Open Access

Schools play an important role in achieving climate protection goals, because they lay the foundation of knowledge for a responsible next generation. Therefore, schools as institutions have a special role model function. Enabling schools to become aware of their own carbon footprint (CF) is an important prerequisite for being able to tap the substantial CO2 reduction potential. Aiming at the direct involvement of students in the assessment process, a new assessment tool was developed within the Schools4Future project that gives students the opportunity to determine their own school's CF. With this instrument the CO2 emissions caused by mobility, heating and electricity consumption as well as for food in the school canteen and for consumables (paper) can be recorded. It also takes into account existing renewable energy sources. Through the development of the tool, not only a monitoring instrument was established but also a concrete starting point from which students could take actions to reduce Greenhouse Gas (GHG) emissions. This paper presents the tool and its methods used to calculate the CF and compares it with existing approaches. A comparative case study of four pilot schools in Germany demonstrates the practicability of the tool and reveals fundamental differences between the GHG emissions.

To address climate change, the decarbonisation of Germany's existing building stock urgently needs to be prioritised. However, the rate and depth of refurbishment has lagged behind official targets for years. This is a particular problem in the rental sector, where the costs and benefits of energy efficiency measures tend to be unevenly distributed between landlords and tenants (the so-called "landlord-tenant dilemma"). Within the context of the current policy landscape, investments in energy efficiency consequently make most sense for landlords if the upfront costs can be refinanced via increased rental income or reduced vacant periods. This paper seeks to investigate the validity of this statement at city level by using a large dataset from one of Germany’s main internet property platforms to examine how the willingness of tenants to pay for energy efficiency varies across residential locations in the city of Wuppertal. The small-scale spatial analysis highlights the existence of a price premium for energy efficiency in the rental market for apartments; however, this premium is generally small (especially in comparison to other property enhancements, especially visible improvements) or even non-existent in some residential areas. Consequently, investing in energy efficiency is rarely an attractive option for landlords. Therefore, strong policy action, aligned with social and urban development policy objectives, is necessary to establish an effective incentive structure in the market and make investing in energy efficiency more attractive for both landlords and tenants.

Cities and municipalities have had to endure a great deal in recent years, including a global coronavirus pandemic, fire disasters in the US and devastating floods like those in Germany. These are also consequences of anthropogenic climate change, and cities have to be better prepared for such events in future. In particular, the cata-strophic flooding Germany experienced in July 2021 demonstrated how ill-equipped municipalities are for this type of incident. In this paper, we look at how cities can become more resilient, sustainable and ready for the future.

Urban development faces numerous challenges in the 21st century and a central task is the sustainable and liveable design of the city. Can the concept of a Smart City be a tool to making cities more liveable and sustainable? To find out, we chose a biographical method to analyse the steps towards a successful Smart City and to better understand the structures behind it. We combine the innovation biography method with a process model from sustainability governance research, namely Steurer's sustainability governance model and apply them to Vienna's Smart City, especially the preparation of the Vienna Smart City framework strategy (Steurer & Trattnigg, 2010). On the one hand, this article shows that a transfer of the innovation biography method to urban research can generate deeper insights on urban development processes in general. On the other hand, the approach chosen can show that Vienna integrates the sustainable urban design into the process of Smart City design. So the smart and sustainable city design, often called for in theoretical contributions, is practised in Vienna. Due to its reconstructive character, the biographical method has revealed that it is possible to govern sustainability by using Smart City as an umbrella strategy, as long as one manages it in an integrated and holistic way, recognises trends and is able to acquire and use research funds effectively and efficiently. The knowledge gained from the new method for urban and Smart City research is twofold. Firstly, the transfer of the method previously developed in the human sciences and subsequently for organisations, institutions and products and services also works in urban research. Second, the innovation biography provides in-depth insights into the process towards the Smart City and the stakeholders involved. The use of the biographical method highlights the relevance of good governance in terms of interdisciplinary cooperation on the one hand and high political commitment on the other through the micro-level perspective and is also sensitive enough to highlight the importance of an appropriate narrative in and for the process towards the Smart City.

