Research Advances and Emerging Trends in the Impact of Urban Expansion on Food Security: A Global Overview

Abstract

Food security constitutes a fundamental pillar of future sustainable development. A systematic evaluation of the impact of urban expansion on food security is critical to advancing the United Nations Sustainable Development Goals (SDGs), particularly “Zero Hunger” (SDG 2). Drawing on bibliographic data from the Web of Science Core Collection, this study employs the bibliometrix package in R to conduct a comprehensive bibliometric analysis of the literature on the “urban expansion–food security” nexus spanning from 1982 to 2024. The analysis focuses on knowledge production, collaborative structures, and thematic research trends. The results indicate the following: (1) The publication trajectory in this field exhibits a generally increasing trend with three distinct phases: an incubation period (1982–2000), a development phase (2001–2014), and a phase of rapid growth (2015–2024). Land Use Policy stands out as the most influential journal in the domain, with an average citation rate of 43.5 per article. (2) China and the United States are the leading contributors in terms of publication output, with 3491 and 1359 articles, respectively. However, their international collaboration rates remain relatively modest (0.19 and 0.35) and considerably lower than those observed for the United Kingdom (0.84) and Germany (0.76), suggesting significant potential for enhanced global research cooperation. (3) The major research hotspots cluster around four core areas: urban expansion and land use dynamics, agricultural systems and food security, environmental and climate change, and socio-economic and policy drivers. These focal areas reflect a high degree of interdisciplinary integration, particularly involving land system science, agroecology, and socio-economic studies. Collectively, the field has established a relatively robust academic network and coherent knowledge framework. Nonetheless, it still confronts several limitations, including geographical imbalances, fragmented research scales, and methodological heterogeneity. Future efforts should emphasize cross-regional, interdisciplinary, and multi-scalar integration to strengthen the systematic understanding of urban expansion–food security interactions, thereby informing global strategies for sustainable development.

1. Introduction

With the accelerating pace of global urbanization, rapid urban spatial expansion has emerged as a critical force in reshaping land use patterns, exerting profound and far-reaching impacts on regional ecological integrity and food supply systems [1]. Existing research indicates that the expansion of urban construction land predominantly occurs at the expense of agricultural land, with farmland accounting for approximately 68.93% of the total converted area [2]. Projections from the United Nations suggest that by 2050, nearly 70% of the global population will reside in urban areas, intensifying spatial pressures on farmland due to the continued outward expansion of urban boundaries [3]. Empirical evidence shows that urban expansion over the past 25 years has resulted in a reduction of cropland and net primary productivity (NPP) totaling 58.71 TgC, equivalent to approximately 0.42% of the multi-year average NPP of cropland between 2000 and 2015. This loss, when translated into grain production (around 14.4 million tons), could satisfy the minimum annual grain intake of approximately 36 million individuals [4]. As urban expansion is projected to continue—potentially causing 1.8–2.4% of global farmland loss by 2030—threats to the stability and sustainability of global food systems are becoming increasingly pronounced [5]. Addressing the tension between urban development and food security has therefore become a pressing priority within the global sustainable development agenda.

Urban expansion impacts food security through a range of direct and indirect pathways. Direct impacts include the continual reduction of farmland area and the spatial compression of agricultural activities [6]. Indirectly, urban sprawl contributes to land degradation, diminished agricultural productivity, and the outmigration of rural labor forces [7]. Furthermore, it may disrupt urban–rural food supply networks, thereby undermining the accessibility and stability of food availability [8]. These interconnected mechanisms underscore the systemic and complex nature of the challenges posed by urban expansion to food security, demanding holistic and interdisciplinary investigations.

In recent years, a growing body of empirical research has explored the interplay between urban expansion and food security, yet consensus remains elusive regarding whether urbanization exerts primarily adverse or potentially beneficial effects under certain conditions. These studies span a wide array of perspectives, including land use change monitoring [9], farmland protection policy assessments [10], and simulations of agricultural production potential [11,12]. While the prevailing consensus underscores the negative consequences of farmland loss for food production capacity, some scholars contend that urbanization may facilitate efficiency gains in agriculture through the promotion of large-scale and mechanized farming practices [13]. Nonetheless, the current literature is marked by several notable deficiencies: (1) the geographical distribution of research is uneven, with disproportionate attention paid to a limited number of countries or metropolitan regions, thereby lacking a comprehensive global assessment; (2) the theoretical frameworks and methodological approaches remain fragmented, impeding the development of a cohesive understanding of the dynamic mechanisms linking urban expansion with food systems [12]; and (3) the existing reviews often focus narrowly on either land use dynamics or specific aspects of the food system, falling short of providing a systematic and integrative analysis of the coupling relationship and evolutionary trajectory between urban expansion and food security [14,15].

Furthermore, this study integrates the four pillars of food security—availability, access, utilization, and stability—outlined by the Food and Agriculture Organization (FAO) of the United Nations, along with the conceptual framework of supply chain resilience, to examine the complex and multidimensional impacts of urban expansion on food systems. This comprehensive analytical perspective enhances both the theoretical rigor and the global relevance of the research framework. Guided by this integrated approach, the study aims to systematically review and synthesize the evolution of scholarly work on the “urban expansion–food security” nexus by addressing the following key questions: (1) What spatiotemporal patterns characterize the development of this research field? (2) How do research priorities and focal areas vary across countries and institutions? (3) What are the predominant research hotspots and emerging thematic directions? (4) What theoretical divergences, methodological approaches, and paradigm shifts have shaped the progression of this domain?

To this end, we employ the bibliometrix package in R 4.4.1, integrating bibliometric techniques with visual analytics to reveal the structural properties and developmental trends of research within this field. This study contributes to the literature in three main ways: (1) by transcending the limitations of case-based and thematically siloed research, it constructs a comprehensive framework for understanding the urban expansion–food security nexus; (2) by tracing the evolution of research themes and identifying emerging consensus and scholarly contention amid shifting paradigms; and (3) by offering theoretical and methodological references for future research that spans spatial scales, regional contexts, and disciplinary boundaries. Ultimately, the findings aim to inform farmland preservation and urban planning policy while supporting global efforts to enhance food system resilience and sustainability.

