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The pressure on reducing greenhouse gas emissions has increased since the focus on climate change mitigation has grown. As the human development index is directly related to per capita energy consumption, sustainable energy production with reduced carbon footprint is the essential pathway for cleaner environment. Over numerous existing biological processes, hydrogen production via photo fermentation and photolysis of water is considered a more sustainable and economical method of hydrogen production. While both biological modes suffer from certain limitations, such as low yields and low production rates, practical implementation is still a long way off due to these limitations. The unique properties of nanomaterials (NMs) can help increase the efficiency of the biomass to biohydrogen process in significant ways. Applications of organic and inorganic nanoparticles in photocatalytic and photo fermentative hydrogen production is discussed in this paper. This review reports a wide range of applications of nanomaterials including the details of photo fermentative microorganisms and their mechanism of action. The maximum photo fermentative bio-H 2 production was reported in the presence of SiC–Fe 3 O 4 (3.02 mol H 2 /mol acetate), Ni (41 mol H 2 /mol sugar), graphite-C 3 N 4 (64.2 mol H 2 /mol sugar) whereas photocatalytic bio-H 2 yield was highest when Pd–Ni/CdS (54 mmol/g.h), Ni-MO/g-C 3 N 4 (1785 mmol/g.h) and CuO/TiO 2 (20.3 mmol/g.h) nanoparticles were employed. To design photocatalytic systems for practical and scalable use, the future research should be focused on deeper theoretical knowledge of mechanisms of light harvesting, ± charge separation and transport, surface biochemical reactions, semiconductor–liquid interactions, and reactor dynamics. [Display omitted] • Recent developments for improving water photolysis and photo-fermentation are reviewed. • Applications of organic and inorganic nanoparticles in hydrogen production are discussed. • The working principle and mechanism of hydrogen production are discussed. • The influence of key operating factors are presented. • Scope for future research was presented. [ABSTRACT FROM AUTHOR]

The mitigation of climate change requires that agricultural development would proceed in accordance with green and sustainable practices. This implies that economic performance should be improved while minimizing the impact on the environment. One way to assess the underlying costs of sustainable agricultural development, and to model the relationship between the environment and the economy in general, is to use the carbon shadow price (CSP). In this paper, we utilize a by-production model within a non-parametric framework to estimate the agricultural CSP from 1997 to 2020 in 31 provinces of China. The patterns of the agricultural CSP are unveiled through kernel density analysis and convergence tests. Additionally, this paper constructs a comprehensive agricultural informatization indicator using the entropy method. We then empirically investigate its influence on agricultural CSP. The results reveal that China's agricultural CSP has demonstrated consistent growth over the past two decades which suggests serious improvement in environmental performance. Furthermore, the CSP show cross-province variation, albeit with conditional β convergence. Our empirical findings indicate that agricultural information technology contributes to an increase in CSP, thereby indicating its positive role on the green growth of agriculture in China. [ABSTRACT FROM AUTHOR]

Trees absorb CO 2 and reduce the impact of GHGs. This paper deals about the carbon uptake dynamics produced by the management of unused lands as tool to help the fulfilment of international commitments on atmospheric CO 2. The paper introduces a new perspective of using the unused lands around Municipalities to compensate the carbon emissions of urban contexts, according to the Sustainable Energy Action Plans as answer to climate change, already approved by the most part of Cities in Europe. The model of the carbon dynamics is based on a genetic algorithm which allows to find the sequence of operations on the unused land in space (portions of the land) and time (rotation of cuts and plantations) to ensure the reaching of a given outcome in terms of carbon captured. The algorithm, therefore, behaves as design support of land management, enriching the literature available for the sector. The paper identifies two possible original scenarios of storing carbon referred as " emergency " and " constant rate "; the first produces after fifty years a maximum carbon uptake of the order of 100 tC/ha while the second a maximum uptake rate of the order of 2 tC/(year ha), after an initial start-up period of 40–50 years. • Mathematical model to evaluate tree growth and carbon sink from reforestation. • Optimization model to manage the carbon uptake in different scenarios. • Forest represents an effective way to remove carbon from atmosphere. • Carbon stock per unit of unused areas around cities and urban area. • Climate mitigation tool suitable by municipality in the context of SECAPs. [ABSTRACT FROM AUTHOR]

