Introduction

Worldwide, cities are responsible for a large share of greenhouse gas (GHG) emissions (67–72% in 2020), with about 100 of the largest emitting cities accounting for nearly 18% of the global carbon footprint1. An ascending trend in their commitment to climate mitigation strategies can be observed, notably in the most recent decade. More cities have engaged in emissions reduction efforts, have pledged to reduce emissions faster than previous years, and/or have established more ambitious targets than their regional or national counterpart2 (by about an additional 37% by 2030, collectively)3,4. Net-zero emissions targets have proliferated, spurred by dedicated initiatives like “Race to Zero” at the global level5 and the 100 Climate-Neutral and Smart Cities Mission in Europe (hereinafter Cities Mission)6. Cities growingly position themselves as trend-setters for their regions and countries by providing bold examples of ways forward to climate neutrality7, harnessing their proximity to places and people to materialise a just transition, and acting as innovation and experimentation hubs for new technologies, governance systems, financial instruments, and integrated multisectoral approaches8,9. Despite this vast potential, a significant ambition-implementation gap persists between aspirational objectives and their practical execution, as evidenced when comparing stated targets with outcomes2.

In a global study considering more than 3000 cities and 170 regions within G20 countries3, only 40% report sufficient data to assess progress toward their mitigation targets, out of which less than 40% are advancing as planned. Aggregating the same data at the national level, several European countries, such as Portugal, Ireland, Latvia, and Cyprus appear on track to meet over 75% of their climate targets; however, these successes often come with less ambitious goals. In contrast, cities and regions in China and Türkiye show little progress, and those in countries with high public engagement in climate issues, such as Canada, the UK, and Australia are reducing emissions by less than a quarter of their climate targets. Overall, only a small fraction of existing targets (7%) are in line with scenarios that limit global warming to 1.5 °C with no or limited overshoot3. In addition to heterogeneous climate targets, there’s a global shortfall in action, with the current annual emissions reduction rate (1.6% per year) falling behind the necessary 2.7%, particularly in the Global South3. Overall, at present, most cities only partially achieve their mitigation goals10,11,12,13. They have generally seen a 10–25% reduction in emissions over the past decade6 largely ascribable to energy efficiency and renewable energy policies, with reductions being more significant in wealthier, northern European cities6. Hence, the gap to climate neutrality (i.e., absolute- or net-zero GHG emissions) is wide. Exemplarily, for those subnational entities that expressed interest in the Cities Mission, reaching the goal of zero emissions by 2030 would require at least a quadruple effort in half the time, on average6.

Climate neutrality refers to a holistic and integrated state where all sectors, gases, and scopes are accounted for, and the balance of positive and negative emissions is demonstrated to be zero at the target year. It implies conceptual, methodological, and procedural differences from regular climate mitigation to enable holistic action and go beyond reduction targets or incremental emissions decreases. Cities on a journey to climate neutrality must wade through unprecedented complexity in climate action as multiple urban systems undergo systemic changes, characterised by nonlinear feedback loops, multiscalar interactions, and legacies - all of which are likely to occur asynchronously14. This complexity also unfolds as cities face multifaceted risks, such as securing adequate financial resources, adhering to precautionary and equal opportunities principles, and establishing the regulatory frameworks, governance structures, and stakeholder networks needed to enable systemic change15,16. Navigating these challenges requires empowering cities, especially those from developing countries, to cultivate a longer-term perspective, self-enforcing power structures, transparent distribution of responsibilities and impacts, and contingency plans7,14.

In this Perspective, we contend that the moment is ripe to empower cities, drawing key lessons from the experience of cities worldwide in climate action. Capitalising on the rapidly growing literature15 on urban climate action, this Perspective proposes 5 practical recommendations to help cities unleash all their potential to meet their climate neutrality goals. These recommendations focus on multilevel governance and co-creation, green finance, citizen engagement, equity and justice, and digitalisation, inter alia. Simultaneously, they emphasise the critical role of transparency and integrity in target- and action-setting. We elaborate on dimensions that are especially salient from the standpoint of a real-world planner and aim to directly respond to the most common risks perceived by climate neutral-to-be cities, as illustrated in Fig. 1. Our recommendations are grounded in the experience of a large urban sample, comprising 13,000+ cities from the Global Covenant of Mayors, 362 cities from the Cities Mission, and the analysis of climate action plans from hundreds of cities worldwide including the Global South. As risks, needs, and opportunities may be city-specific, the recommendations and their possible interactions suggest successful processes towards climate neutrality that are necessary but not necessarily sufficient and whose prioritisation may be different on a case-by-case basis.