2. Research Methods

2.1. Data Sources and Retrieval Strategies

To systematically examine the developmental trajectory and knowledge structure within the research domain of “urban expansion and food security,” this study selected the Web of Science Core Collection (WoS Core Collection) as the primary data source. As an internationally recognized citation indexing platform, WoS offers broad disciplinary coverage, standardized data architecture, and comprehensive metadata, with strong representativeness and citation consistency in fields such as geographical sciences, land use, and environmental research [3]. In contrast, although Scopus provides an advantage in terms of coverage volume, its citation standardization is relatively limited, while PubMed primarily focuses on biomedical sciences, making them less suitable for the interdisciplinary nature of this study. Therefore, WoS was considered the most appropriate database [3].

The literature retrieval was conducted in March 2025, covering the period from 1 January 1982 to 31 December 2024. The starting year corresponds to the publication of the first article in which “urban expansion” and “food security” were jointly addressed, thereby establishing a clearly defined temporal boundary for the thematic emergence. The search strategy was constructed using the topic field (TS) as follows: TS = ((“urban expansion” OR “urban sprawl” OR “urban growth” OR “urban land use change” OR “urbanization”) AND (“food security” OR “food supply” OR “food production” OR “agricultural land” OR “cropland loss” OR “farmland loss”)).

To ensure data representativeness and consistency, only documents categorized as “Article” were retained, without language restrictions. A total of 3786 records were initially retrieved. After manual deduplication and title/abstract screening, 3298 valid articles were included and exported in plain text format for subsequent bibliometric analysis.

2.2. Analysis Tools and Technical Routes

This study utilized the bibliometrix package (version 4.4.1) within the R environment for bibliometric analysis, complemented by the biblioshiny graphical interface to facilitate result visualization [3]. The research workflow encompassed three core stages: data import and cleansing, metric computation and network construction, and visualization of findings.

Initially, raw bibliographic data exported from the Web of Science in plain text format were imported and transformed within R to ensure structural integrity and accurate field recognition. During preprocessing, duplicate records were programmatically detected and removed to prevent analytical bias. Moreover, author names and institutional affiliations underwent standardization to address inconsistencies arising from variations in letter casing, extraneous spaces, or special characters. This harmonization reduced record fragmentation caused by spelling discrepancies or abbreviation differences, thereby enhancing data consistency and reliability for subsequent analyses.

Post-cleaning, essential bibliometric indicators were extracted, including annual publication counts, leading contributing countries and institutions, core author distributions, and journal coverage. Additionally, collaborative networks and keyword co-occurrence maps were generated to elucidate scholarly cooperation and thematic structures. A minimum occurrence threshold was applied to keyword clustering to ensure robust and representative results.

Visualization was achieved via biblioshiny, producing outputs such as publication trends, international collaboration networks, and keyword word clouds. In these visualizations, node size corresponded to publication volume, edge thickness represented collaboration intensity, and word clouds highlighted dominant research themes based on normalized term frequencies. Analytical procedures and parameter configurations adhered to established bibliometric standards, with tailored adjustments to fit the study’s thematic context, ensuring transparency, scientific rigor, and reproducibility (Figure 1).

2.3. Index System and Explanatory Variables

Building on the preceding data processing and analytical framework, this study establishes a comprehensive bibliometric indicator system comprising three principal dimensions: knowledge production, collaboration structure, and knowledge content. This system is designed to systematically reveal the scale of development, collaborative patterns, and thematic evolution within the “urban expansion–food security” research field. The knowledge production dimension encompasses annual publication trends and core journal distributions, reflecting the field’s research intensity and key platforms for knowledge accumulation. The collaboration structure dimension addresses contributions from leading countries and institutions, alongside author collaboration networks, thereby illustrating the spatial distribution and cooperative dynamics of research efforts. The knowledge content dimension utilizes keyword co-occurrence analysis and hotspot identification to delineate principal themes, foundational concepts, and their temporal trajectories. Collectively, these indicators encapsulate both the quantitative and structural aspects of scholarly output, as well as the collaborative networks and knowledge dissemination pathways among research actors, providing a solid basis for subsequent trend evaluation and structural synthesis. Detailed classifications and precise definitions of these indicators are summarized in

Table 1. Bibliometric analysis indicator system and description of explanatory variables.

Indicator Category	Indicator Name	Description
Knowledge Output Features [3]	Annual Publication Trend	Tracks the annual variation in the number of published articles, reflecting research interest and development stages
	Leading Journals	Core journals with the highest publication volumes, indicating primary academic platforms and their disciplinary affiliations
National Research Landscape [3]	Major Publishing Countries	Countries ranked by publication volume, representing the main contributors and their level of international engagement
	International Collaboration Network	Illustrates the breadth and intensity of cooperation among countries, reflecting the global collaborative network in the field
Institutional Collaboration Structure [3]	Leading Institutions	Universities, research institutes, or think tanks with high publication output, indicating institutional concentration of research capacity
	Institutional Collaboration Network	Displays cooperative relationships among institutions, highlighting the integration and sharing of knowledge resources
Academic Contributors and Collaboration Network [3]	Leading Authors	Scholars with high publication counts and impact (e.g., citation frequency), recognized as key knowledge contributors
	Author Collaboration Network	Maps the cooperation network among authors, identifying core collaborative groups and interdisciplinary research trends
Knowledge Content Features [3]	Hot Topic Distribution	Core themes identified through keyword co-occurrence analysis, revealing the main research directions and focus areas

.

3. Results

3.1. Basic Characteristics

3.1.1. Annual Publication Trends

The annual publication trend offers valuable insights into the evolving academic interest and developmental trajectory of the “urban expansion–food security” research domain. Between 1982 and 2024, the number of publications in this field demonstrated a generally upward trajectory with periodic fluctuations, underscoring a growing global focus on the topic (Figure 2). To systematically delineate the field’s evolution, this study adopted a bibliometric lifecycle framework and categorized the development of the research into three distinct phases based on annual publication volumes: the Emergence Phase (1982–2000), the Growth Phase (2001–2014), and the Rapid Expansion Phase (2015–2024). The Emergence Phase was characterized by an annual output of fewer than 10 articles, indicating limited academic engagement and the absence of a stable research community. During the Growth Phase, the annual publication volume ranged between 10 and 100 articles, signifying a gradual increase in scholarly attention, the formation of research networks, and the establishment of preliminary conceptual frameworks. In the Rapid Expansion Phase, the number of publications exceeded 100 per year, reflecting the field’s emergence as a prominent research hotspot with intensive output and expanding influence. Quantitatively, the Emergence Phase yielded an average of 2.21 publications per year, totaling 42 articles and accounting for 1.27% of the overall sample. In contrast, the Growth Phase averaged 36.43 publications annually, contributing 15.46% to the total. The Rapid Expansion Phase experienced a dramatic surge, with an average annual output of 249.64 articles—an increase of 111.93% relative to the Emergence Phase—highlighting a period of prolific academic engagement and the field’s transition into a phase of accelerated knowledge production.