As a response to the increasing threat to sport events from climate change and expectations around climate change mitigation, sport event managers increasingly engage in environmentally-related initiatives that aim to reduce GHG emissions. One of the major contributors to GHG emissions at large sport events is spectators' travel and, thus, their associated modal choices. Building on the Sport Logistics Framework (SLF) and using the case study of Rapid Vienna, the largest football club in Austria, this study investigates spectators' modal choice to systematically assess the total GHGs emitted by spectators at a professional football home game. Data was obtained from two sources: a) an extensive data set collected on Rapid Vienna season ticket holders, and b) three surveys at home games which, together, constituted 3317 valid responses. The calculation of the GHG emissions resulted in 99,548 kg GHG emissions per home game or 6.0 kg GHG emissions per spectator. It was also found that 42.4 per cent spectators arriving by car emit 71.6 per cent of GHG emissions, while in contrast, 52.8 per cent of spectators using public transport emit 27.1 per cent of GHG emissions. The results also indicate that the possession of an annual public transport ticket seems to determine travel behavior, i.e. the majority of spectators with an annual ticket are using it, while spectators without a ticket are using a car. As such, this paper not only provides an opportunity for academics and managers to benchmark the data in order to identify initiatives to reduce the impact of GHG emissions, but also allows for the systematic measuring of the environmental impact of fan and spectator travel. • Fan travel to professional football games is a major contributor to GHG emissions. • We assess fans' modal choices and their carbon footprint at a football home game. • The home game emits a total 99,548 kg GHG emissions or 6.0 kg GHG emissions per fan. • We found that 42.4% fans arriving by car emit 71.6% of GHG emissions. • The study allows for benchmarking and systematic measuring of fan travel behavior. [ABSTRACT FROM AUTHOR]

Woody biomass energy makes up a large share of renewable energy consumption in the EU, and the largest share in countries like Denmark. However, little is known about how the public perceive it. This paper presents the results of a questionnaire-based survey of the public in Denmark focusing on attitudes toward woody biomass for energy. The main findings are that, while more people favor than oppose it, a large proportion are undecided about the use of woody biomass. The survey also revealed a lack of knowledge about this energy source. A Best-Worst Scaling methodology revealed that Danes prioritize environmental sustainability concerns – namely biodiversity loss, the hindering of the development of other renewable energy sources and the climate change mitigation potential of woody biomass – over societal and/or economic ones when it comes to the promotion of woody biomass. Finally, it was found that concern about climate change, belief in the mitigation potential of woody biomass, and being younger explained the formation of positive attitudes toward woody biomass. Policy makers aiming to take public concerns into account in discussions about Denmark's energy future should focus more on minimizing the negative environmental impacts associated with woody biomass rather than on its economic benefits. [Display omitted] [ABSTRACT FROM AUTHOR]

Generation of goods and services are highly dependent on the use of natural resources. Until very recently, there was an implicit belief that the physical expansion of the economic system could be unlimited, as if the planet would have conditions and time enough to recover and continue to supply resources. This belief implies a confidence in an economic system that would provide whatever is necessary for a continuous growing production and consumption. Even believing that technology alone is not enough to solve the current environmental problems, it is certain that it can collaborate to mitigate climate change and to adaptation to changes in the environment. By bringing environmental aspects into discussions, eco-innovations can affect and transform the innovation system in order to create sustainable processes. However, the main challenge towards the transition to a more sustainable, cleaner and more equitable society is to set innovation in a new context, as until very recently it only considered the economic variables. This change means to value the social and environmental dimension of the innovation. In addition to eco-innovation, Life Cycle Assessment (LCA) is spreading in the industrial environment, offering promising perspectives. LCA is considered a valuable methodology in the environmental sustainability of industry. In this context, the present study addresses LCA and its relationship with the generation of eco-innovations. Drawing on contributions from literature on eco-innovation and LCA, the paper analyses available evidence on this relationship in a context of the transition towards sustainable development. To structure the debate, the paper offers a conceptual approach and an illustrative case on international researchers' and practitioners’ perceptions on the potentially positive relationship between eco-innovation and LCA. The study gathers data in the Web of Science (WoS) Core Collection and in Scopus, in order to provide a picture of the distribution of documents retrieved from these databases, dealing with both eco-innovation and LCA topics. The paper concludes that the convergence of the eco-innovation and LCA studies is quite plausible, but at least in its initial phase, the literature that unites both themes is scarcely found in publications in the area of innovation, being more frequent in the area of engineering and management that usually addresses LCA studies. [ABSTRACT FROM AUTHOR]

