivity analysis, the production of PLA and its film product system had a good consistency when parameters like the amount of sugar needed is varied. According to the environmental score obtained, PLA production from sugar cane is the best option in its production in Ecuador. [ABSTRACT FROM AUTHOR]