Fig. 1: Risk mitigation through targeted recommendations in urban climate neutrality.
Fig. 1: Risk mitigation through targeted recommendations in urban climate neutrality.
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Schematic overview of identified risks (represented by specific icons) to urban climate neutrality efforts, as mapped in Ulpiani and Vetters16. Each recommendation is associated with the icons of the risks it can address (with no specific ranking), illustrating the direct impact of strategic measures on mitigating specific challenges within the urban climate action framework. It is important to note that the same actions may introduce new risks, such as increased cybersecurity vulnerabilities. This potential cyclic interaction between actions and emerging risks should be considered in the strategic planning process.

Strive for comprehensiveness, transparency, and integrity

Pursuing climate neutrality requires internalising a process of mapping and integrating emissions data and their sources, to compile comprehensive baseline and monitoring inventories. However, de-facto, urban greenhouse gas emissions inventories are often incomplete (i.e., lacking data across relevant sectors and gases)6,17 and/or outdated. Song et al.3 found that only 22% of almost 1500 local authorities globally had an emissions inventory updated since 2020. This implies that emissions baselines may be unrepresentative of the status quo or even strongly biased by COVID-19 effects18.

To avoid underreporting (and, interconnectedly, undercommitment), cities require accounting methodologies adapted to their scale. Empowering their technical capabilities with dedicated personnel as well as access to high-quality data, including advanced sensor networks and earth observation, is essential to effectively measure and account for all emissions6. This is particularly relevant in the Global South3 and for Scope 3 emissions, which require extensive monitoring and innovative policies to accurately assess and manage the carbon footprint of urban activities and consumption patterns19,20,21. To enhance accuracy and self-sufficiency in areas with inadequate monitoring, the rollout of data acquisition systems and remote sensing might be prioritised over indirect methods (such as downscaling from national data), where feasible. Furthermore, to facilitate the digital transition, the adoption of remotely controlled, intelligent monitoring systems and advanced big data platforms should be promoted.

Preferably, cities should insource the development of emissions inventories6. This is crucial for them to fully own the process and develop a robust territorial understanding of the origins of emissions in the local environment. Additionally, it helps identify which sources are more critical than others (useful for prioritisation) and understand why certain policies have been or will be more effective at reducing emissions (essential for evidence-based policy monitoring, assessment, and updating)17. Further, duly documenting approaches, assumptions, data sources, and possibly uncertainty is beneficial to sense-making and harmonisation across inventory years.

To enhance accountability, once emissions data have been collected and processed, they should be transparently reported and communicated, along with the baseline assumptions and associated targets. Dedicated frameworks and tools exist for cities to streamline measurement and reporting procedures, such as the Common Reporting Framework (CRF) of the Global Covenant of Mayors for Climate and Energy, and the Community-Scale Greenhouse Gas Emission Inventories (GPC) by C40, both based on IPCC Guidelines. Such calculative infrastructures become the means of making net zero manageable and transparent and can be tailored to account for data limitations, such as those faced by cities in Africa22.

Accountability is imperative as climate neutrality targets seldom stipulate the attainment of absolute zero emissions within a specified timeline23. Rather, cities commonly pursue net-zero targets with substantial residual emissions in the target year6.

There is common understanding that residual emissions need to be held at a minimum. Emissions reduction at source is always the priority (“mitigation first principle”23) as only rapid near-term emission reductions are effective in reducing climate risks24. Declaring emissions as residual can be a controversial matter. While compensation offers a means of balancing residual emissions via mechanisms such as carbon sinks and credits, a risk exists that governments may disguise expensive or politically inconvenient operations by categorising them as residual23,25. This can create pressures for an oversized carbon removal infrastructure26 with all associated concerns in terms of feasibility, sustainability, societal impacts, land footprint, food security, energy requirements, and availability/affordability27,28. Transforming residual emissions in a legitimate instrument of climate action requires dedicated planning. The claims of necessity and possibility that underpin the very concept of residual emissions as “unfeasible” or “hard” to “abate” emissions are contingent on values, norms, and interests, where they should be based on science29,30. Current assumptions should be challenged to foster societal debates on what constitutes unavoidable emissions, considering the unequal historical and distributional impacts of emission patterns, as well as power dynamics inherent in these discussions31.

