Local governments face growing risks from climate change, which require substantial investments in climate adaptation to safeguard future generations. Nature-based solutions (NBS) have been recognized as a cost-efficient strategy to redevelop public space, to create greener and more climate adaptive urban environments. However, development of NBS is hindered by a lack of financial resources to fully scale up the transformation. To overcome this barrier, literature calls for clear sustainable finance frameworks and business model approaches to include private financing in the development of public NBS. In our research we consider the perceptions of municipalities and banks, as institutional lenders, towards using green debt-financing to finance NBS. We draw on sustainability transitions literature to theorize NBS as a niche innovation within established banking-municipal relations. Using qualitative interviews with Belgian banking experts and urban and financial planners from Flemish cities, we reveal competing financial logics between municipal financing practices and banking requirements, limiting the uptake of green debt for NBS. While NBS are mostly absorbed in traditional municipal deficit financing, this conceals their value and prevents market development. Alternatively, project finance remains difficult due to capacity constraints and differing valuation logics. Emerging sustainable finance frameworks create opportunities but shift administrative burdens onto municipalities. Overall, current practices mainly support NBS to fit and conform, rather than transform established debt-practices. Substantial upscaling of NBS will require changes in both banking practices and municipal financing approaches, including explicit integration of physical climate risk and collective financing mechanisms.

Cities worldwide are increasingly seeking to offset the environmental harm of motorway infrastructures in dense urban cores. One prominent approach, tunneling over existing motorways, or “capping”, mitigates harm and creates new green spaces but comes with high price tags that often exceed available public funding. Public value capture (PVC) tools are frequently promoted to bridge these financing gaps. However, while PVC has proven effective for large metropolitan transport projects, its potential for projects in smaller urban settings is far less understood. This study examines that question by estimating the revenue potential of five common local PVC mechanisms for a planned capping project in Antwerp, Belgium. Monte Carlo simulations indicate that, collectively, these tools could cover only about 8% of total investment costs. The modest return underscores the limited scalability of conventional PVC in smaller urban contexts. The paper calls for adaptive, context-specific value capture strategies that better monetize the broad public benefits of capping projects, while cautioning against treating them purely as funding sources.

Although the problem of food loss and waste is well known, and there is a desire on societal, political, and academic levels to address it, tangible actions are still lacking. Since all actors in the food supply chain must lower their food loss and waste, it is important to have insight into the actions they perceive as the most effective. In this research, a Q-study is conducted in which Flemish stakeholders across the food supply chain answered the question "What actions to reduce food loss and food waste, will have the greatest potential?". The participants ranked 63 statements about possible actions to lower food loss and waste, collected via literature review and interviews. These statements were cross-classified in seven stages of the food supply chain, by three types of measures (i.e. technical, institutional and societal). The findings show three different viewpoints: the (1) Neo-classical, (2) Consumer-oriented and (3) Transformational perspectives. Perspective one prefers technical measures, whereas the other perspectives see more potential in societal action, combined with institutional ones. The perspectives also differ in terms of the stakeholders that should act, the first perspective puts the greatest burden on the consumers, the distribution and logistics. According to the second perspective, most effort must be demanded from the households. The last perspective believes that all actors in the food supply chain should take responsibility. The identified perspectives provide relevant starting points for further research on food loss and waste reduction, in terms of testing if these perspectives still hold in other samples or when considering related topics.

