Green Infrastructure’s Role in Climate Change Adaptation: Summarizing the Existing Research in the Most Benefited Policy Sectors

Abstract

Extreme climate change is today’s world’s most pressing and challenging problem. Increases in greenhouse gas emissions, the warming of the atmosphere and ocean, increased precipitation, rising sea levels, and temperature rise are the major effects of climate change that significantly affect urban infrastructure. Green Infrastructure (GI) is an increasingly acknowledged tool for climate change adaptation that contributes to sustainable urban and rural development. This study reviewed 111 research articles to identify and summarize the research findings about the role of GI in climate change adaptation. Furthermore, the research articles are grouped into three sectors with the most benefits of green infrastructure in climate change adaptation: mitigating urban heat islands, increasing ecosystem resilience, and flood risk management. The literature was further divided according to the developed or utilized strategies and techniques. The findings suggest that the topic of GI’s role in climate change adaptation is very current and it has been studied frequently in the last five years.

1. Introduction

1.1. General Background

Global climate change is one of the world’s most challenging problems today [1,2,3,4,5,6]. The urban infrastructure is significantly affected by major effects of climate change like the increase in greenhouse gas emissions, the warming of the atmosphere and ocean, the increase in precipitation, the rise in sea level, and temperature rise [7,8,9,10,11]. The application of green infrastructure (GI) has become a widely recognized tool for climate change adaptation and mitigation [2,3,11,12,13,14,15,16]. Adaptation to climate change is a process that can be defined as a response to change to improve and strengthen the system’s resilience [17,18]. In contrast, mitigation addresses issues related to the drivers of climate change and has traditionally received more attention in climate change action plans, primarily because reducing CO₂ and other greenhouse gas emissions leads to significant benefits, such as slowing global warming and improving air quality [19].

GI is a concept (e.g., parks, waterways, wetlands, woodlands, forests, green roofs, and walls) that connects ecosystems, their protection, and the provision of ecosystem services, while also providing benefits to climate change adaptation and mitigation [6,12,13,20,21]. The interdependence of plants, animals, and microbes (i.e., the living world) with their non-living environment is defined as an ecosystem [20]. The benefits that ecosystems provide to people are known as ecosystem services, which are commonly categorized into four main types: (1) provisioning services (such as water management, food production, and security); (2) regulating services (including mitigating urban heat islands, strengthening ecosystems’ resilience to climate change, managing floodwaters, sequestering carbon, and reducing energy use for heating and cooling buildings); (3) habitat services (such as maintaining biodiversity and enabling nutrient cycling); and (4) cultural services (which encompass recreation, tourism opportunities, and a positive impact on land and property) [20,22].

1.2. Conceptual and Theoretical Framework: The Role and Benefits of GI in Climate Change Adaptation and Mitigation

To understand the background of GI, it is necessary to look at the consequences of the Industrial Revolution. With the arrival of the Industrial Revolution in the 1800s, there was an increase in the world’s population and environmental changes, which led to changes in residence from rural to urban areas. Such changes have resulted in the development of urban planning and nature conservation, the two key concepts that support GI [23]. Urban planning and nature conservation merged for the first time in Boston’s “Emerald Necklace”, the park system that developed in the late 19th century [2,23]. With the Garden City movement at the turn of the twentieth century and the United Kingdom’s New Town movement following World War II, urban planning and nature protection were once again linked together [23]. These movements led to the first explicit use of the term “green infrastructure” in the United States in the 1980–90s [2]. The term “green infrastructure” emphasizes the importance of natural environment life-supporting functions, i.e., ecosystem services [2,23].

The most common contributions of GI to climate change adaptation are social capacities, education, thermal comfort, managing flood risks, and improved water quality [11]. The most common contributions of GI to the mitigation of climate change include reduced CO₂ emissions, improved air quality, and enhanced human health outcomes [11].

Social capacities refer to the ability of communities to respond collectively to climate-related challenges by fostering social interaction, inclusion, and cohesion [24]. GI can enhance these capacities by providing accessible green spaces that encourage communal use and interaction across different social groups [25]. Similarly, education within the framework of climate change adaptation refers to increasing awareness, knowledge, and engagement with environmental issues [26]. GI supports this by offering outdoor learning environments and opportunities for environmental education and stewardship [25,27,28]. Moreover, green spaces promote participation in recreational and leisure activities, contributing to physical and mental well-being [27,28]. GI can also support economic resilience through the creation of “green jobs”—employment opportunities in the construction, maintenance, and management of green spaces—thereby contributing to local income generation and long-term sustainability [29].

Regarding social capacities and education, GI can positively impact social interaction and inclusion by providing green spaces for the whole community to use [25], and green spaces increase participation in recreational and leisure activities [27,28]. Also in terms of the positive impacts of GI on social capacities and education is the creation of “green jobs”. The construction and maintenance of GI requires a workforce, and the direct outcome ultimately leads to income generation in many households [29].