The paper draws from the general literature on energy efficiency and historic buildings to explain the importance and potential of user-driven energy efficiency in historic buildings. It is the first review that places the user as a central object of study in the research field of historic buildings and energy efficiency. Relevant interdisciplinary topics and research results that make up the core of the field are presented and discussed in relation to user behaviour and its impact on energy consumption. The paper also investigates how user behaviour aspects can be integrated in a procedural approach to energy refurbishment in historic buildings. Research and experience from the building stock in general clearly shows how a user's awareness and behaviour, such as choice of temperature, zone heating and controlled airing, can have a significant effect on energy demand yet have no physical impact on the building. However, this has not received enough attention with regards to the historic building stock, where many physical energy efficiency measures can have negative impacts on the historic qualities of the building. Modification of user behaviour can therefore be a way not only to reduce energy demand but also to minimise the physical impact of increasing energy efficiency on historic buildings. The paper concludes that the current research agenda on historic buildings and energy efficiency has broken much ground but remains focused more on technical solutions than bottom-up user perspectives. Two main topics are identified as key barriers and future research fields: First, energy performance modelling is identified as a general barrier to developing sustainable strategies that promote user impact in historic buildings. Accurate energy modelling of historic buildings is a complex field reliant on the thermal interplay between user-building and building-district. Improved knowledge and intensified research is necessary to avoid distorted energy modelling results and unwanted rebound effects. Practical tools also require that the modelling can be used for trade-off scenarios where other sustainability aspects such as cultural heritage and economy are weighed in. Second, awareness raising in order to foster a deeper understanding and knowledge about the construction, system and cultural heritage values of a building is proposed as a key ingredient and driver for improved and sustainable energy behaviour. The paper argues that while user-driven energy efficiency represents an important resource for fostering less energy-demanding and less intrusive interventions in historic buildings, there are no guarantees for achieving the planned level of energy efficiency without taking into account user behaviour and the actual operation and energy performance of the historic building. To do this without risking negative consequences, improved decision-making processes are needed on policy, building and user level. An interdisciplinary bottom-up approach to energy refurbishment is presented. The essence of the model is that users and residents should always play a central role in the decision-making process because the well-being of the historic building will always depend on its day-to-day users, and vice versa. [ABSTRACT FROM AUTHOR]

Many ports and terminals endeavor to enhance energy efficiency as energy prices have increased through years and climate change mitigation is a key target for the port industry. Stricter environmental regulations are adopted by authorities to limit pollutants and GHG emissions arising from energy consumption. Increasingly, port operational strategies and energy usage patterns are under scrutiny. To ingrain sustainability and environmental protection of ports, the use of innovative technology appears as a critical conduit in achieving a transition from a carbon-intensive port industry (dependent on fossil fuels) to a low-carbon port model by harnessing renewable energy, alternative fuels (e.g. LNG, hydrogen, biofuel), smarter power distribution systems, energy consumption measurement systems. In this context, this paper conducts a systematic literature review to analyze operational strategies (e.g. peak shaving, operations optimization), technology usage (e.g. electrification of equipment, cold-ironing, energy storage systems), renewable energy, alternative fuels and energy management systems (e.g. smart grid with renewable energy) for improving the energy efficiency and environmental performance of ports and terminals. Research gaps and future research directions are identified. Analysis shows that there is a great potential for ports to achieve further energy efficiency and researchers have many impactful research opportunities. • A detailed literature review on energy efficiency in ports and container terminals is conducted. • Operational strategies such as optimization of port operations and peak shaving methods are presented. • Technologies such as electrification of equipment, cold-ironing, energy storage systems, smart grid, microgrid are reviewed. • Renewable energy and clean fuel use in ports are presented. • Methods regarding energy consumption and emission measuring/assessment are detailed for ports. [ABSTRACT FROM AUTHOR]

The livestock sector in Sub-Saharan Africa (SSA) is under increasing pressure to define its role in jointly addressing food security and climate change. Climate-smart agriculture (CSA) has been widely leveraged as an approach to achieving both food security and climate change outcomes through suites of interventions that maximize synergies and reduce tradeoffs among three pillars: productivity, climate change resilience, and climate change mitigation. However, operationalization of the CSA approach in the livestock sector is hindered by a lack of clarity around what the pillars mean for livestock systems, given their fundamental attributes compared to crops and the spatial and temporal dimensions of these attributes. A conceptual framework is also lacking for assessing and comparing the potential CSA synergies and tradeoffs that different livestock systems and interventions may generate. In this paper we aim to offer guidance on the operationalization of the CSA approach in the livestock sector. We draw on a literature review to explore the essential attributes of livestock systems in SSA as they relate to CSA objectives over different temporal and spatial scales. Based on this review, we propose a practical and flexible framework for assessing and comparing the synergies and tradeoffs that different livestock systems may generate among food security and climate change objectives over different spatial and temporal scales. The framework consists of four elements: CSA pillars, spatial-temporal scales, CSA objectives mapped to each spatial-temporal scale, and indicator guidance. Using farm survey data and national statistics, an illustrative application of the framework to two dairy farms in Rwanda is presented and discussed. The illustrative application demonstrates how the framework can be used to identify important, spatial-temporal CSA synergies and tradeoffs that otherwise may go unrecognized. Additional applications are needed to assess the utility, practicality, and potential of the framework to guide CSA operationalization in the livestock sector in SSA. Maximizing synergies and reducing tradeoffs among food security and climate change outcomes in the livestock sector is critical for a sustainable food future. With an emphasis on flexibility for tailoring to specific development contexts and compatibility with varying levels of data availability and methodological complexity, the framework is intended to support diverse stakeholders involved in policy and development seeking to identify those livestock systems that contribute most to food security and climate change objectives over time and space. [Display omitted] • Maximizing synergies among food security & climate change in the livestock sector is critical for a sustainable future. • However, the climate-smart agriculture (CSA) approach has not been fully operationalized in livestock sector development. • Spatial & temporal dimensions determine when, where, and for whom CSA synergies & tradeoffs in the livestock sector arise. • We propose a spatial-temporal framework to assess and compare the CSA synergies & tradeoffs of different livestock systems. • Applying the framework can help identify important CSA synergies & tradeoffs that otherwise may go unrecognized. [ABSTRACT FROM AUTHOR]

