Unpacking Polycentric Climate Governance: Tracing the Evolution of Transnational Municipal Networks over Time

Kern, Kristine; Eckersley, Peter; Kochskämper, Elisa; Haupt, Wolfgang Article — Published Version Unpacking Polycentric Climate Governance: Tracing the Evolution of Transnational Municipal Networks over Time Global Environmental Politics Provided in Cooperation with: Leibniz Institute for Research on Society and Space (IRS) Suggested Citation: Kern, Kristine; Eckersley, Peter; Kochskämper, Elisa; Haupt, Wolfgang (2024) : Unpacking Polycentric Climate Governance: Tracing the Evolution of Transnational Municipal Networks over Time, Global Environmental Politics, ISSN 1536-0091, MIT Press, Cambridge, MA, Vol. 24, Iss. 3, pp. 121-143, https://doi.org/10.1162/glep_a_00754 This Version is available at: https://hdl.handle.net/10419/328339 Standard-Nutzungsbedingungen: Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden. 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If the documents have been made available under an Open Content Licence (especially Creative Commons Licences), you may exercise further usage rights as specified in the indicated licence. https://creativecommons.org/licenses/by/4.0/ Unpacking Polycentric Climate Governance: Tracing the Evolution of Transnational Municipal Networks over Time • Kristine Kern, Peter Eckersley*, Elisa Kochskämper, and Wolfgang Haupt Abstract All governance systems are polycentric to some extent in that they comprise multiple actors with varying degrees of autonomy. However, there has been limited theorization as to how we might measure polycentricity, even though this could help us unpack networks and understand governance arrangements better. We present three dimensions of governance to conceptualize degrees of polycentricity—governance of networks (internal organization and management at the network level), governance by networks (their impacts at the membership level), and governance with networks (collaboration with other actors at the system level). We then trace the evolution of three transnational municipal networks (the Climate Alliance, Covenant of Mayors, and 100 Resilient Cities/Resilient Cities Network), which are located at different positions along the polycentric–monocentric spectrum. We examine how these networks have become more or less polycentric over time and highlight trade-offs between different dimensions of polycentric governance, most notably governance of and governance by. Keywords: transnational municipal networks, climate governance, polycentric governance, Climate Alliance, Covenant of Mayors, 100 Resilient Cities, Resilient Cities Network By definition, “polycentric”systems feature multiple centers of authority, flexibility, and a lack of hierarchy—attributes that increasingly characterize climate governance arrangements across the globe. In the international climate regime, for example, the lack of a powerful, “monocentric”actor means that few procedures are in place to monitor and sanction noncompliance (Jordan et al. 2018). Indeed, the academic literature has emphasized the importance of polycentric governance for many years (see, e.g., Bulkeley et al. 2003). First-generation transnational municipal networks (TMNs) were characterized as “nonGlobal Environmental Politics 24:3, August 2024, https://doi.org/10.1162/glep_a_00754 © 2024 by the Massachusetts Institute of Technology. Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) license. * Corresponding author: [email protected] 121 Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 hierarchical, horizontal and polycentric”formal organizations (Kern and Bulkeley 2009, 310). 1 However, a new generation of TMNs has emerged that exhibit more monocentric features (Nielsen and Papin 2021). Power and authority are always dispersed to some extent, and therefore all governing systems have polycentric elements (Jordan and Huitema 2023; Tobin et al. 2024). However, few studies have sought to unpack the “black box”of governance to gain a better understanding of the extent to which a system may be polycentric (Dorsch and Flachsland 2017; Galaz et al. 2012; Kim 2020). Thus we introduce three novel dimensions of governance to help unpack and operationalize the concept, locate TMNs along each of them, and track developments over time. These dimensions are governance of networks (their internal organization and management arrangements at the network level), governance by networks (their impact at the membership level), and governance with networks (their collaborations with other networks and organizations at the system level). With this heuristic, we offer a way to conceptualize, understand, and compare how governance may operate in different contexts. By analyzing how TMNs change their positions along the spectrum between polycentricity and monocentricity over time, we highlight potential