3.1.2. Leading Journals

Bibliometric analysis of journal publications enables the identification of core journals and primary dissemination platforms within the research domain of “urban expansion impacts on food security.” From 1982 to 2024, a total of 854 journals published relevant studies, with the top ten journals ranked by publication volume summarized in

Table 2. Top 10 journals by publication volume on the impact of urban expansion on food security.

Journal Name	NP	TC	PY_Start	Country of Publication
Sustainability	206	76	2009	Switzerland
Land	174	34	2012	Switzerland
Land Use Policy	146	6351	1984	The Netherlands
Science of the Total Environment	96	8	1972	The Netherlands
Ecological Indicators	84	4	2001	The Netherlands
Journal of Cleaner Production	58	14	1993	The Netherlands
REMOTE Sensing	5	5	2009	Switzerland
Environmental Science and Pollution Research	55	1	1994	Germany
Environmental Monitoring and Assessment	54	3	1981	The Netherlands
Journal of Environmental Management	50	1	1973	Germany

Note: TC refers to total citations; NP represents the total number of publications; PY_start indicates the year of first publication.

. Sustainability leads with 206 published articles and a total citation count of 76, demonstrating its active engagement in this field. It is closely followed by Land, Land Use Policy, Science of the Total Environment, and Ecological Indicators, which contributed 174, 146, 96, and 84 articles, respectively. Notably, despite ranking third in publication volume, Land Use Policy commands a significantly higher academic impact, with a total of 6351 citations and an average citation rate of 43.5 per article—surpassing the other journals in both metrics. Additionally, Sustainability and Land commenced publishing research on this topic in 2009 and 2012, respectively. Although their inception was relatively recent, both journals have experienced rapid growth, averaging 12.8 and 13.4 publications annually, positioning them as emerging high-output leaders in this research area.

3.2. Research Capacity

3.2.1. Leading Countries

Publication volume and patterns of international collaboration serve as critical indicators of a nation’s research capacity and academic influence within the domain of urban expansion and food security. Between 1982 and 2024, the foremost contributors were China, the United States, India, Australia, Italy, Germany, the United Kingdom, the Netherlands, Canada, and France (Figure 3). China and the United States notably dominated the field with 3491 and 1359 publications, respectively, reflecting their substantial scholarly commitment to this subject. In citation metrics, China and the United States also led significantly, with total citation counts of 38,936 and 19,487, respectively, underscoring their pivotal roles in global academic discourse. Nevertheless, China’s average citations per publication, at 32.3, lag behind the top ten countries’ average of 40.47, suggesting that despite rapid expansion, further efforts are warranted to elevate the international visibility and scholarly quality of its research outputs. Remarkably, Australia, despite a comparatively modest output of 211 articles, attained a total citation count of 3938 and the highest mean citation rate of 61.50 among the top ten countries, emphasizing its distinguished capacity for producing high-impact research.

From the international collaboration network, research within the “urban expansion–food security” domain demonstrates a strong global cooperative orientation, with various countries forming tightly interconnected partnerships (Figure 4). China has established collaborations with 80 countries, recording a total of 670 joint publications, followed by the United States (471) and Germany (265), indicating a leading position in terms of absolute collaboration volume. However, when adjusted for publication output—measured by the ratio of collaborations to total publications—the United Kingdom (0.84) and Germany (0.76) exhibit markedly higher international collaboration intensity compared to China (0.19) and the United States (0.35). This suggests that while China and the U.S. dominate in terms of the number of collaborations, the UK and Germany are more active in international cooperation relative to their publication output. Further analysis reveals that China’s primary international partners include the United States (172 collaborations), the United Kingdom (57), Australia (46), and the Netherlands (33), reflecting a diversified collaboration structure. These patterns indicate China’s growing role not only in scholarly productivity but also in expanding multilateral research networks—enhancing its participation and influence in the global discourse surrounding food security.

3.2.2. Leading Institutions

Between 1982 and 2024, the top ten institutions publishing research on the impact of urban expansion on food security were the Chinese Academy of Sciences, Beijing Normal University, the University of California System, Nanjing University, the Egyptian Knowledge Bank (EKB), Zhejiang University, Wuhan University, the Consultative Group on International Agricultural Research (CGIAR), Wageningen University and Research, and the Ministry of Natural Resources of the People’s Republic of China, collectively contributing 1646 publications (Figure 5). The Chinese Academy of Sciences emerged as the leading institution with 828 publications, highlighting its pivotal role in this field. Notably, the University of California System and CGIAR ranked third and eighth, with 110 and 76 publications, respectively, underscoring their considerable global academic influence. The Egyptian Knowledge Bank and Wageningen University and Research, with 96 and 72 publications respectively, held the fifth and ninth positions, reflecting their significant contributions within developing countries and agricultural science hubs. Overall, the geographic distribution of leading institutions reveals a China-centered yet internationally collaborative research landscape, emphasizing the broad global interest and cooperative potential in this domain.

