Ecological Resilience and Urban Health: A Global Analysis of Research Hotspots and Trends in Nature-Based Solutions

Abstract

With rapid urbanization and increasing climate risks, cities are facing complex challenges related to environmental degradation and public health. This study conducts a bibliometric analysis of 1555 publications from the Web of Science Core Collection (2000–2025), using CiteSpace and VOSviewer to map global research trends, hotspots, and thematic evolution in the field of NbS and urban health. Results show that research interest in NbS has significantly accelerated since 2020, with Europe leading in publication output and international collaboration. Keyword analysis reveals that early studies focused on ecosystem services and climate adaptation, while recent trends emphasize governance, public participation, and environmental justice. The study also constructs a knowledge framework that illustrates how NbS contributes to urban heat mitigation, carbon management, health co-benefits, and resilience governance. This research provides a comprehensive overview of the NbS field and offers theoretical insights and empirical references for integrating NbS into urban planning, health strategies, and environmental governance, with practical relevance for cities worldwide.

1. Introduction

With the continuous acceleration of urbanization in the 21st century, cities are facing unprecedented environmental and health challenges [1,2,3]. According to the United Nations Human Settlements Program (UN-Habitat) in its World Cities Report 2022, the global urbanization rate had reached 56% by 2021, and it is projected to rise to 68% by 2050 [4,5]. Cities play a key role in driving economic development and social progress, but at the same time, they inevitably contribute to a range of environmental and social issues such as global warming, frequent extreme weather events, air and water pollution, insufficient green spaces, and a sharp decline in biodiversity [6,7,8,9,10]. Traditional “gray” infrastructure, primarily based on engineering and technological measures, has effectively supported urban expansion and population concentration in the short term [11,12,13]. However, its high resource consumption, lack of ecological service functions, and resilience have increasingly become limitations, making it difficult to meet the diverse and complex demands of sustainable urban development [14,15,16]. Against the backdrop of rapid urbanization, how to achieve the synergistic enhancement of ecological protection, environmental improvement, and human well-being has become a global challenge in urban governance that urgently needs to be addressed [17].

In recent years, nature-based solutions (NbS) have rapidly emerged in international academic circles and policy practices, becoming a critical tool for achieving the United Nations Sustainable Development Goals (SDGs), the Paris Agreement, and the Kunming-Montreal Global Biodiversity Framework, among other global agendas [18,19]. The NbS concept was first proposed by the International Union for Conservation of Nature (IUCN) and has been actively promoted by international organizations such as the European Union [20,21]. NbS emphasizes the integration of natural processes with engineering measures through the protection, restoration, and sustainable management of natural ecosystems, aiming to achieve a synergistic improvement of ecological, social, and economic benefits [22,23,24,25,26,27]. Numerous empirical studies have shown that NbS have significant effects in mitigating urban heat island effects, enhancing urban disaster risk reduction capabilities, improving green space accessibility, and promoting social equity and public health, while greatly increasing the value of ecosystem services [28,29,30,31,32]. In recent years, NbS have achieved fruitful theoretical developments and widespread practical applications in fields such as stormwater management, urban green space development, river ecological restoration, and climate-resilient infrastructure [33,34,35,36]. The volume of related literature has continued to grow rapidly, with interdisciplinary collaboration and knowledge innovation becoming increasingly active [37].

Despite the positive progress made in NbS in the global urban governance field, there are still many shortcomings in its theoretical framework, knowledge structure, and practical pathways at the urban scale. Current research tends to focus on local case studies or specific types of NbS, such as urban rain gardens and green roofs, lacking a global perspective on the systematic knowledge review and evolutionary analysis of urban NbS [38,39,40]. Moreover, bibliometric studies in the field of NbS are still insufficient, and existing reviews primarily focus on design principles and implementation pathways of NbS, lacking quantitative and visual analyses of the disciplinary structure, research hotspots, evolutionary trends, key scientific issues, and future directions of urban NbS research [41,42]. The spatial distribution, collaborative networks, and policy responses of NbS research across different regions, countries, and urban types have also not been fully explored. These gaps constrain the further development of NbS theory, the summarization of best practices, and the scientific layout for future innovations.

To address these shortcomings, this study conducts a bibliometric analysis based on 1555 NbS-related papers from the Web of Science Core Collection published between 2015 and 2025. The study utilizes bibliometric methods to visually analyze the development history, current status, and future trends of NbS research. It systematically reviews the international status, research hotspots, and trends of NbS in promoting urban health development, providing theoretical references and a data foundation for further research and practical exploration. Specifically, this study will employ CiteSpace and VOSviewer software for bibliometric analysis, tools that efficiently process large volumes of literature data and generate visual knowledge maps to identify research hotspots and trends. The main research objectives include (1) systematically reviewing and quantifying the global NbS urban research output pattern, revealing research publishing trends from 2015 to 2025, the regional distribution of major contributing countries and institutions, and their academic impact, as well as evaluating the current status and shortcomings of international cooperation models; (2) constructing and analyzing a multi-level knowledge network in the NbS field, revealing the cooperation structure, interdisciplinary relationships, and knowledge flow paths among major countries, institutions, and core scholars, and identifying the role of influential figures in theoretical and practical innovations; and (3) identifying and tracking the core themes, hot topics, and dynamic evolution of NbS urban research, analyzing the major challenges currently faced in the field, exploring innovative pathways for sustainable development, and providing scientific support for theoretical improvement and policy formulation.

This study is the first to systematically review the knowledge structure and evolutionary patterns of the global NbS urban field, filling the gaps in existing reviews and bibliometric research. The study not only reveals new features of international cooperation and interdisciplinary collaboration but also addresses emerging frontier issues in the NbS field, such as health and environmental equity, providing more systematic and forward-looking scientific support for the refinement of NbS theory and policy innovation.