dynamics and trade-offs between the three governance dimensions. As such, first, we build theory by providing a better understanding of the interactions between the three dimensions of governance and, in particular, the trade-offs between them, and second, we develop methods for assessing the three dimensions of governance across cases and over time. Assuming that TMNs seek to achieve both compliance with network goals and scaling across municipalities, we trace the evolution of three selected TMNs (the Climate Alliance [CA], Covenant of Mayors [CoM], and 100 Resilient Cities [100RC]/Resilient Cities Network [RCN]) along these three dimensions. Most previous studies into TMNs have tended to focus on single rather than comparative case studies (e.g., Gordon 2020; Nielsen and Papin 2021) and have not considered their development over time. Alongside offering a new theoretical contribution to help conceptualize polycentric governance, our article therefore also fills a gap in the empirical literature. We found that all three networks are converging in terms of governance of and with, but there is far less convergence with respect to compliance with network goals (governance by networks), which is higher in monocentric networks. There is also a persistent trade-off between the effectiveness of monocentric networks and the self-organizing potential of polycentric networks. By this we mean that more polycentric networks require a certain degree of central coordination to balance the high autonomy of members, while more monocentric networks need more self-organization. 1. We use the term transnational municipal networks because all three networks that we analyze in this article include municipalities that do not classify as cities. 122 •Unpacking Polycentric Climate Governance Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 In the next section, we introduce the literature on polycentric governance, with a specific focus on how it applies to TMNs. We then focus on the evolution of TMNs, introduce our case selection and methods, and examine the three networks before setting out how their approaches to governance of, governance by, and governance with networks have evolved since their conception. We then discuss our findings in the context of the literature, summarize our contribution, and identify remaining research gaps. Polycentric Governance and TMNs Polycentric Governance Rather than being characterized by a single actor exercising hierarchical coercion, polycentric systems like first-generation TMNs operate across different levels and include multiple overlapping centers of authority (Skelcher 2005), which are autonomous and collaborate on a voluntary basis. In line with the other articles in this special issue, we build from Elinor Ostrom’s (2010b, 552) definition: Polycentric systems are characterized by multiple governing authorities at different scales rather than a monocentric unit. Each unit within a polycentric system exercises considerable independence to make norms and rules within a specific domain. These multiple centers of authority often emerge “from below,”in response to complex issues that traditional bureaucracies are ill designed to address effectively (Peters and Pierre 2021). They may also include private and voluntary organizations that contribute in some way toward governing a policy issue. Since autonomous centers of authority operate independently of each other, there is no expectation that government bodies are steering and coordinating how these organizations act. As such, there are clear overlaps with concepts like multilevel or network governance (Hooghe and Marks 2001; Rhodes 1997), although polycentric arrangements are perhaps (even) more likely to be characterized by loose, informal, and interorganizational networks and the involvement of nonstate actors than these other two perspectives (Heinen et al. 2022). Scholars have argued that the lack of a coordinating actor within a highly polycentric system may increase the likelihood that governance approaches will be uncoordinated and incoherent, that activities will conflict or overlap, and that “free-riding”will become more common (Galaz et al. 2012). The polycentric governance literature tends to be more positive about the lack of central steering, perhaps because it examines mainly bottom-up arrangements, which allow actors to develop their own context-specific strategies to tackle problems and learn from others’experience (Ostrom 2010a, 2010b). Therefore, where a central coordinator to direct or coerce local actors is lacking, some Kristine Kern, Peter Eckersley, Elisa Kochskämper, and Wolfgang Haupt •123 Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 uncoordinated and possibly incoherent activity may well be preferable to the alternative of no action—particularly if it may have broader impacts that are difficult to capture