The unprecedented challenge of reaching carbon neutrality before mid-century and a large share of it within 2030 in order to keep under the 1.5 or 2 °C carbon budgets, requires broad and deep changes in production and consumption patterns which, together with a shift to renewables and reinforced efficiency, need to be addressed through energy sufficiency. However, inadequate representations and obstacles to characterising and identifying sufficiency potentials often lead to an underrepresentation of sufficiency in models, scenarios and policies. One way to tackle this issue is to work on the development of sufficiency assumptions at a concrete level where various implications such as social consequences, environmental co-benefits, conditions for implementation can be discussed. This approach has been developed as the backbone of a collaborative project, gathering partners in 20 European countries at present, aiming for the integration of harmonised national scenarios into an ambitious net-zero European vision. The approach combines a qualitative discussion on the role of energy sufficiency in a "systemic" merit order for global sustainability, and a quantitative discussion of the level of sufficiency to be set to contribute to meeting 100 % renewables supply and net-zero emissions goals by 2050 at the latest. The latter is based on the use of a dashboard, which serves as a common descriptive framework for all national scenario trajectories and their comparison, with a view to harmonising and strengthening them through an iterative process. A set of key sufficiency-related indicators have been selected to be included in the dashboard, while various interrelated infrastructural, economic, environmental, social or legal factors or drivers have been identified and mapped. This paves the way for strengthening assumptions through the elaboration of "sufficiency corridors" defining a convergent, acceptable and sustainable level of energy services in Europe. The process will eventually inform the potential for sufficiency policies through a better identification of leverages, impacts and co-benefits.

Consumption by private households in various areas of demand - housing, mobility, nutrition, services and products - contributes to around 10 % of total emissions in Germany. Of this, higher-income households are responsible for a disproportionate share. At the same time, many households often lack the knowledge, time, or motivation to deal with their own energy-relevant and climate-impacting behaviours. In this context, energy advice services play an important role for raising awareness, activating consumers and imparting knowledge about available options for action. However, conventional energy advice services are mostly limited to the topics of building and appliance energy efficiency - especially for middle- and high-income households - without considering private consumption behaviour and the related social practices as a whole. In practice, there has been little differentiation to date in addressing target groups in a way that takes into account different lifestyles and realities and the underlying values and motivations in a pluralistic society. The present paper presents a methodological approach to develop targeted energy advice approaches in urban environments that are oriented towards the motivations of different types of households with medium and high incomes. It proposes a three-step approach consisting of 1) a microdata-based population analysis to identify and categorize target subgroups, 2) an inventory of existing advice offers with regard to their coverage and approach and 3) a gap analysis based on the results of the preceding steps. Applied to a large city in Germany, the analysis finds that gaps are rarely found with regard to communicated facts but rather the way in which information is conveyed. Accordingly, recommendations relate to more effectively use windows of opportunity and framing of measures to match target group motivations.

2020 was meant to be the year of climate ambition. Then the COVID-19 pandemic struck, the Glasgow conference was postponed to November 2021, and climate policy generally appeared to have been put on the backburner. But towards the end of the year prospects seemed to brighten with a series of zero-emission pledges and the election of Joe Biden as US President. This article analyses what the year of the pandemic achieved in terms of combating climate change. This article first summarizes the virtual events that were organised to substitute for the physical UNFCCC conferences and what progress was or was not made on the outstanding items of the "Paris rulebook", implementation of the Gender Action Plan, and other items. Subsequently, the article surveys the status of NDC updates and to what extent recovery programmes have been used to advance climate action. Finally, the article takes a closer look at the current dynamics among non-Party actors. In summary, while formal negotiations essentially stopped in the year of the pandemic, the conservation did not. However, implementation is still lagging far behind the ambitious targets that have been set. While implementation is mostly the domain of national policy, the international process has a number of options at its disposal to foster climate action.

