The success of local climate governance in Europe depends not only on leading cities but also on the dynamics between leaders, followers, and laggards. Upscaling local experiments helps to close the gap between these actors. This process is driven by the increasing embeddedness of cities and their networks in EU multilevel governance. Embedded upscaling combines horizontal upscaling between leading cities with vertical upscaling between leaders and followers that is mediated by higher levels of government, and hierarchical upscaling that even reaches the laggards. Various types of upscaling, their combinations, and their impacts are analyzed. Networks have become denser and networking has intensified. City networks and their member cities have become embedded in national and EU governance, lost authority and depend more and more on regional, national, and European authorities.

Climate mitigation and climate adaptation are crucial tasks for urban areas and can involve synergies as well as trade-offs. However, few studies have examined how mitigation and adaptation efforts relate to each other in a large number of differently sized cities, and therefore we know little about whether forerunners in mitigation are also leading in adaptation or if cities tend to focus on just one policy field. This article develops an internationally applicable approach to rank cities on climate policy that incorporates multiple indicators related to (1) local commitments on mitigation and adaptation, (2) urban mitigation and adaptation plans and (3) climate adaptation and mitigation ambitions. We apply this method to rank 104 differently sized German cities and identify six clusters: climate policy leaders, climate adaptation leaders, climate mitigation leaders, climate policy followers, climate policy latecomers and climate policy laggards. The article seeks explanations for particular cities’ positions and shows that coping with climate change in a balanced way on a high level depends on structural factors, in particular city size, the pathways of local climate policies since the 1990s and funding programmes for both climate mitigation and adaptation.

Drawing on data for the 104 largest German cities, and deeper analysis of six mid-sized cities (including forerunners, followers and latecomers in climate mitigation and adaptation), we find that the spread of local mitigation and adaptation strategies across Germany can be explained by a combination of horizontal diffusion and vertical upscaling. Specifically, while the spread of climate mitigation initiatives in the 1990s was triggered primarily by transnational municipal networks (horizontal diffusion), the development and revision of climate mitigation strategies and the emergence of climate adaptation strategies during the last decade have been driven mainly by national and subnational funding programmes (vertical upscaling). Notably, forerunner cities are less dependent on external funding than followers and latecomers, because they have more internal capacity to act. By arguing that upscaling of local climate policies from forerunners to followers and latecomers depends on interventions by national and subnational authorities, we stress that the majority of German municipalities require external support in order to develop and implement effective climate strategies.

We examine how local socioeconomic, institutional and political factors shape climate transformation pathways in 23 mid-sized German cities. We group our cities into three types: industrial cities (which may have experienced recent structural change), historic cities (in which a significant proportion of the buildings or landscape is under monument protection) and university cities (in which academic or research institutions play a major role in the local community). Drawing on document analysis and expert interviews, we find that budgetary constraints, weaker civil societies and lower levels of political support result in unfavourable structural conditions for successful transformations in industrial cities. Historic cities have often only limited options to change their built environments, but many have identified climate change as a major threat to their built heritage and are therefore keen to take action in climate adaptation. Lastly, university cities are further along the transformation pathways than the other city types, largely due to having more favourable economic conditions as well as greater support from civil society, politics and the local research community.

In recent years, real-world labs have become an important part of application-related sustainability research in Germany and Europe. Currently, the international academic debate is shifting more and more towards research on local experiments. Against this backdrop, this paper serves in particular the purpose of placing the German-speaking research on real-world labs within international debates, and of comparing it systematically with debates on urban living labs and experiments. In this context, we concentrate especially on the basic assumptions of these three approaches, their origins and areas of application as well as the importance of learning processes. Although all three approaches aim at urban sustainability transformations, not much is known about their medium- and long-term impacts. Their temporal and spatial scaling, which is critical here, was recognized as problem but has barely become object of systematic research. This paper follows the purpose to enrich the German debate on real-world labs and to link it to the international discussion.

Developing sustainable, carbon-neutral, and climate-resilient districts seems to be particularly challenging with respect to historic city centers. However, barriers posed by legal requirements for historical buildings are counterbalanced by opportunities because historic cities have not undergone urban modernization and did not embrace the concept of functional cities, which nowadays impedes urban sustainability transformations. Thus, this paper focuses on the relationship between cultural heritage, urban sustainable development, and climate policy. We study continuity and change in the mid-sized UNESCO World Heritage cities Potsdam (Germany) and Bern (Switzerland). These matching forerunner cities share many characteristics, which enables them to transfer policies and jointly create new solutions for common problems. We find that national context matters, but we also identify functional equivalents like referenda and active citizen participation. Despite many similarities, Potsdam is ahead of Bern with respect to the institutionalization and integration of climate mitigation and adaptation. The comparative analysis (interviews and document analysis) identifies innovations that can be transferred between the two cities (e.g., Potsdam’s integrative climate policy or Bern’s efforts to become a role model for stakeholders and citizens). Moreover, the challenge to coordinate heritage management and climate governance offers chances for cooperation between matching cities like Bern and Potsdam.