Thanks to their composition and structure, urban surfaces effectively absorb thermal and radiation energy, which further results in increased warming of the urban atmosphere, which is why temperatures in cities are higher than in rural areas [30,31]. This effect, known as the urban heat island (UHI) effect, is more pronounced at night because urban areas cool down more slowly than rural ones [32], which can cause air temperatures critical to human health [33,34] and thermal comfort [35]. Implementing GI—for example, shade trees, parks, green roofs, and facades—reduces the temperature in urban areas [11,36]. The study in Greater Sydney, Australia, showed that the shade of trees (planted in three contrasting contexts: parks, natural belts, and asphalt) can on average reduce the mean air temperature by 1.1 °C and the maximum air temperature by 3.7 °C [37]. By analyzing the influence of the design and location of 86 parks on the cooling effect during a summer daytime in Barcelona across four consecutive years, it was observed that 84 parks showed a cooling impact on their urban environment (such results are related to the diverse relationships between the proportion of naturally vegetated or previous surfaces and built spaces within parks) [38]. Green roofs can achieve an indoor air temperature reduction of up to 15 °C [39]. Implementing green facades showed that during ambient air temperatures of more than 30 °C, the gap temperatures for detached green facades were more than 1 °C cooler than ambient air, and the temperatures of external walls with green facades (detached or attached) were 3.2 to 3.5 °C cooler than those without green facades [40]. During cold periods with ambient air temperature less than 20 °C, external walls with facades were about 3 °C warmer than those without facades [40]. These results show that green facades are good options for reducing energy consumption in buildings, regardless of whether they are in warm or cold climates [40]. These results show that green facades are very good options for reducing energy consumption in buildings, regardless of whether they are in warm or cold climates.

Managing urban floods with GI includes a range of stormwater management practices like rain gardens, green roofs, green streets, bioswales, and urban wetlands [41,42]. For example, rain gardens decrease runoff water, adapt to changing runoff conditions, and improve water quality by removing sediments, heavy metals, pathogens, nutrients, and hydrocarbons from stormwater [42]. Green roofs aid in conserving the control of runoff, water, and air pollution, promoting biodiversity, and providing aesthetic and health benefits [39]. The results of a study in Helsinki showed that the low-level implementation of green roofs with low retention rates reduces the average flood depth by only 1%, and the maximum green roof implementation decreased the average flood depth (13%) and reduced the number of vulnerable sites [43]. Roads and buildings in urban areas are covered with impervious surfaces, which after heavy rains leads to increased surface runoff, which further leads to poor water quality and increased peak flow in urban streams [44,45]. It has been shown that GI elements, such as green roofs and living walls, can act as drainage layers. They release excess water and substrate housing vegetation species that aid in conserving and filtering rainwater [46]. Also, it is reported that GI effectively removes sodium from rainwater [47]. The application of bioretention cells was most effective, followed by vegetated swales and rain gardens, concluding that vegetation type also influenced sodium removal capacity (salt-tolerant plants were more effective for this purpose) [47].

GI contributes to climate change mitigation by removing CO₂ from the atmosphere through photosynthesis [32,48]. For example, it was found that for every 1% increase in green infrastructure investment, the average carbon emission intensity decreases by approximately 1.11% in Chinese cities [49]. In the Guangdong–Hong Kong–Macao Greater Bay Area, the total carbon reduction from urban green infrastructure was 193.6 million tons in 2022 [50]. The whole urban forest of the USA is estimated to remove approximately 25.6 million tons of carbon each year [51].

In the field of human health, for example, GI proved to have a positive association with attention, mood, and physical activity [52,53], and in comparison to a synthetic environment, a meta-analysis showed more positive benefits of walking or running in a natural environment [54]. Also, a causal relationship has been proven between surrounding greenness and mental health in adults [55]. It was proven that the mortality attributable to the urban heat island (UHI) effect (urban areas that are warmer than the surrounding rural areas) [56] could be prevented by increasing parks and tree cover in urban areas [56,57]. Furthermore, air pollution is an environmental hazard to human health, causing diseases such as damage to the respiratory system, cardiovascular system, and lung cancer, ultimately leading to reduced life expectancy [58,59]. The results of a study in the USA estimated that the urban tree canopy of 55 cities in the USA removes 711,000 tonnes of pollution annually [60]. Another example of GI benefits is active green walls (or active botanical biofilters or functional green walls). Active green walls are used indoors for pollutant reduction [61,62]. They involve the active transfer of particulate-matter-polluted air through a plant growth substrate using a form of mechanical air transfer, rather than gravitational and diffusive particulate matter deposition [63].

Despite this initial focus on mitigation, the importance of climate change adaptation is increasingly acknowledged [19] because extreme climate change events (e.g., storms, extreme temperature, sea level rise, extreme precipitation) are inevitable [19,64]. Existing review articles on the role of GI in climate change adaptation involve a wide range of fields. A critical review by Hunter et al. quantifies the thermal performance of green facades [65]. The review draws attention to the inconsistency in research articles on measured microclimate parameters, which is necessary to identify those essential to better understand green facade thermal characteristics. Jayasooriya and Ng summarized tools for modeling stormwater management and the economics of GI practices [66]. They concluded that there is a need for new modules that can be added to existing GI modeling tools that can predict the environmental and economic benefits of different ecosystem services. This would lead to a better urban water management strategy. A literature review by Pitman et al., carried out between 2012 and 2014, provides insight into GI’s contribution to climate adaptation and protection [67]. This review points out that the modifications of urban climates through temperature reductions are one of the outstanding benefits of GI. In their systematic literature review of 85 studies from 15 countries, Bartesaghi et al. evaluated the existing evidence on how GI is being categorized and characterized worldwide [68]. Chatzimentor et al. provided a review of the existing research on GI in Europe considering conceptualizations of GI, research priorities, and thematic clusters within the existing literature [69]. They recommended integrating nature conservation and social-environmental justice objectives into GI research to enhance sustainability transitions both within and outside the city. Dharmarathne et al. explored the connection between climate change and urban flooding, offering valuable resources for policymakers and researchers [5]. The review indicates that addressing climate-induced urban flooding needs to be conducted through a holistic analysis of statistical trends, scientific evidence, infrastructure vulnerabilities, and adaptation measures. The main objective of the review of 582 empirical studies by Aghaloo et al., was to propose a taxonomy for nature-based solutions and identify the potential contribution of various types of urban nature-based solutions to climate change adaptation, with a specific focus on stormwater and flooding management [70]. This analysis demonstrated that sustainable urban drainage systems are the most dominant approaches of nature-based solutions for adaptation, followed by low-impact development and GI.