2. Materials and Methods

2.1. Data Sources and Search Strategy

Data were retrieved from the Web of Science Core Collection database, a reputable multidisciplinary platform extensively recognized for bibliometric studies, ensuring comprehensive data support for rigorous research.

To ensure data comprehensiveness and accuracy, an exact topic search (TS) strategy was applied with keyword combinations reflecting core NbS research themes: TS = ((“nature-based solutions” OR “nature-based approaches” OR “nature-based strategies” OR “ecosystem-based solutions”) AND (“urban” OR “city” OR “urban areas” OR “metropolitan” OR “urban environments”) AND (“solutions” OR “strategies” OR “interventions” OR “approaches” OR “measures”)).

A search from 2015 to 2025 yielded 1884 studies. After screening by language and type, 1737 remained. One researcher further screened for relevance and duplicates, resulting in 1555 valid studies. The review followed PRISMA 2020 guidelines, and the screening process is illustrated in Figure 1.

2.2. Data Processing and Analysis Methods

Bibliometric analysis is a research method that integrates mathematics, statistics, and computer technology to quantitatively analyze and deeply mine scientific literature. This study employs bibliometric methods, combined with various advanced data analysis and visualization tools, to systematically organize and deeply analyze the literature in the field of nature-based solutions for urban development from 2000 to 2025. The analytical framework of this study encompasses multiple key dimensions, including publication trends, geographical distribution, journal contributions, author contributions, journal impact, co-citation analysis, and keyword analysis, in order to comprehensively reveal the current research status, hotspot topics, and development trends in this field. To ensure the analysis is systematic and intuitive, the following tools were used: Microsoft Excel 2021, VOSviewer 1.6.20, CiteSpace 6.4.R1, and Charticulator. Specifically, first, Microsoft Excel 2021 was used to compile and statistically analyze the literature data from 2000 to 2025, enabling an in-depth analysis of annual publication trends and an intuitive presentation of the developmental trajectory of research on nature-based urban solutions. Second, to reveal global scholarly collaboration networks and research hotspots, VOSviewer 1.6.20 was utilized to construct and visualize author and institutional collaboration networks, while also conducting keyword co-occurrence analysis and burst detection analysis to clarify the internal relationships among research topics and the evolution of hot topics. Furthermore, to enhance the visual clarity of information presentation, Charticulator was used to create geographic distribution maps and chord diagrams, clearly showing the contributions of different countries in this research area. Finally, CiteSpace 6.4.R1 was employed to carry out a co-citation analysis of references in order to uncover the research context, hotspot shifts, and frontier trends in the field. The collaborative application of multiple tools not only covers the entire process from data statistics to network construction to visual expression but also forms a complementary advantage in both the presentation of information and analytical dimensions, effectively enhancing the depth of the analysis and the clarity of expression [43,44].

3. Results

3.1. Annual Publication Trend Analysis

Annual publication counts reflect the growth of scholarly output in a field over different years, indicating the field’s level of maturity and future potential. Figure 2 shows the trend of annual publication counts in this research field.

From the publication trend, between 2015 and 2017 the number of publications was small, increasing from 6 to 26 per year, which represents an early exploratory stage of research. In 2018 and 2019, the number of papers increased significantly to 31 and 64, respectively, indicating that the academic community began to pay more attention to the potential value of “nature-based solutions” in cities. Since 2020, annual publication counts have skyrocketed: 134 papers in 2020, 242 in 2021, 248 in 2022, 308 in 2023, and 394 in 2024—an increase of nearly 65-fold compared to 2015. Over the past decade, the annual publication volume has accelerated, reflecting that urban NbS research is receiving increasing attention. This field is expected to remain highly active in the coming years.

3.2. Geographic Distribution of Publications and International Collaboration

The number of publications and global citation counts are important indicators for measuring the scientific research level and academic influence of a country. Figure 3 presents the distribution of research outputs across countries/regions globally in the field of this study from 2015 to 2025.

In Figure 3, it can be seen that European countries perform exceptionally well in this field, with Italy, the UK, Germany, the Netherlands, and Spain all ranking among the top ten, which highlights the dominance of European countries in this research. Italy ranks first with 257 papers, demonstrating a very high level of research activity in this field; the UK (247 papers) follows closely, indicating its strong academic influence in the research.

China (197 papers), as the most representative country in Asia, shows a relatively active research profile. In recent years, China’s increased investments in urban sustainable development, ecological restoration, and green infrastructure construction have spurred rapid development in this field. The United States (194 papers), as a global scientific research powerhouse, also holds a significant position, indicating the notable academic impact of its research output.

Overall, developed countries—especially those in Europe—dominate this field, whereas research output from Africa, South America, and some Asian countries is relatively low. This suggests that the promotion and research potential of NbS in these regions remain to be further tapped. Future research should pay more attention to the specific urban environmental challenges and NbS strategies of developing countries in order to achieve broader global application and dissemination.

The collaboration network between countries reflects the patterns of scientific cooperation and knowledge flow. Figure 4 illustrates the collaborative relationships among countries in this research field from 2015 to 2025, where the size of the nodes represents the number of publications from each country, and the thickness and color depth of the connecting lines represent the strength of the collaboration.

As shown by the international collaboration network in Figure 4, the UK occupies a central hub position in the network, having established widespread and close collaborations with countries such as Germany, the Netherlands, Sweden, and Australia, demonstrating the most active international cooperation. The United States is also a key node in the network, with collaboration intensity second only to the UK, and it shows strong partnerships with Canada, Australia, Germany, and others. Germany, as a major European scientific contributor, not only maintains close cooperation with the UK and the US but has also formed tight regional collaboration clusters with other European countries such as the Netherlands, Sweden, and Switzerland, further solidifying Europe’s leading role in NbS research. Overall, the collaboration network is characterized by “developed countries at the core, European regional cooperation as dominant, with gradual participation of some developing countries.” In the future, strengthening research cooperation between developed and developing countries will help promote the implementation of NbS in urban environments globally.

