Scientific Mapping of Problem-Based and Project-Based Learning for Environmental Literacy Education: A Bibliometric and Content Analysis

Abstract

Background Problem-Based Learning (PBL) and Project-Based Learning (PjBL) have emerged as strategic pedagogies for cultivating environmental literacy (EL) and sustainability competencies within the Education for Sustainable Development (ESD) agenda. Yet the intellectual structure, thematic evolution, and conceptual integration of this body of scholarship remain insufficiently mapped, particularly in relation to the Sustainable Development Goals (SDGs) and to disciplinary contexts such as chemistry and environmental chemistry education. Methods This study integrates bibliometric science mapping with systematic content analysis to examine the scholarly landscape of PBL and PjBL-based EL research published in Scopus-indexed journals between 2011 and 2026 (n = 48). Bibliographic data were retrieved through a Boolean query, screened in accordance with the PRISMA 2020 framework, and analyzed using VOSviewer and the Bibliometrix R package to generate co-authorship, keyword co-occurrence, and thematic-evolution maps. A complementary systematic content analysis coded each included study along five dimensions: educational level, learning approach, learning outcomes, SDG alignment, and research methodology. Results The field exhibits an accelerating trajectory after 2021, anchored by Indonesian and North American institutional clusters and organized around four thematic clusters: experiential PBL/PjBL pedagogy, sustainability-oriented curriculum reform, empirical literacy assessment, and emerging eco-literacy innovation. Higher education dominates the corpus (48%); SDGs 4, 12, and 13 are the most invoked goals. Persistent gaps include the limited integration of chemistry and environmental chemistry education, weak longitudinal designs, and underdeveloped EL assessment instruments. Conclusion PBL and PjBL serve as enabling pedagogical approaches for transformative environmental learning. Future research should prioritize longitudinal designs, validated assessment instruments, interdisciplinary integration across chemistry and other natural sciences, and broader representation from the Global South to strengthen sustainability-oriented science education within the ESD agenda.