Overall, to adhere to the integrity and transparency necessary to uphold the legitimacy of net-zero pledges, cities should clearly disclose the components of residual emissions and ensure they result from a dynamic and multidisciplinary analysis. A conceptual framework to guide this effort has been recently proposed23, requiring cities to scrutinise emissions sources, solutions, and constraints in mitigation (sensitive to their role in the multilevel governance system). Cities should also design adequate compensation strategies (Box 1), while considering what this means for different societal groups.

Engage in financial experimentation and innovation

Recent empirical evidence suggests that green finance is the most effective financial strategy at reducing CO2 emissions, with positive impacts demonstrated in the top ten economies that have historically supported it (i.e., Canada, Denmark, Hong Kong, Japan, New Zealand, Norway, Sweden, Switzerland, the United Kingdom, and the United States)32. An analysis of panel data from 46 countries suggests that this positive effect has increased over time33 and is observed transversally34, including in the construction sector, with the highest intensity in emerging economies35. This finding is crucial as several of these nations are currently experiencing rapid and steady population growth and urban expansion, with ensuing increases in GHG emissions.

Despite this, only a small elite of cities have estimated the capital requirements for funding and financing climate neutrality36,37. Additionally, the methods employed to assess the size of the investment are commonly simplified, resulting in either disproportionally high capital needs or extremely low figures. There is still significant untapped potential for cities to deploy capital market opportunities for green climate financing or establish dedicated investor relations36,38. Further, cities are either in the initial stages of or have limited experience in formulating investment strategies and/or lack a project pipeline. This suggests that, even in cases where financial resources may be available, cities face a competence gap hindering their ability to advance projects or effectively capitalise on available funding36,37. Finally, very few cities consider the importance of creditworthiness and transparency in the use of proceeds as a pre-requisite to obtain financing in capital markets36,38.

Government support and guarantees are relevant in building momentum and enabling early action by derisking projects36; however, net-zero investments should be as future-proof as possible and resistant to political changes16. Therefore, many cities consider necessary to draw from self-owned capital while acknowledging that this would cover only a small share of the costs to transition to climate neutrality36.

Alternatives for financing investments exist, yet cities still favour conventional financing mechanisms available at the local level (such as property taxes and issuing debt in capital markets to finance capital costs), while making little to no use of innovative financing instruments36. This is particularly relevant to the digital transition, where crowding in private financing (whether in the form of public-private-partnerships, investments, or blended finance) and using innovation procurement appear to be a blind spot. Additionally, energy service companies, green bonds, public-private partnerships, and crowdfunding may be attractive to cities in the Global North36 just like in the Global South39,40 and can be positive instruments of climate action when structured to genuinely address urban inequalities and foster socio-ecological transitions41. This is especially important as traditional funding sources often neglect social dimensions, such as gender aspects, intergenerational fairness, or poverty alleviation42,43.

Further, cities can extend their investment power in various ways. Taking the energy sector as an example, cities can engage in joint commitments with e.g., energy suppliers, private district heating owners, building construction and rental companies44. Moreover, energy performance contracting, revolving funds, rewarding systems, and re-distribution of revenues hold promise in the establishment of virtuous loops of investment36 that make decarbonisation efforts cost-neutral in the long term and promote social justice45. For instance, the revenues of energy communities can feed into new projects, new jobs, and new services in circular mechanisms that help sustain the transformative momentum36,46,47. Engaging stakeholders and the investor community helps estimate investment needs and identify financial products that match the risk profile of projects. This is particularly important due to the innovation in business models, the learning curve for investors, citizens and city managers, and the long-term investment horizon.

