## 3 Results
### Research
#### 3.4.9 Research on ESD Trends
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Article** & **Research Theme(s)** & **Research Method(s)** \\ \hline [PERSON] and [PERSON] 2008 [128] & \begin{tabular}{c} Positive and negative trends \\ of ESD in HEIs \\ \end{tabular} & Strategic review \\ \hline [PERSON] et al., 2018 [129] & \begin{tabular}{c} Conditions for integration and \\ mainstreaming of SD into \\ education \\ \end{tabular} & Case study \\ \hline [PERSON] 2014 [130] & Learning processes & Review \\ \hline [PERSON] and [PERSON] 2020 [131] & \begin{tabular}{c} Lifelong learning and \\ sustainable leadership \\ \end{tabular} & Survey \\ \hline [PERSON] et al., 2009 [132] & Rapid curriculum renewal & Literature review \\ \hline [PERSON] et al., 2011 [133] & \begin{tabular}{c} Sustainability \\ curriculum-auditing tool \\ \end{tabular} & Case study \\ \hline [PERSON] et al., 2019 [134] & \begin{tabular}{c} Advantages of introducing \\ the SDGs into teaching \\ \end{tabular} & Survey \\ \hline [PERSON] et al., 2019 [135] & \begin{tabular}{c} Pre-conditions of an authentic \\ sustainability curriculum \\ \end{tabular} & Survey \\ \hline [PERSON] 2010 [136] & \begin{tabular}{c} Adoption and diffusion of SD \\ in curricula \\ \end{tabular} & Case study \\ \hline [PERSON] et al., 2019 [137] & \
\begin{tabular}{c} Sustainability competencies \\ and pedagogical approaches \\ \end{tabular} & Survey \\ \hline [PERSON] et al., 2015 [138] &
\begin{tabular}{c} Strategic environmental \\ assessment in curricula \\ \end{tabular} & Case study \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Articles from the research category focusing on research on ESD trends. and their fellow humans, and systems thinking skills. [PERSON] [136] examined how SD are adopted and diffuse in the curricula at a specific HEI and planned to conduct further research on this topic to more clearly understand how SD is diffused by examining the delivery and assessment of HEI courses. Focusing on European HEIs, [PERSON] et al. [137] investigated how sustainability is being taught, sustainability competences are being developed, and pedagogical approaches are being used. The results show that the social dimension was the least frequently addressed, whereas the economic, environmental, and cross-cutting dimensions were addressed almost equally. The authors identified that relations exist between the contribution to sustainability and the strength of competences, as well as between the strength of competences and the strength of pedagogical approaches. On the basis of these results, the authors proposed to conduct further research to assess the level of sustainability contribution, the competences covered and developed, and the pedagogical approaches used in one or more HEI(s) at all levels of education, regardless of whether sustainability was being taught. They also proposed to conduct a cross-country comparison and follow-up research using interviews or focus groups to gain deeper insight into pedagogical approaches used to ensure more sustainability-oriented education. [PERSON] et al. [138] analyzed the level of integration of strategic environmental assessment (SEA) in HEI programs in two countries, finding that SEA integration is rather unconsolidated. Teaching on impact assessment was well-established and common in many programs; however, SEA was mostly either absent or only a minor topic, and these cases were usually treated as a teaching topic on environmental impact assessment. The authors identified a lack of research on education regarding environmental assessment approaches for strategic levels of decision-making.