and measure (van der Ven et al. 2017). Polycentric governance offers a more comprehensive (and perhaps more realistic) framework than monocentric perspectives, particularly where scholars examine phenomena that a range of different actors are seeking to address and a single coordinating actor does not exist. Societal actors may wish to respond to a challenge like climate change in a bottom-up, polycentric manner by developing their own approaches (Ostrom 2010a, 2010b). Indeed, particularly since the 2015 Paris Agreement, scholars are increasingly viewing global climate governance through a polycentric lens (Jordan and Huitema 2023; Jordan et al. 2018). A key element of this agreement involved governments “self-organizing” and putting forward voluntary emission reduction targets that cannot be enforced through hierarchical legal mechanisms, and it also stressed the key role of nonstate actors. By focusing on three dimensions of TMN governance and the trade-offs between them, we depart from polycentric approaches to global climate governance that include TMNs alongside other types of state and nonstate actors (Dorsch and Flachsland 2017). TMNs as Polycentric Climate Governance First-generation TMNs feature many key characteristics of polycentric governance, including a lack of hierarchical coercion, local self-organization, multiple centers of authority, and rule-making on different scales, and they have long been recognized as important actors in local climate governance. Studies in this field have acknowledged the reality of multiple decision-making centers for over two decades (see, e.g., Bulkeley et al. 2003). Given that various TMNs have developed in the area of local climate and energy policy over recent decades (Gordon 2020; Haupt and Coppola 2019; Kern and Bulkeley 2009; Nielsen and Papin 2021), we can see how they represent a useful case for examining many of the questions that scholars of polycentric governance seek to address, such as why some actors within polycentric systems are more ambitious or innovative than others or how they seek to overcome structural challenges to progress (Cortes et al. 2022; Kern 2019; van der Heijden 2018). However, although we start from the assumption that TMNs are polycentric systems, they may also exhibit monocentric features. Therefore we develop analytic tools to assess differences between TMNs and the implications for governing them. TMNs have to be understood as formal organizations because they have dedicated staff and headquarters (Busch 2016). There is a large literature on TMNs that seek to tackle sustainable development and climate change, including single and comparative case studies (Heikkinen et al. 2020; Papin 2020), for example, on the International Council for Local Environmental Initiatives (ICLEI) (Yi et al. 2017), as well as on newer networks like C40 (Davidson et al. 2019; Gordon 2020) and 100 Resilient Cities (Coppola and Haupt 2023; 124 •Unpacking Polycentric Climate Governance Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 Nielsen and Papin 2021). More recently, scholars have studied the experiences of specific member cities in depth (see, e.g., Coppola et al. 2020; Kochskämper et al. 2024; Moloney and Doyon 2021). However, less prominent TMNs, such as the CA, have received far less attention. Also, few studies have examined how the governance of different TMNs has evolved over time, how TMNs are governed, how TMN membership affects the implementation of local climate policy, or how networks interact with each other (Cortes et al. 2022; Haupt et al. 2020; Kern and Bulkeley 2009; Rashidi and Patt 2018). The dynamic nature of transnational climate governance in general and TMNs in particular suggests that TMNs may have evolved along the three dimensions of governance of networks, governance by networks, and governance with networks. Dimensions of TMN Governance The academic literature conceptualizes governance in multiple ways but shares a desire to understand organizational decision-making and how actors, societies, and systems are governed (Peters and Pierre 2021). Here we develop and present three dimensions of governance to contribute toward this endeavor. We start from the assumption that the governance of TMNs involves three levels of analysis, which correspond to a tridimensional approach to polycentric governance: the network level, the membership level, and the system level. We base our three dimensions on previous studies that suggest it refers to decision-making processes within organizations (Spitzeck and Hansen 2010) at the network level, capacities for steering and enforcement (Pierre and Peters 2020) at the membership level, and collaboration and coproduction with other actors (Sørensen and Torfing 2017) at the system level. First, we examine governance of networks, by which we mean how they are structured and governed internally (Acuto and Ghojeh 2019). In more monocentric TMNs, a central authority dominates decision-making, and members may be less involved. Our focus here is on the multiplicity of internal decision-making bodies (general assembly, executive board, president, secretariat, etc.), members’involvement in organizational committees, boards, strategy development, and the network’s management structure (secretariat, staff). Since polycentric systems have multiple centers of authority and more horizontal power structures, TMNs that are characterized by a multiplicity of internal decision-making bodies, more options for member cities to participate in decision-making, and limited power of the secretariat (and its head) would be located toward the polycentric end of the spectrum. Second, we operationalize steering and enforcement capacities in terms of governance by networks, which relates to their impact at the membership level. We anticipate that where a TMN has fewer steering and coercive capacities, individual members can exercise greater individual autonomy, and the network will therefore be more polycentric. As such, in more polycentric TMNs, members are Kristine Kern, Peter Eckersley, Elisa Kochskämper, and Wolfgang Haupt •125 Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 less likely to monitor, are less likely to report their compliance with the strategic goals of the network (such as climate neutrality) (see also Rayner and Jordan 2013, 80), and do not face sanctions if they fail to comply with network rules. In contrast, more monocentric TMNs would seek to exert increasing pressure on their members to undertake climate action. Our third dimension covers relationships with external actors at the system level (Acuto and Ghojeh 2019): we conceptualize this as governance with networks, and it refers specifically to the openness of the network to external collaboration. We focus on individual networks here, although their initiatives at the system level may have repercussions for the “global ecosystem of city networks”(Acuto and Leffel 2021). We expect more polycentric TMNs to be more open to collaborating with other TMNs, in particular TMNs with similar characteristics; nonstate actors, such as NGOs, which represent another type of network organization; and governmental actors, such as national ministries or the European Commission, on a frequent basis. Collaboration may even lead to mergers between networks and an increasing degree of embeddedness of TMNs in governmental organizations. Empirical Context: Evolution of TMNs Shortly before, and particularly after, the Rio Conference in 1992, the first TMNs, such as the ICLEI, originated around the topic of sustainable development and climate policy. We have identified three trends in their evolution since the early 1990s: 1. While first-generation networks (such as the European Sustainable Cities and Towns Campaign) were founded bottom-up by cities and their mayors in the early 1990s, a new generation of TMNs was initiated top-down by governmental and private actors (including philanthropic organizations). These later networks included the Compact of Mayors, launched by United Nations secretary-general Ban Ki-moon and his special envoy for cities and climate change Michael Bloomberg. 2. TMNs became increasingly exclusive, after previously welcoming any municipality willing to join. An early example for exclusivity, related to size, is Eurocities, which accepts only major European cities as members. 3. While TMNs initially depended mainly on membership fees for funding, they have become gradually more reliant on external sources, for example, European Union (EU)-funded projects. This includes funding by philanthropic organizations that have become important for the funding of networks like C40. Today, a variety of TMNs exist. They can be characterized by type of formation (bottom-up vs. top-down), admission rules (inclusive vs. exclusive), and funding (internal vs. external) (see Table 1). 126 •Unpacking Polycentric Climate Governance Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 Case Selection and Methods Empirically, previous research on TMNs has focused on individual networks, such as the ICLEI (Yi et al. 2017) and C40 (Gordon 2020). Their increasing diversity led scholars to develop a range of different typologies to categorize Table 1 Characteristics of the Climate Alliance, the Covenant of Mayors, and 100 Resilient Cities/Resilient Cities Network Climate Alliance Covenant of Mayors 100 Resilient Cities/Resilient Cities Network Formation Bottom-up by municipalities and NGOs Mixture of top-down (by the European Commission) and bottom-up (by cities and their networks) Top-down by the Rockefeller Foundation Admission Inclusive Inclusive Exclusive, selective Funding Internal funding through membership fees; external project funding (national, EU) EU funding for