Many cities all over the world highlight the need to transform their urban mobility systems into more sustainable ones, to confront pressing issues such as air and noise pollution, and to deliver on climate change mitigation action. While the support of innovations is high on the agenda of both national and local authorities, consciously phasing-out unsustainable technologies and practices is often neglected. However, this other side of the policy coin, "exnovation", is a crucial element for the mobility transition. We developed a framework to facilitate a more comprehensive assessment of urban mobility transition policies, systematically integrating exnovation policies. It links exnovation functions as identified in transition studies with insights from urban mobility studies and empirical findings from eight city case studies around the world. The findings suggest that most cities use some kinds of exnovation policies to address selective urban mobility issues, e.g., phasing-out diesel buses, restricting the use of polluting motor vehicles in some parts of the city, etc. Still, we found no evidence for a systematic exnovation approach alongside the innovation policies. Our framework specifies exnovation functions for the urban mobility transition by lining out policy levers and concrete measure examples. We hope that the framework inspires future in-depth research, but also political action to advance the urban mobility transition.

Energy sufficiency is one of the three energy sustainability strategies, next to energy efficiency and renewable energies. We analyse to what extent European governments follow this strategy, by conducting a systematic document analysis of all available European National Energy and Climate Plans (NECPs) and Long-Term Strategies (LTSs). We collect and categorise a total of 230 sufficiency-related policy measures, finding large differences between countries. We find most sufficiency policies in the transport sector, when classifying also modal shift policies to change the service quality of transport as sufficiency policies. Types of sufficiency policy instruments vary considerably from sector to sector, for instance the focus on financial incentives and fiscal instruments in the mobility sector, information in the building sector, and financial incentive/tax instruments in cross-sectoral application. Regulatory instruments currently play a minor role for sufficiency policy in the national energy and climate plans of EU member states. Similar to energy efficiency in recent decades, sufficiency still largely referred to as micro-level individual behaviour change or necessary exogenous trends that will need to take place. It is not treated yet as a genuine field of policy action to provide the necessary framework for enabling societal change.

Staying within the 2 °C (preferably 1.5 °C) limit requires fast and fundamental system changes, also in urban passenger transport. Shifting car traffic to environmentally friendly transport modes is one central strategy to make urban transport more sustainable and climate friendly. However, in most cities car use remains high. Therefore, this paper analyzes what course change is needed regarding direction, scale and speed of change for urban sustainability and climate protection reasons. The paper analyzes the role of modal shift as a strategy in itself and in relation to land-use (avoid) and efficiency (improve) measures. The paper draws on insights from European frontrunning cities and explorative forecasting scenarios calculated with the sophisticated integrated land-use transport model "Ruhr Region 2050". The paper suggests that a significant reduction of urban car use is needed (direction) that roughly equals a fast halving of car use (scale), which has proven feasible under the current socio-political conditions by annual reduction rates of 0.5 to 1.5 percentage points of the trip-based modal share of car use (speed). Significantly reducing car use requires comprehensive and high-intensive measures that go far beyond usual practices. Modal shift measures need to play a crucial role in integrated approaches with land-use (avoid) and efficiency (improve) measures because they have the potential to significantly reduce car use and CO2 emissions and because they can produce comparatively fast effects - which makes modal shift measures first aid approaches to achieve a fast "bending of the curve" of excessive car use and growing CO2 emissions.

Transport is a key economic sector in Europe, it influences the opportunities of production and consumption. By improving access to markets, goods and services, employment, housing, health care, and education, transportation projects can increase economic productivity and development. The ability to be mobile is also a prerequisite for inclusion. At the same time, transport induces a range of negative effects, most notably the emission of greenhouse gases. At the urban level, motorised transport significantly contributes to air pollution. Since 2013, the European Commission has increased EU funding for projects: The "Urban Mobility Package" provided EUR 13 billion for investments into sustainable urban mobility between 2014 and 2020. This has allowed cities across Europe to put in place a range of initiatives. European funding programmes and financing institutions such as the European Investment Bank increasingly insist on a contribution to more sustainable mobility systems in their financing commitments. The impact, however, is mixed. The European Court of Auditors warned that EU cities must shift more traffic to sustainable transport modes. They found that EU-funded projects were not always based on sound urban mobility strategies and were not as effective as intended. In many EU member states, the transfer of EU funds to cities is contingent on the existence of a SUMP. A statistical analysis of the modal split of 396 cities in the European Union revealed that the implementation of Sustainable Urban Mobility Plans positively correlates with a reduction of the share of the private car in the cities. Such plans include strategies and activities to pursue sustainable mobility. This report analyses transport and mobility in Bratislava with a view to providing a clear picture about its current sustainability state. It points to both good practice and areas of improvement. In so doing, it provides recommendations how mobility in the city can be developed increasingly sustainable. Bratislava is the capital and largest city of Slovakia. In 2016, the population of the city was 426,000 inhabitants, the Bratislava region was home to 642,000 inhabitants.