Despite the growing number of studies investigating the role of GI in climate change adaptation and mitigation [3,11,13,71], a comprehensive synthesis that systematically categorizes GI benefits within key policy sectors remains limited [68,69,72]. In particular, a clear framework in the literature links GI strategies to their practical applications in areas such as mitigating urban heat island effects, strengthening ecosystem resilience, and managing flood risk—sectors that the European Environment Agency has identified as priorities [20,67].

This study addresses the following research questions:

• What is GI’s role and main benefits in climate change adaptation, specifically regarding mitigating urban heat island effects, strengthening ecosystem resilience, and managing flood risk?
• Which strategies and techniques for GI implementation in climate adaptation are proposed in the literature, and how are these studies methodologically structured?
• What are the key trends, challenges, and limitations in GI research, including insights derived from bibliometric and co-citation analyses?

The novelty of this research lies in analyzing 111 scientific articles published between 2012 and 2024 to synthesize knowledge about the benefits of green infrastructure in three fundamental sectoral domains defined by the European Environment Agency: mitigating urban heat island effects, strengthening ecosystem resilience, and managing flood risk [20]. This contributes to a better understanding of the potential of green infrastructure for creating effective policies in urban areas.

The article is organized as follows: the literature search methodology is described in Section 2; the results of the bibliometric analysis, the keyword co-occurrence analysis, co-citation analysis by source, and the literature overview, presented with the proposed strategies and techniques, are provided in Section 3; and Section 4 discusses and summarizes the research findings on the current knowledge on implementing GI.

2. Materials and Methods

This section outlines the methodological approach used to identify and synthesize scientific information regarding the role of GI in climate change adaptation. A comprehensive search of multiple databases was conducted using basic terms regarding urban green infrastructure and climate change adaptation. The selection criteria for this review focused on articles and review papers relevant to key themes and significant to the field.

Figure 1 illustrates the workflow of the review process applied in this paper. In the first step, relevant scientific databases were identified, appropriate keywords for searching articles were selected, and the search results were filtered by language, document type, and research areas directly related to the study objectives. The second step involved overlapping the results and selecting articles based on the quality of indexing in both databases. Furthermore, a thorough analysis of these articles needed to be conducted to distribute them into the three most beneficial policy sectors: the mitigation of urban heat islands, ecosystem resilience, and flood risk management. The third step involved conducting a bibliometric analysis and visually representing the results.

The procedure for the first two steps is described in more detail below. The bibliometric analysis, visualization, and data interpretation, discussed in the third step, are further elaborated in the Section 3.

For the search of scientific articles, two of the most comprehensive and widely used databases, Scopus and Web of Science Core Collection, were selected. The Scopus database includes publications from approximately 28,000 active peer-reviewed journals worldwide, books, and conference proceedings, amounting to over 90 million records [73]. Similarly, the Web of Science encompasses more than 225 million publications from approximately 35,000 journals, in addition to books, conference proceedings, over 115 million patents, and over 14 million data sets [74]. The search was conducted on 3 July 2024, using the following keywords with Boolean operators AND and OR: (“urban green infrastructure” OR “green infrastructure”) AND (“climate change”) AND (adaptation). Only articles and review articles in English were considered.

An initial search in the Scopus database using the specified keywords and searching the Article Title, Abstract, and Keywords fields resulted in 382 articles. In the Web of Science database, an initial search of the Topic field, encompassing Title, Abstract, Keyword Plus, and Author Keywords, yielded 554 articles.

To ensure that the analysis focused solely on articles relevant to the objectives of the study, the second step involved screening papers based on the Subject Area (in Scopus) and Research Areas (in the Web of Science). In the Scopus database, only articles from the following areas were selected for further analysis: Environmental Science, Engineering, Agricultural and Biological Sciences, Energy, Earth and Planetary Sciences, Business, Management and Accounting, Decision Sciences, Multidisciplinary, and Material Sciences. After this additional filtering in Scopus, the search resulted in 167 articles. Similarly, in the Web of Science database, articles from the following areas were selected: Environmental Sciences Ecology, Urban Studies, Water Resources, Meteorology Atmospheric Sciences, Engineering, Forestry, Plant Sciences, Biodiversity Conservation, Geography, Architecture, Agriculture, Development Studies, Material Science, Energy Fuels, Remote Sensing, and Transportation. This additional search in the Web of Science resulted in 310 articles. Since the oldest article in the Scopus database is from 2008 and that in the Web of Science database is from 2011, no publication date restriction was applied during the search.

The succeeding step involved a comparison of the articles acquired from the searches, and only those indexed in both Scopus and Web of Science databases were selected. From this process, a total of 111 articles were identified. These articles were considered for further analysis.

3. Results

Figure 2 presents the number of scientific articles published each year on the topic of the role of GI in climate change adaptation, based on a selection of 111 scientific papers. Among the selected articles, the earliest publication was published in 2012. Over the years, there has been a noticeable increase in the number of publications, reflecting the growing interest in this area of study. This increasing trend certainly indicates a growing awareness of the need for sustainable solutions in urban planning and environmental management.

The basic data for the articles selected for further analysis are presented in

Table 1. The basic data for the selected articles.

Description	Results
Timespan	2012–2024
Sources	43
Documents	111
Article	96
Review article	15
Authors	448
Author Keywords	362
Index Keywords	963
References	7480

.