Within the institutional collaboration network of the “urban expansion and food security” research field, the top ten prolific institutions form two prominent collaboration clusters: the blue cluster, led by the Chinese Academy of Sciences, Beijing Normal University, and the Egyptian Knowledge Bank (EKB); and the red cluster, comprising Nanjing University, the Ministry of Natural Resources of China, Zhejiang University, Wuhan University, the University of California system, Wageningen University and Research (WUR), and the Consultative Group on International Agricultural Research (CGIAR) (Figure 6). Betweenness centrality analysis identifies the Chinese Academy of Sciences (373.398), University of California system (73.734), and Wageningen University (63.568) as key bridging nodes, underscoring their pivotal roles in linking diverse research entities and facilitating the flow of information and integration of knowledge. Closeness centrality metrics further reveal that these institutions—Chinese Academy of Sciences (0.047), University of California system (0.016), and Wageningen University (0.014)—maintain comparatively short network path lengths, enabling rapid access to other nodes and enhancing responsiveness within the global collaboration framework. PageRank influence scores further emphasize the leading roles of the Chinese Academy of Sciences (0.263) and University of California system (0.038), reflecting not only their high frequency of collaborations but also their significant structural influence and academic reach within the overall network. Overall, the collaboration network exhibits a dual-core structure, anchored by Chinese and Western institutions, with the Chinese Academy of Sciences increasingly asserting its role as a central hub in global scientific exchange.

3.2.3. Main Author

Between 1982 and 2024, a total of 9882 authors contributed to research on the impact of urban expansion on food security, with the top ten most prolific authors constituting the core of this scholarly community (

Table 3. Top 10 authors by publication volume and their impact in the field of urban expansion and food security (1982–2024).

Author	h_Index	TC	NP	PY_Start	Affiliated Institutions	Country of Affiliation
Li Xia	16	2493	30	1998	East China Normal University	China
Wang Jieyong	13	714	19	2013	Institute of Geographic Sciences and Natural Resources Research	China
Cui Shenghui	11	487	12	2013	Institute of Urban Environment, Chinese Academy of Sciences	China
Liu Yansui	11	1787	13	2011	Institute of Geographic Sciences and Natural Resources Research	China
Luca Salvati	11	635	16	2014	Council for Agricultural Research, Centre for the Study of Plant-Soil Relationships (CRA-RPS)	Italy
Jin Xiaobin	10	460	15	2016	Nanjing University	China
Long Hualou	10	2117	10	2007	Institute of Geographic Sciences and Natural Resources Research	China
Deng Xiangzheng	9	1674	11	2005	Institute of Geographic Sciences and Natural Resources Research	China
Ke Xinli	9	464	11	2017	Huazhong Agricultural University	China
Song Wei	9	662	10	2014	Institute of Geographic Sciences and Natural Resources Research	China

). Chinese researchers dominate this group, reflecting a robust research capacity and output within the field. Notably, Li Xia leads with 30 publications since 1998, accruing 2493 citations and an H-index of 16, highlighting substantial academic influence. Following closely are Wang Jieyong and Cui Shenghui, with 19 and 12 publications, respectively, and H-indices of 13 and 11, demonstrating sustained and active research engagement. Italian scholar Luca Salvati also features prominently, holding an H-index of 11, on par with Chinese researchers Cui Shenghui and Liu Yansui. Collectively, these findings indicate that Chinese scholars have established a strong and stable research cohort in this domain, increasingly assuming a leading role in international academic collaboration and knowledge generation.

In the author collaboration network of research on urban expansion and food security, distinct differences are observed among countries regarding collaboration frequency and international cooperation intensity. China, the United States, and India occupy central roles in the global collaboration network, producing significantly higher volumes of co-authored publications than other countries (Figure 7). China leads with 1205 collaborative publications, of which 28.3% (341 papers) are internationally co-authored, indicating a dominant focus on domestic collaboration. The United States and India rank second and third with 407 and 186 collaborative publications, respectively. Notably, 27.8% (113 papers) of U.S. collaborations are international, surpassing India’s 19.4% (36 papers), reflecting a stronger propensity for global partnerships in the U.S. Despite lower total collaborative outputs, Germany (101), the United Kingdom (72), and the Netherlands (52) exhibit international collaboration rates exceeding 50%,which are substantially higher than those of major producers such as China, the U.S., and India. This pattern underscores the emphasis placed by several European countries on cross-national cooperation and knowledge exchange within this research field.

3.3. Research Focus

3.3.1. Urban Expansion and Land Use Change

As global urbanization accelerates, urban expansion has become a central driver of land use change, significantly transforming the spatial structure and land use patterns of urban and rural areas. Keywords such as “Urbanization”, “Urban Growth”, “Land Use Change”, “Built-Up”, and “Urban Sprawl” reflect a strong research emphasis on the encroachment of built-up areas into surrounding agricultural lands (Figure 8). This phenomenon is particularly evident in developing countries, where the trend of peri-urban non-agricultural land conversion results in continuous arable land loss, increased farmland fragmentation, and escalating land use conflicts. Research hotspots include dynamic land use modeling [16], delineation of urban expansion boundaries, and evaluation of built-up land intensification potential. Overall, studies consistently indicate that urban expansion not only directly reduces the available space for food production but also disrupts landscape patterns, thereby compromising agricultural ecosystem integrity and weakening regional food security.

3.3.2. Food Security and Agricultural Systems

Research in the domain of food security and agricultural systems emphasizes the protection of cropland resources, sustaining food production capacity, and ensuring agricultural system stability. Key terms such as “Food Security”, “Agriculture”, “Cropland/Farmland”, and “Agricultural Land” reflect the growing concern over the declining food supply amid ongoing farmland loss (Figure 9). With accelerating urban expansion, the preferential occupation of high-quality farmland has become increasingly pronounced, driving discussions on safeguarding both the quantity and quality of arable land [17]. Further studies incorporate concepts like “Food Production” and “Food Supply” to examine spatial variations in cropland productivity, improvements in farmland infrastructure, and the critical role of high-standard farmland in securing regional food supply stability [18]. Especially in peri-urban zones, the multifunctional role of farmland is expanding as food production increasingly intersects with leisure agriculture, facility farming, and urban–rural integration—highlighting a key research focus on the complex interactions between urban expansion and agricultural systems.