The Paris Agreement combines collective goals with individual countries' contributions. This hybrid approach does not guarantee that the individual contributions add up to what is required to meet the collective goals. The Paris Agreement therefore established the Global Stocktake. Its task is to "assess collective progress" towards achieving the long-term goals of the agreement as of 2023 and every five years thereafter. Corresponding to this role, this report addresses three questions: What should an effective Global Stocktake look like? What information and data are needed? Is it possible to execute an effective Global Stocktake within the mandate of the Paris Agreement?

The Digital Product Passport (DPP) is a concept of a policy instrument particularly pushed by policy circles to contribute to a circular economy. The preliminary design of the DPP is supposed to have product-related information compiled mainly by manufactures and, thus, to provide the basis for more circular products. Given the lack of scientific debate on the DPP, this study seeks to work out design options of the DPP and how these options might benefit stakeholders in a product's value chain. In so doing, we introduce the concept of the DPP and, then, describe the existing regime of regulated and voluntary product information tools focusing on the role of stakeholders. These initial results are reflected in an actor-centered analysis on potential advantages gained through the DPP. Data is generated through desk research and a stakeholder workshop. In particular, by having explored the role the DPP for different actors, we find substantial demand for further research on a variety of issues, for instance, on how to reduce red tape and increase incentives for manufacturers to deliver certain information and on how or through what data collection tool (e.g., database) relevant data can be compiled and how such data is provided to which stakeholder group. We call upon other researchers to close the research gaps explored in this paper also to provide better policy direction on the DPP.

This concluding article derives six major findings from the contributions to this special issue. First, the barriers and challenges to decarbonisation vary significantly across sectoral systems. Second, and similarly, the need and potential for the five functions of international governance institutions to contribute to effective climate protection also vary widely. Third, while the pattern is uneven, there is a general undersupply of international climate governance. Fourth, the sectoral analyses confirm that the UNFCCC and Paris Agreement play an important overarching role but remain limited in advancing effective sectoral governance. Fifth, while non-environmental institutions may present important barriers to decarbonisation, more synergistic effects are possible. Sixth, our sectoral approach provides a sound basis on which to identify sector-specific policy options. The paper then offers reflections on the merits and limitations of the sectoral approach, before identifying avenues for future research to further advance the agenda.

This paper examines the Global Climate Action Agenda (GCAA) and discusses options to improve sub- and non-state involvement in post-2020 climate governance. A framework that stimulates sub- and non-state action is a necessary complement to national governmental action, as the latter falls short of achieving low-carbon and climate-resilient development as envisaged in the Paris Agreement. Applying design principles for an ideal-type orchestration framework, we review literature and gather expert judgements to assess whether the GCAA has been collaborative, comprehensive, evaluative and catalytic. Results show that there has been greater coordination among orchestrators, for instance in the organization of events. However, mobilization efforts remain event-driven and too little effort is invested in understanding the progress of sub- and non-state action. Data collection has improved, although more sophisticated indicators are needed to evaluate climate and sustainable development impacts. Finally, the GCAA has recorded more action, but relatively little by actors in developing countries. As the world seeks to recover from the COVID-19 crisis and enters a new decade of climate action, the GCAA could make a vital contribution in challenging times by helping governments keep and enhance climate commitments; strengthening capacity for sub- and non-state action; enabling accountability; and realizing sustainable development.