Table 2. The most influential journals based on the number of published papers.

Rank	Journal	Number of Articles
1.	Urban Forestry and Urban Greening	16
2.	Land	10
3.	Journal of Environmental Management	9
4.	Ecological Indicators	5
5.	Atmosphere	5
6.	Climatic Change	5
7.	Ecology and Society	3
8.	Frontiers in Environmental Science	3
9.	Ecological Engineering	3
10.	Climate	3
11.	Science of the Total Environment	3
12.	Forests	3
13.	Environmental Management	2
14.	Ain Shams Engineering Journal	2
15.	Water Research	2
16.	Mitigation and Adaptation Strategies for Global Change	2
17.	Blue-Green Systems	2
18.	International Journal of Disaster Resilience in the Built Environment	2
19.	Journal of Sustainable Water in the Built Environment	2
20.	Ecological Indicators	2

presents a list of the most relevant journals based on the number of articles included in this analysis. Among the 111 articles analyzed, the highest number were published in Urban Forestry and Urban Greening (16 articles), followed by Land with 10 articles, and Journal of Environmental Management with 9 articles.

Furthermore, in

Table 3. Literature sources with proposed strategies and techniques.

Sector	Strategies and Techniques	Source
Mitigating urban heat islands	Constructing different types of green infrastructure to gain sustainable urban development and climate mitigation strategy.	[2,3,6,13,16,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93]
	The implementation of supplemental irrigation to increase roof cooling and vegetation structure to lower green roof temperatures.	[94,95,96,97,98]
	Improving blue-green infrastructure to assist municipalities and cities in adapting to climate change.	[19,99,100,101,102,103,104,105,106]
	The creation of other structural and environmental measures to increase adaptation to climate change in different aspects of the socio-economic sector.	[19,99,100,101,102,103,104,105,106]
Increasing ecosystem resilience	Improving policies and frameworks for risk reduction strategies, disaster recovery mechanisms, integrating restored and ecologically viable urban green infrastructure to deliver human health benefits by nature while supporting ecological variety, and ecosystem-based adaptation.	[11,88,107,108,109,110,111,112,113,114,115,116,117,118]
	Utilizing decision-making tools and methods such as spatial decision support systems and multi-criteria analysis to assist policymakers, experts, and non-expert planners in managing activities aimed at improving environmental conditions increases the resilience of various species to the climate change impact.	[71,119,120]
	Identifying measures to sustain or enhance the insurance value of urban ecosystems, including nature-based solutions, ecosystem-based adaptation, grey-green infrastructure, and blue-green infrastructure.	[42,72,121,122,123,124,125,126,127,128,129,130]
	Planting different tree species, installing green facades, engaging landscape planning, evolving and involving agroforestry and urban forestry in urban development planning to help prevent serious health problems, lowering the soil temperature and CO2 emission from soils, and adjusting to climate change, particularly in places where vulnerable populations live.	[65,131,132,133,134,135,136,137,138,139]
	In order to guide green infrastructure design and maximize ecosystem services results while minimizing ecosystem disservices, policymakers and planners could combine the biophysical assessment of green infrastructure parametric data with socio-economic data.	[140]
Flood risk management	Urban flood prediction, mitigation, and reduction services through green infrastructure regulations, land use and land cover changes, hydrological modeling, the assessment and monitoring processes of the stormwater infrastructure performance, and creating resilience plans.	[5,141,142,143,144,145,146,147,148,149,150,151,152,153,154]
	Implementing multifunctional stormwater management tools consisting of different elements mutually interacting to provide desired safety levels: Stormwater Management Model (SWMM) or Stormwater Management System (SWM), Environmental Protection Agency’s Stormwater Management Model, Sustainable Urban Drainage Systems (SuDS) and Sponge Cities Program (SCP), Curve Number-Based Watershed Model (CWM), Extreme Weather Layer method (EWL), Global Resilience Analysis framework (GRA).	[15,155,156,157,158,159,160,161]
	Addressing flooding and water quality issues utilizing blue-green infrastructure.	[4,162,163]

, 111 literature sources are analyzed in detail and then divided and grouped into three policy sectors: mitigating urban heat islands, increasing ecosystem resilience, and flood risk management. For each sector, a further division is generated in the strategies and techniques that the authors of the analyzed studies proposed. The studies are then distributed according to these strategies and techniques.

3.1. Bibliometric Analysis

A bibliometric analysis was conducted using VOSviewer version 1.6.20. VOSviewer is a software application developed by Van Eck and Waltman [164], designed for constructing bibliometric maps based on network data. These maps can be used to visualize and examine various items of interest, such as scientific publications, scientific journals, research organizations, countries, keywords, or terms. In general, the constructed network consists of items linked together with different types of links, including co-occurrence, bibliographic coupling, or co-citation. Co-occurrence analysis establishes connections between items based on the number of publications in which they appear together [165]. Co-occurrence maps of keywords can be used to identify key areas and similar research topics [19]. Bibliographic coupling is a technique used to analyze citations, with two publications considered bibliographically coupled if they cite the same reference [164,166]. In this context, the link between two publications is stronger the greater the number of shared references. The number of references shared between two publications is a temporally static value, meaning it does not change over time [167]. Co-citation is a bibliometric method that establishes a relationship between two publications when both are cited in the same third document [165]. This technique can also apply to journals and authors, making it a valuable tool for identifying the most significant publications, journals, or authors within a specific area [19].