3.3. Influential Authors

The analysis of author contributions helps to reveal the current academic development in the field, identify key researchers and their academic influence, and further understand the collaboration network among researchers. In this research field, a total of 6063 authors have participated in related studies over the past decade. Figure 5 displays the top ten scholars with the highest influence in this field.

According to Figure 5, Niki Frantzeskaki is the most influential scholar in this field, ranking first in both H-index (16) and number of publications (27). This indicates that she has not only a significant impact in terms of research quality but is also a major contributor of literature in the field. In addition, Timon McPhearson’s academic performance is outstanding, with an H-index of 13 and 16 publications, placing him second, which further highlights his academic stature in the field.

Further observing the publication trends of each high-impact author in terms of time series reveals that around 2016, Niki Frantzeskaki and Timon McPhearson had already begun to establish steady annual publication outputs, and after 2019, they entered a period of more concentrated research output. In contrast, since 2020, authors such as Dagmar Haase, Raffaele Lafortezza, and Stephan Pauleit have shown steadily increasing numbers of publications and citations, reflecting continually rising research enthusiasm in emerging topics (e.g., climate adaptation, healthy cities, and nature-based planning). These authors not only have different focal areas and regional contexts for their work but also, through multidisciplinary integration and international collaboration, have continually deepened the exploration of the application value and impact mechanisms of nature-based solutions in urban sustainability.

In summary, the above group of authors excel in both quantity and quality, representing the main scholarly force and developmental direction of this research field.

Beyond the individual influence of authors, author collaboration network analysis is an important method for revealing academic collaboration patterns and knowledge exchange characteristics within the field. Using VOSviewer, this study visualized the author collaboration network, as shown in Figure 6. In the figure, each node represents an author (node size corresponds to their number of publications); lines between nodes denote collaborative relationships (line thickness reflects collaboration strength); and different colored nodes indicate different collaboration clusters.

The author collaboration network exhibits several relatively tight collaboration clusters. The red cluster containing Frantzeskaki N. is the largest and most densely connected, including high-output and highly cited authors such as D. Haase, F. Baró, E. Banzhaf, and L. Jones. This cluster has numerous linking edges with the green cluster (e.g., R. Lafortezza, H. Bulkeley, F. Salbitano) and the yellow cluster (e.g., D. Geneletti, C. Cortinovis), reflecting its “hub” position in the collaboration network. Scholars in this cluster typically conduct collaborative research across disciplines—including urban planning, environmental science, and ecology—thereby advancing the exploration of the application and impact of NbS in urban health, sustainable transitions, and social innovation.

Beyond the major clusters, the network also contains a number of smaller but tightly connected clusters. For instance, the purple cluster is centered around Z. Vojinović, S. Di Sabatino, and P. Kumar, primarily focusing on natural solutions in urban flooding and hydrological processes. The blue cluster, led by N. Atanasova, J. Comas, and F. Masi, addresses topics such as municipal wastewater treatment, stormwater management, and ecological infrastructure development. The orange cluster (around A. Galvão) and the brown cluster (around E. Cristiano) are relatively smaller in scale, but they also maintain some degree of knowledge exchange with other clusters. From the overall collaboration structure, although inter-cluster connectivity varies, there is relatively frequent cross-cluster collaboration among the core groups. This suggests that under the drive of interdisciplinary and international research, different teams are integrating diverse perspectives and methods through collaboration, thereby providing broader knowledge sharing and academic support for research on nature-based solutions in urban environments.

3.4. Institutional Contributions

Institutional analysis is of significant importance in revealing the academic landscape and core strengths within a specific research field. By analyzing the academic influence and collaboration networks of institutions, researchers can obtain valuable reference information about key research institutions, thereby providing strong guidance for future research and inter-institutional collaboration. In this research field, a total of 2255 research institutions have participated in related studies over the past decade.

Table 1. Top 10 institutions by number of NbS-related publications (2000–2025) and their citation impact.

Rank	Institutions	NP	NC	AC	Total Link Strength
1	Utrecht University	41	1231	30.02	149
2	Humboldt University of Berlin	35	3122	89.20	136
3	University of Melbourne	32	1060	33.13	120
4	Stockholm University	29	1697	58.52	168
5	Technical University of Munich	28	2189	78.18	107
6	Swedish University of Agricultural Sciences	27	1231	45.59	114
7	Wageningen University and Research	26	879	33.81	111
8	University of Lisbon	26	879	33.81	90
9	Chinese Academy of Sciences	25	448	17.92	102
10	University of São Paulo	25	300	12.00	54

lists the top ten institutions by publication volume, visually presenting the research distribution within this field and the academic influence of each institution.

According to Table 1, Utrecht University (Netherlands) tops the list with 41 papers and 1231 citations, indicating its research is widely recognized internationally; however, its average citations per paper is 30.02, suggesting that despite its prolific output, the impact per paper still has room for improvement. The second-ranked institution, Humboldt University of Berlin (Germany), has published 35 papers with a total of 3122 citations and an average of 89.20 citations per paper, the highest among all institutions, highlighting its outstanding research quality and international influence. The University of Melbourne (Australia) is third with 32 papers and 1060 citations, and an average of 33.13 citations per paper, also demonstrating strong academic influence.

In summary, European research institutions are particularly prominent in their contributions to this field, notably universities in the Netherlands, Germany, and Sweden. At the same time, institutions from Asia (e.g., the Chinese Academy of Sciences) and South America (University of São Paulo) have also shown significant academic strength, indicating that this research field is gradually exhibiting a global development trend.

To further examine inter-institution collaborations, VOSviewer was used to visualize the cooperation relationships among the research institutions. Figure 7 illustrates the collaboration network among major institutions in this field; each node represents a research institution (node size reflects publication count), lines denote collaborations (thickness indicates collaboration closeness), and colors represent different collaboration groups.

