The study, published as an open access article in Discover Education, was conducted by Osman Aksit of Boğaziçi University in Istanbul. It represents the first attempt to compare the Turkish and US K-12 science curricular documents through the lens of GreenComp, the European sustainability competence framework published in 2022. GreenComp organizes sustainability learning into 12 competences grouped under four competence areas: Embodying Sustainability Values, Embracing Complexity in Sustainability, Envisioning Sustainable Futures, and Acting for Sustainability. The framework was designed to give learners of all ages, regardless of their education level, the knowledge, skills, and attitudes to think, plan, and act with empathy, responsibility, and care for the planet. Because its 12 competences cover both cognitive and behavioral dimensions of sustainability education, the framework offers a theoretically consistent benchmark for evaluating complex curriculum structures in a standardized and comparable way.

Aksit employed a multiple case study design with directed content analysis, treating the Turkish national curricula and the NGSS as two bounded cases situated in sharply different socio-political contexts. The analyzed Turkish documents comprised the Science curriculum for grades 3 through 8 and the high school Physics, Chemistry, and Biology curricula, all updated and released in 2024 by the Ministry of National Education. The US counterpart was the NGSS, published in 2013, which organizes science learning through a three-dimensional structure of Disciplinary Core Ideas, Science and Engineering Practices, and Crosscutting Concepts. The primary units of analysis were learning outcomes and their accompanying explanations in the Turkish documents and performance expectations in the NGSS, providing an analytical equivalence between the two systems. All components of the NGSS’s three-dimensional structure were screened, although GreenComp-aligned indicators emerged primarily in the performance expectations and in the Disciplinary Core Ideas sections; no indicators were identified in the Crosscutting Concepts, Science and Engineering Practices, or preface sections.

To ensure objectivity, all curricular texts were independently coded by the author and one independent researcher who was an expert in sustainability and science education. The two coders reached 96 percent agreement on the presence or absence of competences, and inter-rater reliability was high, with Cohen’s kappa equal to 0.90, indicating almost perfect agreement. Discrepancies were resolved by revisiting the text, discussing differences in light of the official GreenComp definitions, and determining final codes through consensus. Because the documents were published in both Turkish and English, particular attention was paid to preserving conceptual meaning across languages, with uncertainties arising from language differences discussed between coders until consensus was reached. Multiple coding was permitted when a single unit of analysis contained elements of more than one GreenComp competence.

The headline finding is a substantial quantitative disparity. The Turkish science curricula contained 740 total references to sustainability competences, compared with 132 in the NGSS. Within the Turkish system, the Chemistry curriculum led with 305 instances, followed by the Science curriculum for grades 3 through 8 with 252 instances, the Biology curriculum with 104, and the Physics curriculum with 79. The NGSS K-8 standards accounted for 81 instances, concentrated in Kindergarten and grades 3 through 5 and in middle school Life Sciences and Earth and Space Sciences, while the high school standards contributed 51 instances that emerged exclusively in Earth and Space Sciences. Notably, no GreenComp-aligned competences were identified in the NGSS high school Physical Sciences or Life Sciences areas at all. Aksit cautions, however, that these frequency counts are descriptive rather than inferential: the documents differ considerably in length and structure, and a single NGSS performance expectation may differ substantially in scope and detail from a Turkish learning outcome, so direct comparisons should not be read as implying equivalence between the two systems.

The disciplinary distribution tells a more nuanced story. In the Turkish Science curriculum, valuing sustainability and promoting nature each recorded 18 percent of references, systems and critical thinking together anchored 32 percent, futures literacy accounted for 9 percent, and individual initiative appeared in 7 percent of cases. The Chemistry curriculum showed a distinct emphasis on Embracing Complexity, which accounted for 48 percent of its references, with the 11th grade alone recording systems thinking at a frequency of 12, critical thinking at 14, and problem framing at 15. The Biology curriculum peaked sharply in the 10th grade, where valuing sustainability reached a frequency of 18, promoting nature 16, systems thinking 14, critical thinking 13, and problem framing 14, before sustainability content largely disappeared in grades 11 and 12. The Physics curriculum was the weakest performer: the Envisioning Sustainable Futures area was not identified anywhere in the document, and supporting fairness and political agency both registered zero frequencies.