To increase momentum in the global transition to climate neutrality, more financial tools that support every stage of the process are needed, especially for cities that are just defining their long-term commitments or are facing significant capacity constraints, such as smaller local authorities36,48. Sandboxes (controlled testing environments) may help to identify innovative financing mechanisms tailor-made for the needs of the cities and their stakeholder community49. New toolkits and funding programmes are also on the horizon50,51, yet for cities in developing countries, national financial development is crucial to temper the emissions augmenting roles of economic growth, energy use, foreign direct investment and trade openness by minimising credit costs, improving credit allocation, and making it easier to invest in green energy sources52. Financial innovation in such urban settings necessitates going beyond conventional sets of instruments (e.g., green bonds, carbon taxes), actors (e.g., real estate developers, private investors), and projects (e.g., large-scale infrastructure), to focus more on the deployment of decentralised, small-scale or community-led efforts, which better match the collective potential for a safe and just transition53. The financial gap is also a matter of careful strategic design, factoring in the efficiency of different technologies and the role of high-tech versus low-tech, soft, or nature-based solutions (NBS) to minimise capital costs from the outset. However, securing financing for softer measures or NBS is a persistent barrier in climate action, highlighting the need for effective co-finance54 and prudent but effective narratives around co-benefits.

Enhance polycentric governance, collaboration and collective ownership

Polycentric governance is essential for cities to address the complexity of achieving climate neutrality as it stimulates experimentation, local adaptation, and learning across scales55,56 while leading to more effective and equitable outcomes57. Cities, as commons, represent shared resources - spaces and infrastructures that are open to all yet prone to congestion and rivalry. This requires rules and governance systems that ensure equitable and sustainable use58. By enabling multiple, overlapping centres of decision-making across different scales, polycentric governance supports the design of flexible rules and equitable frameworks for resource sharing, ensuring that diverse needs are balanced while reducing emissions56. It represents an opportunity to harness shared learnings and promote systemic change, allowing cities to address challenges such as resource scarcity, social inequities and climate resilience59. As climate neutrality entails multidimensionality and cross-sectorality, experience-based, local-knowledge-rich, need-driven, and stakeholder-diverse approaches can help identify and anticipate trade-offs and spillover effects. This approach not only helps cities stay on track, but also meet their citizens’ needs and empower their agency while gaining political consensus60. In practice, this requires evolving governance structures that institutionalise climate action, foster participatory governance, and actively engage key stakeholders in decision-making processes61. Such approaches may need to be evaluated against time and cost overruns; however, they can enhance legitimacy and long-term effectiveness, particularly when addressing cross-sectoral spillovers and social equity dimensions of climate neutrality. Although often associated with democratic and multi-level governance, elements of polycentricity can also be observed in more centralised systems, where accountability and legitimacy tend to rely more on performance outcomes than on participatory deliberation.

As complex nodes within a web of interdependencies, cities can accelerate climate action through participation in inter-city networks62,63 and science-policy-practice (SPP) partnerships engaging citizens, businesses, academia, and other levels of government40,64. Exemplarily, collaborations to match ambition levels across co-located cities and companies could enhance the overall emissions reduction potential by almost 70%65. SPPs can harness epistemic diversity and support an integrated urbanism66, potentially catalysing transformative urban alliances - as observed to some extent in response to the Covid-19 pandemic67 – circular business models, and industrial symbiosis68. This sort of transdisciplinary interaction requires further reinforcement in the Global North and holds the potential for significant transformation in various Global South regions, where the need for enhanced support and cohesion among diverse governmental levels and stakeholders is critical40. Further, given the lack of established models for extrapolating successful climate solutions and the unresolved challenges of generalisability and replicability, SPPs are indispensable to transfer and upscale climate action so as to accelerate the pace and reach of transformation66.

