Table of contents

In recent years, there has been a growing emphasis to incorporate sustainability metrics into geotechnical engineering design decisions, driven by the surging eco-consciousness of industry standards. Consequently, life cycle assessment (LCA) has emerged as a popular method for evaluating the environmental impacts of geotechnical systems or projects. This paper conducts a critical review of 54 publications that apply LCA to various geotechnical systems, including deep foundations, biogeotechnics, dams, ground improvement, earth retaining structures, tunnels, and others. This review assesses the current state of practice for LCA in geotechnical engineering, identifies common barriers to implementation, and provides suggestions for successful execution. While sustainability practices have been more readily adopted by some subdisciplines of civil engineering including structural and transportation, geotechnical engineering faces distinct challenges due to its inherent site-specific nature, characterized by non-homogeneous soils and the necessity for bespoke solutions. Despite the notable increase in geotechnical LCAs, the absence of uniform standards remains a critical issue. Many studies could be improved by enhancing transparency in reporting data and results, clearly justifying input assumptions, and assessing the effects of variable soil conditions. Geotechnical LCA studies often concentrate on highly specialized problems, limiting the relevance of findings to other projects and impeding the development of clear recommendations for industry practitioners. Future research endeavors would benefit from establishment of comprehensive frameworks and multi-indicator models tailored to geotechnical systems to more accurately capture expected environmental impacts and opportunities for their reduction. A standardized approach could reduce redundancy in studies, encourage knowledge transfer, and provide a basis for broader applicability of sustainability practices in the geotechnical engineering profession.

Electrification of road transport is crucial to limit global warming. Battery electric vehicles with stationary charging infrastructure have received considerable attention in the scientific literature for both cars and trucks, while dynamic charging via electric road systems (ERS) has received much less attention and their future role in low-carbon road transport is uncertain. Here, we envision three potential scenarios for the future of ERS in European low-carbon transport. We sketch a potential European ERS network and discuss the political, technological, and market steps needed to realize these. We argue that existing field trials, tests, and research projects have collected sufficient evidence to make the next step: Decide and act. Decision-makers will never have perfect information about all aspects of ERS or competing technologies, but the urgency of the climate crisis requires a commitment one way or the other. A clear decision with respect to ERS would send a clear directive and would help focus time, effort, and money on the necessary infrastructure and policies to implement ambitious GHG abatement targets in road transport.

Green ammonia has been proposed as a technologically viable solution to decarbonise global shipping, yet there are conflicting ambitions for where global production, transport and fuelling infrastructure will be located. Here, we develop a spatial modelling framework to quantify the cost-optimal fuel supply to decarbonise shipping in 2050 using green ammonia. We find that the demand for green ammonia by 2050 could be three to four times the current (grey) ammonia production, requiring major new investments in infrastructure. Our model predicts a regionalisation of supply, entailing a few large supply clusters that will serve regional demand centres, with limited long-distance shipping of green ammonia fuel. In this cost-efficient model, practically all green ammonia production is predicted to lie within 40° latitudes North/South. To facilitate this transformation, investments worth USD 2 trillion would be needed, half of which will be required in low- and middle-income countries.

Decarbonization is essential to meeting urgent climate goals. With the building sector in the United States accounting for 35% of total U.S. carbon emissions, reducing environmental impacts within the built environment is critical. Whole-building life cycle analysis (WBLCA) quantifies the impacts of a building throughout its life cycle. Despite being a powerful tool, WBLCA is not standard practice in the integrated design process. When WBLCA is used, it is typically either speculative and based on early design information or conducted only after design completion as an accounting measure, with virtually no opportunity to impact the actual design. This work proposes a workflow for fully incorporating WBLCA into the building design process in an iterative, recursive manner, where design decisions impact the WBLCA, which in turn informs future design decisions. We use the example of a negative-operational carbon modular building seeking negative upfront embodied carbon using bio-based materials for carbon sequestration as a case study for demonstrating the utility of the framework. Key contributions of this work include a framework of computational processes for conducting iterative WBLCA, using a combination of an existing building WBLCA tool (Tally) within the building information modeling superstructure (Revit) and a custom script (in R) for materials, life cycle stages, and workflows not available in the WBLCA tool. Additionally, we provide strategies for harmonizing the environmental impacts of novel materials or processes from various life cycle inventory sources with materials or processes in existing building WBLCA tool repositories. These strategies are useful for those involved in building design with an interest in reducing their environmental impact. For example, this framework would be useful for researchers who are conducting WBLCAs on projects that include new or unusual materials and for design teams who want to integrate WBLCA more fully into their design process in order to ensure the building materials are consciously chosen to advance climate goals, while still ensuring best performance by traditional measures.