the CoM Office (run by various TMNs) 100RC: external funding from the Rockefeller Foundation RCN: diverse sources (such as Development Bank of Latin America) Goals Original goal (1990): reduce GHG emissions by 50% by 2010 At least 20% GHG emissions reduction by 2020; at least 40% by 2030; climate neutrality by 2050 Resilience strategies Revised goal (2006): reduce GHG emissions by 10% every 5 years; 50% reduction by 2030 Sustainable energy (and climate) action plans, risk and vulnerability assessments Identification of potential shocks and stresses Actions for adapting to shocks and stresses 100RC = 100 Resilient Cities. EU = European Union. CoM = Covenant of Mayors. GHG = greenhouse gas. NGO = nongovernmental organization. RCN = Resilient Cities Network. TMN = transnational municipal network. Kristine Kern, Peter Eckersley, Elisa Kochskämper, and Wolfgang Haupt •127 Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 and analyze TMN activities (Haupt and Coppola 2019). These typologies provide a useful heuristic for mapping and comparing different TMNs, but they are not yet linked to debates on polycentric governance. For our study, we selected the CA, CoM, and 100RC/RCN as comparative case studies based on two criteria. First, each TMN requests that members make specific commitments, which then provide identifiable and measurable outputs (e.g., CO 2 emission reductions) (see Table 1). All three networks have developed such commitments for all members. Second, and in line with Seawright and Gerring’s (2008) characterization of diverse cases, we analyze TMNs that differ in terms of their genesis and general characteristics. The CA started as an inclusive, bottom-up network initiated by pioneering cities in 1990, selffunded by membership fees. In contrast, 100RC was set up as an exclusive, top-down network in 2013, funded by the Rockefeller Foundation. Like the CA, the CoM is an inclusive network, but its establishment in 2008 was a mixture of top-down and bottom-up processes, characterized by the close collaboration between city networks and the European Commission, which has provided funding for the operation of the CoM Office (see Table 1). Thus the three selected cases represent different types of TMNs that were located at different positions along the polycentric–monocentric spectrum at their inception. This research design enables us to trace and compare the evolution of each TMN over time along our three dimensions of governance. For doing this, we apply the criteria mentioned above in the section “Dimensions of TMN Governance”and depicted in Table 2. Table 2 Governance Dimensions and Assessment Criteria for Polycentric Governance Governance Dimension Assessment Criteria Governance of (network level) 1. Multiplicity of internal decision-making bodies 2. Options for members’involvement in organizational committees, boards, and strategy development 3. Limited power of managing bodies (secretariat) at network level Governance by (membership level) 1. Monitoring at local level 2. Reporting on the network’s goals to the network on a regular basis 3. Options to sanction noncompliance Governance with (system level) 1. Collaboration with other TMNs 2. Collaboration with nonstate actors 3. Collaboration with governmental actors TMN = transnational municipal network. 128 •Unpacking Polycentric Climate Governance Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 (GHG) emissions on average by 26 percent between 2005 and 2020 (Joint Research Centre 2022; Rivas et al. 2022). Resilience is more difficult to measure than GHG emissions. Therefore, instead of formal reporting requirements for members, 100RC/RCN proposed milestones, particularly the development of resilience strategies and the institutional integration of CROs. Despite some shortcomings, compliance was high in 100RC. According to interview partners, eighty-three cities developed resilience strategies, with approximately 70 percent currently implementing them in the RCN. One-third of cities are updating their strategies to consider not only specific but also compound risks as highlighted by the COVID-19 pandemic. Interview partners also confirmed that 85 percent of all participating RCN cities have CROs. Although these posts do not always survive a change in city government, the majority of officers are now salaried municipal staff (Coppola and Haupt 2023). The network has sought to gain support from important city stakeholders to help these posts survive mayoral transitions, and 100RC could execute indirect sanctions by terminating their funding. Today, CROs are an integral and institutionalized part of the RCN. Furthermore, instead of focusing on the development of resilient strategies, the RCN is now more concerned with supporting groups of cities within the network on self-identified priorities. Although none of the three networks has the hierarchical