Figure 7 shows that institutional collaboration in this field exhibits a distinctly international and cross-regional pattern, forming different research clusters centered around multiple internationally renowned institutions. European institutions represented by Utrecht University (Netherlands) and Humboldt University (Germany) show high collaboration intensity and broad cooperation networks. Utrecht University appears as the largest node at the core of the network, reflecting its international leadership in this research field and strong research influence; Humboldt University has collaborations across multiple clusters, demonstrating a high capacity for interdisciplinary and cross-border cooperation.

Meanwhile, institutions such as Wageningen University and Research, the Swedish University of Agricultural Sciences, the University of Copenhagen, and Delft University of Technology form clear collaboration clusters as well. These institutions mostly fall within the environmental science, ecology, urban planning, and landscape design domains, displaying significant interdisciplinary and cross-sector research characteristics, particularly focusing on ecological infrastructure construction, urban ecological restoration, and green infrastructure planning. This reflects the leading role of European countries in related research areas.

However, although there are many connections in the network, the closeness of collaboration between different clusters still needs to be strengthened, as the overall institutional network shows evident regional clustering. In particular, deep cross-regional collaboration between European institutions and those in Asia and the Americas remains insufficient. In the future, research institutions should further deepen cross-regional and interdisciplinary collaborations to foster coordinated global development and innovative breakthroughs in this research field.

3.5. Most Influential Journals

Identifying the most influential journals in the field is of significant value for understanding the research dynamics and distribution of academic outcomes. This study reviews the top ten journals by publication volume from 2015 to 2025 (

Table 2. Top 10 journals by number of NbS-related publications (2000–2025).

Rank	Journal	NP	NC	AC	H-Index	Journal IF (JCR 2023)
1	Sustainability	178	178	2342	13.16	24
2	Urban Forestry and Urban Greening	85	85	1945	22.88	24
3	Science of the Total Environment	54	54	2401	44.46	24
4	Journal of Environmental Management	53	53	771	14.55	17
5	Water	48	48	742	15.46	16
6	Land	46	46	488	10.61	3.2
7	Environmental Science and Policy	43	43	2360	54.88	4.9
8	Landscape and Urban Planning	40	40	1259	31.48	18
9	Sustainable Cities and Society	34	34	1226	36.06	16
10	Environmental Research	23	23	2145	93.26	17

). In terms of publication volume (NP), Sustainability ranks first with 178 relevant articles, clearly outpacing other journals. This journal is dedicated to research on sustainable development, covering multidimensional topics related to environmental, social, and economic issues, making it the preferred journal for researchers in the intersection of NbS and urban environments. Following this, Urban Forestry and Urban Greening ranks second with 85 articles, and Science of the Total Environment ranks third with 54 articles. These journals focus on urban ecosystems, environmental science, and related themes, closely aligning with research on NbS in urban environments.

Next, in terms of total citations (NC) and average citations per paper (AC), Science of the Total Environment stands out with a total of 2401 citations and an average of 44.46 citations per paper, reflecting its high recognition in the environmental science and interdisciplinary research domains. Additionally, although Environmental Research has published only 23 NbS-related papers, it has the highest average citations per paper at 93.26, indicating the high quality and significant impact of its articles.

The core journals in this research field are diverse, covering various directions such as environmental science, urban ecology, policy guidance, and sustainable development. Journals such as Sustainability, Environmental Research, Environmental Science and Policy, Science of the Total Environment, and Sustainable Cities and Society have become important academic venues for NbS urban research. The studies published in these journals are not only highly recognized in academia but also continually lead the frontiers and developmental directions of research in the field. It is recommended that researchers closely follow these core journals to stay abreast of emerging hotspots and research trends in the field.

3.6. Keyword Analysis

3.6.1. Keyword Co-Occurrence Analysis

Keyword co-occurrence analysis reveals the associations between themes within a research field and the distribution of research hotspots, providing a clear reflection of the evolving trends and directions in the discipline. This study used VOSviewer software to perform a co-occurrence analysis of keywords in the relevant literature. A threshold of 25 was set for the co-occurrence frequency of keywords, resulting in the selection of 103 high-frequency keywords from 6043 keywords. Subsequently, synonyms were merged, leaving 78 keywords to construct a co-occurrence network map of high-frequency keywords, as shown in Figure 8.

Cluster #1 is centered around “nature-based solution,” “green infrastructure,” and “management,” radiating out to include keywords such as “water management,” “stormwater management,” “low impact development,” “climate change adaptation,” “barriers,” and “systems.” This cluster emphasizes strategies for advancing nature-based urban solutions from a management and systems perspective [38,40,45,46,47,48,49]. Researchers focus on how to deploy green infrastructure in urban water resource management, stormwater runoff control, flood risk reduction, and climate change adaptation, conducting empirical or modeling studies on bottlenecks, co-benefits, and systemic management in the implementation process [12,50,51,52,53].

Cluster #2 revolves around keywords such as “water,” “vegetation,” “urban heat island,” “trees,” “temperature,” “pollution,” “performance,” “model,” and “mitigation,” highlighting the functional mechanisms of nature-based measures in regulating urban ecological environment indicators [45,54,55,56,57,58,59]. The research focuses on urban heat island mitigation through water bodies and vegetation cover, runoff and pollutant interception, ecological performance assessment of green roofs and urban green spaces, and the quantification of the mitigation effects of various ecological elements on energy consumption, microclimate, and air quality improvement based on numerical simulations or field monitoring [60,61,62,63,64,65].

Cluster #3 gathers keywords such as “urban planning,” “sustainable development,” “environmental justice,” “policy,” “governance,” “health,” “justice,” “framework,” and “environmental justice,” reflecting researchers’ exploration of nature-based urban solutions in urban and rural planning, policy frameworks, and social equity [38,66,67,68,69]. This cluster focuses on how to ensure the fair distribution of green infrastructure across different social groups through institutional design and regulation, thereby achieving public health, social justice, and sustainable development goals [70,71,72,73,74]. Typical topics include policy tools for urban ecological planning, environmental governance mechanisms, and multi-stakeholder collaborative governance models [75,76,77].