More than 150 municipal utilities (so-called Stadtwerke) were established in Germany from the beginning of the millennium, bringing the total number of Stadtwerke currently established within the country to approximately 900. With responsibility for more than half of the supply of electricity, gas and heat in Germany, these Stadtwerke play a central role in the transformation of the energy sector, or Energiewende. In addition, due to their local and regional ties, Stadtwerke have a particular role to play in energy politics, the economy and across society. This article focuses on the motives behind, and grounds for, the current wave of newly established Stadtwerke. Further, it discusses the factors that were critical to the successful formation of new Stadtwerke in recent years. The results of our survey indicate that the establishment of municipal Stadtwerke is a suitable measure to implement the energy transition at the local level, whereby the concept of public value has a high level of importance for the local decision-makers. Collaboration and cooperation, as well as a resilience-oriented strategy, are important success factors for new Stadtwerke.

Climate change is a transformation challenge. It requires the transformation of a patchwork of independent socio-technical systems. These complex systems have their own specific challenges and path dependencies. Lukas Hermwille introduces a perspective on socio-technical complexity to the study of global climate governance and asks what governance arrangements on the international level, in particular the United Nations Framework Convention of Climate Change (UNFCCC) and its Paris Agreement, can offer to facilitate and foster the required transformational change. His work shows the importance of the discursive power of global climate governance, shifting the expectations and visions of the future of key actors and, as a corollary, changing their investment decisions of today towards a more sustainable future.

The expansion of photovoltaics in German cities has so far fallen short of expectations. The concept of "tenant electricity" ("Mieterstrom" in German), in which tenants of a building are supplied with solar power produced on site, offers great potential here. A study on behalf of the German Federal Ministry for Economic Affairs and Energy estimated the number of tenant households with good conditions for solar tenant electricity at 3.8 million. At the same time, the federal tenant electricity promotion scheme has been in place since 2017, but only about 1% of the annual budget has been claimed. The aim of this study is to identify the barriers for and drivers of diffusion of the tenant electricity model. To this end, a qualitative document analysis and a range of semi-structured expert interviews have been conducted. The theoretical framework used to guide the analysis is the multi-level perspective. The main barrier found for tenant electricity diffusion is the legal framework on the regime level, which also leads to high transaction costs of implementing tenant electricity. A social barrier is the inertia of some residents to actively concern themselves with their electricity supply and switch to a tenant electricity contract. Among its drivers are long-term trends such as the increasing electricity demand in urban areas, technical developments like blockchain technology and the increasing deployment of smart meters, and the EU Renewable Energy Directive. As long as the restrictive legal framework prevails, the further diffusion of tenant electricity will remain limited.

This article aims to analyse the potential for international climate governance to promote the decarbonisation of land transport. It first summarises challenges and barriers that impede the transformation of the sector. On this basis, the article discusses how international governance could potentially assist with overcoming these barriers and mobilising potentials. Subsequently, the article analyses to what extent existing international governance institutions deliver on the potential identified. The analysis finds that while there is a large number of international institutions trying to promote the decarbonisation of land transport, none of them emerge saliently as hubs or core institutions. There is a substantial amount of activity to generate and disseminate knowledge and learning, but the potential for providing guidance and signal, setting rules, providing transparency/accountability and means of implementation could be further exploited. The article concludes with suggestions on how international governance may be strengthened.

Cities are becoming digital and are aiming to be sustainable. How they are combining the two is not always apparent from the outside. What we need is a look from inside. In recent years, cities have increasingly called themselves Smart City. This can mean different things, but generally includes a look towards new digital technologies and claim that a Smart City has various advantages for its citizens, roughly in line with the demands of sustainable development. A city can be seen as smart in a narrow sense, technology wise, sustainable or smart and sustainable. Current city rankings, which often evaluate and classify cities in terms of the target dimensions 2smart" and "sustainable", certify that some cities are both. In its most established academic definitions, the Smart City also serves both to improve the quality of life of its citizens and to promote sustainable development. Some cities have obviously managed to combine the two. The question that arises is as follows: What are the underlying processes towards a sustainable Smart City and are cities really using smart tools to make themselves sustainable in the sense of the 2015 United Nations Sustainability Goal 11? This question is to be answered by a method that has not yet been applied in research on cities and smart cities: the innovation biography. Based on evolutionary economics, the innovation biography approaches the process towards a Smart City as an innovation process. It will highlight which actors are involved, how knowledge is shared among them, what form citizen participation processes take and whether the use of digital and smart services within a Smart City leads to a more sustainable city. Such a process-oriented method should show, among other things, to what extent and when sustainability-relevant motives play a role and which actors and citizens are involved in the process at all.