In the past 50 years, rice has become an important crop for food security in sub-Saharan Africa. However, rice yields remain relatively low, and large yield gaps exist. This Special Issue brings together agronomy research on rice-based farming systems in sub-Saharan Africa and addresses three main, overarching questions: (1) what has been achieved in the past decades in terms of rice agronomy in sub-Saharan Africa, (2) what is the state-of-the-art regarding development of technologies and (3) what will be likely or required future directions? The broad topics included in this Special Issue are (1) yield trends and yield gap analyses, (2) soil & nutrient, water, weed and integrated crop management practices, (3) cropping systems, (4) genetic improvements, (5) crop simulation modeling, and (6) assessment of farmers' rice cultivation practices and the sustainability of these practices. The papers cover different sub-regions, from the Sahel to the highlands of Madagascar and three major rice growing environments (irrigated lowlands, rainfed lowlands, and rainfed uplands). In this paper we describe the major challenges in the rice production sector in sub-Saharan Africa and historical efforts on agronomy research, and we provide a short introduction and discussion on the papers presented in this Special Issue. This Special Issue arrives at six main recommendations. 1. There is a need to increase research and development efforts focusing on rainfed rice-based systems. 2. More attention needs to be paid to research on the farming system or landscape level, aimed at development of integrated cropping and farming systems and integrated agronomic solutions. 3. Current and future agronomic rice research should thematically center around sustainability, including judicious natural resources management, climate change adaptation and mitigation, and conservation of biodiversity and environments. 4. To operationalize this, sustainability performance indicators need to be developed and used. 5. There is broad consensus regarding the need for more labor-saving technologies, including mechanization options, provided these do not increase the ecological footprint of production systems. 6. Future rice agronomy research work should be interdisciplinary and transdisciplinary, to better address the myriad of challenges of smallholder farmers in Africa. Papers presented in this Special Issue should inform on the state-of-the art in rice agronomy in SSA, and on ways to sustainably enhance rice production and self-sufficiency in this region. • A Special Issue on rice agronomy research in Africa recommends future research to. • Focus on the dominant rainfed systems and develop labor-saving technologies. • Consider farming systems, landscape level issues and integrated cropping systems. • Focus on sustainability and develop and use sustainability performance indicators. • Work in partnership with non-agronomy researchers and non-research stakeholders. [ABSTRACT FROM AUTHOR]

A dramatic expansion of the worldwide wind power capacity is underway which is critical to an effective mitigation of climate change. However, wind tower infrastructure is susceptible to extreme weather conditions such as tropical cyclones and thunderstorms. Under the context of global climate changes and intense weather events, it is imperative to assess the impacts of extreme conditions on the susceptibility of the global wind power with important implications on energy security and power system resilience. In this paper, we discuss the necessity and rationality of wind power deployment considering extreme weather perspectives on enhancing the global sustainability, security, economics, and resilience. We assess the vulnerability of wind power to extreme weather events under climate change and present the correlation of wind power proliferation, extreme weather events, and climate change issues. Our results indicate that, if extreme wind speed increases by 20% considering a 50-year return wind speed and load safety factor is changed from 1.35 to 1.7, the initial capital cost of wind unit installation by the end of this century could increase by about 12% because of the higher strength in tropical cyclones. In this period, upward lightning strike will be intensified due to the use of taller wind turbines and higher angular speed of blades. Also, additional storm surges and sea ices will potentially cause higher risks to inland and offshore wind tower structures and foundations because of the continuously rising sea levels. It is confirmed in our discussion that the proliferation of wind power generation would be beneficial despite its vulnerabilities by curbing the use of fossil-based power generation units, mitigating severe carbon emission, and reducing climatic changes and extreme weather events, which could also cause significant structural damages to wind turbines installations globally. The article concludes that it is vital in the scientific community to further analyze the relationship among global wind energy integration, extreme weather events, and climate changes, and for politicians to formulate a comprehensive energy policy strategy, as engineers continue to investigate the means of deploying additional inland and offshore wind farms and consider other types of renewable energy resources with a direct link with weather conditions, for a sustainable, economic, secure, and resilient energy production. [ABSTRACT FROM AUTHOR]

