Low-Carbon Education: Insights and Trends for Sustainable Development Through Knowledge Graphs

Abstract

Sustainability is an inherent requirement of scientific development, and low-carbon development is the key to sustainability. Low-carbon education (LCE) can spread environmental concepts and provide talent support for sustainable development. However, there is still an obvious gap in systematic research on LCE, let alone in visual research. From the perspective of scientometrics, 189 papers on LCE from 2015 to 2024 were systematically analyzed. Software such as Gephi 0.10.1, VOSviewer 1.6.20, and CiteSpace 6.3.3 was used to visually analyze the references and keywords of the collected literature, identifying research hotspots and emerging trends in LCE. The results show that educational subjects, educational methods, educational courses, and educational evaluation are hot topics in the field of LCE. Explosive themes such as “sustainable power generation”, “education facilities”, “higher education expansion”, and “artificial intelligence of things” are emerging trends in LCE. The overall evolution trend in LCE after 2015 can be divided into two stages: an explosive stage (2015–2020) and an emerging stage (2020–2024). University LCE, social LCE, and behavioral LCE are the main research directions of LCE. Through the visual analysis of the LCE literature, the research hotspots and emerging trends in LCE can be more intuitively and comprehensively understood, providing a valuable reference for subsequent research.

1. Introduction

With the continuous growth of the global population and economy, the environmental problems caused by energy use and its causes are increasingly being recognized by people [1]. Sustainability has become a necessary requirement to balance the economy and environment [2]. Under the concept of sustainable development, through technological innovation, institutional innovation, industrial transformation, new energy development, and other means, achieving low-carbon development has emerged as a new economic development model [3]. Low-carbon development is the organic combination of “low carbon” and “development” [4], on the one hand aiming to reduce carbon dioxide emissions and, on the other hand, aiming to achieve economic and social development [5]. Low-carbon development is not blindly reducing carbon dioxide emissions; rather, it involves adopting a new economic development model that reduces carbon emissions while improving efficiency, competitiveness, and economic and social development [6]. Promoting green and low-carbon (GLC) development and achieving the goals of “carbon peak” and “carbon neutrality” involve complex system engineering, which requires overall coordination in all fields of society and concerted efforts in all industries [7]. Promoting low-carbon economic development is inseparable from high-quality professionals with GLC awareness and relevant knowledge and skills [8]. LCE is an educational concept and practical activity aimed at cultivating individuals’ awareness of reducing carbon emissions and promoting resource conservation and environmental protection in daily life, study, and work [5]. For sustainable development, the significance of LCE lies not only in the cultivation of talents but also in the cultivation of social consciousness [9]. In order to achieve sustainable development, cultivate low-carbon talents, and increase social low-carbon awareness, the development of LCE has become particularly important. At present, the academic community has carried out a wealth of research on LCE. We summarize the main research directions in three aspects, the first of which is university LCE. Some scholars believe that integrating the concept of GLC development into the higher education system, cultivating college students’ awareness of GLC development, improving college students’ knowledge level of GLC development, and guiding college students to practice GLC lifestyles are important for promoting the country’s GLC development and the realization of the goals of “carbon peaking” and “carbon neutrality”, which are of great significance [9,10,11]. The second aspect is social LCE. Some scholars put forward that GLC development cannot be separated from the common support of all members of society [12]. Therefore, LCE groups should include all members of society. Encouraging citizens to establish the GLC concept and GLC knowledge and forming a green talent chain in society are particularly important for promoting the development of economic GLC [7]. The third aspect is behavioral LCE. Some scholars have suggested that LCE should focus on the behavioral education of citizens [13]. These scholars no longer pay attention to the groups of LCE but instead focus on the content [14]. They believe that LCE should be carried out in an interdisciplinary form with a multi-angle construction of evaluation indicators to guide people to engage in the right low-carbon behavior to guide daily activities [15]. The existing results of scholars have laid a solid foundation for the further development of LCE research, but there are still some shortcomings: First, there is a lack of systematic combing of the LCE literature, and a review paper is urgently needed to guide future research. Second, the lack of visual research on LCE does not allow scholars in this field to understand the current state of the field in an intuitive way. Third, most of the existing research focuses on one aspect of LCE and lacks interdisciplinary and multi-angle thinking on LCE. Based on the shortcomings of the existing research, we will choose a different method from previous research, innovatively use a scientometrics map visual analysis method based on the systematic collection of the relevant literature on LCE, and display research hotspots and emerging trends in LCE through visual methods. The aim is to provide a more intuitive display of LCE research hotspots and emerging trends for scholars in this field. Moreover, we will analyze the following questions:

• RQ1: What are the research hotspots of LCE?
• RQ2: What are the emerging trends in LCE research?
• RQ3: What is the evolution trend in LCE research?
• RQ4: How might we understand LCE correctly?

The remainder of this paper is organized as follows. In Section 2, the data source and research methods used are outlined. In Section 3, based on the collected literature, the references and keywords are visually analyzed using Gephi, VOSviewer, and CiteSpace, and the research hotspots and emerging trends are explored. In Section 4, based on the visualization results and the existing research results, we deepen our understanding of LCE from the aspects of university LCE, social LCE, and behavioral LCE. In Section 5, the text is summarized, presenting new findings, theoretical and practical significance, limitations, and prospects.

2. Data Collection and Research Methods

2.1. Data Sources

To eliminate the interference of low-quality literature on the results of the study, we selected only the SCI, SSCI, and SCIE databases in the core collection of Web of Science to screen the literature related to LCE. To make the collected data as comprehensive and objective as possible, we chose a topic search method. First, to ensure the novelty and frontier of the collected literature, we collected literature on LCE for nearly ten years, with a specific time range of 2015–2024. Second, we used this topic to search for relevant literature on LCE over the entire period. To improve the accuracy and comprehensiveness of the search results, we divided them into two keywords: “carbon” and “education”. The advanced retrieval format used is Ts = (Carbon (Topic) and (Education (Topic))). After obtaining the search results, we screened the database and the elimination time and obtained 2601 relevant studies. Finally, the title, abstract, keywords, and research conclusions of the literature were obtained by reading and searching one by one, and the literature was screened according to the following criteria: ① the main content being LCE; ② the research object belonging to the category of education; ③ being based on environmental protection. After excluding the literature with low correlation with the research topic, a total of 189 articles were finally obtained, and the specific process is shown in Figure 1.