Failures in urban water systems are becoming a common occurrence in the US due to disasters, aging infrastructure, and financial constraints, among other concerns. For example, Jackson, Mississippi has experienced reoccurring water outages, burdening community members as they must seek alternative water sources. Prior research has primarily focused on technical, institutional, and public health aspects of water crises, with limited attention to community perspectives. Understanding such social aspects can shed light on, for example, community priorities, levels of trust, mental health concerns, and communication gaps. Here, we document the temporal experiences and perceptions of community members during the Jackson Water Crises. To do so, we qualitatively analyzed news media data and employed topic modeling techniques on social media data from two years, capturing two service disruption events. Our results reveal the cascading impacts of water outages on end-users, including financial, social, and technical issues. For example, over time, results indicate that trust in the government and water providers in Jackson eroded, which may hinder public support. Our results show that social media can be a useful tool for utilities to understand public perceptions in real-time. Recommendations proposed here can inform future responses to water crises in Jackson and other communities, ensuring end-users' perspectives are incorporated.

Global progress in energy transitions to support climate mitigation goals has been slower than anticipated; this has prompted shifts away from traditional paradigms of regulated energy ownership towards a model of energy democratization by local communities and individuals. For example, in the United States, local communities in over 250 cities, counties, and states have made pledges to reach 100% renewable electrification by target dates ranging from 2020 to 2050. However, the availability of infrastructure and the competition for renewable energy resources, as well as lack of awareness of these limitations, present significant barriers to overcome. In this study, we explored a subset of 31 of these cities to assess their current electricity generation and how much further they have to go to meet their goals. Through an energyshed framework, we estimated powerplant electricity allocation to each city assuming competition for power from various renewable and non-renewable resource types, as well as look at the 'best case scenario' assuming 100% allocation of renewable-sourced electricity for a handful of cities in order to understand the existing and planned energy mixes for 2021 and the following 20 years. It is likely most cities will meet 10% of their energy demand with renewable energy, with best cases scenarios reaching between 35% and 65% renewable penetration, within the next 20–30 years. This highlights the need for infrastructural development in the energy sector, as well as intentional planning efforts in order to make these energy goals a reality.

To reduce the environmental effects caused by building construction and operation, life cycle assessment (LCA) is increasingly applied. In recent years, national building regulations have implemented LCA requirements to support building life cycle impact reduction. A key element in these regulations are environmental benchmarks which allow designers to compare their building designs with reference values. This study aims to develop bottom-up life cycle environmental benchmarks that represent the range of environmental impact results achieved with conventional construction in Flanders, Belgium. For this purpose, the study investigates the potential of using a database of building energy performance calculations. Specifically, this study considers 39 residential buildings identified as representative of the Flemish energy performance of buildings database of 2015–2016, applying modifications to establish scenarios that are still relevant in 2025. The buildings are assessed with the Belgian LCA tool TOTEM to calculate an aggregated environmental score based on the European product environmental footprint (PEF) weighting approach and including 12 main impact categories. In addition to the aggregated score, the climate change (CC) indicator is analysed individually. In view of the benchmarks, variations were applied to the 39 original buildings in terms of heating system and materialisation. The variation in heating system included changing gas boilers to electric heat pumps to comply with upcoming (2025) Flemish building regulations. The variations in building materials included three sets of conventional Flemish building element compositions that were applied to generate a wider spread of impact results as a basis for benchmarks. Benchmark values were derived through a statistical analysis of the 117 modelled variants: a best-practice value (10th percentile), reference value (median) and limit value (90th percentile). For the environmental score, the benchmark values are 86, 107 and 141 millipoints per square meter of gross heated floor area (GHFA) (mPt m⁻²GHFA), respectively; and for CC, the benchmark values are 844, 1015 and 1284 kg CO₂-eq m⁻² GHFA. Finally, the study discusses the representativeness, implications and limitations of the final benchmarks and benchmark approach.