The effective implementation of sustainable forest management depends largely on carrying out forest operations in a sustainable manner. Climate change, as well as the increasing demand for forest products, requires a re-thinking of forest operations in terms of sustainability. In this context, it is important to understand the major driving factors for the future development of forest operations that promote economic, environmental and social well-being. The main objective of this paper is to identify important issues concerning forest operations and to propose a new paradigm towards sustainability in a changing climate, work and environmental conditions. Previously developed concepts of forest operations are reviewed, and a newly developed concept – Sustainable Forest Operations (SFO), is presented. Five key performance areas to ensure the sustainability of forest operations include: (i) environment; (ii) ergonomics; (iii) economics; (iv) quality optimization of products and production; and (v) people and society. Practical field examples are presented to demonstrate how these five interconnected principles are relevant to achieving sustainability, namely profit and wood quality maximization, ecological benefits, climate change mitigation, carbon sequestration, and forest workers' health and safety. The new concept of SFO provides integrated perspectives and approaches to effectively address ongoing and foreseeable challenges the global forest communities face, while balancing forest operations performance across economic, environmental and social sustainability. In this new concept, we emphasize the role of wood as a renewable and environmentally friendly material, and forest workers' safety and utilization efficiency and waste management as additional key elements of sustainability. [ABSTRACT FROM AUTHOR]

Urban water services are challenged from many perspectives and different stakeholders demand performance improvements along economic, social and environmental dimensions of sustainability. In response, urban water utilities systematically give more attention to criteria such as water safety, climate change adaptation and mitigation, environmental life cycle assessment (LCA), total cost efficiency, and on how to improve their operations within the water-energy-carbon nexus. The authors of this paper collaborated in the development of a 'Dynamic Metabolism Model' (DMM). The model is developed for generic use in the sustainability assessment of urban water services, and it has been initially tested for the city of Oslo, Norway. The purpose has been to adopt a holistic systemic perspective to the analysis of metabolism and environmental impacts of resource flows in urban water and wastewater systems, in order to offer a tool for the examination of future strategies and intervention options in such systems. This paper describes the model and its application to the city of Oslo for the analysis time period 2013-2040. The external factors impacting decision-making and interventions are introduced along with realistic scenarios developed for the testing, after consultation with officials at the Oslo Water and Wastewater Works (Norway). Possible interventions that the utility intends to set in motion are defined and numerically interpreted for incorporation into the model, and changes in the indicator values over the time period are determined. This paper aims to demonstrate the effectiveness and usefulness of the DMM, as a decision-support tool for water-wastewater utilities. The scenarios considered and interventions identified do not include all possible scenarios and interventions that can be relevant for water-wastewater utilities. [ABSTRACT FROM AUTHOR]

Wood has been presented as a carbon-neutral material capable of significantly contribute to climate change mitigation and has become an appealing option for the building sector. This paper presents the quantification of the organization environmental footprint of a wood parquet company. The multi-regional input-output (MRIO) database EXIOBASE was used with a further structural path analysis decomposition. The application of the proposed method quantifies 14 environmental impacts. Highly influential sectors and regions responsible for these impacts are assessed to propose efficient measures. For the parquet company studied, the highest impact category once normalized was ozone depletion and the dominant sector responsible for this impact was the chemical industry from Spain and China. The structural path decomposition related to ozone loss revealed that the indirect impacts embedded in the supply chain are higher than the direct impacts. It can be concluded that the assessment of the organizational environmental footprint can be carried out applying this well-structured and robust method. Its implementation will enable tracking of the environmental burdens through a company's supply chain at a global scale and provide information for the adoption of environmental strategies. [ABSTRACT FROM AUTHOR]

Research on sustainable practices has attracted increasing interest as a way to understand energy demand and transitions towards sustainability. In this paper we elaborate on how practice theories can inform the discussion of experimentation. Practice theory suggests that the everyday life of people appears recalcitrant. Practices are robust, resilient and have multiple, historically formed constituents and are thereby difficult to destabilize and change quickly. The making and breaking of links inside and between practices is highlighted, as is the need for enduring, multi-sited change efforts. Practice theory further helps us to better understand the constitution of new, levelled forms of expertise, the distributed nature of experimentation and the enrolment of citizens as active participants in sustainability transitions. We have operationalized and examined these suggestions in a Finnish research project related to climate change mitigation and energy use in detached houses. We report specific modes of experimentation and innovation, including user innovations, and the shared resources of situated expertise, the collective and shared processes of empowerment and the ways in which normality is challenged by ruptures in everyday life. Based on the results, we derive suggestions for effective policy interventions. We also bring forward a set of generic suggestions for more sensitive, appreciative and effective public policies on sustainability transitions and cast experimentation in a particular and partial role in such policies. [ABSTRACT FROM AUTHOR]

