**2. Methods**

Student questionnaire data were collected in three waves (September 2017–June 2019) in accordance with a longitudinal design. In total, 760 Swedish upper secondary students participated in the waves, starting in grade 10 and 11, through grades 11 and 12 in the second and the final wave. Two scales were used, the SPACS-scale (α = 0.90) [3] and the ESD, holism, and pluralism scale (α = 0.80) [2]. Our data were analyzed using latent growth modeling and structural equation modeling. Measurement invariance between the waves was established using multiple fit indices.

**Citation:** Olsson, D.; Gericke, N.; Pauw, J.B.-d. Students' Action Competence for Sustainability and the Effectiveness of Sustainability Education. *Environ. Sci. Proc.* **2022**, *14*, 11. https://doi.org/10.3390/ environsciproc2022014011

Academic Editors: Andreas Ch. Hadjichambis, Pedro Reis, Marie-Christine Knippels, Audrone Telesiene, ˙ Daphne Goldman, Demetra Paraskeva-Hadjichambi, Jan Cincera and Kateˇrina Janˇcaˇríková

Published: 9 March 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

### **3. Results**

The longitudinal results reveal a significant increase for students' experience of holism, but not for their experience of pluralism. This result show that the students have experienced something in the sustainability teaching, especially in relation to the approach to the content, but not in relation to the pluralistic approach in teaching to the same degree. The results also reveal a significant increase over time regarding students' SPACS. Finally, our SEM analyses show that experiencing the SE dimensions of holism and pluralism at the student level will have a positive effect on their action competence for sustainability (self-perceived) (β between 0.14 and 0.30).

### **4. Conclusions and Recommendations**

Our results show that SE as a teaching approach is effective in fostering environmental citizenship in terms of the important aspect of action competence for sustainability. Moreover, the results shed light on the fact that a SE school development project to some degree can support the development of students' experiences of SE teaching at their school, which then positively influence their self-perceived action competence for sustainability.

**Author Contributions:** This conference paper is the result of a collaborative work where all the authors significantly contributed to its conceptualization, methodology, validation, formal analysis, data curation, and the writing. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by the Swedish Institute for Educational Research under Grant [number 2017-00065].

**Institutional Review Board Statement:** The study follows the ethical guidelines in Sweden and the specific guidelines provided by Karlstad University.

**Informed Consent Statement:** The participants were informed about the purpose of the project and they all provided active informed consent for participating.

**Data Availability Statement:** Data supporting the findings of this study are available from the corresponding author upon reasonable request.

**Acknowledgments:** We are grateful to Teresa Berglund at Karlstad University for sharing her expertise and for her important contribution during the development of this article. This research was supported by ROSE (Research On Subject-specific Education), Karlstad University.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study, in the collection, analyses, or interpretation of data, in the writing of the manuscript, or in the decision to publish the results.