The question is how to stimulate the “active interface” of collective intelligence and commitment. We argue that valuing climate neutrality as a whole, including its co-benefits such as improved air quality, improved resource access (e.g., transport, energy), public health, and green jobs69, can play a key role. By measuring, monetising and making these co-benefits salient, cities can show how climate neutrality speaks to the needs and well-being of all citizens and stakeholders, especially in rapidly urbanising emerging economies70. By showing how these co-benefits are currently being distributed and how they can be more equitably distributed, cities can garner more public support and make investments in climate action more accountable71. At the same time, integrating climate co-benefits into all municipal decisions and leveraging sector coupling and synergies can enhance the cohesion of actions and foster a shared commitment to climate goals72. Linguistic and cultural barriers, stereotypes, and biases should be explicitly addressed to prevent miscommunication and ensure all stakeholder groups are heard73. Further, co-creating SMART (Specific, Measurable, Achievable, Realistic, and Time-bound) targets, actions, and key performance indicators (KPIs) can help keep climate neutral objectives accountable and in line with collective needs. This process strengthens the social contract by fostering community bonds. Further, setting intermediate targets for KPIs creates spaces to celebrate and communicate successes, which in turn would improve public acceptance and engagement.

Cities are encouraged to explore a variety of methods to engage citizens and stakeholders, as different groups and urban contexts have distinct needs74,75. An efficient and meaningful citizen engagement strategy should include two elements: a clear objective and a defined role for citizens (co-creative, decisional, or consultative) along with the expected contribution. Further, cities should foster bottom-up initiatives and elicit citizens’ preferences on engagement methods, which can introduce innovative perspectives into engagement strategies76. A meaningful citizen engagement strategy must centre on collective deliberation, where citizens come together to reflect on shared challenges and co-create solutions77. This process relies on empowering individuals with the information and competences they need to participate fully - whether to weigh the benefits of a green alternative or contribute to decisions that affect their communities. At the same time, the collective dimension must be nurtured through dialogue that encourages diverse perspectives and fosters mutual understanding. By making information accessible and relevant, cities can enable informed, reflective engagement, build trust, and strengthen social cohesion (Box 2). Conversely, a climate urbanism with little to no consideration of different groups’ experiences risks perpetuating inequalities, compromising the socio-technical and financial viability of city-wide climate neutrality targets and potentially leading to exclusionary net-zero commitments. An intersectional approach that ensures the needs of vulnerable groups and minorities are duly considered is crucial78,79, as these communities face disproportionate climate risk exposure, have limited influence over policy decisions, yet possess valuable local knowledge (e.g., indigenous communities)80,81. Inclusive processes that go beyond consultation towards co-creation prevent social mistrust, polarisation, divide, and pauperisation while enhancing the effectiveness and legitimacy of climate actions (as evidenced, for instance, in the case of public space redevelopment82 and local heat decarbonisation83).

Yet co-creation is not a silver bullet. Cities should be mindful, as engaging a diverse array of stakeholders in climate neutrality efforts can introduce risks, such as poor coordination, conflicting objectives, and organisational inefficiencies. These challenges can lead to operational paralysis, hinder accountability and ambition, and potentially exclude certain groups from the process, slowing down the pace of transformation and limiting inclusive participation16. Further, in stimulating societal participation, there is no straight line from unawareness and inaction to action and empowerment (see Fig. 2). Indifference, unwillingness, denial, and local opposition are just as easily triggered as positive levers such as interest, proactiveness, leadership, and activism84. To build sustained positive engagement, investing in an inclusive and evidence-based training programme about the climate-neutral transition, free from biased information, could be an effective option. Additionally, clear accountability mechanisms must be established to ensure transparency and trust.

Fig. 2
Fig. 2
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Representation of the non-linear climate citizenship awareness ladder, adapted with permission from the EU project GRETA106. Green and red lines link to positive and negative outcomes, respectively. Green lines in the lower section indicate transitions that may occur from a negative to a positive outcome that reroute citizens on a virtuous pathway towards advocacy.

Use equity and inclusion as a compass for holistic action

While the transition to climate neutrality brings many benefits, it may also induce negative consequences that often disproportionately affect the most vulnerable. This is why climate action cannot be implemented in a moral vacuum; equity and justice must guide every step of the process85 (Box 3).