2.2. Research Methods

Scientometrics is a discipline that applies quantitative methods to studying the laws of scientific and technological development and uses mathematical and statistical methods to quantitatively analyze the results, processes, and related activities of scientific research [16,17]. Scientometrics is an extensive and evolving field that not only helps people understand the dynamics of scientific activities but also provides a scientific basis for the formulation and management of science and technology policies [18,19]. A knowledge graph is a semantic network used to describe the relationship between entities, which graphically expresses knowledge and its relationship [20]. The knowledge graph transforms real-world information into graphics, where nodes represent entities and edges represent relationships between entities [21]. The structured representation method enables the knowledge graph to systematically display the knowledge system and reveal the internal relationships between the knowledge [22]. The analysis of research hotspots and emerging trends of LCE through scientometrics knowledge graph research methods has the following advantages, the first of which is objective and accurate data analysis. Comprehensive and accurate data can be collected based on a large amount of academic literature, patent data, industry reports, and other information sources; LCE-related research can be collected and collated. The second advantage is the precise identification of the hot areas. Using the analysis method of knowledge graphs, such as keyword co-occurrence analysis and literature cluster analysis, we can quickly identify research hotspots and emerging trends that have received widespread attention in LCE. Finally, information can be systematically evaluated. Its focus is not on information from the literature but on helping scholars to explore the essential relationship between literature information and assess the quality of literature information. This is consistent with our research objectives.

Through previous analysis, it can be seen that scholars have produced a wealth of research results based on LCE, which has provided a solid database with which we can use scientometrics for visual analysis. Considering the convenience, effectiveness, and scientific nature of research tools, and to better show the research focuses and emerging trends of LCE with visual landscapes, we chose CiteSpace, VOSviewer, and Gephi for further research. CiteSpace is a scientific citation analysis software developed based on the Java language, which can help us explore and understand knowledge structures and evolution in academic fields [20]. Compared with other tools, CiteSpace can also provide quantitative indicators, such as the citation frequency of papers and the intensity of author cooperation, which can help to evaluate the importance and influence of nodes in the literature network [20]. Second, VOSviewer is a software tool for constructing and visualizing a bibliometrics network [21]. Compared with other tools, VOSviewer can more easily realize co-occurrence clustering analysis; reveal the correlation between keywords, authors, or publications in the literature; and help us find hot topics and trends in the research field [19]. Finally, Gephi is an open-source graphic analysis software based on Java that is mainly used to create relational network diagrams. More intuitive than other software, Gephi presents a variety of networks and complex systems and is a tool for interactive visualization and detection of dynamic and hierarchical graphs [22].

3. Results

3.1. Research Hotspots and Emerging Trends Based on the Literature

In order to make readers better understand the key information of LCE and construct the cognitive system of this study, we used the open knowledge map (https://openknowledgemaps.org/index, accessed on 26 December 2024) to conduct a preliminary study of LCE, and the results are shown in Figure 2. Figure 2 shows the open knowledge map search to match the LCE 100 references with the most relevant literature and according to the similarity of the topic to aggregate and display publications, thus forming a cluster. It can be seen that the quantitative analysis method plays an important role in LCE research and is one of the largest clusters. Second, the cultivation of public low-carbon awareness and the transformation of socialized low-carbon behavior are also focuses of scholarly research.

The number of citations and publications in the relevant literature on LCE are shown in Figure 3. On the whole, it can be divided into three stages, the first of which is the steady development stage (2015–2019). At this stage, LCE research had experienced early development and already had a preliminary foundation, resulting in a number of influential papers, especially milestones in the literature such as the study by Zhang et al. [23]. However, during this period, there was no breakthrough growth in the number of articles or citations. The second phase was the explosive growth phase (2020–2023). Since 2020, LCE has experienced explosive growth. Especially in 2021, the number of publications increased by nearly 70%, and the number of citations exceeded 120%. The number of publications and citations in 2020 and 2021 developed by leaps and bounds and continued to grow through 2023, remaining at a high level. The third stage is a stable stage of development (after 2024). Since peaking in 2023, there has been a small decline in the number of publications and co-citations in 2024, but it remains high. This shows that the research in the field of LCE has gradually matured since 2023 and has become a key research area for scholars. However, restricted by the research perspective, the next outbreak period has not been formed.

To further demonstrate the research hotspots and emerging trends in the collected literature, we used Carrot2 4.7.0 (https://search.carrot2.org/#/search/web, accessed on 26 December 2024) to generate tree and pie charts of LCE, and the results are shown in Figure 4. It can be seen from the tree diagram that “Education System” is the main research topic of LCE, which is consistent with our previous conclusions. “Educational Campuses”, “Footprint of a University” and “Low-carbon Education” are the key directions of LCE, covering three aspects: research sites, research contents and research topics. This shows that university LCE is still the main direction of LCE, and the academic circles have tried to explore the field of LCE from multiple perspectives and in various directions to promote the development of this research. From the pie chart, “Energy Efficiency” and “Urbanization and Education” are also research focuses of LCE. LCE emphasizes that through education and training, people’s awareness and understanding of low-carbon life, low-carbon economy, and low-carbon technology can be improved to promote the transformation of society to low-carbon. At the same time, LCE is also an important way of spreading low-carbon knowledge and cultivating low-carbon awareness. This shows that research in the field of LCE pays more attention to practicality and the role of education in energy efficiency. At the same time, LCE also attaches great importance to social LCE and behavioral LCE.

