Since the official proposal of environmental education (EE) in the Belgrade Charter in 1977, research and practice in this field have received increasing attention. Sustainable development education (ESD), a cornerstone concept in education, holds a significant position in both the UN Decade of Education for Sustainable Development (DESD) and the 2030 Agenda(Walshe, 2016), accompanied by a vast and growing number of practices and research endeavors.Despite their distinct focuses, EE and ESD exhibit a growing convergence trend, which is reflected in the widespread advocacy from environmental academia in different cultural backgrounds and aligned with the cultivation of sustainable development literacy (Kyburz-Graber et al., 2016).Some studies that defines environmental education as the embodiment of environmental content in both environmental and education for sustainable development (Pihkala, 2020). Given the intrinsic link between the two, this paper adopts this definition.

Although significant research has been conducted in the field of environmental education, the transition from theory to practice has been slow, and a consensus on teaching methodologies remains elusive (Vesterinen & Ratinen, 2023). Nonetheless, there is a widely acknowledged goal: to enhance the humanization and contextualization of environmental education by adopting emerging pedagogical practices (Strife, 2010; Swarts, 2023).

Despite this shared aspiration, several critical issues persist within current research endeavors: (1) the effectiveness of different pedagogical approaches remains unclear, making it difficult to determine their global applicability; (2) while research in higher education is abundant, studies in basic education are relatively scarce (Vesterinen & Ratinen, 2023); and (3) the varying effectiveness of the same pedagogical approach across different grade levels highlights the necessity for differentiated instruction (Lin, Yang, & Lin, 2024). In this context, exploring effective environmental education strategies in basic education is particularly urgent.

To address these concerns, this study undertakes a systematic review to investigate two key research questions: (1) Do existing pedagogical approaches for teaching environmental education in middle schools share common characteristics?  (2) Are the metrics used to evaluate the effectiveness of these approaches comprehensive?

The review analyzed 23 studies, identifying 24 teaching methods, including hybrid designs. Among these, 21 methods adopted standalone environmental education courses, 12 utilized project-based learning, and 9 employed place-based learning. Additionally, 5 methods incorporated artistic works (e.g., films, cartoons, popular music, documentaries), and 4 methods leveraged technological tools as teaching aids. In terms of effectiveness measurement, 16 studies assessed environmental affect, 16 focused on environmentally responsible behaviors (ERB), 10 measured environmental knowledge, and 5 evaluated cognitive skills.

The findings reveal that real-life-based teaching methods, such as project-based and place-based learning, are widely recognized for their practicality and relevance. However, while environmental affect and behaviors are heavily emphasized, the limited focus on environmental knowledge and cognitive skills suggests a need for more balanced and comprehensive evaluation metrics. Overall, this study provides critical guidance for future environmental education practices.

This study conducted a systematic literature review in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines（Page et al., 2021）. The search strategy was developed using the following Boolean operators: (“environmental education” OR “sustainability education”) AND (“middle school” OR “secondary education”) AND (“teaching strategy” OR “pedagogical approach”). Extensive searches were carried out in three electronic databases: Web of Science, Scopus and ERIC. The search was restricted to peer-reviewed articles published in English between 1 January 2010 and 31 December 2024. The initial search identified 765 records from Web of Science, 344 from Scopus and 77 from ERIC. After removing duplicates, 1,170 unique records remained for screening. The screening process consisted of two stages: (1) title and abstract screening, which excluded 1,121 records for irrelevance, and (2) full-text review, which resulted in the exclusion of a further 24 records that did not meet the eligibility criteria. Exclusion criteria were as follows: (1) studies conducted in non-school settings (e.g., community workshops, corporate training, non-formal education); (2) studies targeting levels of education other than middle or secondary school (e.g., higher education, vocational training, early childhood education, teacher education); (3) studies without a focus on teaching strategies or pedagogical approaches (e.g., those emphasizing curriculum design, policy analysis, or institutional strategies without classroom-level interventions); (4) purely theoretical studies without empirical data; and (5) studies that did not report on the effectiveness of pedagogical methods. Following this rigorous screening process, 25 studies were deemed eligible and included in the final analysis.An analysis process inspired by thematic analysis was applied to identify the characteristics of the literature in order to address two research questions posed in the abstract.“NAAEE's environmental literacy framework” will serve as the categorical guidance for the effectiveness measurement indicators of teaching methods.

In the analysis of commonalities among pedagogical approaches, 23 studies reported a total of 24 teaching methods. 21 studies adopted standalone environmental education course designs. Specifically, 12 studies utilized project-based learning, while 9 studies employed place-based learning, an approach that helps establish connections between students and real-life contexts. Additionally, 5 studies incorporated the use of artistic works (e.g., films, cartoons), and 4 studies leveraged technological tools as teaching tools. Despite the diversity in research methods, real-life-based instructional designs (such as project-based and place-based learning) have gained widespread recognition among educators and researchers. These approaches not only enhance the practicality and contextual relevance of teaching but also foster students' deeper understanding of and engagement with environmental issues. In terms of the effectiveness measurement indicators for pedagogical approaches, 16 studies reported students' environmental affect, 16 studies focused on environmentally responsible behaviors (ERB), 10 studies measured environmental knowledge, and 5 studies assessed students' cognitive skills.From the research findings, it is evident that researchers place greater emphasis on environmental affect and behaviors, likely because these indicators more directly reflect the practical outcomes of environmental education, particularly in fostering students' emotional connection to environmental issues and their capacity for actionable change. In contrast, measurements of environmental knowledge and cognitive skills, while present, are relatively less emphasized. This may indicate a current research preference for focusing on affective and behavioral dimensions of educational outcomes rather than solely on knowledge transmission or cognitive development. This trend aligns with the goals of education for sustainable development, which aims to cultivate environmentally responsible and action-oriented citizens. Furthermore, the studies collectively highlight the following recommendations: first, the sample sizes in existing research are generally small, and future studies should expand sample sizes; second, researchers advocate for the long-term implementation of environmental education courses to ensure consolidation of students' environmental literacy. 

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