The challenges of climate change on ecosystems and the ongoing energy transition call for further exploration and understanding of climate-aware solutions. Despite its hidden nature, the subsurface is increasingly recognised as vital natural capital, offering geosystem services such as geothermal energy, groundwater and storage options for carbon dioxide (CO2), nuclear waste, natural gas and hydrogen. Although generally regarded, but not yet universally acknowledged, as a common-pool resource (CPR), the subsurface holds substantial potential to provide environmental and economic benefits deriving from its multitude of activities and uses.We conducted a PRISMA-guided systematic literature review of game-theoretical applications for geological resource governance through a geosystem services lens. We selected 40 peer-reviewed articles for their methodological choices (game model, objective function, treatment of uncertainty), governance insights (identifying key players, regulatory settings, institutional mechanisms) and environmental focus.From a subsurface activity perspective, technology-diffusion (particularly CO2 storage and geothermal energy) and groundwater studies dominate the corpus. On the game-theoretical management side, net present value maximisation and economic objectives prevail, even when models included regulatory players intended to steer strategic behaviour. Consequently, environmental goals are typically relegated to secondary/compensatory offsets, with limited considerations of broader ecosystem and geosystem implications. This reflects the subsurface’s atypical CPR nature, where capital-intensive, quasi-private governing regimes, shaped by evolving use, challenge the traditional assumptions of Ostrom’s commons. Governance guidance can be sensitive to the choice of game model and its embedded assumptions (e.g., Stackelberg versus Cournot) selected for a given scenario.Careful model selection, hybrid methodological approaches, and an institutional regime lens better capture externalities and trade-offs across geosystem service flows to strengthen subsurface governance. Integrating game theory with real option analysis and multi-criteria decision-making incorporate strategic flexibility under uncertainty and bring non-market socio-environmental values into appraisal, linking subsurface decisions with wider geosystem and ecosystem impacts.

The transport sector accounts for around 20% of global carbon dioxide emissions, with passenger ground transport responsible for a substantial share. At the same time, mobility is essential for accessing goods, services, and social participation. This creates a central challenge for sustainable transitions: how can emissions related to passenger ground transport be reduced without undermining human well-being? The concept of a sustainable consumption corridor provides a framework that distinguishes a lower boundary representing the minimum level of goods and services required for well-being, and an upper ecological ceiling of consumption. While research on sustainable transport has largely focused on environmental limits, far less attention has been paid to defining a social floor of mobility. This paper presents a systematic literature review of studies that conceptualize and operationalize minimum levels of mobility provision in relation to human well-being. The review focuses on passenger ground transport. Three research questions guide the analysis: (1) How is the relationship between the mobility provisioning system and well-being conceptualized? (2) Which indicators define a minimum level for the mobility provisioning system? and (3) Which threshold values can be used to establish this minimum level for the mobility provisioning system? Objective approaches, often grounded in human needs theory or decent living standards, attempt to define a social floor using indicators related to mobility, accessibility, affordability, and transport-related externalities. However, these studies show limited consistency in indicator selection and threshold values, which are frequently generalized and weakly linked to cultural and contextual differences. Subjective well-being approaches, by contrast, focus on individual experiences and self-reported outcomes such as life satisfaction and travel satisfaction. While these studies do not define explicit sufficiency thresholds, they shed light on how mobility systems shape everyday experiences and on potential barriers for reducing travel demand. The review highlights the lack of consensus on what constitutes a sufficient level of passenger mobility for well-being. It argues for a dual strategy that combines expert-defined indicators with participatory and context-sensitive approaches, integrating objective thresholds with subjective experiences. Such an approach can support the development of socially just and environmentally sustainable mobility provisioning systems aligned with human needs.

The increasing exploitation of geological resources requires sustainable management frameworks that balance resource utilisation with the long-term conservation of the geophysical environment's functions. Despite growing recognition of geosystem services (derived from geophysical structures and processes), the current literature lacks a comprehensive discussion of their sustainable management that integrates established ecological economics principles. This study aims to (1) systematically assess existing geosystem services management literature and (2) develop a framework for their sustainable management based on geophysical constraints. Through a systematic review of 40 publications, we find that the literature has developed foundational work on the classification and mapping of geosystem services, with limited subsequent development of operational guidance for sustainable resource management. No existing framework links resource-use rates to geological regeneration capacities and defines sustainable scales in terms of geophysical constraints. To address these shortcomings, we introduce a process-based geosystem service cascade model that links geophysical structures and processes to their functional outputs and societal benefits. This cascade classifies services by function and reveals the regeneration timescales of the geophysical processes that produce them. Guided by the sustainable development principles of Daly (1990), we use this classification to develop a conceptual scheme that identifies which services are suitable for steady-state exploitation and which require pairing with renewable alternatives. The proposed scheme provides a conceptual basis for assessing the scale at which geological resource use can be sustained, grounded in the underlying geophysical structures and processes that determine geological limits and regenerative capacity.