Massive grasslands on the Qinghai-Tibetan Plateau(QTP) provide vital ecosystems services, which have been decreased by land degradation associated with global change. Effective efforts and actions of restoration and management are required to promote the sustainable development of these grassland ecosystems with global importance. This special issue collected numerous papers to address share the innovative theoretical foundations and practical approaches for restoring and protecting QTP's grassland ecosystems in the era of global change. The findings from the collected papers of this special issue stated that the ecosystems services of the QTP's grasslands are declining due to weakened interfaces among soil, plant and grazing animals in the QTP's grassland ecosystems by climate and land use changes. Applicable actions such as climate change mitigation and adaptation, close-to-nature restoration, rotational grazing regime with moderate grazing intensity should be taken to enhance the ecosystem services through rebuilding rational soil-plant-animal interfaces. • Both climate change and human activities led to grassland degradation. • Grassland degradation have weakened the ecosystem services. • Restoration and rational grazing can enhance sustainability of grasslands. [ABSTRACT FROM AUTHOR]

Abstract: International agreements have led to an increase of national climate policies. The selection and analysis of policy instruments are mainly oriented at their technical effectiveness and financial feasibility while social sustainability plays a minor role. As a consequence, the impact of climate policies on individuals’ life situation is largely unknown even though the design of these policies suggests effects on national and international patterns of income inequality. Focusing on the residential sector, this paper investigates how national climate policy strategies affect the relationship between income and utility costs of households within nation states. It is argued that the effect of climate policy on income inequality depends on the specific design of these policies. Market-based solutions of energy efficient housing insulation, for example, focus more on effectiveness and less on social justice. In contrast, financial benefits from regulatory climate policies like eco-taxes on fuel can be configured as an instrument for income-redistribution. This paper sets a link between environmental politics and social justice research in a multi-level approach focusing on inequalities in housing utility costs among socio-economic groups. The analysis is based on EU SILC data which is combined with climate policy instruments in the field of housing. [Copyright &y& Elsevier]

• Relative and absolute home retrofit targets are reviewed and discussed. • Retrofit depth is determined by policy targets or practical cost-effectiveness. • Research studies find feasible energy savings of around 60% maximum. • Neighbourhood is optimal spatial scale to large-scale deliver home energy retrofit. • Future retrofits to be phased instead of one-off, and less primacy of fabric first. Home energy retrofit has been a publicly-funded policy in many countries since the 1990s. Government motivations have spanned from combating energy poverty to climate action and sustainability. Given the ambition of public policy, this paper reviews the targets, spatial scales and metrics used to deliver and evaluate home energy retrofit. Large-scale retrofit projects do differ: by spatial area, by retrofit depth and in evaluation metrics (if used). This review surveys first, the quantities of homes and inhabitants in intermediate spatial scales used to plan retrofit programmes. Second, the optimal spatial scale and retrofit depth to deliver large-scale home retrofit. Third, the quantitative metrics to evaluate retrofits, and future trends in occupant-based metrics. Neighbourhood is found to be the optimal spatial scale for home energy retrofit. Deep retrofit is described as 60% energy savings that, in synergy with energy supply decarbonisation, promises to deliver 80% or higher emission reductions. Recent evidence shows a shifting primacy from fabric-first retrofit to decarbonisation of heat generation and occupant health and well-being. [ABSTRACT FROM AUTHOR]

With nearly 70% of the world population expected to live in cities by 2050, assessing the sustainability of urban systems, both existing and future ones, is becoming increasingly relevant. Making cities more sustainable is a global priority, which is highlighted by 'Sustainable Cities and Communities' being listed as one of the Sustainable Development Goals (SDG) adopted by United Nations Member States in 2015. This Virtual Special Issue (VSI) explores the implementation and assessment of policies and technologies that contribute to the transition to a sustainable, energy efficient and regenerative society. We organized the issue according to four main research themes: 1) Renewable Energy Systems (i.e., different types of systems, qualitative assessments and public acceptance); 2) Sustainable Built Environment (which includes construction, operation and refurbishment); 3) Multi-Scale Models (considering urban sustainability transition from building to districts, or cities and regions to multi-country comparisons and their scaling across different countries); and 4) Governance and Policy (climate change mitigation and adaptation plans/policies that are reported across countries, urban services and infrastructures). This paper serves two purposes. The first is to provide an analysis about patterns, correlations and synergies found across the different topics that have been addressed over the last 20 years in the literature about cities' sustainability paths. A bibliometric analysis and a contingency matrix show the degree of correlation between scientific journals and main topics addressed by published articles. Secondly, the paper acts as an Editorial to the VSI, introducing the wealth of research articles and topics included in it. Both the bibliometric analysis and the papers published in this VSI demonstrate the interconnectedness of energy consumption, pollutant emissions and the competition for finite resources. The aim is to present advances and challenges of this exciting and ever-evolving research field to inform and guide future studies of urban sustainability. • We carried out a bibliometric analysis of the literature using the Cortext Manager platform· Using network analysis of a corpus of paper spanning 20 years we identified 8 major clusters. • The paper serves also as editorial for a virtual special issue dealing with urban sustainability pathways. • The virtual special issue is organised in four main themes, which touch upon different Sustainable Development Goals. [ABSTRACT FROM AUTHOR]