The strength of the connection between two items is determined by the strength of the link. In the case of co-occurrence links, the strength reflects the number of publications in which the terms appear together. For bibliographic coupling links, it represents the number of shared cited references between two publications. In the visual representation of a network, the size of the graphical marker and the font size of an item indicate its weight. More important items, such as keywords with higher occurrences, have greater weight and are displayed more prominently. Similarly, the thickness of the line representing the link between two items indicates the strength of the connection between them. Apart from the thickness of the link line, the distance between nodes also graphically describes the strength of the link [165].

Items in a network can be grouped into individual clusters based on similarity or co-occurrence patterns. For example, in the case of co-occurrence analysis, keywords are grouped into a cluster if they frequently appear together in publications. In bibliographic coupling analysis, clusters are formed by grouping publications based on the frequency of references they share. The stronger the connection between the two publications, the more references they cite in common.

A bibliometric analysis was conducted to gather and systematize existing knowledge and identify certain gaps in the literature regarding the role of green infrastructure in climate change adaptation. The VOSviewer software was used for this purpose, facilitating analyses of co-occurrence with all keywords, co-citation analysis by source, and bibliographic coupling analysis with documents. The results of these analyses are presented below.

3.1.1. Keyword Co-Occurrence Analysis

During the implementation of this analysis, an initial review of the keywords was performed. Keywords related to the article structure that were not directly relevant to the article’s topic (such as “article” and “literature review”) were excluded. Following this, adjustments were made to keywords with similar meanings using a thesaurus file (e.g., “city” and “cities,” “floods” and “flooding”, etc.).

The results of the co-occurrence analysis with all keywords are presented in Figure 3. A minimum occurrence threshold of four keywords was defined, resulting in 74 keywords exceeding this threshold from a total of 1180 keywords. The five most frequently occurring keywords are climate change, green infrastructure, infrastructure, climate change adaptation, and green space.

Four clusters were formed during this analysis, each represented visually by different colors. The blue cluster contains keywords related to water and flood risk management, such as floods, runoff, stormwater, water management, and rain. The green cluster includes keywords like climate change, green infrastructure, green space, climate change adaptation, nature-based solutions, urban heat island, urban area, and urban planning. This cluster groups the keywords with the most frequent occurrences in the publications analyzed in the search. The red cluster contains keywords like adaptation, ecosystem services, biodiversity, and resilience. The yellow cluster, which is the smallest, includes 12 keywords such as infrastructure, land use planning, remote sensing, sustainability, urbanization, risk assessment, and risk management.

The grouping of these clusters reflects the categorization of terms based on key ecosystem services. The largest, green cluster focuses on climate change adaptation regulating ecosystem services, particularly the urban heat island effect. The red cluster relates to biodiversity and habitat ecosystem services and climate change-regulating services that strengthen ecosystem resilience. The blue cluster refers to climate change adaptation regulating services concerning flood risk management. Lastly, the yellow cluster highlights the role of GI in land use, spatial, and urban planning approaches.

3.1.2. Co-Citation Analysis by Source

A co-citation analysis at the level of cited sources was conducted, using source titles (e.g., journals, books, conference proceedings) from the reference lists of the analyzed papers as the unit of analysis. This bibliometric technique was employed to identify the most influential sources in this field. By examining the frequency with which two sources were co-cited, the most impactful sources were highlighted. A minimum threshold of 40 citations per source was set, resulting in 30 sources meeting the threshold out of a total of 3337 sources.

During the database screening process, only articles and review articles were selected, resulting in all 30 sources being scientific journals. These journals were categorized into three distinct clusters, each represented by a different color in Figure 4. The urban sustainability and ecosystem services cluster (red) is the largest, both in the number of journals and total citations. This cluster encompasses journals addressing topics such as urban planning, sustainability, ecosystem services, and the effects of climate change on urban and natural environments. The second largest cluster, marked in green, is the environmental management and hydrology cluster. It includes journals focused on environmental management, hydrological research, water resource management, and pollution control. The smallest cluster, shown in blue, is the urban environment and pollution management cluster, comprising journals that emphasize environmental sustainability, urban greening, pollution management, and energy efficiency in urban areas.

Table 4. The most influential journals based on total citations.

Cluster	Journal	Total Citations
Red cluster	Landscape and Urban Planning	321
	Sustainability	143
	Ecological Indicators	81
	Environmental Science and Policy	78
	Ecosystem Services	70
Green cluster	Journal of Environmental Management	111
	Journal of Hydrology	62
	Water	68
	Climatic Change	63
	Journal of Cleaner Production	55
Blue cluster	Urban Forestry and Urban Greening	214
	Science of the Total Environment	135
	Building and Environment	124
	Sustainable Cities and Society	77
	Energy and Buildings	76

highlights the five most influential journals from each cluster.

From Figure 4, the distance between individual items (journals) and the thickness of the lines connecting them represent the strength value of the relationship links. The strength of the co-citation link between two sources indicates the number of times they have been cited together in the same third paper. In addition to the co-citation relationships between sources, Figure 4 visually displays the significance of each source based on its total citation count. The citation count refers to the number of times specific journals have been cited in the 111 analyzed articles. Journals with higher citation counts are more prominently represented, with larger circles and a larger font size.

3.1.3. Bibliographic Coupling Analysis with Documents

A bibliographic coupling analysis with documents was conducted to identify groups of studies addressing similar topics based on the number of shared references and to determine the most influential publications by citation count. A minimum threshold of 20 citations per document was applied. Out of the 111 analyzed publications, 42 met this threshold. The visual representation of the analysis results is provided in Figure 5.

