As of 2016, governments globally adopted the task to achieve social, economic and environmental sustainability by committing to the targets from the UN Sustainable Development Goals (SDGs). The SDGs incorporate a set of 17 goals and 169 targets accompanied with more than 200 indicators that can guide towards achieving sustainable development by 2030. Sustainable development and human wellbeing fundamentally rest on the capacity of the biosphere to sustain us. In other words, the economy or society related SDGs can only be reached if the biosphere related SDGs, in which they are embedded, are respected. To ensure the achievement of all SDGs, the environmental impact as a result of human activity needs to be reduced to safe levels. Doing so requires quantification of both impacts and safe operating spaces in the environmental domain. However, from the SDG framework it does not become clear what safe operating spaces are because for many of the environmental issues addressed, quantitative targets based on ecological boundaries are lacking. Life-Cycle Assessment (LCA) is a method that enables holistic analysis of the environmental impact of product-systems by analyzing the impacts over the complete life cycle. Yet, as a comparative method it can only identify the most sustainable product system relative other alternative product-systems. In contrast, there have been developments to develop Absolute Life Cycle Assessment (ALCA), in which the environmental impact of a product-system is compared against a benchmark based on the earth’s ecological carrying capacity, in order to define if the system is absolutely sustainable. Such a benchmark is obtained by allocating a share of the environmental carrying capacity to the product system, using a specific allocation principle. The most recognized expression of environmental carrying capacity has been provided by the planetary boundary (PB) framework, offering a set of quantitative biophysical limits for nine critical earth system processes (ESP). The functioning of these ESPs is critical to keep the earth in its stable Holocene state, which is required for anthropogenic prosperity. Using the LCA method to quantify impacts, and the PB framework to provide quantitative ecological boundaries, ALCA could be useful to identify absolutely sustainable product-systems and support contributions from product-systems towards environmental SDG targets. Yet, an overview showing the availability of different ALCA methods and their applicability at the product level is lacking. Therefore, this master thesis provides a systematic literature review of ALCA methods and applications, that use the planetary boundary (PB) framework as an implementation of carrying capacity. The main research question is formulated as: To what extent is absolute life cycle assessment possible and does it enable a comparison of environmental impact against product-level benchmarks based on the PB-framework, to support the identification of absolute sustainable products contributing to the UN SDGs? With a database search on Web of Science (WoS) and a snowballing approach, possibly relevant publications were identified. Afterwards, 14 key publications were selected that entail either an ALCA method or application. The review was conducted with criteria primarily based on an absolute environmental sustainability assessment (AESA) framework identified from literature. The criteria cover aspects related to LCA, the PB framework and allocation approaches needed to obtain benchmarks at the product-level. The results showed that there are 5 dominant methods, and 9 applications of these methods. Only one of these methods includes a direct comparison of impact against a benchmark specifically allocated to the assessed product-system. Therefore, we concluded that only one method can truly be considered as an ALCA method that is also potentially usable in the context of SDGs. However, even claims of absolute sustainability that are made using this method are not fully conceptually consistent because a comparison is made between an annual benchmark (derived from the PB framework) and LCA impacts that are in reality exerted over many years. Other methods were considered usable for different purposes. Some methods only facilitate a comparison of impact against a per-capita benchmark, representing the occupation of an individual’s environmental budget by the product-system. These methods are rather usable for identifying sustainable consumption patterns. Some methods only enable the determination of impact reduction targets against which future impact reductions might be compared. Others do not involve any form of absolute sustainability comparison and are rather usable in conventional comparative LCA. We provided a terminology proposition for PB related concepts because there seemed to be inconsistencies across publications regarding the use of PB-related concepts and their terminology. Also, there were inconsistencies in the terminology for different allocation principles. We stated that all allocation principles could be classified in three main categories. Yet, further research is recommended to find common ground on the choice for specific allocation principles to obtain benchmarks for product-systems. Also, we recommend further research to focus on getting insights in linkages between LCA impact categories, PB’s and SDGs and combining these insights with the knowledge on ALCA methods that has been provided in this thesis. Such a combination would be the next step to find the potential of ALCA methods for supporting contributions from product-systems towards environmental SDG(-target)s.

The Azolla Filiculoidis is a subtype of aquatic fern species that thrives on fresh surface water bodies, and has a nutritive profile similar to soybean. In this thesis research, it was examined to what extent the large-scale implementation of Azolla-based livestock feed production will affect the future environmental sustainability performance of the Dutch livestock feed sector, in the context of the transition to a circular agricultural system (CAS). To that end, two novel, circular, Azolla-based feed production systems (FPSs) were designed as alternatives to the incumbent, linear, soy-based FPS. Subsequently, these FPSs were combined into three feed production scenarios: a business-as-usual (BAU) scenario which primarily relies on soy, as well as a local farming project (LFP) and a regional supply chains (RSC) scenario, in which the Azolla-based FPSs become dominant by 2050. The environmental impacts of each scenario were quantified in an ex-ante life cycle assessment (LCA), using the Activity Browser (AB) modelling tool. It appeared that, under the given assumptions, the LFP and RSC scenarios perform substantially better on all included environmental indicators by mid-century. This study opens the way for more profound future-oriented environmental modelling research, and recommends follow-up research on the biogeochemical carbon cycle of agro-industrial production systems in an LCA context, the development of fore- and background data for (circular) feed production, and the advancement of the AB software tool.