3.2. Research Hotspots and Emerging Trends Based on References

3.2.1. Co-Citation Network of LCE References

Gephi provides a variety of layout algorithms to show the network structure, which can adjust its visualization effect according to the different properties of the nodes and edges [24]. We imported the dataset into Gephi and used the “Fruchterman Reingold” layout for the reference co-citation network, as shown in Figure 5. This algorithm was selected for clarity of visualization. The spherical section at the lower left includes 173 nodes and 183 connections. The node represents a different reference. The size of the node represents the number of references, the color represents the time when the reference occurred, and the color of the connection represents the time when the connected reference was first cited. It can be seen that the literature on LCE basically shows an increasing trend year by year. The literature is mainly concentrated in 2022–2024, and the colors are mainly green, blue, and brown. This is consistent with our previous division of the literature. The number of citations in this field has increased in recent years, indicating that LCE research is in a period of explosive growth. We further classified the network according to “PageRank”, as shown in the spherical diagram on the right. The nodes in this section still represent different references, but the colors of the nodes indicate the importance of a reference to the entire field. Combined with the table on the right side of the figure, it can be seen that the articles written in 2023 are not only cited many times but also ranked very high in the PageRank. A series of articles published in 2023 had a great impact on LCE research. In terms of research content, the main research hotspots in 2023 are still “College Students” and “Society Education”, which is consistent with our previous research. It can be observed that the study of the subject will remain a trend in LCE in the future.

3.2.2. Co-Citation Clustering Network of LCE References

To further explore the research hotspots and emerging trends of LCE, we used CiteSpace software to further analyze the collected data and form a clustering network. We set the time slice from January 2015 to December 2024. In order to ensure the clarity and validity of the clustering network, we adjusted the parameters several times and finally selected the result of the top N = 30, as shown in Figure 6. Figure 6 shows the cluster network landscape of the LCE references, which contains 2294 nodes and 6001 links, forming a total of 12 large-scale clusters. The cluster names are indicated in black text. The smaller the number, the larger the cluster. The time axis in the lower-left corner of the figure represents the time when the study appeared. The closer the color is to the warm color, the more advanced the topic is. The circles represent the nodes, and the color of the annual rings corresponds to the time axis. The larger the node, the more important the study. The line between the nodes corresponds to the timeline, and the color indicates the time at which the node was first introduced. As can be seen from the figure, “#1 education research” is the largest cluster and a popular research topic. This also reflects the perspective of major educational research in the field of LCE; namely, most scholars analyze LCE from the perspective of education. At the same time, we can divide the clusters into several categories: the first category is educational research. This is the main research direction of LCE. In addition to the largest cluster “#1 education research”, several important clusters have been formed in the cluster network, such as “#2 online education”, “#13 education level”, “#16 distance”, “#17 lesson” and “#18 university student”. The number of educational research clusters reaches half of the total, and the ranking is very high. This shows that scholars have carried out research on LCE from the aspects of education subject, education mode, education curriculum and education evaluation. And from the perspective of time, “#2 online education” and “#16 distance” are emerging trends. Combining information network technology to explore the transmission of LCE will become an important research direction for scholars. The second category is low-carbon research (LCR). This kind of research takes carbon reduction as the main goal and focuses on environmental, economic and social perspectives. Three clusters are formed: # 7 deep decomposition, # 9 decomposition technologies deployment, and #15 carbon management. These scholars are concerned with how we might achieve the goal of “reducing carbon” through education and explore effective methods and means of LCE [8,20,25]. They believe that “carbon reduction” is the core goal of LCE, which aims to raise people’s awareness of environmental protection, reduce carbon emissions, and achieve sustainable development through education and practice [6,26,27]. The third category is research perspective. The main clusters formed are “#12 review” and “#14 trend”. This shows that literature reviews and research on trends have become hot topics in LCE and are welcomed by scholars. However, after our careful reading, we found that literature reviews and research on trends are basically the result of “carbon emissions”, “carbon management”, “sustainable education”, “environmental education” and other topics, and there is still a lack of direct research on LCE. Combined with the slight decline in the number of LCE publications and citations in 2024, we infer that the lack of a direct systematic literature review of LCE makes it difficult for many scholars to clearly understand the research hotspots and trends in this field, thus limiting the further development of research in the field of LCE. This is consistent with our proposed research gap. We note particularly that “#8 shanghai jiao tong university fahua” has formed an important cluster as a research institution, and from the perspective of time and nodes, it has produced a large number of milestone studies in the past two years. This shows that LCE has become a key research direction for some institutions and has formed a special research group. We infer that the establishment of these research groups will promote a qualitative leap in the field of LCE research again and may cause a further period of explosive growth in this field.

Table 1. The 10 most cited references in LCE from 2015 to 2024.

References	Theme	Year	Strength	Begin	End	2015–2024
Disterheft A., 2012, J. Clean Prod [28].	Educational Institutions	2012	1.59	2015	2017	▃▃▃▂▂▂▂▂▂▂
Ozawa-Meida L., 2013, J. Clean [34].	Carbon Performance	2013	2.22	2017	2018	▂▂▃▃▂▂▂▂▂▂
Townsend J., 2015, J. Clean Prod [35].	Carbon Footprinting	2015	2.53	2017	2019	▂▂▃▃▃▂▂▂▂▂
Baldini M., 2018, Energ. Policy [36].	Low-carbon Behavior	2018	0.90	2019	2020	▂▂▂▂▃▃▂▂▂▂
Wang Z.H., 2017, Energ. Policy [37].	Carbon Consumption	2017	0.65	2019	2020	▂▂▂▂▃▃▂▂▂▂
Gu Y.F., 2019, Appl. Energ [30].	Low-carbon Campus	2019	0.97	2021	2024	▂▂▂▂▂▂▃▃▃▃
Helmers E., 2021, Environ. Sci. Eur [29].	Carbon Footprinting	2021	6.33	2022	2024	▂▂▂▂▂▂▂▃▃▃
Udas E., 2018, Int. J. Sust. Higher Ed [31].	Carbon-neutral Universities	2018	3.82	2022	2024	▂▂▂▂▂▂▂▃▃▃
Balaguer J., 2018, Energ. Econ [32].	Environmental Education	2018	2.78	2022	2024	▂▂▂▂▂▂▂▃▃▃
Zafar M.W., 2020, J. Clean Prod [33].	Energy Consumption	2020	2.31	2022	2024	▂▂▂▂▂▂▂▃▃▃