Cluster #4 is centered around “ecosystem services,” “biodiversity,” “green space,” “land use,” “restoration,” “landscape,” “conservation,” “ecology,” and “diversity,” emphasizing the ecosystem functions and biodiversity maintenance that nature-based solutions rely on [78,79,80,81]. The research covers urban green space ecosystem service assessment, landscape pattern optimization, the impact of land use change on biodiversity, ecological restoration and conservation strategies, and how to achieve ecological corridors and biodiversity spatial planning at the urban scale to enhance overall ecosystem resilience [82,83,84,85,86,87,88].

Overall, the keyword co-occurrence network demonstrates the multidimensional and interdisciplinary nature of NbS research, spanning from theoretical mechanisms and practical applications to policy governance and ecological protection, forming a close and organic knowledge system. Current research hotspots in the NbS field mainly focus on green infrastructure development, urban climate adaptation, ecosystem services, and social governance [41,78,89,90,91,92]. Future research could further strengthen exploration and deepening in areas such as multi-scale collaborative governance, ecosystem service assessment, and the localization of these practices in different urban contexts worldwide.

3.6.2. Keyword Temporal Evolution

The temporal evolution analysis of keywords provides a clear reflection of the development trajectory of research topics and the dynamic changes in research hotspots. In this study, VOSviewer software was used with a threshold set at 17 to select 161 high-frequency keywords from 6043 keywords. After merging synonyms, a final time-evolution visualization map containing 145 keywords was generated, as shown in Figure 9. In the figure, the color of each circle represents the average year of occurrence for that keyword, with the gradient color bar in the lower-right corner indicating this: blue represents keywords that appeared earlier, while yellow represents keywords that have only recently become research hotspots.

From an overall distribution perspective, core keywords such as “nature-based solutions,” “ecosystem services,” “city,” and “urbanization” are centrally located in the network with larger nodes, indicating their dominant role in the entire research field. At the same time, early research mainly focused on foundational topics such as “ecosystem services,” “management,” “restoration,” “climate change,” and “sustainability,” emphasizing the role of natural ecosystems in urban management, climate change mitigation, and sustainability [93,94,95,96]. Research during this period concentrated on the foundational theories, management frameworks, and ecological restoration mechanisms of NbS, laying the theoretical groundwork for subsequent studies [59,97].

In the mid-term, research hotspots gradually shifted toward urban practices and specific applications. Keywords such as “urban resilience,” “infrastructure,” “green space,” “adaptation,” “mitigation,” and “flood risk” frequently appeared, reflecting ongoing academic interest in NbS for enhancing urban resilience, optimizing infrastructure, constructing green spaces, and mitigating climate risks [38,97,98,99]. Furthermore, the increased activity of keywords such as “benefits,” “health,” “community,” and “policy” demonstrates the growing recognition of NbS’s practical value in promoting urban health, community engagement, and policy development [100,101].

Recent hotspots exhibit a trend of diversification and interdisciplinary integration. Keywords such as “environmental justice,” “justice,” “governance,” “framework,” “participation,” “lessons,” “values,” and “barriers” have emerged, indicating that recent NbS research not only focuses on ecological and environmental outcomes but also delves into social justice, governance models, public participation, experience sharing, and barrier analysis [102,103,104]. This shift reflects the movement of NbS research from a purely ecological-engineering application to a more integrated social-ecological system governance approach, focusing on multi-stakeholder collaboration, policy framework innovation, and equity assurance [105]. It reflects a deeper integration of theory and practice in the field.

In summary, research on nature-based urban solutions has undergone a multi-dimensional transformation, evolving from theoretical foundations to applied practices and, more recently, to social governance and justice [106]. Research hotspots have continuously evolved, closely aligning with global issues in urban sustainable development [107]. The analysis of temporal keyword changes not only reveals the development trajectory of the discipline but also provides important insights for future research directions.

3.6.3. Keyword Burst Analysis

Keyword burst intensity provides a clear reflection of the rapid rise and fall of specific research topics over time, revealing dynamic changes in the field’s focal points. This study used keyword burst detection (Citation Burst) analysis with CiteSpace software to analyze in depth the keywords that showed significantly heightened attention during the study period. Figure 10 displays the top 25 keywords with the strongest bursts over the past 25 years. The red line indicates the duration of the keyword’s burst period, the dark blue line indicates the overall period the keyword appeared, and a more significant “strength” value suggests a higher likelihood of the keyword being a frontier topic. The labels “begin” and “end” mark the start and end years of each keyword’s burst.

Between 2015 and 2021, keywords such as “public health” and “mental health” had high burst intensities, reflecting a strong focus on human well-being in the early stages of applying NbS to urban environments [108,109]. Meanwhile, “ecosystem services” had the highest burst strength (8.67), indicating that early NbS research focused on exploring the multiple benefits that natural ecosystems bring to cities [24]. Subsequently, concepts such as “sustainability,” “restoration,” and “urban resilience” gradually gained widespread recognition among researchers, illustrating the continuous expansion and enrichment of the NbS theoretical framework.

Since 2020, research hotspots have clearly shifted toward more technical and fine-grained exploration of practical applications. For example, bursts in keywords such as “waste water” (wastewater treatment) and “urban parks” highlight increased attention to the effectiveness of specific ecological infrastructures and technologies by urban practitioners [110,111]. At the same time, keywords such as “thermal comfort” and “life cycle assessment” have shown significant bursts in recent years, revealing that research is moving towards more detailed assessments of technical performance and environmental outcomes [112,113].

Notably, “Nature-based Solutions” itself has shown a significant burst starting in 2023 (predicted to continue through 2025) with a burst strength of 6.17, reflecting its emergence as a key research theme in the present and near future. Additionally, newly bursting keywords such as “heat island effect,” “urban ecology,” and “carbon emissions” demonstrate the growing urgency and application potential of NbS in addressing urban environmental issues in the context of global climate change [30,35,114].