Neglecting climate justice in the pursuit of a climate-neutral future can undermine the transformative aspirations of this transition. It can perpetuate extant social disparities or catalyse novel inequities. Addressing issues like renoviction, where tenants are displaced due to renovations for energy efficiency measures, or ensuring access to public transport, green corridors and energy-efficient solutions for vulnerable communities is imperative86. Otherwise, the transition to climate neutrality risks becoming exclusive, benefiting only certain groups while leaving vulnerable communities behind77. Further, social polarisation and poverty, in any form (including energy and transport poverty) will make it difficult to switch to new models and practices because of the inherent operational barrier and socially divisive potential and because it reduces spendable income16. Cities should thus integrate in their climate planning a systematic assessment of the distributional effects of climate policies to ensure that climate action benefits all, including socioeconomic, age, and gender groups, businesses of all sizes, and communities in wealthy and vulnerable situations alike. In addition, cities must recognise the specific needs of marginalised groups and of current and future generations to ensure that their voices are heard in decision-making processes87. For instance, valuing the perspectives and role of youth in implementing solutions towards their climate neutrality targets, a hundred cities (such as the city of Hobart in Australia, the city of Despeñaderos in Argentina, Mykolaiv in Ukraine) have joined the Youth Climate Action Fund supported by Bloomberg Philanthropies and the World Organisation of United Cities and Local Governments (UCLG) through which actions designed by youth can be delivered88.

Encouragingly, there is evidence that cities more engaged in climate change mitigation tend to better integrate the social justice dimension into their policies89. However, significant variations exist due to geographical location and the relationship with higher governance levels, necessitating targeted support for capacity building and financial advisory services to enhance climate justice awareness89. Equally interesting is that some cities targeting climate neutrality are prioritising interventions to improve the quality of life and the well-being of the most deprived first16. By focussing on the needs of the most vulnerable, these cities aim to mitigate, if not prevent, the risks of exacerbating injustices and pauperisation, while fostering social cohesion.

Champion integrated and interoperable urban planning

Cities should adopt comprehensive planning strategies that consider sectors (e.g., energy, transport, waste, water, agriculture, industry, land use), goals (e.g., GHG emissions reduction, climate adaptation, air quality, liveability, economic prosperity), and resources in a cohesive manner, embedding climate neutrality goals into existing and innovative planning tools and approaches and interweaving the threads of green finance, digitalisation, and circular economy90,91. For instance, while pursuing buildings decarbonisation, cities should strive to maximise co-benefits and synergies (e.g., combining building energy retrofit with social housing initiatives, seismic resilience interventions and/or asbestos removal) and include the construction process and the life cycle of products in their quest for sustainability68,92.

Spatial planning plays a crucial role in orchestrating integrated, multi-sectoral, and cross-scale actions that acknowledge the intricate relationships between policy domains, sectors, and challenges, thereby fostering a holistic and adaptive approach to climate neutrality93,94. Further, integrated urban planning promotes land use efficiency (and can therefore save surrounding carbon sinks)95 and enables territorial cohesion96, which is essential for cities striving for climate neutrality7. By fostering an urban-rural balance, cities can value the strengths of both landscapes, such as the innovation and infrastructure of urban centres and the natural carbon sinks and agricultural practices of rural regions, while promoting a safe ratio in terms of surface permeability and sealing1. This balance is critical for the equitable distribution of resources and opportunities, preventing the overburdening of urban systems and the neglect of rural communities. Further, integrating diverse territories in climate action plans encourages shared responsibility, synergies and maximises the potential for renewable energy use, waste reduction, and conservation efforts. Exemplarily, 78% of the photovoltaic, onshore wind and hydropower potential in Europe is rural97. Accessing these resources while retaining local value and needs, for example through the promotion of renewable energy communities, would allow rural areas to contribute and benefit from the energy transition while preserving their natural and agricultural assets. Further, as cities are open systems that depend on their hinterlands for imports and exports, urban-rural linkages constitute a means for cities to influence large upstream emissions and decarbonise their supply chains, while promoting a sustainable approach to waste, food, and water1. Ultimately, a strong urban-rural partnership is a cornerstone of resilience, allowing cities to achieve climate neutrality while promoting regional development and quality of life for all inhabitants. Changes in land use efficiency is also about patterns of urban growth. A shift toward vertical development is being observed among a large sample of cities around the world, carrying important consequences for material and energy use98. In addition, urban characteristics can provide different potentials for rain harvesting and can be planned together in an integrated manner99.

By investing in integrated urban planning, cities can minimise the need for costly remedial measures that arise from haphazard or short-sighted development practices, thereby ensuring budget efficiency and correct allocation of resources. Further, an integrated approach promotes attention to co-benefits, which, as mentioned, are precious levers to stimulate the appetite of a wide range of investors and interested parties, while also helping citizens recognise meaningful improvements in their quality of life. Integrated planning and holistic assessments can be supported by open-source tools100,101.