3.3.3. Environmental and Climate Factors

The interlinkages between urban expansion and food security are increasingly being explored within the broader context of environmental change and climate dynamics. The prominence of keywords such as “Climate Change”, “Ecosystem Services”, “Environment”, and “Land Degradation” highlights a growing scholarly emphasis on the ecological pressures triggered by urbanization and their far-reaching implications for the sustainability of agricultural systems (Figure 10). In particular, the urbanization-driven loss of vegetation and alterations in land cover have been shown to exacerbate local climate variability, intensify water scarcity, and accelerate soil degradation [19], all of which undermine ecosystem service functions [20] and pose substantial risks to food production systems. Furthermore, the unpredictability associated with global climate change continues to elevate the vulnerability of agricultural landscapes, thereby reinforcing the need to design climate-resilient urban–agricultural spatial frameworks that can enhance both the adaptive capacity and robustness of food systems. Beyond localized ecological pressures, the global trend of “land grabbing”—characterized by large-scale transnational acquisitions of agricultural land and extensive exploitation of green and blue water resources—has introduced new geopolitical and ecological complexities. While such practices may bolster food security in importing nations, they often disrupt the ecological equilibrium and exacerbate inequalities in water and land resource distribution in exporting countries [21]. In response to these multifaceted challenges, recent research has adopted multi-scale temporal greenhouse gas forecasting models (MST-GHF), which integrate both short-term fluctuations and long-term climate trajectories. These models significantly enhance the precision and timeliness of food security risk assessments under varying climate scenarios, thereby offering critical insights to inform evidence-based climate policy and support the achievement of long-term sustainability goals [22].

3.3.4. Socioeconomic and Policy Drivers

Urban expansion is frequently shaped by the combined influence of demographic trends, economic growth, and policy direction. Recurring keywords such as “Population”, “Economic Development”, “Policy”, “Governance”, “Planning”, and “Socio-Economic” underscore the increasing scholarly attention to the interplay between human agency and institutional frameworks in the context of urban expansion and food security (Figure 11). Population growth intensifies urban land demand, often pushing agricultural land to the periphery of land markets [23]. Simultaneously, shifts in economic models and widening urban–rural income disparities contribute to the declining prominence of agriculture in urban planning priorities [24]. In this context, policy interventions and planning instruments play a pivotal role in managing land-use transitions. Recent studies focus on assessing the efficacy of farmland protection policies, the responsiveness of urban land-use plans, and the alignment of multiscale governance mechanisms [25].

4. Discussion

4.1. Analysis of Driving Mechanisms Behind the Evolution of Research Hotspots on Urban Expansion and Food Security Across Different Stages

As global urbanization accelerates, increasing attention has been directed toward the impacts of urban expansion on land use patterns, agricultural system stability, and food security. Through a systematic review of keyword evolution from 1991 to 2024, this study delineates the emergence and development pathways of four major research paradigms in the field of urban expansion and food security, further investigating the underlying driving forces shaping their temporal evolution.

4.1.1. Urban Expansion and Land Use Change: From Spatial Outward Growth to Dynamic Land Use Modeling (1991–2000)

During the 1990s and early 2000s, research primarily centered on urban spatial expansion and its immediate effects on land use patterns. Fueled by rapid advancements in remote sensing and Geographic Information System (GIS) technologies, studies emphasized keywords such as “Urbanization,” “Land Use Change,” and “Urban Growth” to examine how the expansion of built-up areas altered urban–rural boundaries, agricultural lands, and natural landscapes [26]. This period highlighted urban expansion as the principal driver of land use change, providing early evidence of farmland encroachment and escalating land use conflicts at urban fringes. Nevertheless, the complex interactions among urban expansion, agricultural systems, and food security remained insufficiently investigated [27].

4.1.2. Food Security and Agricultural Systems: Focus on Farmland Conservation and Sustaining Food Production Capacity (2000–2010)

Since the early 2000s, propelled by recurrent global food price crises and the Millennium Development Goals (MDGs) advocating agricultural advancement, research has increasingly concentrated on food security amid urban expansion. Keywords such as “Food Security,” “Cropland,” and “Agricultural Land” prominently reflect rising concerns about farmland loss, cropland conversion, and declining agricultural productivity [28]. Studies in this period not only characterized the spatial patterns of farmland reduction but also emphasized the degradation of food production capacity resulting from the preferential conversion of high-quality farmland. Additionally, the exploration of “Food Production” and “Food Supply” broadened the research focus beyond land area to encompass cropland productivity and the balance between food supply and demand, laying the foundation for an integrated framework linking urban expansion with transformations in agricultural systems [29].

4.1.3. Environmental and Climate Factors: Integrating Ecosystem Services and Climate Resilience Perspectives (2008–2024)

Since 2008, environmental and climate factors have increasingly been recognized as pivotal intermediaries linking urban expansion and food security. The marked rise in keywords such as “Climate Change,” “Ecosystem Services,” and “Land Degradation” reflects a paradigm shift from focusing solely on physical land transformations to addressing the degradation of ecosystem services and their consequences for agricultural system stability [30]. Urban-expansion-driven vegetation loss, land cover changes, and intensified pressure on water and soil resources have been demonstrated to impair farmland ecosystem service functions, thereby indirectly undermining food production capacity [31]. Simultaneously, the increasing vulnerability of agricultural systems under the influence of global climate change has spurred calls for establishing climate-resilient urban–agricultural frameworks. Approaches including green infrastructure implementation and ecological compensation mechanisms are widely advocated to harmonize urban development with ecological preservation [32].

4.1.4. Socioeconomic and Policy Drivers: Strengthening Institutional Regulation and Multi-Scale Governance (1991–2024)

Socioeconomic and policy factors have consistently served as fundamental drivers in the interplay between urban expansion and food security, gaining heightened attention in recent years. The sustained prominence of keywords such as “Population,” “Policy,” “Governance,” and “Planning” underscores the gradual incorporation of human behavior, institutional frameworks, and policy tools into analytical models. On one side, population growth and economic restructuring have intensified the demand for urban construction land, accelerating the marginalization of farmland. On the other, adaptive policy guidance and spatial planning have become critical determinants influencing the magnitude and pathways of urban expansion [33]. Research in this period increasingly emphasizes the effectiveness of farmland protection policies, the feasibility of land-use regulation across urban–rural interfaces, and the establishment of coordination mechanisms across governance scales. Collectively, these efforts have shaped a tripartite research paradigm focused on the governance coupling among urban expansion, agricultural systems, and policy frameworks [34].