Resource recovery can provide opportunities to mitigate the negative impacts of conventional organic waste management such as landfilling to the environment, economy, and society in rural agricultural regions. However, region-specific assessment of such opportunities can be challenging due to lack of data, limited economic resources, and inadequate policy support to meet community needs. Therefore, we developed a framework utilizing open-source data and methods informed by community engagement to assist stakeholders in rural agricultural regions in considering strategies to recover resources from organic waste. The framework was applied in Hardy County (one of the largest agricultural regions in rural West Virginia) to compare the sustainability of current management practices (landfilling of sewage sludge and organic municipal solid waste such as food and yard waste, land application of sewage sludge and poultry litter, and transportation of poultry litter out of watershed) with different anaerobic digestion scenarios. The results indicated that co-digesting alum-treated poultry litter with organic municipal solid waste and sewage sludge would result in the most sustainable organic waste management under stakeholder-preferred weighting of environmental (global warming and eutrophication potential), economic (annual worth), and social (potential to benefit vulnerable households) factors. Interestingly, the current management practices received the second-highest score. The results were further utilized to develop recommendations for relevant policies related to nutrient management and decarbonization. Overall, the framework can be a useful tool for rural agricultural regions to promote sustainable organic waste management.

Climate-related disruptions to water supply infrastructure services incur direct financial losses to utilities (e.g. to repair damaged assets) and externalise a societal cost to domestic customers due to additional costs that they may incur (e.g. to acquire water from alternative sources). The latter often represents an uncompensated social burden, which should be properly accounted for in investment planning. Here we present a new framework for quantifying direct financial risks burdened by utilities and alternative water purchase losses incurred by domestic customers, including those in low-income groups, during flood- and drought-induced utility water supply disruptions. This framework enables the comparison of benefit-cost ratios of a portfolio of flood protection and leakage reduction for water supply systems across the island of Jamaica. A system-level optioneering analysis allows the identification of the optimal adaptation option per system. We estimate that 34% of systems would benefit from flood defences and 53% would benefit from leakage reduction to adaptation to droughts. The benefit that could be achieved by implementing all system optimised adaptation options is estimated to be 720 million Jamaican dollars per year on average, representing a substantial saving for the utility and its customers, including low-income customers. We identify options that offer strong synergies between economic and equity objectives for both types of adaptation option. The proposed framework is established to support the business case for climate adaptation in the water supply sector and to prioritise across flood and drought mitigation options. We take a first step towards mainstreaming equity considerations in water supply sector optioneering frameworks by estimating the contribution of adaptation options towards reducing household costs for low-income customers.

The high cost of purchasing electric vehicles (EVs) compared to internal combustion engine vehicles (ICEVs) is a major barrier to their widespread adoption. Additionally, the price disparity is not the same for all households. We conducted a total cost of ownership (TCO) analysis to compare the net present value of EV versus ICEV ownership for various household categories across Canada. We observed spatial and behavioral factors, including variations in costs of electricity, temperature, household archetypes and their purchase decisions, and access to charging infrastructure. We found that EVs are more cost-effective than ICEVs for certain daily driving distances, but typical households in Canada generally do not drive enough for lifecycle costs of EVs to be less than ICEVs. The province of Quebec has the most favorable conditions for EV ownership due to high purchase subsidies and low electricity prices. Variability in costs across other provinces and territories is mainly due to differences in rebates, electricity and gasoline prices, and tax rates. Our findings have implications for policymakers and consumers. For consumers comparing ICEVs to EVs based on a fixed budget, which may be consistent with how many households frame their purchase decision, willingness to accept smaller, non-luxury EVs can result in large cost savings. We also find that although temperature variation has a minimal effect on TCO, it does impact the 'number of charge-ups'—a metric that we introduce to compare how many charging cycles a user may expect over the lifetime of a vehicle. The policy implication of this would be a need to consider regional differences in cold weather patterns when planning charging infrastructure deployment and the extent to which households in shared dwellings may face additional costs. Lastly, our findings strengthen the argument that equitably decarbonizing transportation will also require investment in strategies other than electrifying personal vehicles.