The subsurface is increasingly being recognized as a multifunctional resource supporting key activities in the transition towards a sustainable society (e.g. geothermal energy, CO 2 storage and groundwater extraction). In existing literature, there remains a lack of integrative, cross-disciplinary research addressing the interactions and trade-offs between these activities. Addressing this gap is essential for sustainably managing the subsurface. This paper introduces the DIAMONDS Elevator, a conceptual framework designed to support such collaboration by organizing subsurface decision making across interconnected levels and facilitating knowledge exchange between disciplines. The framework is developed within the DIAMONDS research initiative and is applied to a case study on the multifunctional use of the subsurface in Flanders, focusing on interactions between aquifer thermal energy storage and groundwater extraction. Through this case study, we demonstrate how the DIAMONDS Elevator can be used to structure interdisciplinary analyses and decision-making processes, illustrated in detail from the perspective of an economics researcher. In addition, we position integrative methods and tools, including principles, criteria and indicators, within the Elevator framework. This paper shows how structured interdisciplinary approaches can enhance transparency, support scenario development and inform more sustainable subsurface governance. The DIAMONDS Elevator, as a visual guideline, intends to support interdisciplinary collaboration for sustainable subsurface management.

Solar cookers can substantially reduce reliance on charcoal; yet, the comparative life cycle impacts of a solar cooker with thermal energy storage (TES) versus charcoal cooking have not been quantified. We conducted an attributional life cycle assessment (LCA) for Mbarara City, Uganda, using ecoinvent v3.10 and Environmental Footprint 3.0. The functional unit is cooking two meals per day over 10 years for a typical household (3–6 people). Three scenarios capture different charcoal consumption levels. The solar system comprises a parabolic dish with aluminium components, a vegetable oil TES, and end-of-life (EoL) treatment. Across scenarios, solar cooking markedly lowers impacts: for most categories, burdens are 8–9 × lower than charcoal. Weighted single-score results range from 141.5 to 302.9 points for charcoal and 64.4 to 82.3 points for the solar cooker (ratio 2.2–3.7). The most influential categories are climate change, human toxicity (non-cancer), photochemical ozone formation, and water scarcity—each lower for solar. The main exception is freshwater ecotoxicity, which is higher for the solar option due to aluminium production, EoL processing, and disposal of vegetable oil residues from TES; repurposing these residues could mitigate this burden. In contribution analysis, freshwater ecotoxicity accounts for > 67

Food loss and food waste put pressure on society, the environment and the economy. A variety of experimental interventions to reduce food loss and waste have been conducted, as well as several review studies. However, it remains unclear which intervention is the most effective and which characteristics contribute to the effectiveness. As there is an urgent need to reduce food loss and waste, it is important to know how this reduction can be achieved effectively. Following the PRISMA guidelines, we conduct a systematic review and meta-analysis to assess which type of interventions are most effective in reducing food loss and waste, focusing on pretestposttest-control experiments and considering the whole food supply chain. Twenty articles meet all inclusion criteria, of which nineteen focus on consumers and nineteen concentrate on high-income countries. Overall, a significant but small effect of the food waste reduction interventions is found (dPPC = -0.258). However, not all intervention types resulted in a significant effect. Several of the tested design characteristics significantly influence the effect size (such as using a theoretical framework, the country in which the study is conducted, the type of intervention and the duration of the study). Only a few studies performed long-term follow-ups, and the interventions' effects were not found to be sustainable. Based on these findings, recommendations for future research are formulated related to three major topics: what should be examined in further research, how different food loss and waste behavioral experiments can become more consistent, and what should be reported.