Note: The red line indicates the outbreak period. The blue line represents the time from the keyword release to the present. Light blue represents the overall time span of 2015–2024.

shows the 10 most influential references for LCE in 2015–2024. The red line indicates the outbreak period. The blue line represents the time from the release of the LCE keywords to the present. Light blue represents the overall time horizon for 2015–2024. The results show that the research topics of landmark references of LCE mainly focus on campuses, behavior and cognition, which is consistent with our classification of scholars’ research topics into university LCE, social LCE, and behavioral LCE. Judging from the proportion of the three parts, university LCE is still the main research subject in the field of LCE, and it has an absolute advantage within the themes of the popular literature. In addition, the discussion of low-carbon policies, the awareness of social citizens, and their resulting behavior have also attracted great attention from scholars. From the specific literature, Disterheft (2012) [28] is the earliest example of this in the literature; although it is not within the time range of our selection, it has been cited many times in the literature of the past decade. From 2015 to 2017, there was an outbreak period, and this topic will continue to have an impact until 2024. Helmers (2021) [29] is the study with the largest burst intensity, and its intensity has an absolute advantage over other studies. It is found that the campus carbon footprint plays an important role in the field of LCE, and the relevant research often takes research results as its supporting basis. Gu (2019) [30], Helmers (2021) [29], Udas (2018) [31], Balaguer (2018) [32] and Zafar (2020) [33] are the latest emerging hot studies, which still have an important impact. Their research topics focus on university LCE and social LCE. Overall, the milestone studies on LCE were published in a relatively recent year, largely after 2022. The literature that broke out after 2022 had a high outbreak intensity. This shows that after 2022, LCE has attracted great attention from scholars. Moreover, university LCE and social LCE are still the “darlings” of the emerging literature, and they will still be emerging trends in research in the future.

3.3. Research Hotspots and Emerging Trends Based on Keywords

3.3.1. Co-Citation Network of LCE Keyword

We used the VOSviewer software to further analyze the literature results of LCE. We imported 189 studies into VOSviewer, fixed the time node from January 2015 to December 2024, selected “Create a map based on bibliographic data”, selected “Read data from bibliographic database files”, and imported the data from the core collection of Web of Science. We then selected “All keywords” in “Co-occurrence” in the “Type of analysis.” In order to make the network content of co-occurrence keywords clear and effective, we chose parameter 8 in “minimum number of citations of a literature” to make a density visualization keyword map created by VOSviewer, and the final landscape map is shown in Figure 7a. Figure 7a forms four clusters, including 29 nodes and 295 links, with a total link length of 711. Different clusters are distinguished by color. It can be seen from Figure 7a that “carbon footprint” is the biggest hot keyword and the keyword with the most total connections. In addition, keywords such as “sustainability”, “consumption” and “greenhouse-gas commitments” also have an important influence, which is the research focus of LCE at present. From a time point of view, university LEC is still a research hotspot in the field of LCE, and the future is also an emerging trend in this field. It is worth noting that “consumption” occupies an important position in the co-citation keywords. According to the path of “theory–consciousness–behavior”, LCE research has been conducted at the level of behavior, and consumption behavior caused by LCE has become the focus of scholars.

In order to further explain the symbiotic keyword network, we further explained the keyword cluster and found that among the four clusters formed, except the smallest cluster (only containing “carbon neutrality” and “footprint”), the other three clusters are in line with the main research direction of university LCE, social LCE, and behavioral LCE. Therefore, we chose three keywords which are representative of the three clusters (keywords that can best reflect the characteristics of the cluster), namely, higher education institutions, carbon footprint, and carbon emissions, to further form a sub-cluster landscape map. The results are shown in Figure 7b–d. As can be seen from the figure, there is a close relationship between “higher education institutions”, “carbon footprint” and “carbon emissions. Therefore, we inferred that research in the LCE field has formed a close research structure, and a close knowledge network has been formed between various disciplines and fields. How might we effectively manage LCE institutions? How can we better disseminate environmental engineering knowledge? This is a research topic worthy of attention in the future of LCE. What we notice is that the main keywords in the three clusters are closely related to the “carbon neutrality” and “footprint” of the smallest cluster. This shows that research in the field of LCE is inseparable from the main body of research on “carbon reduction”. It also shows that existing scholars believe that for LCE, “low-carbon” is the purpose, and education is the means of achieving “low-carbon”. We believe that the relationship between low-carbon and education in LCE is not a one-way knowledge transfer but a two-way symbiotic relationship between construction and mutual empowerment. The concept of low carbon realizes value dissemination through education, while education reshapes its social function with the help of low carbon and jointly promotes the transformation of human civilization to sustainable development. Future research should focus on the relationship between low carbon and education to promote the coordinated development of LCE.

Table 2. The 18 most prominent keywords created by VOSviewer in LCE.

Keyword	Occurrences	Total Link Strength
Sustainability	33	158
Carbon footprint	31	148
Consumption	23	111
Performance	21	104
University	18	98
Greenhouse-gas emissions	19	95
Energy	22	94
Renewable energy	23	94
Sustainable development	22	92
Higher education	19	87
China	21	80
Emissions	17	75
Campus	12	74
Carbon emissions	18	70
Impact	18	64
CO2 emissions	16	61
Higher education institutions	11	60
Climate change	16	58

shows that VOSviewer created the 18 most prominent keywords for LCE, which were closely related. We divided the keywords into three categories; the first category is educational research, including “”,university”, “higher education”, “campus” and “higher education institutions.” The second category is low-carbon research (LCR), which includes sustainability, carbon footprints, greenhouse gas emissions, energy, renewable energy, sustainable development, carbon emissions, climate change, and CO₂ emissions. The third category is behavioral research. It includes consumption, performance, assignments, and impacts. This is highly consistent with the clustering network study of our reference. What is worth our attention is that “China” as a regional noun also occupies a prominent position in the key words. We believe that, since the concept of LCE was first proposed by Chinese scholars, the research results and development trends of LCE in China have obvious advantages. This led to “China” featuring as a key keyword. Judging from the total length of keywords, “sustainability” and “carbon footprint” have absolute advantages over other keywords. Therefore, we infer that LCE may form an emerging trend of diversified development in research fields with keywords such as environment and energy as themes.

