A central challenge for sustainable urban development is balancing the trade-offs of high urban density. We examined whether biodiversity can be supported within dense or compact urban areas by analyzing bird species richness and composition across 30 sites in Gothenburg, Sweden, representing three urban form types (two compact and one dense) and reference areas with abundant vegetation. Results showed that species richness was significantly lower in the three urban form types than in the reference areas, and species composition differed significantly between the two groups. However, there were no significant differences in species richness or composition between the individual urban form types themselves. Across the three urban form types, nevertheless, sites with larger local natural habitat area and/or better connectivity to surrounding natural habitats had higher species richness, whereas variation in species composition was associated primarily with local habitat area. This highlights that increasing habitat area remains the most effective strategy for supporting avian diversity, even in dense or compact urban areas. Species that are less common in urban areas were also recorded at sites within the three urban form types where suitable conditions existed. These results not only suggest that biodiversity can exist within dense or compact urban areas but also that it can be supported through both site-level interventions and broader-scale planning for habitat connectivity.
The growing importance of inter-city and urban-rural relations has focused attention on the regional performance of regions in which smart cities are situated. This study examines the associations between regional spatial distribution and regional scaling performance (RSP), defined as the population-outcome scaling pattern across cities within a region. Using data for 18 European countries, including the UK, from 2000 to 2014, we estimate RSP across five dimensions: labor market, productivity, economy, education, and social equity. We then evaluate, through dimension-wise panel regressions, a synthesized RSP model, and regional spatial-pattern analysis, how RSP is correlated with two morphological spatial-distribution indicators, namely primacy (capturing the dominance of the largest city) and polycentricity (capturing the balance among urban centers). The findings show that spatial distribution is related to RSP in dimension-specific ways. Primacy is positively associated with productivity and economic scaling but negatively associated with labor-market scaling and the probability of belonging to the high RSP group, while polycentricity supports social-equity scaling but is negatively associated with education RSP. The interaction results further suggest that hierarchical concentration and networked balance are not simple alternatives: polycentricity reinforces the positive association between primacy and economic/productivity RSP, while primacy strengthens the positive association between polycentricity and social-equity RSP. These findings highlight the need for context-sensitive regional strategies that align spatial-structure interventions with specific performance priorities.
Drawing on five urban nature-based solutions being implemented across the world, we show how relationships influence adaptation processes and outcomes. Relationality is not abstract or peripheral but a concrete enabling condition for successful climate adaptation. Relationships emerge, evolve, and dissolve over time, shaping adaptation processes accordingly. We propose an agenda for evaluating relationships as core signals of adaptation success.
Despite growing evidence of urban gardening’s health benefits, studies in the Pacific Islands facing an obesity crisis remain extremely limited. In Palau, compared with non-gardeners, urban gardeners had a 0.86-point higher dietary diversity score (p < 0.001), 2.92 kg/m2 lower BMI (p = 0.011), and 3.49-fold higher odds of reporting good health (p < 0.001). These findings suggest the importance of integrating urban gardening into public health and spatial strategies.
As climate change, geopolitical instability, and environmental degradation accelerate, urban infrastructures play a pivotal role in either enabling or inhibiting regenerative transformation. Drawing on a multidisciplinary theoretical review, this paper presents a conceptual framework for integrated social, ecological, and technological infrastructures as the connective tissues of autopoietic urban socio-technical ecosystems. This framework reimagines infrastructures as dynamic, interstitial networks that enable cities to sense, interpret, and reorganize in response to rapidly changing conditions. The paper concludes by identifying design lessons for infrastructures capable of recovering from disruptions, adapting to changing conditions, and proactively transforming to sustain long-term vitality in the face of increasingly uncertain times.
Nature contact is a low-cost intervention shown through experimental studies to improve many aspects of mental health. The ‘equigenesis’ hypothesis indicates that nature contact may disproportionately benefit less advantaged persons, however, evidence remains nascent. This cross-sectional study of validated measures of depression, anxiety, stress and wellbeing in 1433 adults aged 18–64 in Sydney and Brisbane conducted in 2021 found support for equigenesis. Nature visits once per week or more were associated with constrained income inequities in depression, anxiety and stress, compared to less frequent visits, though mainly for moderate income earners. Nature visits of 2 h per week or more (versus less) and visits to three or more different nature spaces (versus none) also constrained income inequities in wellbeing, mainly for participants on lower incomes. Associations were negligible for those on higher incomes, highlighting the potential of nature contact to level-up mental health inequities by supporting those less advantaged most.