Geosystem services as a concept allow for understanding the benefits that are gained from abiotic processes and structures that contribute to human welfare. These services are obtained from the diversity of the geosystem (of which the subsurface is a part) are often overlooked and undervalued. Intense anthropogenic utilization of these finite services, emphasizes the need for pre-emptive management of the subsurface. While the concept of geosystem services allows for capturing the plurality of the subsurface (in terms of different functions and services), it is often under-emphasized in subsurface management. The objective of this paper is to systematically review the existing approaches for the management of geosystem services in literature and contextualize the principle of sustainable scale in terms of a conceptual scheme for the subsurface. The systematic review's findings reveal a lack of comprehensive discussions on the management of geosystem services. Instead, the current discourse revolves around identifying various components that require management and emphasizing the necessity for active management. Although the articles propose recommendations for the management of geosystem services, they lack a set of operationalized principles that can be used by policymakers. To establish a conceptual scheme for the sustainable management of the services obtained from the services, the principle of sustainable scale as found in the literature of Ecological Economics was contextualized. The proposed conceptual scheme resulted in the following key aspects: (a) connects the subsurface characteristics (e.g. replenishment rates, different functions) and the nature of benefits (economic, environmental, and social) (b) provides the conceptual basis for defining the scale of subsurface utilization based on the type of service and its regeneration rate.

Geothermal energy is a renewable energy source that can contribute to a decarbonized European energy mix. Geothermal Organic Rankine Cycle (ORC) units can produce power from medium enthalpy hydrothermal resources that are commonly available in Europe. However, their techno-economic and environmental performance is greatly dependent on the site-specific geological conditions. This study proposes a two-step framework to optimize the design and investigate the Levelized Cost Of Electricity (LCOE), Global Warming Impact (GWI), and fifteen other environmental indicators of geothermal ORC units for various geological conditions. First, the LCOE and GWI of the system are calculated via integrated geo-technical, ORC process, techno-economic and life cycle analysis calculations. Second, artificial neural networks (ANN) are used to model for the system and genetic algorithms are used to optimize its design for multiple techno-economic and environmental objectives. It is shown that the techno-economic and environmental performance of the geothermal ORC are driven by the same factors. A higher geofluid temperature results into higher power production and lower LCOE and environmental impacts. Similarly, the LCOE and environmental impacts reduce for increasing reservoir permeability and thickness because the pumping capacity to extract the geofluid reduces. This study shows that geothermal ORCs can be a promising alternative for power production in Europe, though their techno-economic and environmental performance are strongly dependent on the local geological conditions. These conditions can also influence the optimal ORC design. This study also demonstrates the benefits of using ANNs for the optimization of geothermal ORC units.

Deep geothermal energy (DGE) is a renewable energy source that is considered to cause a low global warming impact. The potential of DGE for heating is widespread and interest in deep geothermal heating (DGH) has been growing in Europe to help achieving the decarbonization of the heating mix. Nevertheless, despite its large potential, DGH development in Europe remains underexplored. DGH investments are hindered by the risks born by geological and market uncertainties. However, various flexibility options inherent to the development process, such as the option to abandon or defer, could partly mitigate these risks. To account for managerial flexibility in the investment analysis, this study suggests a novel real options (RO) framework. The RO model splits DGH development into five phases, and considers several compound options and geological and market uncertainties to investigate the timing and value of DGH development at the Campine Basin in Northern Belgium. The RO model is coupled to a geo-techno-economic model and is solved using the Least Squares Monte Carlo algorithm. The RO analysis finds a 51% probability of abandonment and an average deferral time for the development of 12 years. The abandon option mitigates the risk of large financial losses in case of inadequate geological conditions. The defer option allows the investors to wait for more favorable market conditions before investing, to increase the project value. The results show that DGH development in the investigated area is not economically desirable. However, the investors' flexibility increases the project value by 12.16 million EUR, compared to a conventional techno-economic analysis. The implementation of supporting policy measures improves the economic performance of the plant. The consideration of flexibility leads to supporting policy measures with 3-4 times lower governmental expenditure, compared to a conventional techno-economic analysis. This study shows that a RO approach is more suitable to investigate DGH investments than static technoeconomic methods. The inclusion of flexibility allows for identifying development pathways that increase the project value and for designing more cost-efficient supporting policy schemes.