Based on the shared references, the analyzed works were grouped into five clusters. The largest is the red cluster, dominated by the works of Choi [71], Maragno [150], and Pauleit [75]. In the green cluster, the most significant works based on shared references, are Zölch [90], Herath [91], and Sharifi [19]. The blue cluster highlights Brudler [155], Dong [148], and Zahmatkesh [156]. The yellow cluster consists of three studies: Meyer [152] and Wamsler [115,116]. Lastly, the purple cluster includes only two studies: Koch [77] and Hunter [65].

Analyzing the clusters grouped based on shared references, it becomes apparent that studies published in the same journal are often grouped into the same cluster. For example, Zölch [90] and Herath [91] are both published in Urban Forestry and Urban Greening; Brudler [155] and Dong [148] are published in Water Research; and Wamsler [116] and [115] are published in Ecology and Society. This can be explained by the fact that these studies address similar topics, which is why they are published in the same journal and share many of the same references.

From Figure 5, it is possible to identify the most influential works based on citations, as the size of the graphic marker for each publication represents the total number of citations that the document has received in Scopus. Among the 42 papers shown in Figure 5,

Table 5. The most influential papers based on total citations, with review articles highlighted in bold.

Rank	Authors	Reference	Publication	Total Citations
1.	Zölch, T. et al. (2016)	[90]	Using green infrastructure for urban climate-proofing: An evaluation of heat mitigation measures at the micro-scale	272
2.	Dong, X. et al. (2017)	[148]	Enhancing future resilience in urban drainage system: Green versus grey infrastructure	227
3.	Sharifi, A. (2021)	[19]	Co-benefits and synergies between urban climate change mitigation and adaptation measures: A literature review	212
4.	Pauleit, S. et al. (2019)	[75]	Advancing urban green infrastructure in Europe: Outcomes and reflections from the GREEN SURGE project	196
5.	Hunter, A.M. et al. (2014)	[65]	Quantifying the thermal performance of green facades: A critical review	184
6.	Zahmatkesh, Z. et al. (2015)	[156]	Low-impact development practices to mitigate climate change effects on urban stormwater runoff: Case study of New York City	183
7.	Muerdter, C.P. et al. (2018)	[151]	Emerging investigator series: the role of vegetation in bioretention for stormwater treatment in the built environment: pollutant removal, hydrologic function, and ancillary benefits	133
8.	Herath, H.M.P.I.K. et al. (2018)	[91]	Evaluation of green infrastructure effects on tropical Sri Lankan urban context as an urban heat island adaptation strategy	127
9.	Wamsler, C. (2015)	[116]	Mainstreaming ecosystem-based adaptation: transformation toward sustainability in urban governance and planning	107
10.	Maragno, D. et al. (2018)	[150]	Fine-scale analysis of urban flooding reduction from green infrastructure: An ecosystem services approach for the management of water flows	95
11.	Choi, C. et al. (2021)	[71]	The climate benefits, co-benefits, and trade-offs of green infrastructure: A systematic literature review	91
12.	Sussams, L.W. et al. (2015)	[2]	Green infrastructure as a climate change adaptation policy intervention: Muddying the waters or clearing a path to a more secure future?	91
13.	Brudermann, T. and Sangkakool, T. (2017)	[95]	Green roofs in temperate climate cities in Europe—An analysis of key decision factors	89
14.	Koch, K. et al. (2020)	[77]	Urban heat stress mitigation potential of green walls: A review	79
15.	Larsen, L. (2015)	[89]	Urban climate and adaptation strategies	77
16.	Moore, T.L. et al. (2016)	[157]	Stormwater management and climate change: vulnerability and capacity for adaptation in urban and suburban contexts	71
17.	Wamsler, C. et al. (2016)	[115]	Operationalizing ecosystem-based adaptation: harnessing ecosystem services to buffer communities against climate change	68
18.	Meyer, M.A. et al. (2018)	[152]	Participatory action research: tools for disaster resilience education	68
19.	Green, T.L. et al. (2016)	[168]	Insurance value of green infrastructure in and around cities	67
20.	Hamel, P. and Tan, L. (2022)	[169]	Blue-green infrastructure for flood and water quality management in Southeast Asia: Evidence and knowledge gaps	65

Note: Review articles are highlighted using bold text.

presents the 20 most influential works based on the total citation count. Review articles are highlighted in bold.