This paper operationalises the capability approach to analyse the tensions and trade-offs in assessing well-being outcomes generated by the production of wind energy, and how these reflect social acceptance at the local level. Specifically, the paper addresses the difficulties in understanding the voice of Indigenous people living near wind energy infrastructure in Southern Mexico and how their conceptions of well-being can be used to estimate the impact of wind energy development on three different communities. The methodology involved a three-stage process that integrated semi-structured interviews, focus groups, a survey, and participatory workshops, involving 450 participants. The findings conclude that community acceptability of energy infrastructure such as wind farms will only be achieved through inclusive community engagement that considers valued ways of being and doing of the local population. These include increasing the opportunities for people to live in good health, skilled employment in the industry, engaging and integrating local culture, values, worldviews and needs, and having a collective approach to the distribution of economic benefits that may strengthen social networks. By focusing on the recognition of valuable human capabilities from a participatory mixed-methods perspective, this paper contributes to a more compelling body of theory on social wind energy impacts that focuses on locally defined priorities and perspectives. Furthermore, this study also shows how the inclusion of community members as co-researchers is crucial to validate and locate local knowledge at the forefront while allowing local stakeholders to exercise greater voice and agency in how the research is conducted and designed. We hope that this methodology can offer useful insights for the design and implementation of future renewable energy projects that have environmental and social sustainability in mind.

With both global and national targets to reduce greenhouse gas (GHG) emissions the improvement of existing buildings will be key to realising these ambitions. How this can be achieved, and the impact of whole-life emissions from retrofit remains a key question. This paper investigates the potential of retrofit to reduce and limit lifecycle GHG emissions resulting from an existing house, typical of one of the predominant housing typologies in Northern Ireland. Through the use of lifecycle assessment a range of retrofit scenarios are considered for an early 20th century, solid wall, terraced house, to understand the impacts of retrofit on lifecycle emissions. A range of retrofit scenarios were modelled and simulated, considering both embodied and operational emissions over the building's lifetime, to understand how net emissions can be reduced. The results show that although fabric and some technological measures can reduce emissions by over 60% when applied in isolation, a holistic approach is required to achieve the greatest reductions. Although operation remains the largest single source of emissions, the results also show the importance of taking a holistic approach to the assessment of retrofit with varying lifecycle stages responsible for considerable emissions. It is seen that emissions reductions of up to 99% may be possible when taking a holistic approach to retrofit and its assessment, considering whole-life emissions. This study highlights the potential benefits of retrofit and how it could be effectively applied to the existing housing stock in Northern Ireland creating low-emission or net-zero emission buildings.

Effective disaster risk reduction (DRR) for flooding requires a comprehensive estimate of the whole value at risk (WVAR) to inform appropriate and proportionate mitigation expenditure. Conventional flood risk estimation methods focus on the direct effects of inundation on community value and generally ignore collateral effects on assets and populations outside the flooded area. Consequently, conventional methods tend to underestimate the cost of flooding, leading to an underestimate of the return on DRR investment. Using spatial data analysis in an urban case study for Toronto, Canada, we identify and capture the collateral value at risk (ColVaR) to estimate the WVAR more comprehensively. In our case study, ColVaR (mean estimate) amounts to 70% of direct losses (ColVar = $344 M; direct losses = $475 M CAD), ranging from 20%–150% (ColVar $100–$740 M) when spanning the 90% confidence intervals of our Monte Carlo simulations. Thus, we demonstrate that if the collateral value at risk is ignored, WVAR can be significantly underestimated, potentially leading to reduced disaster risk reduction resource allocations and thereby adding risk exposure for communities. We present an accessible, seven-step process using existing spatial analysis tools and techniques that infrastructure stakeholders and planners can use to estimate ColVaR and better formulate DRR measures for their communities.