How to ensure success for climate change mitigation policies? For the past decades, local climate action has been amongst the main global priorities. The Covenant of Mayors initiative is a major example of bottom-up climate initiative gathering municipalities of all sizes towards GHG reduction under a harmonised framework. Now, after the end of the first phase of the initiative in 2020, would be the time to assess the impact and effectiveness of the planed actions, based on the results of the monitoring exercise. However, the level and quality of monitoring reported by participating municipalities was not as expected and required an initial deep analysis. This study investigates the reasons behind this low number by comparing statistically the action plans of the 1643 CoM municipalities monitoring their emissions against the 3411 municipalities not doing it. The paper describes how, despite technical and financial barriers, key factors such as the direct involvement of local staff, stakeholders in participatory processes from an early stage, accurate budget allocation, or the development of the plan and deployment of actions as soon as possible, enabling municipalities to track and monitor their progress towards their climate target. • Assessing CoM impact is challenging due to the lack of monitoring/progress reports. • The lack of monitoring is explained by technical and financial barriers. • Direct engagement of local staff and stakeholders is key for successful monitoring. • Barriers and drivers found are a valuable guidance for global climate actors. [ABSTRACT FROM AUTHOR]

Abstract: This paper reviews research on the ecosystem services or multifunctionality of paddy rice cultivation in Japan, focusing on biodiversity as a basis for ecosystem services, with the aim of describing the current status and impact of the subject and exploring options for sustainable practices. Ecosystem services provided by paddy fields include; groundwater recharge, production of non-rice foods, flood control, soil erosion and landslide prevention, climate-change mitigation, water purification, culture and landscape, and support of ecosystems and biodiversity. Among these services, the value of services that regulate ecosystem functions was estimated to be US$ 72.8 billion in Japan. More than 5000 species have been recorded in paddy fields and the surrounding environment. Because paddy fields are artificially disturbed by water level management, plowing, and harvest, most species move between paddy fields and the surrounding environment. The linkage between paddy fields and the associated environment plays an important role in biodiversity. Two changes that have affected the ecosystem of paddy fields are modernization and abandonment of farming. Satoyama, a traditional socio-ecological production landscape, which provided a functional linkage between paddy fields and the associated environment has lost its functions. Biodiversity-conscious rice farming has been promoted by collaborations among farmers, consumers and governments. Biodiversity certification programs are successful examples of biodiversity-conscious framing. In these programs incentives include direct payments and/or premium prices paid by consumers, as well as farmers willingness to improve the safety of food and environment. [Copyright &y& Elsevier]

The paper analyses six international-scale responses to the financial and climate change ‘double crisis’ in order to: review how they define problems and solutions, analyse what underpins the policy choices revealed in these responses (the ‘green turn’), reflect on the implications of the proposed solutions in terms of sustainability and global environmental justice, and to suggest three elements for a paradigm shift towards an ‘alternative’ turn embedded in ecological economics theory. The analysis reveals that responses by leading international organisations continue to appeal to the precepts of neoclassical economy. We argue that from an ecological economics perspective, policy responses under the various labels of green economy, green growth, sustainable growth, green new deal, fall well short of what is needed to fight the environmental crisis and rising inequality across and within countries. The idea of justice and equity that underpins the mainstream approach seems inadequate in terms of sustaining our environmental base and global environmental justice. Based on this critical review, we propose an ‘alternative turn’, centred on three elements of a paradigm shift leading to a new economy where the environmental base and global environmental justice are at the centre of the discourse. [Copyright &y& Elsevier]

Bioenergy is considered a promising alternative to achieve carbon neutrality and emission reduction. There is a debate over the role of bioenergy in climate change mitigation because of carbon emissions from the production and utilization of biofuels. Recently, studies on emissions of biogenic volatile organic compounds (BVOCs) have substantially increased as they have a significant impact on human health and climate change due to large emissions and high reactivity. A scientometric analysis of 2895 journal papers during 1991 and 2020 related to BVOC emissions from the Web of Science Core Collection was conducted by CiteSpace and Carrot2. Results showed that three main knowledge domains were BVOC emissions and drivers, BVOCs and their oxidation products in biosphere-atmosphere exchange, and soil BVOCs in plant-microbe interactions during the period under study. Generally, the relationships between plant BVOC emissions and environmental variables (e.g., temperature, drought, light solar radiation, humidity, availability of nutrients, carbon dioxide, ozone, etc.) can be investigated by measurement techniques (i.e., chamber) or models (i.e., Model of Emissions of Gases and Aerosols from Nature). Soils could work as both the sink and source of BVOCs through various processes that are affected by soil temperatures, pH, organic matter, and moisture. Anthropogenic activities might affect the emission of BVOCs and promote the formation of BVOC-derived pollutants (e.g., ozone, particles, etc.). Incorporating BVOC emissions and their relationships with pollutants, biomass, and energy into environmental management and decision-making is a promising direction. [Display omitted] • A scientometric analysis was conducted on the research evolution of BVOC emissions. • Ten clusters generated by CiteSpace were logically reclassified into three hotspots. • MEGAN is the most frequently empirical model for BVOC emission assessment. • BVOC-derived pollutants like SOA are likely affected by anthropogenic activities. • Soils in terrestrial ecosystems can act as both the source and sink of BVOCs. [ABSTRACT FROM AUTHOR]