3.2. Reviews on Green Infrastructure Application in Climate Change Adaptation

Monsalves-Gavilán et al. systematized the impacts of climate change on urban spaces in Chile between 2000 and 2012 [99]. The main conclusions include increasing temperatures, more frequent droughts, and floods, which negatively affect urban planning and development. A critical review by Hunter et al. quantifies the thermal performance of green facades [65]. The review draws attention to the inconsistency of research articles on measured microclimate parameters, which is necessary to identify those essential to better understand green facade thermal characteristics. The study from Larsen [89] explored how the urban environment affects the microclimate of cities. Larsen suggests various approaches (e.g., green roofs, urban forests) to reduce the negative impacts of climate change on the urban environment and highlights the importance of climate change adaptation. Rowe et al. performed an online survey that was sent to various officials in each of the New Jersey state’s municipalities. The survey showed that stormwater management was the most common primary motivating factor to use GI techniques, while climate change adaptation was not chosen by any respondents [147]. In 2016, Wamsler et al. reviewed the research on ecosystem services in urban areas and examined four Swedish coastal municipalities to identify the key characteristics of both implemented and planned measures that support ecosystem-based adaptation [115]. Their results showed that many of the measures that have been implemented focus on biodiversity rather than climate change adaptation. They concluded that a more comprehensive approach to sustainable ecosystem-based adaptation planning is required. Pauleit et al. synthesized the results of the GREEN SURGE project [75], which advanced the concept of urban green infrastructure in European cities by strengthening conceptual foundations; developing methods for assessing conditions, benefits, and management; and building a stronger evidence base. The project identified good practices and opportunities to better link government-led planning with bottom-up initiatives in the creation and management of urban green infrastructure. A review by Koch et al. explored how green walls can be used to mitigate heat stress in urban environments [77]. The review provides summary tables and figures that can assist policymakers and researchers in planning and implementing green walls and identifies knowledge gaps that require further research to fully exploit their benefits. Choi et al. systematically reviewed 141 research articles about the climate benefits, associated co-benefits, and trade-offs of GI [71]. Researchers and practitioners can use their study to identify opportunities to deliver multiple ecosystem services and benefits whilst recognizing disservices and trade-offs that need to be avoided or managed. Sharifi’s review [19] provided a bibliographic analysis of the existing knowledge surrounding the interactions between adaptation and mitigation. The co-benefits and synergies of adaptation and mitigation measures were explored. Smith et al. explored the effectiveness of nature-based solutions in Bangladesh to address climate change and achieve sustainable development goals [125]. A systematic literature review by Almaaitah et al. analyzes the effectiveness of blue-green infrastructure as a climate change adaptation strategy [4]. The study highlights that blue-green infrastructure can reduce flood risk, mitigate the UHI effect, and also improve air quality and increase biodiversity. Li et al. reviewed the available literature between 2000 and 2021, focusing on Africa’s urban thermal environment under the combined effect of urbanization and climate change [103]. They highlight that researchers need to focus on the urban thermal environment because the current stage of urbanization offers a time-limited opportunity if sustainable development is to happen within the context of global climate change. Singhvi et al. provided a review of 105 studies on coastal infrastructure, extending the existing dual insurance framework to provide an approach that takes into account external and internal resilience factors [128]. The review suggests that coastal planners should consider a wider range of options that integrate gray and green interventions, taking into account internal resilience factors such as the diversity of responses, multifunctionality, modularity, and participatory management. The review by Shao and Kim provides an overview of different types of GI to mitigate the effect of UHIs, analyzing their progress, functions, and benefits [81]. They conclude that the implementation of GI can significantly reduce temperatures in urban areas, improve air quality, and provide environmental, social, and economic benefits. Zhang and MacKenzie reviewed 96 case studies globally to explore interrelations between ecosystem services and ecosystem disservices provided by GI in urban areas [140]. They suggested that an effective approach to explore the causation of trade-offs and synergies in GI is by analyzing the functional traits of GI.

4. Discussion and Conclusions

The presented study investigated the role of green infrastructure in climate change adaptation, focusing on hazard prevention, systems and models for mitigating negative impacts, and strategies and policies for managing sustainable urban development. The investigation conducted a thorough literature review of the previous studies and an analysis of these studies using the methodology of bibliometric analysis. The methodology was carried out to identify the most influential sources in the studied field. It started with database screening, then keyword selection using Boolean operators “AND” and “OR”. After filtering, the Web of Science database yielded 310 articles, while Scopus had 167. Finally, the comparison of the articles succeeded with the number of articles that were indexed in both databases, which was 111, of which 15 are reviews and 96 are research papers, published between 2012 and 2024. Four clusters formed during analysis, dealing with stormwater management, urban heat islands and green infrastructure, ecosystems, land use planning, and remote sensing. Analyzing 111 papers, 20 of them are the most influential with the highest total citations, among which 5 are reviews. These, the most influential studies, deal mostly with hazardous management and the mitigation of heat waves and a few of them with ecosystem resilience. Therefore, the authors designed a workflow to achieve a better understanding of the analyzed research dealing with climate change adaptation by utilizing green infrastructure, dividing them into the three most beneficial policy sectors: the mitigation of urban heat islands, increasing ecosystem resilience, and flood risk management. Most of the studies examined the mitigation of urban heat islands, according to Table 3, and fewer examined an increase in ecosystem resilience and flood risk management. Section 3.2. presents the analyzed review papers. These papers give reviews of green infrastructure applications in adaptation to climate change. Although most of these reviews give in-depth systematic reviews, none have analyzed studies on green infrastructure’s role in the way that is proposed in this research.

Figure 6 presents the number of papers throughout the period from 2012 to 2024. It is clear from the figure that climate change adaptation studies in three sectors have mostly been published in the last five years, especially in mitigating urban heat islands and increasing ecosystem resilience. Interest in increasing ecosystem resilience has notably grown in the last three years. A number of published papers in sector flood risk management, among the analyzed ones in this study, have been almost continuous in the last five years. Before the year 2020, studies were not that numerous, and some of the sectors had a year without published papers. Hence, it can be concluded that the role of green infrastructure in climate change adaptation has been gaining a very important role in research in recent years.

Each of the sectors was divided into a few groups according to strategies and techniques that were used or suggested in the studies. Most of the papers in the sector of mitigating urban heat islands proposed or utilized different types of green infrastructure for sustainable urban development and strategies for climate change impact and mitigation. Others from the same sector dealt with micro-strategies like roof cooling vegetation designs, blue-green infrastructure in municipalities, and using other structural and environmental measures in different socio-economic aspects.

In the sector of increasing ecosystem resilience, most of the studies examined the planting of different tree species, involving agroforestry and urban forestry in the urban development of the cities that have shown to be very useful in preventing serious health problems, lowering the soil temperature and CO₂ emission from soils. Improving policies and frameworks for risk reduction and disaster recovery, integrating restored and ecologically viable urban green infrastructure by nature to support ecosystem-based variety, and including nature-based solutions, ecosystem-based adaptation, and blue-green infrastructure were other strategies and techniques proposed in this sector by published papers.