3.3.2. Clustering Network of LCE Keywords

We used CiteSpace to generate keyword clustering landscape maps. We set the time slice from January 2015 to December 2024. We selected a keyword in Node Type. The study found that the clustering network effect is clear and effective when the top N = 50, and the results are shown in Figure 8. The network consists of 811 nodes and 2951 connections, forming 23 clusters. In the lower left corner of the figure is the timeline where the literature appears. Nodes represent keywords, and colors represent the year of first occurrence. The size of the “tree wheel” depends on the number of citations of the keyword per year, and the color matches the lower left corner. The lines that connect the nodes are called co-reference links, and the color of these lines is set to show when the connection was first established. The cluster name is indicated in black text, and the smaller the number, the more important the cluster is.

Through the observation of Figure 8, it can be seen that from the perspective of forming clustering themes, low carbon and education are still the research themes in the field of low-carbon education. Simultaneously, the role of education in low carbon has been paid more and more attention by scholars. Moreover, “#0 education institution”, “#1 green education”, and “#2 comparative role” are the three largest clusters, all of which belong to scholars’ thinking on low carbon from the perspective of education. From the perspective of the main research directions in the field of LCE, “#0 education institution”, “#1 green education”, “#2 comparative role”, “#10 university student”, “#13 university ambition”, “#17 college”, “#19 private universities” are the contents of university LEC; “#4 air pollution”, “#6 business practice”, “#7 driving factor”, “#8 silver ballet”, “#9 energy-generation system”, “#12 green space”, “#16 global multiregional input-output model”, “#30 effectiveness” belong to the content of low-carbon social education; “#3 low-carbon behavior”, “#5 carbon footprinting”, “#14 low-carbon attribute”, “#15 human factor”, “#18 Korean public acceptance”, “#22 governance quality”, “#23 sustainable development strategy” can be regarded as the content of behavior LCE. We note that “#14 Germany Poland” is a separate cluster, outside of the three main research directions. By further analyzing the keywords within the cluster, we find that the main keywords in “#14 Germany Poland” focus on low-carbon research. Because Germany is the first country to put forward the concept of “low-carbon” and actively advocate for a low-carbon economy; its mature research in the field of low-carbon has caused scholars to gradually extend their view to the reflection of education and has produced many achievements in the field of LCE. Compared to the clusters covered by the main research directions, university LCE is still the main research direction, which has advantages in terms of the number and importance of its clusters.

Compared with social LCE, behavioral LCE has two high-ranking clusters: “#3 low-carbon behavior” and “#5 carbon footprinting“. Overall, behavioral LCE is less important than social LCE. This shows that the current research in the field of LCE mainly focuses on the change in citizens’ cognition and consciousness, and the research on changing consciousness into behavior and putting it into practice is still in a weak position. In addition, this is also in line with the promotional path of “theory–consciousness–behavior”, as mentioned above in LCE. This shows that LCE has been fully developed at the theoretical level and has gradually extended to the level of consciousness and behavior. Because theoretical research is not yet mature, the research results of consciousness and behavior also show a step-by-step decline, which is consistent with our previous research conclusions. From the perspective of specific clusters, “#0 education institution” is the largest cluster, which shows that the research on the promotion of LCE has become a hot topic for scholars to carry out LCE more effectively. From this, we inferred that the research on the development and dissemination of LCE is the biggest hot spot. In addition, “#1 green education” and “#2 comparative role” are also among the top clusters, representing the research contents and methods of LCE, respectively. According to the time axis, the three largest clusters are relatively close, which is the latest research hotspot. From this, we infer that LCE research has begun to pay attention to education itself, rather than as an extension of low-carbon education. However, considering the coordination of low-carbon and education in research, we suggest that LCE should carry out more interdisciplinary cooperation, absorb the results of low-carbon research, and integrate its concepts into educational research. Moreover, “#3 low-carbon behavior” is the largest cluster except the research direction of university LEC, and its key words mainly focus on citizens’ acceptance of low-carbon products and low-carbon practical behavior in life. For example, “low-carbon products”, “low-carbon consumption”, and “green behavior”.

3.3.3. Mutation Keywords of LCE

Table 3. Top 10 outbreak keywords of LCE from 2015 to 2024.

Keywords	Year	Strength	Begin	End	2015–2024
Environmental education	2015	1.18	2015	2016	▃▃▂▂▂▂▂▂▂▂
Higher education	2015	0.91	2015	2017	▃▃▃▂▂▂▂▂▂▂
Higher education institutions	2018	0.95	2018	2019	▂▂▂▃▃▂▂▂▂▂
Environmental knowledge	2019	0.89	2019	2020	▂▂▂▂▃▃▂▂▂▂
Energy saving behavior	2021	0.91	2021	2022	▂▂▂▂▂▂▃▃▂▂
Climate change education	2019	0.81	2021	2022	▂▂▂▂▂▂▃▃▂▂
Carbon neutrality	2017	2.55	2022	2024	▂▂▂▂▂▂▂▃▃▃
Carbon emissions	2017	1.38	2022	2024	▂▂▂▂▂▂▂▃▃▃
Education level	2022	1.15	2022	2024	▂▂▂▂▂▂▂▃▃▃
Environmental quality	2022	1.15	2022	2024	▂▂▂▂▂▂▂▃▃▃

Note: The red line indicates the outbreak period. The blue line represents the time from the keyword release to the present. Light blue represents the overall time span of 2015–2024.