4.2. Regional Variations in the Impact of Global Urban Expansion on Food Security

The influence of urban expansion on food security demonstrates significant spatial heterogeneity, driven by variations in natural resource endowments, population density, economic development stages, urbanization trajectories, and land management frameworks across regions. This study conducts a comprehensive analysis across five key regions—Africa, Asia, Latin America, Europe, and North America—systematically revealing the principal challenges and distinct mechanisms that shape the interplay between urban expansion and food security in diverse geographic contexts.

4.2.1. Africa: Heightened Vulnerability of Food Systems Under Rapid Urban Expansion

In recent decades, Africa has emerged as one of the fastest urbanizing continents globally, with sub-Saharan countries exhibiting especially rapid growth. However, this urban expansion is frequently marked by unregulated sprawl, largely attributed to inadequate infrastructure, insufficient spatial planning, and underdeveloped institutional frameworks. Consequently, vast areas of agricultural land—particularly high-quality cropland on urban fringes—have been continuously encroached upon [35]. The simultaneous reduction in arable land and agricultural output has significantly undermined food accessibility, disproportionately affecting urban low-income populations [36]. Notably, agricultural development across Africa exhibits pronounced regional heterogeneity. In North Africa, for instance, investments in irrigation infrastructure and targeted policy support have facilitated improvements in agricultural productivity and technological uptake. In stark contrast, many sub-Saharan nations face persistent challenges, including limited agricultural extension services, low levels of mechanization, and under-resourced adaptive support systems [37]. Additionally, poorly developed agricultural supply chains and logistical networks further impair the responsiveness and resilience of local food systems, exacerbating their susceptibility to urbanization-induced pressures.

4.2.2. Asia: Escalating Pressures Between Urban Development and Farmland Preservation

Asia, home to the highest global population densities, faces acute stress on its agricultural land resources. Rapid industrialization and urbanization across countries such as China, India, and Indonesia have intensified the encroachment of urban areas into prime croplands [38]. Although several nations have enacted institutional safeguards—such as the farmland redline system and strict farmland protection regulations—the influence of local fiscal incentives and land-use interests often undermines these efforts, leading to the fragmentation and marginalization of productive farmland. Moreover, the functional transformation and diversified use of peri-urban agricultural zones have disrupted conventional food production landscapes, contributing to regionally variable food security outcomes [39].

4.2.3. Latin America: Urban Sprawl as a Direct Competitor to Agricultural Space

Urban growth in Latin America is predominantly concentrated around a limited number of megacities, including Mexico City and São Paulo, where urban sprawl poses direct and substantial threats to the surrounding agricultural land. Urban expansion has driven land prices upward, forcing agricultural activities into increasingly marginal areas. Simultaneously, landscape fragmentation and environmental degradation have significantly weakened the resilience and productivity of regional agricultural systems. Persistent land tenure inequalities further exacerbate the vulnerability of rural populations to food insecurity, deepening the urban–rural divide in food access and availability [40]. These vulnerabilities were starkly exposed during the COVID-19 pandemic, with household food insecurity rates reaching approximately 60% in countries such as Honduras, Peru, and Ecuador during the early stages of the crisis. While improvements were observed in Peru, Guatemala, and Bolivia over the course of the pandemic, the overall food security conditions remain fragile [41]. The influx of Venezuelan migrants into countries like Ecuador has intensified pressures on urban food systems, particularly affecting low-income populations, with women disproportionately bearing the burden of household food provisioning during lockdowns [42].

4.2.4. Europe: Regional Imbalances in Urban Expansion Intensify Farmland Pressures

Although Europe has largely reached an advanced stage of urbanization, with urban expansion proceeding at a relatively modest pace, certain regions continue to face mounting pressure on agricultural land [40]. High-density urban agglomerations such as Greater London, the Paris Basin, and the Ruhr Area in Germany exhibit persistent patterns of non-agricultural land encroaching upon high-quality farmland along urban fringes. This has led to increasing farmland fragmentation, limiting opportunities for large-scale agricultural operations. In Southern Europe, particularly the coastal areas of Italy and Spain, urban expansion is further compounded by tourism development and illegal construction activities. These factors have contributed to widespread unplanned farmland conversion, resulting in a coexistence of land abandonment and plot fragmentation, which collectively weaken the resilience of agricultural systems [43]. Disparities in land value between urban and rural zones continue to marginalize agricultural land, while weak policy enforcement in certain regions has exacerbated the spatially uneven threats that urban expansion poses to food security.

4.2.5. North America: Structural Challenges from Low-Density Urban Expansion

In North America—particularly in the United States—urban expansion is primarily characterized by suburbanization and low-density sprawl, which has incrementally encroached upon agricultural spaces [40]. Despite the region’s advanced agricultural technologies and high level of food self-sufficiency, emerging challenges such as farmland marginalization, declining agricultural labor, and landscape fragmentation are becoming increasingly evident [44]. Moreover, under a highly market-driven and globalized agricultural supply chain, disruptions to logistics networks caused by urban sprawl may also indirectly affect regional food security.

4.2.6. Oceania: Coupled Risks of Ecological Fragility and Urban Growth

Urbanization in Oceania is most pronounced in Australia and New Zealand, particularly in coastal lowland regions. The prevalence of low-density urban sprawl has placed sustained pressure on high-quality farmland. While both countries boast highly modernized agricultural sectors, expanding urban land uses—including residential, industrial, and infrastructural developments—have progressively reduced both the area and contiguity of arable land. The region’s ecologically sensitive systems further compound these issues; land cover changes have intensified water scarcity, soil degradation, and habitat loss, collectively undermining the stability and resilience of agro-ecosystems [45].

4.2.7. Antarctica: Indirect Impacts on Global Food Systems Through Climate Regulation

Although Antarctica is not directly involved in urban expansion or agricultural production, it plays a critical role in global climate regulation. The melting of the Antarctic ice sheet contributes to sea-level rises, posing existential threats to low-lying agricultural zones. Additionally, alterations in ocean circulation and atmospheric systems induced by polar ice loss generate long-term climatic feedback processes that affect major agricultural producers in the Southern Hemisphere, such as Australia, Argentina, and South Africa [21]. In the context of global climate change, shifts in Antarctica’s polar systems have far-reaching indirect implications for global food production capacity and climate stability, making it a key factor influencing global food security.

