Recent research suggests that over 75% of resources extracted globally now go toward creating, maintaining, or operating material stocks (MS) to provide societal services like housing, transport,... Show moreRecent research suggests that over 75% of resources extracted globally now go toward creating, maintaining, or operating material stocks (MS) to provide societal services like housing, transport, education, and health. However, the integrity of current and future built environments, and the capacity of the system to continue providing services, are threatened by extreme events and sea-level rise (SLR). This is especially significant for the most disaster-prone countries in the world: Small Island Developing States. In the aftermath of disasters, complex rebuilding efforts require substantial material and economic resources, oftentimes incurring massive debt. Understanding the composition and dynamics of MS and environmental threats is essential for current and future sustainable development. Drawing on open-source OpenStreetMap (OSM) data, we conducted a spatially explicit material stock analysis (MSA) for The Bahamas for 2021, where we included buildings and transport MS, and SLR exposure scenarios. Total MS was estimated at 76 million tonnes (Mt) or 191 tonnes per capita (t/cap) of which transport comprises 43%. These MS are likely to increase by 36 Mt in the future. Simulations show that under 1-, 2-, or 3-m SLR scenarios, around 4, 6, and 9 Mt of current MS will be exposed, with transport MS at greatest risk, with over 80% of total exposure in each scenario. Our findings highlight the critical role that key MS play in sustainability and resilience, contributing to the emphasis on effective development planning and climate change adaptation strategies, and to the exploration of the use of OSM data for studying these objectives. Show less
Over the past years, an increasing number of scholarly papers have used the planetary boundaries (PBs) within life cycle assessment (LCA) to determine if the life cycle impacts of a product system... Show moreOver the past years, an increasing number of scholarly papers have used the planetary boundaries (PBs) within life cycle assessment (LCA) to determine if the life cycle impacts of a product system fit within those PBs and thereby establish the absolute sustainability of the product system. This type of LCA is nowadays coined as LCA-based Absolute Environmental Sustainability Assessment (AESA). "Absolute" thereby refers to methods enabling the comparison of environmental impacts of products, companies, nations, and so on, with an assigned share of environmental carrying capacity for various impact categories. A recent review of LCA-based AESA methods and their applications characterized 47 studies "according to their intended application, impact categories, basis of carrying capacity estimates, spatial differentiation of environmental model and principles for assigning carrying capacity." However, the review and the majority of studies reviewed did not, or only to a limited extent, discuss potential temporal issues of assigning carrying capacity to product systems. Several of the carrying capacity estimates have a time dimension while LCA results lack a time dimension. In this article, we show that assigning PBs to product systems is only technically possible when adopting several fundamental though unrealistic assumptions, and conclude that even product LCA-based AESA is relative. This should not withhold scholars from developing approaches applying the PBs in LCA, but it should prevent them from claiming and using the term "absolute." Show less
Cucurachi, S.; Blanco Rocha, C.F.; Steubing, B.R.P.; Heijungs, R. 2021
Life cycle assessment (LCA) models and databases have increased in size, resolution, and complexity, requiring analysts to rely on an ever-increasing number of uncertain model inputs. Such... Show moreLife cycle assessment (LCA) models and databases have increased in size, resolution, and complexity, requiring analysts to rely on an ever-increasing number of uncertain model inputs. Such increased complexity calls for systematic approaches to assessing the uncertainty of the output results of LCA models and the sensitivity of LCA model outputs to the model's uncertain inputs. In this contribution, we provide a theoretical basis and present a practical software implementation that combines uncertainty analysis and moment-independent global sensitivity analysis, which can be readily applied to full-scale LCA models. We implemented our approach in the Activity-Browser open source LCA software and it is made available for use in LCA studies. We demonstrate the approach and software implementation with a case study of crystalline silicon photovoltaics. Show less
Sustainability challenges raised by built environment development are two-folds: on the inflow side these include resource depletion and emission problems due to material production (pre-use); on... Show moreSustainability challenges raised by built environment development are two-folds: on the inflow side these include resource depletion and emission problems due to material production (pre-use); on the outflow side they include problems of construction and demolition waste (after-use). Understanding how the future construction inflow and demolition outflow will develop is essential for early recognition of these problems. A traditional approach is through extrapolation, which is risky because changes of trends may occur. A Dynamic Material Flow Analysis approach, based on the Law of Mass Preservation, provides a better framework for long-term projection. The challenge is to understand the dynamics of the built environment stocks. It is especially true for the emerging countries, where the combined influences of rapid economic development and urbanization have to be considered but are yet rarely investigated. This thesis develops the currently available approaches by including general socio-economic and specific urbanization-driven factors in China. Case studies on Chinese housing stock dynamics indicate: demolition activities in Chinese cities will continue to grow throughout the rest of the 21st century; a shrinking demand for residential steel may be expected over the next few decades, which may lead to a decrease in global steel consumption of up to 10%. Show less
The research presented in this thesis falls within a relatively new scientific field of research: Industrial Ecology, which is concerned with studying society’s metabolism to analyze the causes of... Show moreThe research presented in this thesis falls within a relatively new scientific field of research: Industrial Ecology, which is concerned with studying society’s metabolism to analyze the causes of environmental problems and indicate possibilities for more sustainable management of materials. The research is aimed at developing a dynamic substance flow-stock model that can be used to estimate future resource availability, emissions and waste streams. The developed model extends the currently available SFA models in three respects. Firstly, by combining flows and stocks. Secondly, it combines physical and economic elements. And thirdly, it operates at two levels: those of products and substances. The model has been applied to two case studies aimed at evaluating the economic and environmental consequences of the developments of lead flows and stocks and investigating the potential long-term impact of the use of platinum in fuel cell technology. The main outcome of the lead model suggests that in the Netherlands the amount of lead available for recycling is expected to exceed its demand. If comparable developments can be detected on a larger scale, the landfill and incineration streams might increase at the expense of recycling and consequently an increase in emissions. The outcome of the platinum model suggests that the identified resources of platinum will be depleted before the end of the century if no additional measures are taken. Moreover, the increased production of platinum will not have major consequences for the co-produced copper cycle. For nickel, the supply from platinum ores is expected to exceed its demand, which will have profound consequences for both the primary mining and the recycling of nickel. Show less