shows the top 10 keywords generated by CiteSpace that have the strongest outbreak of LCE. The red line represents the outbreak period. The blue line represents the time from the release of keywords in LCE to the present. Light blue represents the overall time range from 2015 to 2024. The results show that “environmental education” and “higher education” were the first keywords to break out, representing the content and subject of education, respectively. “Higher education institutions” replaced “higher education” in 2018 and became an emerging research hotspot. From the perspective of keyword categories, educational content keywords such as “environmental education,” “environmental knowledge,” and “climate change education” occupy a high proportion, accounting for 30% of the total. Compared with other keywords, “carbon neutrality” and “carbon emissions” have higher outbreak intensity. Since 2017, these keywords have had a significant impact. Especially in 2022, they had an explosive impact and have continued up to the present. From the perspective of keyword outbreak time, “carbon neutrality”, “carbon emissions”, “education level”, and “environmental quality” are still emerging keywords and may become emerging trends in development. Among the keywords that have already emerged, low-carbon research is the main topic, and only “education level” belongs to educational research. Based on the previous analysis, we inferred that as research on LCE deepens in areas such as dissemination, scope, and methods, scholars are once again emphasizing the study of the essence of low carbon to better explore LCE research and support the implementation of related activities. In addition, we have found that the research on LCE in universities and society has made considerable progress. It can be predicted that future research is likely to gradually expand to the practical level, that is, behavioral LCE research may experience large-scale development. Research in the field of LCE will also change from the development of cognition and thought to research on behavioral practice. In the future, scholars will conduct more research on how LCE can be transformed into low-carbon behavior. The emergence of the keyword “energy-saving behavior” further confirms our conjecture.

3.3.4. Timeline of Keywords of LCE

To further study the research direction of different keyword clusters, we further processed the keyword clustering network and generated a keyword timeline diagram of LCE, as shown in Figure 9. The figure includes 20 clusters (the other 3 are automatically eliminated owing to too few keywords), which shows the evolution process of keywords over time.

From the time axis, the evolution of LCE research can be divided into two stages; the first stage is the outbreak stage, from 2015 to 2020. Based on previous research, LCE at this stage ushered in the outbreak of keywords. Many prominent keywords with great influence, such as “carbon footprinting”, “sustainable development”, “higher education”, “climate change”, “greenhouse gas incidents”, and “consumption”, have gradually attracted the attention of scholars. At this stage, research on LCE has made great progress from the perspectives of university LEC, social LCE, and behavioral LCE. From the perspective of university LEC, basic keywords such as “higher education”, “environmental education”, and “institutions” played an important role in the early stages and became the basis for later research. At the same time, some influential keywords such as “low-carbon education”, “sustainable campus” and “environmental knowledge” have begun to emerge. This shows that the development of university LEC has gradually matured from 2015 to 2020, demonstrating the characteristics of focus. From the perspective of social LCE, keywords such as “energy consumption”, “emission reduction”, and “environmental impact” are constantly highlighted. Academic circles have focused on educating citizens by promoting the importance of low carbon emissions. At this stage, social LCE emphasizes the promotion of public awareness of environmental protection and plays an educational role through cognitive changes. From the aspect of behavioral LCE, “performance”, “consumption” and “lifestyle” are the focus of scholarly research. Scholars have considered how to put the concept of LCE into practice from micro (individual), meso (enterprise or organization), and macro (government) perspectives. At the same time, emerging clusters such as “# 16 global multi-regional input-output model”, “#17 college”, “#18 Korean public acceptance”, and “#19 private universities” also formed during this period.

The second stage is the emerging stage from 2020 to 2024. At this stage, many emerging and prominent keywords, such as “renewable energy”, “household consumption”, “sustainable development goals” and “willingness to pay” were produced based on the research in the early stages of LCE. At this stage, LCE is influenced by the development of clean technology, and the research topic is more concrete. It is characterized by the inheritance of traditional research and the proposal of new ideas. Some traditional themes, such as “productivity”, “low carbon emissions” and “consumption behavior”, still have great vitality. At the same time, with the development of clean technology, brand-new educational ideas are constantly being put forward by scholars, such as “renewable energy sources”, “adult learning for sustainability”, and “education level”. some keywords representing emerging trends, such as “sustainable power generation”, “education facilities”, “higher education expansion”, and “artificial intelligence of things”, have become the research hotspots of scholars, representing an emerging trend in LCE research.

4. Discussion

4.1. University LCE

From the perspective of the mutated keywords of LCE, university LEC is the first research hotspot that attracted the attention of scholars, and it is also the main research direction of current academic circles. At present, university LEC presents an interdisciplinary trend. For example, “economics education”, “green education”, “ecological education”, etc. are important keywords. In the reference clustering network, a specialized cluster “#18 university student” is formed. Especially in the keyword clustering network, “#1 education research”, “#2 online education”, “#13 education level”, “#16 distance”, and “#17 lesson” have formed clusters with greater influence. Scholars have also launched rich discussions on the implementation and value of LCE in colleges and universities. For example, Zhang (2024) proposed that the implementation of LCE should cover all stages of individual human development, of which the university stage is particularly critical, and that LCE for college students is essential to cultivate environmental awareness, enhance environmental protection awareness, and promote green development [38]. Guerrieri et al. (2019) proposed that the university campus is not only a talent training base for LCE but also an important area for energy consumption; taking the university campus as the epitome of the city to carry out low-carbon emission work can be used as a regional planting strategy through which to evaluate the effectiveness of urban energy policy actions [39]. Specifically, academic research around university LCE mainly focuses on the following aspects. The first is research on the LCE curriculum. LCE curriculum research mainly focuses on curriculum construction, curriculum implementation, curriculum evaluation, and other traditional curriculum research [27].However, some scholars adopt an interdisciplinary approach and take sustainability as the research direction, believing that low-carbon curriculum education should not only achieve the sustainability of curriculum content and constantly solve the environmental problems faced in practice but should also pay attention to the sustainability of economic transformation so that LCE can promote the development of circular economy and realize the sustainability of economic development [25,40]. Combined with the high frequency and strong connections of “Sustainability” in the LCE co-occurrence keyword network, we infer that a sustainable low-carbon curriculum may be an emerging trend in LCE curriculum research. Second, this study was conducted on a low-carbon campus. As the place of university LCE, the campus itself is also the gathering place of energy consumption [4]. Low-carbon campus research involves a wide range of topics, including low-carbon laboratory research, carbon footprint research, low-carbon campus construction and other content [41]. Meanwhile, how we might reflect LCE in the construction and evaluation of low-carbon campuses may become an emerging trend. Third, this study focused on the low-carbon behavior of college students. As the main body of college education, the low-carbon behavior of college students not only reflects the results of university LCE but also has an important impact on social LCE and low-carbon behavior education [27,42]. In the keyword clustering network, an important cluster of “#18 university student was formed. Scholars have conducted extensive research on the driving forces [11], influencing factors and paths [42], and guidance and cultivation [27] of college students’ LCE. Moreover, we can infer how LCE affects college students’ low-carbon behavior and how we might integrate it into the educational framework, for example, through ABC behavior analysis (antecedent, behavior, consequence), positive behavior support (PBS), technology-driven framework, etc., which will become research hotspots and emerging trends of LCE.