As for the sector of flood risk management, studies mostly developed and used different stormwater management tools; urban flood prediction, mitigation, and reduction services through green infrastructure regulations; hydrological modeling; and others to create resilience stormwater plans. Few of them examined utilizing blue-green infrastructure to address flooding and water quality issues.

4.1. Green Infrastructure Contribution to Policy Sectors

Green infrastructure (GI) represents a set of multifunctional nature-based solutions that play a pivotal role in urban adaptation to climate change. Building upon the conceptual foundations established in urban planning and ecosystem services [2,20,23], GI provides effective support in three main policy sectors, which are mitigating urban heat island effects, enhancing ecosystem resilience, and managing flood risk [11,20].

In the context of flood risk management, GI elements such as rain gardens, bioretention systems, wetlands, green roofs, and permeable pavements are employed to regulate stormwater runoff, improve water infiltration, and reduce flood peaks [41,42,43,46]. These systems emulate natural hydrological processes and offer cost-effective and sustainable solutions for urban resilience. Urban green spaces, including street trees and parks, not only serve as buffers that slow and filter water, but also provide co-benefits such as biodiversity support, aesthetic value, and thermal comfort [11,39,41].

Similarly, GI plays a critical role in mitigating urban heat island effects, which are exacerbated by impervious surfaces and limited vegetation in urban areas. Urban vegetation like trees, green roofs, green facades, and parks reduce ambient temperatures through shading and evapotranspiration [11,36,37]. Green roofs can lower indoor air temperature significantly, by up to 15 °C [39], while green facades have demonstrated consistent thermal regulation in both hot and cold climates [40]. Increasing the albedo of urban materials and integrating blue-green infrastructure, including urban water bodies and fountains, further supports temperature regulation and microclimatic balance [38,56].

GI also strengthens ecosystem resilience by enhancing biodiversity, supporting soil structure, sequestering carbon, and facilitating nutrient cycling [20,22,29]. Measures like urban forestry, habitat corridors, agroforestry practices, and ecosystem-based approaches contribute to maintaining ecological balance and supporting adaptation in the face of increasing climate variability [11,12,13]. Furthermore, GI promotes social and economic resilience by enabling environmental education, creating green jobs, and fostering inclusive public spaces [24,25,27,29].

Multiple studies emphasize the necessity of integrated and multifunctional GI strategies such as grey-green and blue-green infrastructure systems, which maximize synergies across sectors while minimizing disservices [19,71,72]. These approaches align with broader sustainability and climate policy frameworks and are recognized by institutions like the European Environment Agency [20].

In summary, GI provides a robust, flexible, and adaptive foundation for addressing urban climate challenges. Its contribution to flood mitigation, urban heat island reduction, and ecosystem resilience is well documented in the literature and supported by empirical evidence [11,39,41,46,56]. Integrating GI into urban planning is essential for sustainable development, especially in light of projected increases in climate-related risks.

4.2. Final Remarks, Limitations, and Future Directions

The study provides an overview of green infrastructure’s role in climate change adaptation, and it gives a comprehensive literature analysis and insightful context to the importance of this nature-engineering construction. To provide extensive literature research, two of the most comprehensive and widely used databases, Scopus and Web of Science Core Collection, were used. The initial search in both databases resulted in a few hundred papers from each database, but the final review resulted in 111 articles, which were indexed in both databases. The main keywords that were used with Boolean operators “AND” and “OR” were urban green infrastructure, green infrastructure, climate change, and adaptation.

The scientific contribution and innovation of this study are found in the detailed review and the analysis of the literature on the research topic, which was conducted through the steps presented in Figure 1. The process of the review was carried out systematically, starting from the main idea, selecting keywords, analyzing the literature, and then cross-referencing the articles in the databases. Although this study provides a detailed and structured review of the previous literature, the initial search was deliberately limited to a set of core keywords. This intentional narrowing of the search scope was aimed at ensuring a focused, relevant, and methodologically manageable selection of articles. While this approach enhanced the consistency and clarity of the dataset, it may have influenced the outcomes of the co-occurrence analysis by potentially excluding studies that used alternative terminology to describe similar concepts.

The main innovation of the study is its structure of methodology that conventionally did not present just a bibliometric analysis of the literature review but also further in-depth research of the 111 articles. This resulted in the definition of the three main policy sectors and then the distribution of the articles into these sectors. The motivation for the study was its topicality and ubiquity, with extensive available literature. The review on this topic was not conducted until now by the proposed methodology, according to the authors’ investigation. From all the above-mentioned, it may be concluded that the provided topic is very current and it is evolving over time.

The main finding of this research refers to the comprehensive systematization of the existing literature on the role of green infrastructure in adapting to climate change, through clearly identified sectors with the greatest benefits, which are mitigating urban heat islands, strengthening ecosystem resilience, and flood risk management. This classification contributes to a better understanding of the thematic focus of previous research and represents the basis for the design of effective and targeted policies in urban planning and adaptation to climate change. In addition to all of the above, answers can be given to the three key research questions posed. The analysis showed that GI has multiple applications in all three sectors, dominated by measures that include natural solutions such as green roofs, urban forests, rain gardens, and blue-green infrastructure. Numerous implementation approaches have been proposed in the literature, based on interdisciplinary models, participatory planning, and decision-support tools. Bibliometric and co-citation analysis indicated a growing scientific interest in the last five years but also methodological challenges such as a lack of standardization and limited geographical representation, which represent an important direction for future research.

In future directions, the authors will include a meta-analysis, which will be used to conduct a quantitative review of different domains of articles and studies dealing with the same issue.