In summary, the keyword burst analysis results clearly show that in the application of nature-based solutions in urban environments, research hotspots have gradually shifted from theoretical exploration to concrete practical applications, revealing a process of deepening and refining research focus in the field. These findings provide a clear direction and important reference for future research.

4. Discussion

4.1. Key Research Findings

This study, based on bibliometric methods and utilizing visualization tools such as CiteSpace and VOSviewer, systematically reviews and summarizes the research hotspots, development trends, and challenges in nature-based solutions (NbS) for promoting urban health development from 2015 to 2025 and proposes future research directions. Figure 11 illustrates the main contributions and research framework of this paper. The specific research findings are as follows:

With the growing prominence of global climate change and urbanization issues, NbS-related research has shown a significant upward trend. Since 2020, annual publication volumes have rapidly increased, reaching 394 papers in 2024, indicating that NbS is gradually becoming a hotspot in the academic community. This growth trend is mainly driven by the global demand for climate adaptation and urban health, with NbS being widely recognized as an effective strategy for enhancing urban ecological resilience and public health. Among the factors contributing to the rapid development of NbS research, policy support has been a key driver. Policy frameworks such as the European Green Deal and carbon neutrality targets have provided ample funding and institutional support for NbS-related research, particularly in European countries such as Italy, the United Kingdom, and Germany, which are leading the way in NbS research. High level research institutions such as Utrecht University, Humboldt University in Berlin, and the University of Melbourne have become core contributors to NbS research, driving interdisciplinary collaboration and knowledge innovation. Journals such as Sustainability, Urban Forestry and Urban Greening, and Science of the Total Environment have provided important academic platforms for NbS research, expanding research themes from single ecological functions to multidimensional areas such as integrated governance, climate adaptation, and public health, further enhancing the academic influence and practical value of NbS.

Overall, European countries, with their well-established policy frameworks and strong research foundations, have long maintained a dominant position in NbS research [115]. The European Union not only encourages green urban planning but also incorporates NbS into its core strategies for climate change response and sustainable development, promoting the implementation of green infrastructure and climate adaptation measures through stable funding support and policy guarantees. These policy initiatives have spurred interdisciplinary technological innovation and international cooperation, making Europe a leader in NbS research and application. However, developing countries lag behind in NbS research and practical application, reflecting the uneven global NbS research network. Despite facing similar challenges such as climate change, ecological degradation, and urbanization, these countries still have relatively weak research foundations and levels in NbS, mainly due to insufficient policy support, inadequate environmental legislation, and incomplete green infrastructure construction systems, lacking necessary policy guarantees and financial investment. Moreover, the lack of research capacity and technological innovation is also a limiting factor. Many research institutions in developing countries have limited capacity, and financial shortages further exacerbate this issue, particularly in low-income countries, where insufficient financial support for NbS projects hinders large-scale promotion and systematic application.

To narrow the north–south gap, future research should strengthen scientific cooperation between developed and developing countries. Developed countries can assist developing countries by transferring technology, sharing experiences, and providing financial aid to support the successful implementation of NbS projects. At the same time, efforts should be made to support developing countries in improving NbS-related laws, regulations, and policy environments, facilitating the implementation of green infrastructure and climate adaptation strategies. By establishing international collaboration and cross-national research platforms, promoting knowledge sharing and interdisciplinary cooperation, and developing countries can learn from the successful experiences of developed nations and design NbS application solutions more suited to their national contexts. This cooperative model not only helps to narrow the global gap in NbS research and application but also contributes to achieving global sustainable development goals.

Through keyword analysis, this study reveals the core themes of NbS research and the evolving trajectory of its hotspots. Early NbS research largely focused on ecological functions, particularly the mitigation of urban heat island effects and the enhancement of ecosystem service values. For instance, New York City’s green roof project effectively lowered urban temperatures and improved air quality, becoming a typical case of addressing urban heat island effects. As research deepened, emerging topics such as climate change adaptation, governance coordination, and environmental justice gradually became new hotspots in NbS research, signaling the shift of NbS applications from a single ecological compensation tool to multi-objective, multi-level system governance. The academic community’s increasing attention to NbS’s role in social equity and environmental governance has become evident.

In terms of urban heat island mitigation, NbS applications have greatly enhanced urban climate adaptation capabilities. Berlin, through urban forests, green roofs, and other green infrastructure, effectively reduced urban temperatures and improved air quality, not only mitigating heat island effects but also improving residents’ quality of life. Similar measures have been widely practiced in cities such as London and Tokyo, significantly strengthening urban resilience to extreme weather events. In climate change adaptation, NbS also plays a key role. For example, Tokyo’s wetland restoration project has demonstrated outstanding performance in flood and waterlogging prevention and enhancing climate resilience, while Amsterdam has comprehensively improved its city’s climate resilience through green infrastructure. NbS’s role in disaster risk reduction and ecological restoration has become increasingly prominent. Governance coordination is crucial for the successful implementation of NbS. Germany’s green infrastructure projects have achieved effective integration of funds and technologies through cross-sectoral collaboration, greatly enhancing the application effectiveness of NbS. However, in many developing countries, the lack of governance coordination severely limits the promotion of NbS. Future efforts should strengthen collaboration across sectors and stakeholders to ensure the efficient implementation of policies.

Environmental justice issues are also gaining increasing attention in NbS applications [37]. While NbS overall improves urban environmental quality, the benefits are not equally distributed. For example, in Stockholm, local authorities prioritized providing green spaces to low-income communities, ensuring fair distribution of environmental benefits and offering valuable experience for NbS in promoting social equity [116].