authority to force members to act, local climate action has increased in all of them over time. The development of the CoM has been described as a “two-speed climate action process”because compliance is much higher in larger cities and in municipalities located in northern and central Europe (Rivas et al. 2022). The CA provides monitoring tools and supports its members to establish monitoring systems, but reporting is not required, and there are no sanctions in case of noncompliance. Compliance seems to be higher in monocentric networks with quasihierarchical features, such as 100RC. However, the RCN has loosened its uniform approach and now relies on more decentralized solutions. Overall, 100RC shows the fewest, and the CA the most, polycentric features due to the high degree of autonomy of its members (see Table 3 and Figure 1). Governance with Networks Not only does the CA facilitate knowledge transfer between its members but it has also collaborated extensively at the system level with other municipal networks, nonstate actors (such as environmental NGOs), and governmental agencies, thereby building on its initial cooperation with indigenous groups in the Amazonas region (Climate Alliance 2020, 2021). For example, instead of competing for external funding, the CA joins forces with other organizations and applies for joint projects (often nationally or EU funded). It has run numerous EU-funded projects (Climate Alliance 2023, 53–56) and opened an office in Brussels in 2007, which serves as a contact point for members and facilitates direct lobbying of and collaboration with EU institutions. The Declaration of Kristine Kern, Peter Eckersley, Elisa Kochskämper, and Wolfgang Haupt •135 Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 Wels (Climate Alliance 2021) emphasizes strong alliances and global partnerships. Additionally, the CA has been involved in managing the CoM, which has been run by a meta-network of TMNs since its inception in 2008. The CA has been a central part of this “network of networks”from the outset, which requires close collaboration between all consortium partners on a daily basis. The CoM frequently collaborates with EU institutions and has become embedded in EU multilevel governance (Kern 2019). This is a unique multilevel arrangement that involves close collaboration not only between all networks 5 running the CoM Office but also between the networks, the European Commission (which funds the operation of the CoM Office), and the JRC as a monitoring agency (Kern 2019, 2023; Kona et al. 2021; Rivas et al. 2022). In addition, among the covenant coordinators and supporters are many governmental organizations and NGOs. Another indication for the CoM’s high degree of collaboration with other organizations is the fact that it merged with the Compact of Mayors in 2016. This merger was the best option for the CoM to create the largest global coalition of cities committed to climate leadership and to develop a harmonized monitoring system (Bertoldi et al. 2018; Joint Research Centre 2020, 2022, 2023). Whereas 100RC cut ties with other TMNs, such as the ICLEI, with which it collaborated for implementation (Coppola et al. 2020), the RCN now works again with the ICLEI in a strong partnership. However, the RCN is not collaborating with other TMNs that focus on resilience (such as C40), due to differing member city sizes and the fact that it adopts a broader, more systemic definition of resilience than other networks. Although the RCN recognizes that national governments provide useful funding opportunities and influence urban policies, it does not provide support to help member cities access this funding or lobby for national policy changes. Nonetheless, political commitment to the RCN from powerful regional policymakers has increased over time. In 100RC, a strong focus was put on business partners (Nielsen and Papin 2021), which has now, in the RCN, shifted toward international organizations and initiatives, such as Making Cities Resilient by the United Nations. Levels of external collaboration with other municipal networks, governmental organizations, and NGOs are high for the CA, which collaborates closely with other organizations, particularly in the context of the CoM, leading to increasing embeddedness in a polycentric “network of networks.”This also applies to the CoM, which is run by a consortium of TMNs and associations of local authorities, has set up networks of covenant coordinators and covenant supporters, and even merged with the Compact of Mayors. While the organizational structure of 100RC focused primarily on the collaboration with business partners, the RCN seems to have a more open approach to collaboration with 5. The CoM Office is operated by a consortium that consists of Energy Cities, the CA, Eurocities, the European Federation of Agencies and Regions for Energy and Environment (FEDARENE), ICLEI, the Council of European Municipalities and Regions (CEMR), and an information technology company (Akaryon). 