Geodiversity and geosystem services are confronting global threats. However, the majority of conservation strategies tend to overlook the geological component within ecosystems. The existing literature centres on biodiversity, ecosystem services and their economic valuation. In this paper, we conduct a systematic literature review to identify the gap in the assessment of geological diversity, pinpointing areas where scientific contributions are needed to safeguard geological resources. Our findings reveal a concentration of studies assessing geodiversity in European and Asian countries. While the majority of the reviewed papers emphasizes the recreational features and associated values of geological resources, promoting geotourism and recognizing its potential for economic growth, there is a significant oversight concerning the impact of tourism on geological resources. Existing assessments predominantly focus on visitors' perceptions and preferences, sidelining the inhabitants' perspective and their crucial roles in the conservation of geodiversity.This article is part of the Theo Murphy meeting issue 'Geodiversity for science and society'.

Effectively managing Marine Protected Areas (MPAs) requires recognising and understanding the fundamental services offered by marine ecosystems and the socio-economic consequences that their changes will have. A systematic literature review was performed to generate a first in-detail screening and assessment of monetary and non-monetary methods for the valuation of ecosystem services (ES) and their application in MPAs and MPA networks. A total of 100 peer-reviewed papers on ES valuation within MPAs and MPA networks were identified and analysed. Valuation methods can be classified into nine monetary and seven non-monetary methodologies. There is a predominant use of monetary valuation methodologies, especially stated preference methods. However, combining monetary with non-monetary valuation approaches can provide deeper insights into the underlying reasons for assigning values to ES and offer enhanced opportunities to capture the value of services that may be challenging to express solely in monetary terms. Besides, the review underscores the gaps in assessment methodologies, particularly in addressing supporting and regulating ES, as well as non-use and option values related to MPAs, underscoring the need for innovative approaches to overcome challenges in capturing these essential components of marine ecosystems.

The emerging reductive catalytic fractionation biorefinery which is currently under development aims to convert woody biomass efficiently into high-value products. Despite its potential, the environmental consequences of its implementation are not well known. Therefore, a forward-looking consequential life cycle assessment examines greenhouse gas emissions associated with its products (pulp, phenolic monomers, and oligomers) compared to alternative market options. Findings indicate that current greenhouse gas emissions exceed those of the existing alternatives, with by-products and the gaseous waste stream as major contributors. Process adaption to (i) produce higher-valued products (bleached pulps, phenols, and propylene) and (ii) incinerate gaseous waste stream for energy are proposed, potentially reducing emissions by up to 50 %, outperforming alternative options. Compared to land-based transportation, waterways can increase feedstock availability by up to 1000 km without an increase in emissions. In conclusion, the consequential approach provides valuable insights for enhancing and optimizing the environmental performance of the process.

Plastic packaging recycling has gained momentum as it can improve the circularity of this typical linear product. However, reuse ranks as a preferred strategy over recycling because product reuse can reduce material usage compared to product recycling and keeps material value higher for a longer time. Such reusable plastic packaging requires, besides a more robust product design, an additional return system. It is crucial to minimize the impact of this product system and ensure that reusable plastic packaging is not only more circular, but also more environmentally friendly than its single-use alternative. For this purpose, understanding the factors contributing to its environmental impact is key. In this paper, a new design of reusable packaging for two kilogram rice is compared with a conventional fully-optimized single-use packaging using a prospective extended life cycle assessment, including a circularity (using material flow analysis and specific circularity indicators, among which the Material Circularity Index), environmental impact (using a life cycle assessment with 16 midpoint indicators) and packaging-related food losses and waste assessment (using the food-to-packaging ratios). On average, the reusable rice packaging could be reused five times, due to losses at the distribution, use, and reuse preparation phase. While the reusable packaging scores better on the circularity indicators (a Material Circularity Index of 91 %, compared with 39 % for single-use packaging), its global warming and fossil resource depletion impact are respectively two and three times higher, considering a functional unit of one kilogram cooked rice to be consumed. The reusability and return rate, providing the retention of reusable packaging at the reuse preparation and use phase, respectively, were identified as the most determinative parameters by the sensitivity analysis. If these parameters could be optimized to a value of 99.75 %, corresponding to a total of 16 uses, the climate change impact of reusable packaging would be lower than its conventional single-use counterpart. The high foodto-packaging ratios (more than 18 for all impact categories) point to the importance of reducing food waste. If the packaging design could reduce food losses in the product system with 0.2 %, the reusable packaged rice would have a lower water use and mineral and metal resource use impact compared to the single-use packaged rice, despite the higher environmental impact of the reusable packaging unit itself. Therefore, this should be prioritized when further optimizing the reusable packaging design.