4.2. Social LCE

Some scholars believe that the development of LCE should not only focus on colleges and universities but also expand the scope of the group to all citizens. For example, providing LCE to production activists can effectively reduce carbon emissions and achieve the goals of “carbon peaking” and “carbon neutrality” [43]. In the keyword clustering network, clusters “#4 air pollution”, “#6 business practice”, and “#7 driving factor” were formed, which proves the scholars’ thinking about LCE in production activities. In terms of educational subjects, these scholars believe that the popularization of LCE is an important support for a low-carbon economy [44]. The implementation of low-carbon cities [26] and low-carbon standards [45] is inseparable from the help of all citizens. Compared with university LCE, social LCE started later and was mainly born from scholars‘ thinking about the “low-carbon economy”. Therefore, social LCE research is influenced to some extent by university LCE [46]. On the whole, social LCE research focuses on the following aspects. The first is the social activities of LCE research. Research on social LCE activities mainly focuses on economic activities, forming reference clustering network clusters such as “#7 deep decarbonization”, “#9 decarbonization technologies deployment” and “#15 carbon management” and keyword clustering network clusters such as “#4 air pollution”, “#6 business practice” and “#30 effectiveness”. Scholars believe that LCE transmits the pressure of energy conservation, emission reduction, and the concept of sustainable development to traditional high-carbon industries, which can promote the transformation and upgrading of traditional industries and help realize a circular economy [47]. We infer that the impact of LCE on the circular economy and low-carbon economy may become an emerging trend. The second is citizen LCE research. Scholars believe that social LCE involves all aspects of the lives of citizens. In the keyword clustering network, two top-ranked clusters”, #7 driving factor” and “#12 green space”, were formed. Scholars believe that the LCE of social citizens is of great significance in promoting the transformation of society as a whole to a low-carbon, green, and sustainable development model [48]. As a social activity, LCE affects all aspects of citizens’ lives, and citizens’ activities such as production, life and consumption will have an important impact on the construction of a low-carbon society [49]. Individual low-carbon behavior changes and active participation can effectively promote the low-carbon sustainable development of society [50]. Therefore, it is important that we explore the impact of LCE on personal production activities. The third is social LCE advancement research. Some scholars believe that social LCE advancement is essential for building a green and sustainable future [1]. However, social LCE advancement research is a multidimensional and multilevel complex process involving policy formulation, curriculum development, teacher training, student participation, and extensive cooperation from all walks of life [51]. Therefore, how we might carry out the LCE system, the formation of the government, schools, families, enterprises, and multi-coordinated promotion of the situation are emerging trends in LCE.

4.3. Behavioral LCE

Some scholars believe that the purpose of LCE is to change people’s behavior and encourage individuals and collectives to adopt a lifestyle of energy saving, emission reduction, and environmental protection [52,53]. The behavior of individuals in the consumption of various products or services such as food, clothing, housing and transportation has a key impact on climate change [44]. Some scholars have suggested that global household consumption accounts for 72% of global CO₂ emissions [54]. Therefore, low-carbon behavior education has attracted increasing attention from the academic community. In the visualization results, important clusters such as “#3 low-carbon behavior”, “#5 carbon footprinting” and “#14 low-carbon attributes” were formed in the keyword clustering network. This shows that scholars’ research on low-carbon behavior education is not limited to the scope of traditional consumption, production, and consciousness but also extends to the specific activities of citizens. From this, we infer that research on the specific behavior of citizens may become an emerging trend. In terms of the mutated keywords of LCE, keywords such as “environmental performance”, “consumer behavior”, and “willingness to pay” occupy an important position in the study of LCE. It can be seen that the study of individual and collective (especially family) behavior has become a hot topic in academic circles. In addition, scholars have proposed that individuals do not always adhere to low-carbon behaviors or make behavioral changes that favor a low-carbon lifestyle [55]. Therefore, how can we understand which factors determine individual attitudes towards climate change? How do these factors affect individual behavior? What influence can be exerted to promote changes in consumer behavior, and how can these changes be achieved? Research on these issues has become a popular topic in LCE research. In addition, some scholars believe that enterprises and the public are the basis of social production and economic activities and are the decisive forces affecting the economic development of GLC [56]. Given that the behavior of enterprises and the public is not always low-carbon, they suggest that, in addition to guiding the low-carbon behavior of individuals and collectives, it is also necessary to establish a necessary regulatory system [57]. Only by properly supervising the behavioral GLC of enterprises and the public can the GLC development of the economy be truly implemented [58]. How can a reasonable restraint mechanism be established between enterprises and the public to open the shared market of green and low-carbon products? How might we effectively guide the green and low-carbon behavior of enterprises and the public and establish a perfect dynamic response mechanism? These studies are related to whether a green and low-carbon economy can be effectively developed in the future, and whether sustainable development of the economy can be realized. Thinking about this kind of problem will become a new trend within LCE.