Engineered wood (EW) has the potential to reduce global carbon emissions from the building sector by substituting carbon-intensive concrete and steel for carbon-sequestering wood. However, studies accounting for material use and embodied carbon in buildings rarely analyse the city-scale or capture connections between the city and supplying hinterlands. This limits our knowledge of the effectiveness of decarbonising cities using EW and its potential adverse effects, such as deforestation. We address this gap by combining bottom-up material accounting of construction materials with life cycle assessment to analyse the carbon emissions and land occupation from future residential construction in Montreal, Canada. We compare material demand and environmental impacts of recent construction using concrete and steel to future construction using EW at the neighbourhood, urban scales under high- and low-density growth scenarios. We estimate that baseline embodied carbon per capita across the Agglomeration of Montreal is 3.2 tonnes per carbon dioxide equivalents (CO₂eq.), but this ranges from 8.2 tonnes CO₂eq. per capita in areas with large single-family housing to 2.0 tonnes CO₂eq. per capita where smaller homes predominate. A Montreal-wide transition to EW may increase carbon footprint by up to 25% under certain scenarios, but this varies widely across the city and is tempered through urban densification. Likewise, a transition to EW results in less than 0.1% land transformation across Quebec's timbershed. Moreover, sustainable logging practices that sequester carbon can actually produce a carbon-negative building stock in the future if carbon in the wood is not re-emitted when buildings are demolished or repurposed. To decarbonise future residential construction, Montreal should enact policies to simultaneously promote EW and denser settlement patterns in future construction and work with construction firms to ensure they source timber sustainably.

Aircraft condensation trails, also known as contrails, contribute a substantial portion of aviation's overall climate footprint. Contrail impacts can be reduced through smart flight planning that avoids contrail-forming regions of the atmosphere. While previous studies have explored the operational impacts of contrail avoidance in simulated environments, this paper aims to characterize the feasibility and cost of contrail avoidance precisely within a commercial flight planning system. This study leverages the commercial Flightkeys 5D algorithm, developed by Flightkeys GmbH, with a prototypical contrail forecast model based on the Contrail Cirrus Prediction (CoCiP) model to simulate contrail avoidance on 49 411 flights during the first two weeks of June 2023, and 35 429 flights during the first two weeks of January 2024. The utilization of a commercial flight planning system enables high-accuracy estimates of additional cost and fuel investments by operators to achieve estimated reductions in contrail-energy forcing and overall flight global warming potential. The results show that navigational contrail avoidance will require minimal additional cost (0.08%) and fuel (0.11%) investments to achieve notable reductions in contrail climate forcing (−73.0%). This simulation provides evidence that contrail mitigation entails very low operational risks, even regarding fuel. This study aims to serve as an incentive for operators and air traffic controllers to initiate contrail mitigation testing as soon as possible and begin reducing aviation's non-$\mathrm{CO_2}$ emissions.

Adoption of the design for disassembly (DfD) concept is suggested as a promising strategy to cope with the climate targets and increase circular economy in the construction sector. Yet, the concept is little used partially due to technical challenges, including inadequate information about demolition and the characteristics of components. This study aims to investigate the demands for information linked to new concrete components with the purpose of reuse. In the building phase, concrete components cause the majority of emissions. Thus, these components also have the greatest potential for CO₂ emissions savings. A comprehensive list of information related to DfD concrete components and their characteristics was gathered in a workshop with experts of DfD concrete elements. Furthermore, the stakeholders of DfD components data processing were considered. The results of this study may support the adoption of DfD with concrete components as it provides information for designers and builders to implement in early phases of building projects.