4.2. Analysis of Research Hotspots and Trends

4.2.1. Mitigating Urban Heat Islands and NbS Microclimate Regulation Effectiveness

The urban heat island effect is a prominent environmental issue in the urbanization process, severely impacting residents’ health and ecological environmental quality [117,118]. Using NbS approaches, by increasing green-blue infrastructure such as urban forests, park green spaces, and green roofs, cities can effectively regulate the microclimate, lower local ambient temperatures, and enhance thermal comfort [56,91]. Empirical research shows that areas implementing NbS can experience a significant reduction in daytime peak temperatures by approximately 2–6 °C, with especially pronounced cooling in areas with forests and green spaces. Further studies indicate that the cooling effect of NbS exhibits clear regional differences: high-latitude, affluent cities see more pronounced cooling benefits compared to developing regions [119]. This suggests that NbS spatial configurations need to be optimized according to the climatic characteristics and socio-economic conditions of different cities [92]. Future research should explore the long-term cooling effects of various types of NbS, their efficacy in mitigating heat risks, and their precise application in urban planning decisions so as to help cities address extreme heat and climate risks [56].

4.2.2. Carbon Emission Control and the Coupling Potential of Natural Infrastructure in Low-Carbon City Development

Urban carbon emissions are a core driver of global climate change. NbS can not only improve the urban environment but also serve as carbon sinks, aiding in the transition to low-carbon cities [120,121]. Urban forests and wetland restoration can directly absorb and store CO₂, achieving emission reductions [122]. Additionally, NbS can indirectly reduce emissions by improving the urban microclimate and lowering building energy consumption [55]. Studies have found that under scenarios of maximal NbS implementation, urban carbon emissions can be significantly reduced, with a maximum reduction of up to 25%. The carbon reduction benefits of different types of NbS vary significantly between cities and show clear spatial heterogeneity. In the future, a unified carbon sink evaluation framework and dynamic monitoring system should be established, and the linkage between NbS and carbon market mechanisms should be strengthened. Incorporating NbS into urban climate action plans in an institutionalized manner—supported by regulations, planning, and finance—would further optimize strategies for urban carbon emission reduction.

4.2.3. Multiple Pathways Through Which NbS Promote Urban Health Development

NbS, by increasing urban green and blue spaces and improving environmental exposure conditions, significantly enhance residents’ physiological, psychological, and social health [123]. Studies have shown that individuals living near areas of high greenness experience marked improvements in mental health, with community green spaces exerting a protective effect against anxiety and depressive symptoms—particularly pronounced among vulnerable populations [124,125]. Moreover, green spaces foster community interaction and enhance environmental aesthetics, thereby strengthening social cohesion and overall well-being [126].

For example, in Amsterdam’s Zuiderpark, the introduction of native vegetation corridors and discrete water features along both sides of the streets increased residents’ average daily walking time by approximately 15%, effectively reduced skin temperature and Physiological Equivalent Temperature (PET), raised the frequency of community activities by nearly 30%, and significantly improved subjective well-being among vulnerable groups [127,128].

Despite these benefits, current research on the health effects of NbS has largely focused on developed countries, lacking studies with generalizability across diverse socioeconomic and cultural contexts. Future efforts should establish an integrated “environment–health” assessment framework to elucidate the mechanisms by which NbS influence health and fully incorporate health outcomes into urban planning and public health policies, thereby consolidating the strategic importance of NbS in the development of healthy cities.

4.2.4. Emerging Issues in Urban Resilience Governance and Environmental Justice

As climate change intensifies and the spectrum of urban risks expands, enhancing urban resilience has become one of the core themes in urban research and governance [129]. Studies indicate that NbS have more marked effects in mitigating extreme heat and flood risks in small and medium-sized cities [130]. At the same time, the effective implementation of NbS requires support at institutional and societal levels, and multi-stakeholder collaborative governance has emerged as a hot research topic. Multiple studies emphasize that public participation and stakeholder consultation help increase the social acceptance and long-term effectiveness of NbS [131]. Practice cases from Latin American cities’ climate action plans also demonstrate that NbS projects co-designed with the public are more capable of achieving the twin goals of environmental benefits and social equity [132]. Moreover, issues of environmental justice are becoming increasingly salient: current urban NbS exhibit inequities in spatial distribution and benefit allocation, necessitating policy measures to ensure equitable resource allocation [133,134]. Organizations such as the EU have proposed NbS planning principles of “inclusive, fair, and accessible,” which aim to advance the institutionalization and mainstreaming of NbS. Future research should deepen interdisciplinary collaboration on human–nature interactions and foster the integration of ecological knowledge with innovations in social governance in order to achieve a combined enhancement of urban resilience, ecological protection, and social equity.

4.2.5. Participation, Governance, and Environmental Justice: Key Factors in Promoting Urban Sustainable Development

With the widespread application of nature-based solutions (NbS) in enhancing urban health and ecological resilience, public participation, governance coordination, and environmental justice have gradually emerged as new focal points of research [135,136]. The implementation of NbS requires not only the assessment of ecological benefits but also consideration of social and policy-level collaboration to ensure its long-term sustainability and equity [137,138].

Public participation plays a crucial role in NbS governance. Studies indicate that active involvement of residents and stakeholders can enhance the social acceptance of NbS projects, thereby improving their implementation outcomes [139]. For instance, in Latin American cities, NbS projects designed with public participation in climate adaptation plans significantly improved the social benefits of these projects [140]. However, in some cities, low levels of public engagement resulted in the failure to effectively align the projects with community needs, affecting the outcomes [141,142]. Therefore, future research should place greater emphasis on the participation of low-income and other vulnerable groups to ensure that NbS better serve diverse communities.

Governance coordination is key to ensuring the long-term effectiveness of NbS. The implementation of NbS involves multiple stakeholders, including governments, businesses, and academia [143]. In the Netherlands, the green infrastructure policy has advanced NbS effectively through multi-stakeholder collaboration [144]. However, in some developing countries, the lack of interdepartmental coordination and resource integration has limited the successful implementation of NbS. Future research should explore ways to strengthen collaboration among different stakeholders and establish effective governance mechanisms to ensure the smooth execution of NbS.