Across both systems, two competence areas dominated. Embodying Sustainability Values and Embracing Complexity in Sustainability accounted for the bulk of references in the Turkish curricula and in the NGSS alike, indicating a strong curricular focus on the ethical foundations and analytical tools for understanding sustainability, including systems thinking, critical thinking, and problem framing. In the NGSS high school standards, Embracing Complexity accounted for 50 percent of references, with systems thinking at a frequency of 10 and problem framing at 9, while Embodying Sustainability Values contributed 37 percent, led by valuing sustainability at 10 and promoting nature at 9. This emphasis aligns with the goal of centering scientific literacy in sustainability education and with international research stressing that sustainability education must address complex, interdependent problems.

But the transformative competence areas were systematically underrepresented in both contexts. Envisioning Sustainable Futures, which covers adaptive thinking, exploratory thinking, and futures literacy, and Acting for Sustainability, which covers individual initiative, collective action, and political agency, were marginal in every document analyzed. Supporting fairness and political agency were not identified in any of the analyzed documents for either the Turkish curricula or the NGSS. In the NGSS high school standards, the Acting for Sustainability area registered zero frequencies for political agency, collective action, and individual initiative. The complete absence of futures-oriented competences in the Turkish Physics curriculum is particularly notable, and Aksit suggests it may reflect an insufficient integration of context-based approaches rather than an inherent characteristic of the discipline, since previous research has shown that contextualizing physics concepts in real-life scenarios can enhance conceptual understanding and promote meaningful learning.

The discussion points to structural explanations that transcend national borders. Aksit argues that the underrepresentation of action-oriented competences may reflect shared pedagogical norms rather than merely different national policies. Recent work cited in the study emphasizes that policymakers often reduce Education for Sustainable Development to a superficial add-on and fail to provide the robust teacher training and assessment systems necessary for deeper curriculum integration. Science educators, meanwhile, frequently prioritize empirical evidence over value-laden dimensions, viewing competences such as political agency as beyond the scope of science learning, a disciplinary tradition that potentially marginalizes civic participation regardless of the national educational framework. The study also highlights a fundamentally different architectural approach between the two systems: in the NGSS, human-environment interactions appear deliberately concentrated within the Earth and Human Activity disciplinary core ideas, clustering sustainability content in Earth and Space Sciences by design, while the Turkish Chemistry curriculum embeds sustainability directly into disciplinary learning outcomes through contexts such as green chemistry, ecosystem and biodiversity protection, and water management and recycling. The disparity in frequencies, Aksit concludes, should therefore be interpreted as a reflection of different structural integration approaches rather than a simple difference in how much each system values sustainability.

The implications reach beyond the two countries examined. Aksit recommends that the Acting for Sustainability area receive intentionally designed curricular targets, suggesting that learning outcomes related to political agency could be incorporated into physics topics concerning energy production and policy, while collective action could be reinforced through sustainability contexts such as waste management in chemistry and biodiversity conservation in biology. Curriculum developers could also integrate socio-scientific issue-based argumentation, project-based investigations of local environmental challenges, and community-based learning experiences. The limited representation of the socio-political dimension of sustainability, particularly supporting fairness and political agency, suggests that current science standards struggle to address issues such as climate justice and structural socio-economic inequalities, and adopting a social justice perspective is essential for moving sustainability beyond a purely ecological framing. Aksit also acknowledges important limitations: the analysis examined only official written documents, reflecting the intended rather than the implemented curriculum, and the two systems differ in scope and structure, with the Turkish documents released in 2024 and the NGSS in 2013, a gap of more than a decade. Future research, the study concludes, should investigate how students actually acquire sustainability competences, complementing curriculum analysis with learner-focused work, particularly since previous research in Türkiye has shown that students who understand climate change still struggle to translate that understanding into individual responsibility and sustainability-related action.

Subject of Research: Education Research

Article Title: Mapping sustainability competences in the NGSS and Turkish science curricula using the GreenComp framework

Article References: Aksit, O. (2026). Mapping sustainability competences in the NGSS and Turkish science curricula using the GreenComp framework. Discover Education, 5(1), Article 1184. https://doi.org/10.1007/s44217-026-02199-x

Image Credits: AI Generated

DOI: 10.1007/s44217-026-02199-x

Keywords: Mapping, sustainability, competences, NGSS, Turkish, science, curricula, GreenComp, framework, scientific research