This study explores the environmental sustainability of digital health devices, specifically smart pillboxes, which are designed to help patients manage their medication, improve their health, and reduce medication non-adherence. The use of such devices has increased electronic and plastic waste and has resulted in a higher demand for critical raw materials, raising questions about their potential environmental impacts. The Digital Health in Circular Economy (DiCE) project aims to address these issues by examining the environmental sustainability of digital health devices and providing solutions to reduce their impact on the environment. This research uses Life Cycle Assessment (LCA), Disassembly Map, Recovery Assessment, and Circular Product Readiness methods to assess the environmental impact of smart pillboxes at both product and functional levels. The study examines the potential environmental impact of the product's materials, production, use, and end-of-life disposal. The research suggests improvements to increase the product's environmental sustainability, such as the use of screws instead of snap fits to attach the sub-assemblies, fixating the battery in a designated spot to prevent detaching, and promoting environmentally desirable habits, such as prolonging battery life and guiding end-of-life recovery of the product. The study concludes that there is potential for further improvement to increase the product's environmental sustainability, which could lead to an improved overall health. While the current findings do not lead to absolute conclusions, this research provides a basis for comparing the environmental impact (in DALY) and benefits of digital health devices (in QALY).

The study discusses the challenges posed by substances of concern (SoCs) in products, emphasizing the need to address them within the framework of a circular economy (CE). It introduces the Safe and Circular Design (SCD) method as a potential solution but notes its lack of practical testing. The study focuses on implementing the SCD method in addressing indium tin oxide (ITO) within a liquid crystal display (LCD) monitor, highlighting difficulties due to limited data on SoCs and strategies for their management. An ex-ante life cycle assessment (LCA) compares ITO and an alternative, revealing environmental impacts and challenges in evaluating toxic trade-offs. The application of the SCD method to the LCD case identifies insights and challenges, emphasizing the importance of data availability and multidisciplinary collaboration for safer and sustainable product development. The study recommends refining the SCD method and conducting further case studies to assess its effectiveness across different scenarios. It underscores the need for enhanced data transparency and collaboration among stakeholders to advance safe and sustainable product design.

The UNEP-SETAC framework is the most well-known framework for including land use and land-use change (LULUC) impacts in life cycle assessment (LCA) in scientific literature. Yet issues regarding the framework’s validity have been recognized by several researchers and the framework has not been implemented in common LCA practices. Due to the need in both policy and science for a consensus on a method to include greenhouse gas (GHG) impacts deriving from LULUC in LCA, research in an improved framework is warranted. Therefore, the objective of this master thesis was to evaluate the UNEP-SETAC framework and propose improvements, with the overall goal to advance the method development of LULUC frameworks that quantify LULUC GHG emissions of agricultural products in LCA studies. A significant issue that was found was the UNEP-SETAC framework’s applicability to an attributional LCA (ALCA). The framework provides the LCA practitioner with various methodological choices that should be taken based on either an ALCA (i.e., an LCA that provides information on what portion of global burdens are associated with a specific product life cycle) or consequential LCA (CLCA; i.e., an LCA that provides information on the environmental burdens that occur, directly or indirectly, as a consequence of a decision). The analysis showed that the UNEP-SETAC framework is not suitable in its current form for an ALCA study. To advance method development, several weaknesses of the UNEP-SETAC framework were addressed in an improved conceptual framework. Using this improved framework for ALCA studies leads to additive results of all measurable anthropogenic emissions, relative to a pre-anthropogenic baseline. For CLCA, the forgone sequestration can be quantified to indicate the impact of using the land for the functional unit, relative to abandoning the land and letting it regenerate. A comparative LCA case study comparing the LULUC GHG emissions of sunflower oil cultivated in France and palm oil cultivated in Indonesia showed different results using the UNEP-SETAC framework and the improved conceptual framework. When using the UNEP-SETAC framework, it could be concluded that that the use of land for 1 kg of sunflower oil caused more GHG emissions, while when using the improved conceptual framework, it could be concluded the use of land for 1 kg of palm oil caused more GHG emissions. The results of the case study illustrated that the choice of LULUC framework can invert the conclusions of LULUC GHG emissions between two alternatives. This showed that it is highly important that the academic community reaches consensus on using one type of framework. It is essential that governmental and international bodies are aware of the weaknesses in the UNEP-SETAC framework that were identified in this thesis, as they potentially lead to inverted conclusions and a misinterpretation of results. For mitigation strategies of LULUC GHG emissions to be successful, it is important that the scientific community develops a more sound framework for including LULUC GHG emissions in LCA.

In order to live more sustainably on this planet, the world’s population needs to transform the current take-make dispose society towards a society with more maintainable consumption patterns and more sustainable business models. A way to achieve this, is a circular economy in which value is maintained within the product cycle, by sharing, repairing, reusing, refurbishing and recycling. Product-service systems, such as leasing, sharing and pay-per-use models, are presented as a way to contribute to the circular economy. Product-service systems (PSS) could potentially reduce environmental impacts, however, PSS do not automatically lead to positive environmental impacts and not all PSS are by default environmentally benign. Therefore, several authors call for quantifications of PSS’ environmental impacts, because the benefits of PSS remain inexplicit in literature and are mostly qualitatively described. Life Cycle Assessment (LCA) is a common method to evaluate the environmental impacts over a product’s lifecycle. LCAs compare the function that products or services fulfil over their entire life cycle and over various impact categories. As such, they provide an appropriate method to assess PSS’ environmental impacts.