Environmental justice is particularly important in the application of NbS. Although NbS can improve urban environmental quality, its benefits are often unevenly distributed among different groups [26,145,146]. In London, the green space initiative prioritized the needs of low-income communities, ensuring equitable environmental improvements [147,148]. In contrast, some NbS projects in developing countries have failed to balance resource distribution, leading to less benefit for vulnerable groups [24,149]. Therefore, policymakers should pay more attention to ensuring equity in the implementation of NbS, especially concerning the participation and benefits of low-income communities [150].

4.3. Current Challenges

However, in practice, NbS also face numerous challenges in advancing urban health development. First are technical challenges: the ecological benefits of NbS show significant spatiotemporal variability [24,38,151]. For example, in practice NbS also face numerous challenges in advancing urban health development. First are technical challenges: the ecological benefits of NbS show significant spatiotemporal variability [38,152]. Additionally, monitoring and simulation methods for NbS outcomes are not yet mature, and the evaluation indicator system remains to be improved.

Second, equity and governance challenges: Because the spatial distribution of urban NbS and the access to their benefits are uneven, the benefits obtained by vulnerable groups are relatively limited, highlighting issues of environmental justice [37,153]. A review by Kato-Huerta and Geneletti (2022) noted the need for policies to ensure fairness in resource distribution and to increase inclusiveness in decision-making processes [154]. In line with this, international frameworks (e.g., from the EU) stress that NbS planning should adhere to the principles of “inclusive, fair, and accessible” to ensure all groups can benefit equitably from NbS improvements. Furthermore, in current NbS practice, insufficient public participation and the lack of collaborative governance mechanisms among government, community, business, and academia stakeholders have weakened project social acceptance and long-term effectiveness [131,155]. This has meant that NbS projects often fail to fully align with community needs and also limits the sustained realization of NbS benefits. Strengthening public participation and multi-stakeholder cooperation is regarded as a key step to improve NbS governance performance, requiring the establishment of more inclusive decision-making mechanisms in real-world planning [156].

Finally, institutional challenges: NbS have not yet been fully institutionalized; they lack stable funding support and regulatory guarantees, and there remain barriers to cross-departmental coordination. How to scale NbS pilot projects up to city-level institutional arrangements—and provide continuous support in regulations, planning, and financing—is a pressing issue that needs to be resolved.

5. Conclusions

Based on 1555 NbS-related articles indexed in the Web of Science Core Collection from 2015 to 2025, this study employs bibliometric and visualization analysis methods to systematically reveal the research patterns, hotspot evolution, and development trends of nature-based solutions (NbS) in promoting urban health development. The results show that since 2020, NbS research has entered a period of rapid growth, with the annual publication volume increasing from 134 papers in 2020 to 394 papers in 2024, reflecting the academic community’s high focus on climate adaptation and urban resilience issues. European countries (such as Italy, the United Kingdom, and Germany) have continued to lead in research output and international collaboration, while China and the United States also show strong research momentum. However, related research in developing countries, such as in Africa and South America, remains relatively weak, highlighting the need to enhance research capabilities and policy support.

Keyword analysis indicates that NbS research hotspots have shifted from early focuses on “ecosystem services,” “urban heat island effect,” and “sustainability” to topics such as “urban resilience,” “green infrastructure,” and “climate adaptation,” and more recently to emerging themes such as “environmental justice,” “governance coordination,” “public participation,” and “lifecycle assessment.” Co-citation analysis emphasizes the central role of scholars such as Frantzeskaki in advancing NbS theory and exploring governance pathways. Author and institutional collaboration networks reveal that interdisciplinary and international cooperation are key drivers of continuous progress in the NbS field. However, cooperation remains uneven between regions, disciplines, and developed and developing countries, which has, to some extent, limited the global promotion and application of NbS.

Based on these findings, this paper proposes the following recommendations at both the theoretical and practical levels. First, a more comprehensive NbS quantitative assessment system should be developed, including a multi-scale, dynamic, integrated environmental-health-carbon sink evaluation framework, providing a scientific basis for policymaking and project implementation. Second, multi-stakeholder collaborative governance should be strengthened to promote deeper cooperation among governments, research institutions, communities, and businesses in areas such as planning, funding, and technology, enhancing the feasibility and sustainability of NbS projects. Third, environmental justice and social equity should be prioritized, ensuring that vulnerable groups are included in benefit distribution and decision-making mechanisms to ensure the balanced distribution of green infrastructure benefits. Finally, the technology transfer and experience sharing between developed and developing countries should be strengthened. International collaboration platforms and financial support should help developing countries improve NbS policies, regulations, and implementation systems.

6. Research Limitations

Although this paper provides a comprehensive and in-depth review and analysis of the field of nature-based solutions (NbS) for urban areas using systematic bibliometric methods, it still has certain limitations. First, in terms of data sources, this study relied solely on the Web of Science Core Collection as the primary data source. While this database is highly authoritative and comprehensive, it may still exclude some relevant literature indexed in other international databases such as Scopus and PubMed, as well as local databases, particularly non-English literature and grey literature, such as policy reports and technical guides. This limitation may affect the comprehensiveness and representativeness of the research findings. Second, the study’s time window is limited to July 2025. Given the rapid development of the NbS field, some of the most recent research advancements and policy trends may not have been included in the analysis, potentially affecting the timeliness and forward-looking nature of the conclusions.

Future research could consider integrating multiple mainstream databases, such as Scopus, PubMed, and CNKI, while also focusing on the collection of non-English literature and grey literature to enhance the breadth and representativeness of the literature coverage, thereby providing a more comprehensive reflection of global developments and regional differences in the NbS field. Moreover, as the NbS field continues to develop rapidly, subsequent studies should regularly update data and analysis results, incorporating the latest research findings and policy developments to maintain sensitivity to the cutting edge of the field and improve the timeliness and relevance of the research conclusions.