136 •Unpacking Polycentric Climate Governance Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 other TMNs than its predecessor. Table 3 summarizes our findings for the evolution of the three networks regarding the governance dimensions over time. Figure 1 presents these dynamics and the spectrum between polycentricity and monocentricity in a three-dimensional diagram. Discussion With respect to our three dimensions of governance, the three TMNs analyzed in this article have moved along the polycentric–monocentric spectrum in different ways. Research has shown an overall trend toward top-down-initiated, more exclusive and externally funded networks (Nielsen and Papin 2021). However, the development from 100RC to the RCN shows a trend toward a stronger bottom-up approach at the membership level, which is also reflected in the institutional changes of the network. Overall, 100RC/RCN is the most dynamic and the CA the most stable network. More generally, our findings suggest that TMNs may become more polycentric over time in response to external and internal drivers, as depicted in Figure 1. While the CA was located within the polycentric area at its creation, and stayswithinthisarea(movingfrom1to2inFigure1),100RCwasinthe monocentric area initially, but after reorganization, the RCN moved toward the polycentric corner (moving from 5 to 6 in Figure 1). Overall, the three TMNs converge to a certain degree along our governance of and governance with dimensions but remain quite far apart from each other in terms of governance by (see Figure 1). There are trade-offs between the three dimensions of governance. For example, our comparison between the CA and 100RC shows a trade-off between the governance of and governance by dimensions (see Figure 1). This is because a disaggregated organization that involves autonomous members in decision-making may lead to noncompliance, whereas monocentric structures may result in a loss of members or pressure to reorganize the network. There are also trade-offs between the governance with dimension, on one hand, and the governance of and by dimensions, on the other. In 100RC, a strong central authority limited the openness for collaboration with other TMNs and governmental organizations at the system level, while the CA’sdecentralized structure facilitates collaboration (see Figure 1). The CoM seems to be in the best position to find a balance between the three dimensions of governance. For the governance of and by dimensions, the CoM reached a medium, and with respect to the governance with dimension, even a high score (moving from 3 to 4 in Figure 1). Our findings suggest that more polycentric networks along the governance of dimension, such as the CA, require a certain degree of central coordination to balance the autonomy of members. Lower scores in this dimension suggest the need for a shift toward more self-organized internal decision-making, which takes greater account of members’interests, as we have seen with the transition Kristine Kern, Peter Eckersley, Elisa Kochskämper, and Wolfgang Haupt •137 Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 from 100RC to the RCN. Governance by TMNs is highest in networks that seek to enforce compliance. The CoM and RCN lie in between the CA as the most polycentric and 100RC as the most monocentric TMN along this dimension. In the absence of coercion, polycentric networks need to develop positive incentives for joining the network and comply with rules and overall network goals. In the governance with dimension, the CA scores much higher than 100RC, with its strong focus on business partners. This governance dimension is also high for the CoM, which is open to collaboration with different types of partner organizations. Conclusions By focusing on three elements of governance—internal decision-making at the network level, steering and enforcement at the membership level, and openness to collaboration with other actors at the system level—we present three dimensions of TMN governance (respectively, governance of, by,andwith)thatcan help us to examine, assess, and understand governing arrangements better. Focusing on how three selected TMNs have evolved, we applied these dimensions empirically to illustrate their degree of polycentricity over time. While our study was restricted to examining governance relating to TMNs, we suggest that our three dimensions of governance may provide useful lines of inquiry for scholars wishing to gain a greater understanding of how governance operates in transnational network organizations, such as transnational certification systems. More research is needed to fully assess the implications of our tridimensional governance approach and thereby paint a more nuanced picture of