5. Conclusions

In this study, we examined research hotspots and emerging trends in LCE. We considered various concerns about LCE (research hotspots, emerging trends, evolution trends, and understanding) and obtained new findings.

5.1. New Findings

In terms of research hotspots, we inferred that university LCE is the main research direction through the visual analysis of LCE references. Through the cluster analysis of references, it was found that education subject, education mode, education curriculum, and education evaluation are research hotspots. The keyword visual map shows that education, low carbon, and behavior are the main research hotspots. From the clustering results, “carbon footprint”, “sustainability”, “consumption” and “greenhouse-gas emissions” are important keywords, and the development and dissemination of LCE is a research hotspot. From the perspective of mutated keywords, low-carbon research accounted for a high proportion and was the main research hotspot.

In terms of emerging trends, through the visualization of references and cluster analysis of LCE, we found that the research on educational subjects is highly valued by scholars, and shows diverse trends, such as “college students”, “social public”, “organization” and so on. For different research subjects, different educational models, methods, and effects will be derived, which will be a promising emerging trend in the future. University LCE and social LCE are the “darlings“ of the most prominent literature and will remain the emerging trend in future research. “Shanghai jiao tong university” has set up a special research institution around this kind of theme [42] and has also produced scholars’ research on the specific group named “Korean public acceptance” [50]. After analyzing the keywords of the existing achievements of LCE, we conclude that LCE may form an emerging trend of diversified development in research fields (with keywords such as environment and energy as the theme) such as “carbon neutrality” and “carbon emissions.” The keyword “Germany Poland” advocates that low carbon is not only a technical issue but also a reshaping of values [52]. Understanding low carbon itself is an education [7]. From the perspective of keyword burst time, current and emerging burst keywords may become emerging trends, such as “carbon neutrality”, “education level”, and “artificial intelligence of things”.

In terms of evolving trends, the evolution of LCE research is divided into two stages. In the first stage, the outbreak stage, from 2015 to 2020, LCE witnessed a burst of keywords based on previous of development research. The second stage is the emerging stage from 2020 to 2024. This stage, based on the early research of LCE, has produced many emerging prominent keywords, and having been affected by the development of clean technology, the research theme is more concrete.

In terms of understanding, we recognize that LCE is an educational activity that aims to guide individuals and society to form a green low-carbon behavior model with the core goal of spreading low-carbon concepts and cultivating environmental awareness. Combined with the existing research results, we believe that university LCE, social LCE, and behavioral LCE are the main research directions for LCE. Research on university LCE focuses on LCE courses, low-carbon campuses, and the low-carbon behaviors of college students. Research on social LCE has mainly focused on social activities, civic education, and the promotion of education. Research on low-carbon behavior mainly focuses on the behavior and supervision of individuals, families, and enterprises.

5.2. Theoretical and Practical Significance

This study makes the following theoretical contributions to LCE. First, to the best of our knowledge, this is the first visual study of LCE from the perspective of sustainable development. It provides a more intuitive and comprehensive understanding of the research hotspots and emerging trends of LCE for scholars in this field, rather than simply analyzing the research results of LCE in specific fields. This is convenient for scholars who want to conduct research in this field. Second, by using scientometrics to visualize and analyze LCE, we can clarify the diversified, interdisciplinary, and specific development directions of LCE. For example, the emergence of words such as “carbon footprint” [38], “air pollution” [23], “public acceptance” [5], etc. provides a new perspective for LCE research from disciplines such as environmental engineering, sociology, and management. Finally, we obtained clustering and landscape maps by visualizing the focus and emerging trends in LCE. For the first time, many focuses and emerging trends have been identified through visual analysis methods, such as reference networks and mutation keywords, which fill the gap in the academic community through systematic research on existing LCE-related research results through visualization. These conclusions can not only further enrich the relevant theories of LCE but also provide new insights into the development of LCE.

This study has important practical significance for educators and educated groups in LCE. LCE is a new focus in the field of education and an important component of adapting to sustainable development [8,20,42]. The above analysis shows that university LCE is still the research focus of LCE, which is consistent with the research results of other scholars [25,38,46,54]. Our research not only provides educators with an important direction for practice but also provides a reference for the development of low-carbon courses to form interdisciplinary integration capabilities, such as integrating STEM (science, technology, engineering, and mathematics) education into the carbon footprint calculation module [38], introducing carbon neutralization in geography classrooms [10], and reflecting STSE (science, technology, society, and environment) thinking in classroom teaching [59]. It also helps to promote the reconstruction of educators‘ evaluation systems and the further formation of the SDGs‘ literacy evaluation framework. Simultaneously, educators are encouraged to break through traditional knowledge-based teaching, focus on action and changing teaching methods, provide real social cases and practical opportunities in classroom teaching, and adopt diversified teaching methods.

From the perspective of education, our research expands the educated group. Previous studies tend to take colleges and universities and college students as the main research objects, and there are relatively few studies on the public; there is also no focus on their education [4,13,19,21,24]. By combing the existing research results, we summarized the research directions of LCE as university LCE, social LCE, and behavioral LCE and creatively included the public into the grouped categories of LCE. This will help to guide educated people to practice low-carbon behaviors in life and make their own contributions to environmental protection. At the same time, it will also act as a wake-up call to groups that ignore environmental protection actions and place themselves outside the environmental context. LCE is not limited to universities and college students. Every individual in the public has an inescapable responsibility to practice low-carbon behavior. This is very important for the formation of low-carbon social consciousness.

5.3. Limitations and Prospects

Despite employing multiple perspectives and indicators to ensure more comprehensive and accurate conclusions, we acknowledge that there is no guarantee of obtaining all the possible results. Consequently, our conclusions regarding the research hotspots and emerging trends in LCE may contain omissions or deviations. Furthermore, while our selected databases offer extensive coverage of the current high-quality global literature, there may still be significant studies that were not included due to their absence from these databases, thereby potentially influencing our research outcomes. Therefore, in a follow-up study, we will further refine the relevant parameters, broaden the data scope, and strive for continuous improvement in the quality of our research.