Urbanization implies a massive expansion of built-up land globally. The magnitude of this phenomenon, however, largely depends on the degree to which growing urban populations spatially concentrate around existing settlements. Here we measure population centrality, or the inverse of residents’ average travel time to the urban core, in over 7000 urban areas worldwide between 2000 and 2020, and test its association with urban land expansion. We observe rising dispersion (i.e., lower centrality) in most urban areas everywhere except Europe and the Americas. This is concerning as the two variables are negatively related: all else being equal, each additional minute from the urban core comes with an extra 1.6 km2 of built-up land. The association, however, is clearly negative only in small- to mid-sized and low- to mid-income urban areas, but poorly so otherwise. Moreover, higher centrality goes hand-in-hand with a modest containment of built-up land in Southeast Asia, Europe, Canada, and the USA, and an expansion of it in Eastern Asia and Oceania. Our findings suggest that increasing centrality may be a powerful tool for curbing urban land expansion in certain contexts, but an ineffective one in others, and that planning is needed to mitigate the spillovers of centralization.
This paper explores how Nature-Based Solutions (NBS), introduced through processes of Europeanization, are grounded in, and co-opted by, the post-socialist, neoliberal, and increasingly authoritarian Belgrade. The analysis focuses on the EU-funded CLEVER Cities project, which introduced NBS to Belgrade through the Linear Park, which was later absorbed into Marina Dorćol—a commercial waterfront development by European investors. Despite being celebrated as a best - practice example, the paper indicates that the NBS framework built on participation and socio-ecological benefits is turned into a tool for profit-making and political legitimation by an increasingly authoritarian Serbian regime. Building on document and media analysis, the paper identifies how this local co-optation of NBS is both mediated and reinforced by processes of Europeanization. The findings contribute to the critical debates on NBS by revealing structural limitations rooted not only in the local context but also in the way NBS are created and diffused in Europe. The paper argues for more politically reflexive approaches to NBS that prioritize power redistribution and social justice across diverse urban contexts.
Despite their ecological value and operational carbon sinks, the large-scale construction of public building-attached green spaces remains an overlooked source of urban carbon emissions. This study develops a process-based carbon accounting framework integrating quota-based emission factors, applied to three attached green space types (rooftop gardens, green squares, and sunken yards) in a representative public building in Wuhan, China. Construction activities were decomposed into 6 sub-projects and 22 unit processes. Results reveal total emissions of 2,080,646.86 kg CO2 (95% CI: 1,946,777–2,244,308 kg CO2), with an emission intensity of 95.12 kg CO2/m². Road engineering (808,761.21 kg CO2, 38.9%) and the base subproject (672,634.38 kg CO2, 32.3%) are the primary sources, while granite driveway construction and planting activities are the most emission-intensive unit processes. Emission intensity varied substantially, from 650.3 kg CO2/unit for permeable asphalt driveways to 0.32 kg CO2/unit for stone ball barriers. Scenario analysis shows that a 10% reduction in material consumption achieves the greatest reduction (137302 kg CO2), with road engineering and the base subproject contributing 75,990.68 kg CO2 and 61,311.49 kg CO2, respectively. LCA verification confirms the framework’s reliability (relative difference: 3.54%). The framework supports activity-level emission management and mitigation strategy selection for low-carbon urban green infrastructure planning.
Urban street reallocations and redesigns are central to sustainable mobility transitions, yet public acceptance remains a major challenge. While previous research has examined general attitudes toward transport policy, little is known about how specific design features shape support across diverse user groups. We conducted a large-scale stated choice experiment (N = 5991) embedded in a nationally representative mobility panel in Switzerland. Respondents evaluated navigable 360° and static visualizations of redesigned fictional urban streets, varying in infrastructure, greenery, and social space. We examine effects on three outcome dimensions: acceptance, willingness to live nearby, and willingness to cycle. Greenery consistently increases support across both formats. How the redesigns are visualized shapes which features become salient: the 360° condition increases sensitivity to social features, while the static condition increases sensitivity to environmental and infrastructural features. Subgroup analyses reveal substantial cleavages by gender, age, transport behavior, and political ideology. The results show that design-sensitive, visually supported planning strategies can build broader public coalitions for urban street transformations. Our findings inform participatory planning and policy design for more inclusive and context-sensitive urban transitions.