A future bio-based economy envisions the transformation of the petrochemical industry into using biomass such as wood (waste) as a major resource. The early-stage evaluation of a biorefinery project requires the optimization of the lay-out of the supply chain considering the spatio-temporal variability of the availability of feedstock and the techno-economical characteristics of the biorefinery process. Therefore, the presented methodology was developed combining three models: (1) a forest management and planning tool providing a detailed prediction on the wood resource availability as well as the harvested feedstock quantity and cost with respect to location and time, (2) a techno-economic assessment model of the biorefinery process (e.g., species-specific conditions, capacity, CAPEX, OPEX), and (3) a strategic supply chain optimization model combining the insights of (1) and (2) into a spatio-temporal explicit supply chain analysis. The developed methodology has been evaluated through a case-study on the emerging reductive catalytic fractionation (RCF) biorefining in the Flanders region (EU) and shows that the most economically interesting configuration is one large biorefinery with a yearly wood chip intake of 150 kton. The biorefinery location reflects the available feedstock distribution in Flanders and is suggested to be situated best in the most forested region. The proposed methodology proved to be dynamic and robust: (1) input data and technical calculations can easily be adapted or updated; (2) the methodology can be applied to a broad range of applications beyond the scope of the biorefinery, to different feedstock choices; (3) the impact of the biorefinery location on e.g. energy balance, CO2 emissions, and financial balance can be assessed.

The decarbonization of the heating sector is crucial for the green transition of the energy mix. This study investigates threefold the economic and environmental performance of deep geothermal heating investments in Northern Belgium First, techno-economic and life cycle assessment (LCA) are performed, followed by a global sensitivity analysis focusing on the geological uncertainty. Lastly, real options analysis (ROA) is employed to investigate the economic and environmental value of the investors’ flexibility. A novel ROA method is proposed that considers the LCA results to calculate development decisions that minimize the expected environmental impact of the investment. The results show that the economic and environmental performance of the investment vary with the energy prices and the electricity mix. The performance of the investment is driven by the plant’s pumping requirements, which are induced by the relatively low rock permeability at the targeted location. Also, the results’ variability mainly originates by uncertainty regarding the permeability value. Nevertheless, the investors’ flexibility adds large economic and environmental value to the investment. However, the development strategies that optimize the economic or the environmental performance of the plant present some trade-offs. This study demonstrates that the economic and environmental performance of deep geothermal heating investments in Northern Belgium can be improved by focusing on the factors that simultaneously drive the costs, environmental impacts, and their variability. It also shows that utilizing the investors’ flexibility to optimize the investment’s economic and environmental performance can add significant value to the investment.

Complexity in megaprojects leads to uncertainty about the future, which means forecasting is difficult, and perceptions of uncertainty can differ among stakeholders based on differing interests and values. We contribute to uncertainty and stakeholder management research and practice in megaprojects by conceptualising perception of uncertainty and by adopting Q methodology as a mixed method for stakeholder analysis to empirically study stakeholders' perceptions of uncertainty in the Flemish A102 road project. Four perception groups are revealed that show why understanding perceptions of uncertainties in megaprojects matters: (i) uncertainty management must be broadened by considering relations between uncertainties; (ii) assessing whether uncertainties are irreducible or reducible and how they should be managed can be perceived differently; (iii) stakeholder analysis must aim to understand stakeholder heterogeneity and avoid classifying stakeholders based on a priori assumptions; (iv) revealing perceptions of uncertainty can help project managers anticipate conflict and prepare for stakeholder dialogue and engagement.