Education for Sustainable Development (ESD) plays a significant role in the environmental, economic, social and cultural spheres and is a key element in achieving sustainable development goals. Higher education institutions, as the main producers of future leaders, are essential to the practice of ESD. Higher Education for Sustainable Development (HESD) is still in its infancy in many higher education institutions.
Sustainable development (SD) has been a major global concern for decades. As a key means to achieve SD, Education for Sustainable Development (ESD) has received increasing international attention in recent years. Environmental education, which was introduced at the United Nations Conference on the Human Environment in 1972, served as the precursor of ESD 
. In the 1980s and 1990s, the United Nations shifted its discourse from environmental education to ESD. The concept of ESD first appeared in the Brundtland Report in 1987 and was formally included in Chapter 36 of Agenda 21 in 1992, which stated that education, public awareness and training are essential means to achieve progress towards sustainable development 
. In 2015, the 17 United Nations Sustainable Development Goals (SDGs) were launched, and ESD was included, specifically reflected in target 4.7 of SDG 4: by 2030, ensure that all learners acquire the knowledge and skills necessary to promote sustainable development 
Higher Education for Sustainable Development (HESD) is widely recognized as an essential means of promoting and supporting a sustainable future. This recognition has been captured in numerous declarations, such as the Halifax, Talloires, Tbilisi and Kyoto declarations 
. For individuals, higher education is the last formal stage of education, allowing them to enhance their knowledge and skills required for SD and improve their capacity for sustainable learning. For society, higher education is an important symbol of social progress since higher education institutions (HEIs) generate new knowledge and train future leaders 
. Higher education is also an important base for scientific research. Compared to all other levels of education, higher education has a stronger scientific research character than any other level, which can help HEIs to continuously improve the quality of ESD through the integration of scientific research and education.
2. Optimizing Higher Education for Sustainable Development
The concept of sustainable development emerged in the 1980s due to increasing economic and population pressures, environmental degradation and resource depletion. The Brundtland Report’s definition of sustainable development, which states that “Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs” 
(p. 41), is now widely accepted. In 2000, the United Nations Millennium Development Summit adopted a “United Nations Millennium Declaration” aimed at addressing extreme poverty, hunger, disease, death, illiteracy and environmental degradation and promoting global sustainable development 
. In 2015, the United Nations Sustainable Development Summit adopted the “2030 Agenda for Sustainable Development” and the 17 Sustainable Development Goals (SDGs). These SDGs build on the achievements of the Millennium Development Goals and aim to end poverty, protect the planet and improve the lives and prospects of everyone, everywhere 
The sustainable development of the global economy and society calls for the practice of Education for Sustainable Development. Many studies have shown that ESD is one of the key factors in achieving sustainable development 
. ESD is one of the important means to make people understand and participate in the realization of sustainable development. Research on Education for Sustainable Development has focused on the following areas: first, research focuses on the macro level. Such research tends to focus on national-level actions, such as policy introduction, etc. Wang (2017) summarized the policy orientation and practical characteristics of ESD in Germany 
. Fredriksson (2020) compared the implementation of ESD in Sweden and Japan and found that, in Sweden, ESD is often used as part of the guiding principles of education, while, in Japan, it is emphasized to integrate ESD into subject teaching outlines 
. Second, it focuses on implementation at the micro level, exploring how ESD can be integrated into certain disciplines, fields or educational levels. For example, Cheng and Nie (2021) proposed that young children have enough experience in terms of learning the concept of sustainable development, and early childhood education is also an indispensable part of the ESD 
. Guo et al. (2022) pointed out that ESD is an important choice for improvement in quality of engineering education, analyzing the demand for engineering science and technology talents that empower ESD 
. In addition, a small number of studies have specifically discussed the definition of ESD, and such studies are usually early in the emergence of ESD.
Higher Education for Sustainable Development belongs to the second research category that focuses on the practice and application of ESD and explores the link between higher education and ESD. Some researchers pay attention to the competencies fostered by HESD. Although there is still no international consensus on the most important key competencies, related papers provide directions for HEIs to implement ESD. Wiek et al. (2011) used a literature method to conclude that the key competencies fostered by HESD include systems thinking competence, anticipatory competence, normative competence, strategic competence and interpersonal competence 
. Rieckmann (2012) used the Delfi method to identify twelve key competencies that are critical for sustainability, of which the most relevant are systemic thinking, anticipatory thinking and critical thinking 
. Brundiers et al. (2021) critically reviewed the framework of key competencies in sustainability by Wiek et al. 
and proposed two additional key competencies, intrapersonal and implementation competencies 
In addition, there is no lack of research on the specific practice of HESD, which focuses on how to promote SD through curriculum and teaching innovation in higher education. Kagawa (2007) used an online questionnaire to understand university student perceptions, understanding and attitudes towards SD and relevant concepts and issues and, based on this, proposed improvements to university courses on sustainability. One of the suggestions is to pay attention to the combination of theory and practice, recognizing and re-examining the importance of lectures 
. Lozano (2010) reviewed 5800 course descriptions from Cardiff University, focusing on the adoption and dissemination of SD in courses. He put forward suggestions for HESD curriculum, pointing out that the concept of sustainable development as a whole should be integrated into multiple disciplines 
. Ter Horst and Pearce (2010) emphasized the importance of foreign languages in multidisciplinary learning, which helps to develop students’ understanding of HESD-related concepts and greater participation in the global community 
. Ahel and Lingenau (2019) discussed the opportunities and challenges of digitalization to improve access to HESD and pointed out that digitalization could be the key to enlarge the scale of students obtaining access to ESD in HEIs 
. There are also studies using the method of case study. Jones et al. (2008) explored the perceptions of academics and students towards embedding ESD into undergraduate degree programs in the School for Earth, Ocean and Environmental Science at the University of Plymouth 
. Novo-Corti et al. (2018) discussed how economics courses offered at higher education institutions can influence sustainable development 
Based on the review, several key points can be summarized regarding the implementation of HESD. In terms of teaching content, many researchers have emphasized the importance of inter-disciplinarity. HESD should include all SD-related dimensions and integrate science and social science as much as possible. Additionally, foreign languages should not be overlooked as they provide further opportunities. Regarding teaching forms, the focus is to explore and enrich teaching forms beyond the curriculum and to combine theory with practice. This is also the result of HESD’s complex competency requirements for students. The role of extracurricular activities, such as lectures, needs to be re-examined since they provide more possibilities for enriching teaching content and cultivating the competencies needed for a sustainable future.