This study provides empirical evidence that slum upgrading programs are associated with meaningful climate adaptation benefits as an unintended consequence. Leveraging the staggered rollout of 31 interventions in Rio de Janeiro, Brazil, between 2006 and 2019, we employ a difference-in-differences design with fixed-effects Poisson models applied to daily mortality records across 806 healthcare facilities. We find that heatwaves increase mortality by 5.1% to 8.2%, and that proximity to slum upgrading interventions is associated with a 3.9%–5.5% reduction in this excess mortality, mitigating nearly half of the heatwave mortality penalty. Effects are concentrated in cardiovascular and respiratory causes of death, consistent with the biological pathways linking heat exposure to mortality. These findings have direct implications for the over 1.1 billion people residing in informal settlements, many in tropical regions where heatwave frequency and intensity are projected to increase under climate change, and suggest that large-scale infrastructure investment in slums should be recognized as a tool for climate adaptation in urban policy.
Ecosystem functioning enabled by urban ecosystem restoration (UER) contributes to sustainable cities. We examine how artificial intelligence (AI) supports integrated UER approaches by linking monitoring, simulation, and participatory processes within a social–ecological–technological systems framework, forming an AI-integrated UER feedback cycle. AI can contribute to social-ecological monitoring, multisource data integration, landscape simulation, citizen understanding, co-design, and adaptive management in UER under expert oversight and with attention to associated risks.
The implementation of urban nature-based solutions (NbS) is gaining momentum, with significant efforts to advance the use of green walls, constructed wetlands, raingardens and other solutions in Europe. We examine nine case studies across the Mediterranean to analyse different mechanisms that contribute to institutional mainstreaming of NbS for climate resilience in urban and peri-urban areas. Drawing on targeted interviews and workshops with representatives of academia, governments and project managers, we offer insights into how these solutions can gain scale through different pathways that account for both disruptive and anchoring mechanisms by (i) adapting existing processes and gradually changing institutions (embedding), (ii) leveraging gaps in institutions and finding opportunities to build momentum from previous initiatives (capitalising), (iii) convincing actors and proving the effectiveness of NbS (grounding), and (iv) creating knowledge to respond to future demands (anticipating). Responding to unique policy landscapes and geo-climatic and cultural contexts, the cases offer insights into how different pathways can create institutional space for climate adaptation or leverage existing institutions to consolidate transformative change for implementing NbS in the Mediterranean and beyond.
Urban agriculture (UA) is increasingly recognized as a transformative nature-based solution for enhancing food security, community wellbeing, and urban sustainability. However, efforts to scale UA depend critically on public support, which remains poorly understood. Here we investigate the social, environmental, and psychological underpinnings of public support for UA by adapting the Value–Belief–Norm framework. Results reveal a strong and broad base of support spanning financial contributions, participation, purchasing, and policy advocacy, and suggest a shift from private-oriented behavior toward greater civic and institutional engagement. Our findings show that UA support emerges through distinct behavioral pathways across private and public spheres: donation is socially motivated, participation is experience-driven, and both purchasing and policy support are rooted in perceived responsibility. These insights highlight actionable and transferable strategies to mobilize diverse publics and translate broad societal interest into concrete support for scaling UA to advance urban resilience and sustainability.
Wildfires intersecting developed land cover are a growing urban disturbance, yet national evidence on their frequency, ecological impacts, and social distribution remains limited. Using 141 U.S. urban-intersecting fires (1984–2025), we integrated fire perimeters, Landsat-derived NDVI and land-surface temperature, hydroclimate records, and census data. Annual fire counts did not increase, whereas burned area for larger events rose 0.22 km² yr⁻¹ (conventional p = 0.035; heteroskedasticity-robust p = 0.058), a positive trend sensitive to variance assumptions and to a few extreme fire years. Residents of fire-exposed tracts grew from 2.06 to 2.80 million despite stable per-capita exposure. Fires were preceded by short-term drying rather than long-term deficits, with wet-to-dry hydroclimate whiplash in 41–43% of events. High-severity pixels showed median NDVI declines of 41% and land-surface temperature increases of 2.35 °C, and 73% and 78% failed to recover greenness and temperature, respectively, within five years. Exposure concentrated in lower-density, owner-occupied, higher-income tracts, yet thermal recovery was faster in wealthier neighborhoods, revealing a two-stage inequality in who burns and who recovers. Because these dynamics are not unique to the United States, our framework transfers to fire-prone urban regions with comparable satellite and demographic records.