Digital and smart city solutions are a powerful instrument of integration in the pursuit of climate neutrality102. Despite urban entities increasingly acknowledging the strategic value of investments in digital twins, IoT, and open data platforms, the imperative of cultivating people-centric design and ensuring the infrastructural integrity of both the physical and cybernetic dimensions within the smart city ecosystem is often overlooked, along with the challenges of interoperability and data ownership103.

The digital transformation may deepen the digital divide and introduce cybersecurity vulnerabilities. Addressing these issues is crucial for an inclusive and secure transformation, as the transition to smart, interconnected systems heavily relies on digital infrastructure and technologies that may not be accessible to all citizens16. This divide can lead to inequalities in benefitting from low-carbon solutions and participating in sustainable initiatives. For example, in Vienna people with lower social status, or belonging to certain gender and age groups, showed a lower adoption of smart home energy management systems104. Furthermore, as cities become more digitally integrated, the scope for cybersecurity threats expands, potentially endangering critical infrastructure and the privacy of residents. Consequently, inclusive digital education, interoperable data systems and robust cybersecurity measures are essential to safeguard urban sustainable development goals against the risks of an increasingly connected world. At the global level, the Urban Transitions Mission - focused on supporting net-zero, resilient, and people-oriented cities - is also initiating efforts to provide data analytics to support urban planning105.

Conclusions

The transition to zero emissions within urban contexts demands an orchestrated approach centred on the triple ‘inter’ synergy (integrity, interaction, and integration), where integrity addresses the ethical and moral foundations, interaction the consultative process, stakeholder involvement and multi-level governance aspects, and integration the holistic nature of the transition, including co-benefits, synergies, and trade-offs. This Perspective enucleates five practical recommendations that translate this synergy in the domains of emissions accounting and target setting, financial innovation, collaborative and reflexive governance, equity and inclusion, and integrated urban planning. The recommendations are interdependent and hinged on the need to generate, restore and/or protect consensus around the transition, to overcome the pitfalls of short-termism, top-down governance and unilateralism. The recommendations zoom in on the need to address interactions related to (i) residual emissions strategies and climate justice as critical to ensuring the integrity of net-zero commitments, (ii) advanced science-policy-practice partnerships and well-crafted citizen engagement methods to operationalise co-creation and collective intelligence, and (iii) territorial cohesion and digital infrastructure as fundamental elements to pursue integrated urban planning and evidence-based policymaking. This confluence of strategies is not a mere aggregation but a harmonised interface of practices with synergistic connections, leveraging cities as centres of change. The recommendations and their summary overview in Fig. 3 can be used as a checklist by cities to perform a first high-level assessment of their climate neutrality plans. The proposed recommendations and the possibility of bringing them into reinforcing interactions are essential yet not necessarily sufficient to achieve climate neutrality. Further, their implementation may necessitate navigating barriers in implementation and trade-offs, such as balancing the allocation of resources and capacity to build comprehensive inventories, formulate compelling business plans, and create new governance structures simultaneously. Cities may need to prioritise and sequence their efforts, acknowledging that enhancing polycentric governance, for instance, may require diverting resources from financial experimentation or integrated planning. Ultimately, each city must navigate its own course within this framework, tailoring strategies to local contexts and capabilities, and fostering a transition that is not only environmentally sustainable but also socially robust and technologically secure.

Fig. 3: Summary of practical recommendations and associated specific measures and how they relate to the triple ‘inter’ synergy.
Fig. 3: Summary of practical recommendations and associated specific measures and how they relate to the triple ‘inter’ synergy.
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The recommendations that are given in boxes are connected to associated measures as indicated in the legend. The icons representing integrity, interaction, and integration are sized proportionally to their relevance, on average terms, for each recommendation. The recommendations and specific measures are based on insights developed from listening to the voices of cities and their stakeholders. The emphasis that is placed on the three elements of integrity, interaction, and integration can also vary across time as a city navigates its own course to climate neutrality and seeks to tailor strategies to local contexts and capabilities.