4.3. Regional Policy Recommendations for Addressing the Impacts of Urban Expansion on Food Security

The implications of urban expansion on food security exhibit substantial regional variation that is shaped by geographic, socioeconomic, and institutional contexts. To promote a more integrated relationship between urban development and food systems, policy responses must be context-specific, aligning with the unique developmental trajectories and governance capacities of each region.

4.3.1. Africa: Building a Multi-Level Governance Framework for Farmland Protection and Food System Resilience

In Africa, accelerated urbanization in the context of underdeveloped land governance structures has intensified pressures on agricultural land. A comprehensive, multi-level governance framework is essential, comprising national policy leadership, regional coordination mechanisms, and effective local implementation. Defining urban growth boundaries and reinforcing land-use regulations are critical to mitigating unregulated urban sprawl. Simultaneously, policy efforts should aim to enhance the productivity and supply capacity of peri-urban agriculture by expanding irrigation networks, improving cold-chain logistics, and strengthening localized food reserve systems. These interventions are pivotal for improving urban food accessibility and bolstering the resilience and adaptive capacity of regional food systems [46].

4.3.2. Asia: Advancing Farmland Compensation and Urban Growth Boundary Mechanisms

As the most densely populated continent, Asia is experiencing acute pressure on arable land due to rapid urban expansion [47]. Strengthening existing farmland occupation–compensation mechanisms requires a shift toward “quality-for-quality” principles, ensuring both quantitative replacement and qualitative equivalence of farmland. Establishing dynamic urban growth boundaries can effectively demarcate areas designated for urban development and those prioritized for agricultural protection, thereby improving spatial efficiency. In peri-urban zones, the adoption of modern agricultural models—including controlled-environment agriculture and urban farming—can diversify food supply channels and reinforce the multifunctionality and sustainability of agricultural systems [48].

4.3.3. Latin America: Enhancing Agricultural Resilience and Institutional Governance Synergies

Latin America continues to experience pronounced conflicts between urban expansion and agricultural land use. Strengthening land-use zoning frameworks and designating priority agricultural protection zones are critical to mitigating farmland loss and landscape fragmentation [49]. Policy instruments such as subsidies and tax incentives should be leveraged to encourage agricultural stakeholders to participate actively in land conservation. Furthermore, aligning land-use policies with agricultural development strategies is essential to establishing an integrated governance system that supports both urban growth and food system sustainability. This integrative approach can enhance the economic resilience and ecological integrity of agricultural landscapes.

4.3.4. Europe: Strengthening Green Infrastructure and Ecological Compensation Mechanisms

Europe, with its well-established institutional frameworks, is well-positioned to leverage its strengths in spatial planning and ecological governance. The development of integrated green infrastructure systems that incorporate agricultural land into urban ecological security frameworks can enhance urban resilience. Concurrently, a robust ecological compensation mechanism for farmland protection should be implemented to incentivize farmers and landholders to conserve high-value agricultural areas [50]. Promoting compact urban development models and optimizing urban spatial structures are key strategies for mitigating the encroachment of urban expansion onto agricultural space, thereby supporting the stability and sustainability of regional food systems. The Mediterranean region offers a representative case study, underscoring the importance of aligning food security policies with local environmental conditions and spatial structures. To prevent the spatial disconnect between farmland and urban consumption zones, locally led food self-sufficiency strategies should be supported through multi-level modeling tools, thereby enhancing the resilience and adaptability of agricultural systems [51].

4.3.5. North America: Guiding Low-Density Expansion and Securing Agricultural System Functionality

Urban growth in North America, particularly in the United States and Canada, is characterized by low-density sprawl, necessitating strengthened land-use control and development intensity regulation to promote more compact and efficient urban forms [44]. Establishing agricultural priority zones is essential for maintaining the functional integrity of farmland within national spatial frameworks. Leveraging digital and precision agriculture technologies can boost both the productive and ecological performance of agricultural systems [52]. Additionally, improving inter-regional food supply chains and transportation networks is critical for enhancing the adaptability and resilience of food systems under continued urban expansion.

4.3.6. Oceania: Coordinating Farmland Protection with Compact Urban Development

In Oceania, particularly in Australia and New Zealand, urban spatial planning should prioritize the protection of arable land. Promoting compact urban development can reduce the encroachment of cities onto high-quality farmland, while rational zoning and the protection of agricultural functional areas can support sustainable land use. Enhanced regulation of ecologically fragile zones, coupled with stricter land-use policies, is necessary to ensure ecosystem health and agricultural sustainability [53]. Coordination between urban expansion and farmland preservation should be emphasized, alongside increased regional cooperation and policy integration to safeguard long-term food security.

4.3.7. Antarctica: Linking Antarctic Environmental Protection with Global Agricultural Early Warning Systems

Although Antarctica does not host agricultural activities or direct urban expansion, its role in global climate regulation has profound implications for food security. Strengthening international cooperation to protect and monitor the Antarctic environment is crucial. Antarctic climate dynamics should be integrated into global agricultural early warning systems, enabling timely tracking and forecasting of polar system changes through multinational collaboration. Policy frameworks should focus on enhancing global climate regulation mechanisms and taking action to slow Antarctic ice sheet melt, thereby mitigating its downstream effects on global climate systems and agricultural productivity [22]. Furthermore, protection measures in Antarctica should be coordinated with climate adaptation strategies in major agricultural regions to bolster the resilience of global food production systems.

4.4. Multipath Mechanisms of Urban Expansion’s Impact on Food Security and Divergent Scholarly Perspectives

The accelerating pace of global urbanization has intensified the spatial competition between urban development and agriculture, posing growing challenges to the coordinated management of food production, ecological protection, and urban growth [54]. Extensive research has demonstrated that urban land expansion—particularly through the conversion of high-quality farmland, degradation of agricultural infrastructure, and increased land fragmentation—undermines the productivity and ecological resilience of agricultural systems, thereby generating multifaceted threats to food security [5,55]. These pressures are particularly acute in low- and middle-income countries, where rapid urban boundary expansion and weak land governance heighten agricultural vulnerability.

However, urban expansion does not uniformly exert negative effects. Under favorable conditions, the improved infrastructure and market access associated with urbanization can enhance agricultural productivity and distribution efficiency, indirectly supporting food security objectives [56]. Moderate urban development may also facilitate the reallocation of marginal farmland and promote the transition toward large-scale, mechanized farming, thereby improving land-use efficiency and overall yield [57]. The coexistence of both adverse and beneficial effects has led to ongoing debate regarding the net impact of urban expansion on food systems.