Urbanization has intensified human heat-stress risk. Although vegetation transpiration (Ec) can partly mitigate the urban heat island, the associated rise in local humidity may also exacerbate heat stress. How rapid urbanization and its associated three-dimensional (3D) urban form regulate vegetation’s coupled “cooling–humidifying” effect remains poorly understood. To address this gap, we analyzed 251 rapidly developing cities in China, classified them into four background-climate types based on temperature and specific humidity, constructed a 3D urban form index, and assessed the impacts of Ec on wet-bulb temperature (Tw) and how these impacts vary across different urban forms. Results show that as the background climate becomes hotter and more humid, Ec is increasingly likely to have a warming effect on Tw. In humid heat cities, the number of cities in which Ec exhibits a warming effect on Tw increases, and 63.8% of this upward trend is attributable to urbanization. Under high-rise compact forms, Ec raises Tw primarily by significantly enhancing humidity, while the cooling pathway is not significant. For the same Ec increase, the population-weighted Tw exposure intensity is 23 times that of low-rise dispersed forms (p < 0.05). These findings underscore the need to account for 3D form when evaluating vegetation cooling in humid heat regions and to mitigate health risks through coordinated optimization of urban form and vegetation configuration.
Cities are leading efforts to mitigate emissions and adapt to climate change, yet most comparative studies capture static outcomes rather than the dynamic processes that drive urban transitions. This paper introduces the concept of core dynamics as the finest recurring causal feedback structures that serve as building blocks that collectively shape a city’s transition trajectory. Each core dynamic consists of causal interlinkages among actors, instruments, enabling conditions, outcomes, barriers, and triggers. We propose a framework and derive an initial set of core dynamics from an illustrative base case (Copenhagen) through causal mapping and comparative analysis and then examine their recurrence in two contrasting cases: Canberra and Shenzhen. Our proof-of-concept analysis reveals some common mechanisms of change across diverse urban contexts. Although a larger scale analysis is required to validate and quantify core dynamics across cities, by shifting from static to dynamic process-based comparison, our approach provides systemic insights into not only what cities achieve, but also how and why effective transitions occur. It can therefore help identify common leverage points for more targeted policy transfer.
Urban heat risk is intensifying, yet many cities continue to rely on static assessment approaches that inadequately capture how risk evolves spatiotemporally. We argue for a more dynamic and context-sensitive approach to urban heat assessment and action. We outline five shifts that recognize the interacting roles of hazard, exposure, vulnerability, and adaptive responses, and propose a decision-support framework to support more targeted, equitable, and actionable urban heat preparedness and adaptation.
Abolitionist and critical climate justice approaches provide a theoretical framework beyond environmental justice for identifying inequities driving or stemming from climate change, specifically those related to recognitional injustice. Leveraging these insights, we provide an empirical assessment of how U.S. cities are considering mobilizing recognitional justice while implementing climate adaptation efforts on the ground. Doing so illustrates the ways in which critical climate justice theories have and have not yet been put into practice to ameliorate inequality. To do this, we analyze adaptation plans across 25 U.S. cities using a robust content analytical approach. Despite increasing scholarly attention on abolitionist climate justice, we find that, in practice, cities are only beginning to center their plans on recognizing historical inequalities, with attention paid to racism and redlining, a discriminatory practice of restricting who can live where based on race or ethnicity, in particular. We see fewer examples of how cities are considering or addressing systemic drivers of climate vulnerability and socio-economic inequality. Our focus on recognitional dimensions complements and builds on existing research on procedural and distributive equity in urban climate action, and supports ways to advance and implement broader, more comprehensive climate justice goals in cities across the U.S.
Temporary urban greening may be especially valuable in dense cities where permanent greening is constrained by limited space, structural conditions, or competing land uses, yet its reception in different urban contexts remains insufficiently understood. This study examines user responses to “Mobile Green,” a movable tree-based greening system designed for temporary deployment on artificial ground. Questionnaire data were collected at three Japanese sites with contrasting visibility and surrounding green coverage: KK Line in central Tokyo, JR Sakuragicho Station Square in Yokohama, and Tsukuba Center Square in Tsukuba. The results indicated two complementary pathways. First, visibility-related site contrasts were associated with more favorable perceptions, particularly prominence and brightness, which were in turn linked to more positive evaluations. Second, lower-green-coverage sites were associated with stronger stated preferences for introducing Mobile Green into everyday settings such as workplaces and homes. By contrast, preference for event-oriented deployment was relatively stronger in the civic plaza context of Tsukuba, suggesting that site meaning and routine use are also related to how temporary greening is interpreted. These findings indicate that the value of Mobile Green is context-dependent and suggest its potential as a flexible, temporary, and adaptive public-space intervention within broader strategies of sustainable urban transformation.