Recent literature is increasingly highlighting the role of individual behaviours for tackling societal challenges like Climate Change. Indeed, the largest source of global greenhouse gas (GHG) emissions is related to electricity and heat production, with residential and commercial buildings being responsible for 60% of global electricity demand. At the same time, the agri-food system is also very energy and carbon intensive and it is responsible for a considerate amount of GHG emissions. Individual behaviours related to electricity, heat, and food consumption may have strong impacts on GHG emissions opening interesting opportunities for climate change mitigation among end-users. In this direction, this paper aims at investigating the impact (if any) of two important 2015 events on consumer behaviour and awareness about the climate and environmental impacts of their everyday choices. Indeed, in current society, media coverage of events has shown to be relevant in affecting consumer perceptions and behaviour. The events analysed are: the release of Pope Francis' encyclical 'Laudato si' - On Care For Our Common Home' about environmental issues and climate change; and the 2015 United Nations Climate Change Conference (COP21) with the signature of the Paris Agreement. Data were collected via interviews with a sample of consumers in the context of Milan, a large European city. Data were analysed by means of descriptive statistics and ordinal regression models. Results indicate that such events have had an effect, mostly on people that have a positive attitude towards such events but were not so much aware about the related discussions beforehand. Policy implications highlight the role of opinion leaders in engaging the segments of population that are not already proactive on the matter, which is indeed the target of well-aimed policies. • Individual behaviours are crucial for tackling societal challenges like Climate Change. • Media coverage of events affects consumer perceptions and behaviour. • We investigate the Laudato Sì encyclical impact on sustainable consumer behaviours. • We investigate the impact of the COP21 on sustainable consumer behaviours. • Statements by opinion leaders and international events affect those less engaged. [ABSTRACT FROM AUTHOR]

This paper examines a pathway for small islands to replace fossil fuels by renewable sources, such as wind and solar, up to 100% to economically achieve energy security and satisfy The Paris Agreement to limit temperature rise as close as possible to 1.5 °C, in an economically beneficial manner. Using Jamaica, as an example, it is shown that the introduction of intermittent renewable energy to an island grid, which is electrically isolated, relying totally on itself for backup, causes serious frequency fluctuations and load shedding. Simulations show that a Battery Energy Storage System (BESS) using Li-ion batteries can be employed to economically overcome these problems. It is also noted that the cost of batteries with longer discharge capacity is on the decline and their use is expected to be become economical in about 10 years. Looking at the reported pathway to satisfy The Paris Agreement, a 2-phase pathway is suggested. In the Phase 1 (2020–2030) 30% integration of intermittent renewables with BESS backup can be implemented in a manner that is not economically burdensome whilst the remaining fossil fuel system can provide the firm energy needed. In Phase 2 (2030–2055), more renewables can be implemented, provided sufficient long term storage, including batteries, can be added to provide firm energy. By 2030 the cost of such storage is expected to fall resulting in increased deployment without a financial burden to the islands. Ideally, during the period 2020 to 2055, there should be no new additions of fossil fuel plants and retiring plants should be replaced by renewable energy plants; although an account is necessary for plants already in the planning and development stages. The leeway period of 2020–2030 should be used for the preparation and planning of adding up to 100% renewables in all sectors. • Sensitivity of isolated island grid systems to intermittent renewables. • Demonstration of frequency regulation control using simulations of Li-ion battery storage. • Mitigation pathway utilizing 100% renewable to limit temperature rise to 1.5″.C [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO 2) has been proposed to be used as the geothermal working fluid, as it presents enhanced thermodynamic properties for this application when compared with the water-based system. This paper aims to present an overview of the recent research advances on CO 2 -based geothermal systems, particularly CO 2 -enhanced systems and CO 2 -plume geothermal energy technology. The results of the recent operational projects are also described. This emerging technology can improve the efficiency of geothermal systems and their environmental impact, promoting the process sustainability and helping to tackle some of the most important issues that Humanity is facing: (i) global climate change; (ii) energy availability; and (iii) water scarcity. For deployment of this technology at a large scale, some issues and uncertainties were identified. Special attention was focused on the basic findings achieved in operational projects. • CO 2 has enhanced thermodynamic properties for geothermal energy production. • CO 2 -based geothermal systems can offset carbon dioxide capture and storage costs. • The use of CO 2 in these systems improves the energy conversion efficiency. • CO 2 -based systems are a promising technology for climate change mitigation. [ABSTRACT FROM AUTHOR]