Beyond food production, ecological integrity is increasingly recognized as a critical dimension. Some studies have shown that farmland expansion may pose greater threats to natural habitats than urban growth, emphasizing the need to balance food security with biodiversity and ecosystem conservation goals [58,59]. In response, the concept of “inclusive urbanization” has emerged, advocating for optimized urban–rural land use configurations and regulated population mobility to reconcile urban development with farmland preservation [60]. Under specific institutional and spatial conditions, this model may improve land-use efficiency and mitigate the displacement of agricultural land by urban areas [57]. Nevertheless, the practical implementation of inclusive urbanization is frequently constrained by limited planning capacity, weak regulatory oversight, and spatial inequality, sometimes resulting in fragmented farmland and heightened ecological risks.

Moreover, empirical analyses suggest that megacities, on a per capita basis, consume less farmland than small- and medium-sized cities, indicating higher land-use efficiency [61]. This challenges the notion that restricting megacity growth in favor of smaller urban centers inherently benefits farmland preservation. Without strategic planning and coordination, such transitions may compromise both development efficiency and food security goals.

Taken together, the effectiveness of inclusive urbanization depends strongly on local land resource endowments, urbanization trajectories, and institutional frameworks. Future research should focus on identifying context-specific thresholds and trade-offs and designing spatial governance strategies that integrate ecological, agricultural, and urban priorities. A shift away from one-size-fits-all policies toward differentiated, landscape-based planning approaches is essential for achieving synergistic outcomes in food security and sustainable urban development.

4.5. Study Limitations

While this study provides a comprehensive, large-sample overview of the research evolution and thematic focuses within the “urban expansion–food security” domain, several limitations remain that warrant further investigation.

First, the bibliographic data were exclusively drawn from the Web of Science Core Collection (WoS). Although WoS is widely recognized for its coverage in physical geography and environmental sciences, it is predominantly composed of English-language publications and underrepresents research from developing countries. This may introduce biases in linguistic, geographical, and disciplinary representation. Moreover, key region-specific or policy-oriented studies indexed in databases such as Scopus or CNKI might have been omitted, potentially limiting the completeness of the global research landscape.

Second, despite the use of rigorously constructed search queries and a full-sample review approach to maximize coverage, no standardized sampling techniques were employed. Consequently, temporal, regional, and methodological imbalances may persist within the sample, which may be skewed toward high-visibility, highly cited works, thus constraining the generalizability of findings.

Additionally, the analytical framework focused primarily on English-language journal literature, excluding Chinese publications and non-journal outputs such as policy reports and technical documents, which may restrict a holistic understanding of global urban expansion and food security dynamics. The absence of stratification by development stage or regional typologies also limits insights into the heterogeneity of urban expansion impacts. Likewise, the collaborative network analysis may underestimate some interactions due to data source limitations.

Future research should integrate multiple databases to enhance sample representativeness and diversity. Combining multi-scale spatial analyses with qualitative methods could further elucidate the complex mechanisms through which urban expansion influences food security across diverse contexts.

5. Conclusions

This study presents a comprehensive bibliometric review of research exploring the nexus between urban expansion and food security from 1982 to 2024. Utilizing data from the Web of Science Core Collection that was analyzed using the bibliometrix package in R, this study aims to elucidate the evolution of knowledge structures, thematic orientations, and emerging research frontiers within this interdisciplinary domain. The findings reveal the following: (1) Global scholarly output has exhibited a sustained upward trajectory, with the average annual publication rate during the rapid growth period increasing by 111.93% compared to the initial stage. Over the past decade, publication volumes have remained consistently high, reflecting the increasing academic and policy relevance of this topic in the context of land system science. (2) Research contributions are predominantly concentrated in China and the United States. However, their international collaboration frequency per publication remains relatively limited, whereas countries such as the United Kingdom and Germany demonstrate higher levels of cross-national research engagement. (3) Thematic foci have progressively expanded from initial concerns over farmland loss to encompass broader multidimensional mechanisms, including agricultural systems, ecosystem services, and policy frameworks. Four primary thematic clusters were identified: “Urban Expansion and Land Use Change”, “Food Security and Agricultural Systems”, “Environmental and Climate Factors”, and “Socioeconomic and Policy Drivers”.

Unlike previous reviews that have predominantly emphasized case-specific studies or theoretical modeling, this work employs a multi-dimensional bibliometric approach to construct a detailed knowledge map encompassing publication trends, collaboration networks, keyword co-occurrence, and thematic evolution. The study underscores a paradigm shift from static assessments toward mechanism-based inquiries, contributing to a clearer understanding of scholarly consensus and divergence. In particular, it highlights key pathways through which urban expansion influences food security, including urban boundary extension, agricultural land restructuring, and ecosystem service degradation.

Methodologically, the integration of the bibliometrix package enhanced the rigor and visualization of literature analytics. Nonetheless, several limitations warrant consideration. First, reliance solely on the Web of Science database may introduce language and regional representation biases. Second, the exclusion of qualitative content analysis constrains the exploration of theoretical heterogeneity and the evolution of conceptual frameworks. Third, this study does not distinguish between different types of urban expansion, nor does it incorporate scenario-based simulations to assess policy relevance and application.

Future research should advance in several key directions: (1) integrating diverse bibliographic databases and including multilingual sources to broaden coverage and enhance global representativeness; (2) combining remote sensing, land-use simulation, and agricultural systems modeling to improve dynamic process modeling and predictive capacity; (3) examining how regional development stages and institutional frameworks modulate the interactions between urban expansion and food security, thereby informing more nuanced spatial governance strategies; and (4) fostering interdisciplinary integration by drawing on insights from geography, agricultural economics, and policy science. Additionally, future studies are encouraged to incorporate the Food and Agriculture Organization’s (FAO) four pillars of food security—availability, access, utilization, and stability—together with supply chain resilience frameworks, to establish a more comprehensive and systematic research paradigm. These efforts will contribute to a stronger theoretical foundation for addressing the global challenges of food security under rapid urbanization.