## 3 Results
### Research
#### 3.4.9 Research on ESD Trends  
A full summary of the articles focusing on research on ESD trends is represented in Table 9. These articles are further addressed in more detail. [PERSON] and [PERSON] [128] summarized positive and negative ESD trends across the HEI sector in a specific country. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Article** & **Research Theme(s)** & **Research Method(s)** \\ \hline \multirow{2}{*}{[PERSON] 2018 [116]} & Evidence-based model for embedding & \\  & education for sustainability & Case study \\ \hline [PERSON] et al., 2017 [117] & ESD transition & Case study \\ \hline [PERSON] et al., 2018 [118] & ESD & Case studies \\ \hline [PERSON] 2005 [119] & Obstacles to greening the curriculum & \\ \hline [PERSON] and [PERSON] 2018 [120] & Incorporating sustainability into general & Case study \\  & education & \\ \hline [PERSON] 2002 [121] & Research project on education for & Survey \\  & sustainability in higher education & \\ \hline [PERSON] et al., 2016 [122] & Challenges in ESD implementation in & \\  & educational institutions & Case studies \\ \hline [PERSON] et al., 2016 [123] & Role of project-oriented learning & Case studies \\ \hline [PERSON] and [PERSON] 2014 [124] & ESD initiatives & Case studies \\ \hline [PERSON] and [PERSON] 2014 [125] & Constraints of ESD & Survey \\ \hline [PERSON] and [PERSON] 2010 [126] & Drivers of ESD & Content analysis and survey \\ \hline [PERSON] et al., 2018 [127] & Measures for specific training elements & \\  & laying to foundations for SD & Survey \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Articles from the research category focusing on research on ESD integration and implementation. [PERSON] et al. [129] discussed factors that enable the successful integration of mainstream SD into education at an HEI. Based on a review of the UN DESD, [PERSON] [130] described the outcome of phase II of this review, focusing on processes and learning in ESD. The authors presented and discussed key outcomes documented in the report's section on higher education. [PERSON] and [PERSON] [131] described executives' strategies, perceptions, and experiences in higher education in a specific country with regard to lifelong learning and sustainable leadership. The authors planned to carry out a quantitative investigation in the future, and specifically a scale development, based on this study's qualitative findings. Targeting curricula and their content, [PERSON] et al. [132] presented emerging elements of rapid curriculum renewal and described how these elements could be applied based on the available literature. The authors proposed to conduct further research on the practical application of these elements in various disciplines. [PERSON] et al. [133] discussed how a particular sustainability curriculum-auditing tool could be applied and assessed its validity in terms of supporting sustainability in the higher education sector. Although the audit identified what the curriculum offered, the quality and effectiveness of the curriculum content was not identified. [PERSON] et al. [134] surveyed how SDGs were currently being integrated in teaching, exploring the advantages of this integration and common barriers encountered. The authors concluded that SDGs are still only initially and tentatively being integrated in HEIs and that although much literature on ESD exists, research on how the HEIs engage with SDGs is lacking. [PERSON] et al. [135] analyzed three essential pre-conditions of an authentic sustainability curriculum (ASC), acknowledging and emphasizing (i) the primary importance of meditative mindfulness, (ii) the impossibility of limitless economic growth, and (iii) the impossibility of reconciling ideals of neoliberal capitalism and consumerism with human and environmental justice. The authors surveyed undergraduate students and focused on their views on mindfulness, economic growth, and sustainability, concluding that students lack mindfulness, sustainability literacy, universal values concerning nature