Non-residential buildings in the European Union consume more than one third of the building sector's total. Many non-residential buildings are owned by municipalities. This paper reports about an energy saving competition that was carried out in 91 municipal buildings in eight EU member states in 2019. For each public building an energy team was formed. The energy teams' activities encompassed motivating changes in the energy use behaviour of employees and small investments. Two challenges added an element of gamification to the energy saving competition. To assess the success of the energy saving competition, an energy performance baseline was calculated using energy consumption data of each public building from previous years. Energy consumption in the competition year was monitored on a monthly base. After the competition the top energy savers from each country were determined by the percentage-based reduction of energy consumption compared to the baseline. On average, the buildings had an electricity and heat consumption in 2019 that was about 8 % and 7 %, respectively, lower than the baseline. As an additional data source for the evaluation, a survey among energy team members was conducted at the beginning and after the energy competition. Support from superiors, employee interest and motivation and behaviour change as assessed by energy team members show a positive, if weak or moderate, correlation with changes in electricity consumption, but not with changes in heat consumption.

This paper explores how the European Commission promotes the concept of Sustainable Urban Mobility Planning (SUMP) among European cities. Despite the strong uptake of the SUMP concept, mobility-related problems persist in European municipalities. Linking theoretical approaches to understand the diffusion of policies with empirical findings from working with cities in the SUMP context, this article explores channels of policy diffusion and investigates shortcomings related to the respective approaches. Studies on the diffusion, the transfer and the convergence of policies identify formal hierarchy, coercion, competition, learning and networking, and the diffusion of international norms as channels for policy transfer. The findings which are presented in this paper are twofold: First, the paper finds evidence that the Commission takes different roles and uses all mechanisms in parallel, albeit with different intensity. It concludes that the approaches to explain policy diffusion are not competing or mutually exclusive but are applied by the same actor to address different aspects of a policy field, or to reach out to different actors. Second, the article provides first evidence of factors that limit the mechanisms' abilities to directly influence urban mobility systems and mobility behaviour.

The impacts of the COVID-19 crisis and the global response to it will co-determine the future of climate policy. The recovery packages responding to the impacts of the pandemic may either help to chart a new sustainable course, or they will further cement existing high-emission pathways and thwart the achievement of the Paris Agreement objectives. This article discusses how international climate governance may help align the recovery packages with the climate agenda. For this purpose, the article investigates five key governance functions through which international institutions may contribute: send guidance and signals, establish rules and standards, provide transparency and accountability, organize the provision of means of implementation, and promote collective learning. Reflecting on these functions, the article finds that the process under the United Nations Framework Convention on Climate Change (UNFCCC), together with other international institutions, could promote sustainable recovery in several ways.

The paper provides an integrated assessment of environmental and socio-economic effects arising from final consumption of food products by European households. Direct and indirect effects accumulated along the global supply chain are assessed by applying environmentally extended input-output analysis (EE-IOA). EXIOBASE 3.4 database is used as a source of detailed information on environmental pressures and world input-output transactions of intermediate and final goods and services. An original methodology to produce detailed allocation matrices to link IO data with household expenditure data is presented and applied. The results show a relative decoupling between environmental pressures and consumption over time and shows that European food consumption generates relatively less environmental pressures outside Europe (due to imports) than average European consumption. A methodological framework is defined to analyze the main driving forces by means of a structural decomposition analysis (SDA). The results of the SDA highlight that while technological developments and changes in the mix of consumed food products result in reductions in environmental pressures, this is offset by growth in consumption. The results highlight the importance of directing specific research and policy efforts towards food consumption to support the transition to a more sustainable food system in line with the objectives of the EU Farm to Fork Strategy.