network governance. This may help us to better understand whether and to what extent the characteristics of transnational network organizations can contribute to governance outcomes and impacts and to assess the overall impact of TMNs on global climate governance. Our study also highlights the need for further research on TMN governance. First, most research on municipal networking has focused on individual TMNs, such as C40 or the ICLEI. Our study shows that a comparative approach that also takes the evolution of TMNs over time into account may offer more insights on how TMNs operate. Second, there are still research gaps with respect to the trade-offs between the three dimensions of TMN governance. A more open approach to collaborating with external actors could weaken the agency of individual networks, leading to cities questioning the value of their membership and ultimately leaving the network. Third, there is also a need to investigate the coexistence and complementarity of networks, for example, between inclusive networks, such as the CoM, and exclusive networks, such as the recently established EU City Mission (EU Mission on 100 Carbon-Neutral and Smart Cities by 2030; European Commission 2022). This coexistence may help to avoid two-speed processes and provide new avenues to overcoming the trade-off between the effectiveness of monocentric networks and the self-organization and collaborative potential of polycentric networks. 138 •Unpacking Polycentric Climate Governance Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 Kristine Kern is a professor at the Leibniz Institute for Research on Society and Space in Erkner, Germany (research group “Urban Sustainability Transformations”). She is also affiliated with Åbo Akademi University in Turku, Finland. She holds a PhD in political science from Freie Universität Berlin and has also worked at the Berlin Social Science Center and the Universities of Potsdam (Germany), Wageningen (the Netherlands), Södertörn (Sweden), and Minnesota (Minneapolis, United States). Her research concentrates on environmental governance, climate governance, and sustainability transformations in multilevel systems, including transnational governance of cities and regions. Peter Eckersley is an associate professor in public policy and management at Nottingham Trent University, United Kingdom. At the time of writing this article, he was also a research associate in the research group “Urban Sustainability Transformations”at the Leibniz Institute for Research on Society and Space, Erkner, Germany. His research focuses on local climate policy, central–local relations, public accountability, and the power dynamics involved in policymaking decisions. He holds a PhD in political science from Newcastle University, and his work has appeared in a range of politics, public policy, human geography, accounting, environmental science, and public management journals. Elisa Kochskämper is a postdoctoral researcher in the research group “Urban Sustainability Transformations”at the Leibniz Institute for Research on Society and Space, Erkner, Germany. She holds a PhD in political science, which she completed at Leuphana University Lüneburg. After her master’sstudiesat Ludwig Maximilian University in Munich (political science), she worked with the German Corporation for International Cooperation (GIZ) in the Mexican Environmental Ministry in Mexico City. She has also worked at Utrecht University, the Netherlands, and the University of Potsdam. Her research focuses on local environmental governance and covers topics such as urban resilience and sustainability, social justice, municipal decarbonization policies, and urban experimentation. Wolfgang Haupt holds bachelor’s and master’s degrees in geography (Dresden University of Technology) and a PhD in urban studies (Sasso Science Institute L’Aquila and Sant’Anna School of Advanced Studies Pisa). Wolfgang regularly teaches at the Universitat Internacional de Catalunya and the Brandenburg University of Technology Cottbus-Senftenberg and has conducted research visits to IHE Delft Institute for Water Education (2017) and the University of Cardiff (2023). His research focuses primarily on the urban level. Currently it mainly includes climate governance (climate change mitigation and adaptation), resilience, and material and immaterial cultural and world heritage and its significance for urban development. Kristine Kern, Peter Eckersley, Elisa Kochskämper, and Wolfgang Haupt •139 Downloaded from http://direct.mit.edu/glep/article-pdf/24/3/121/2469572/glep_a_00754.pdf by guest on 17 October 2025 References Acuto, M., and M. Ghojeh. 2019. C40 Cities Inside Out. Global Policy 10 (4): 709–711. https://doi.org/10.1111/1758-5899.12760 Acuto, M., and B. Leffel. 2021. Understanding the Global Ecosystem of City Networks. 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