Many higher education institutes have tried to promote students’ pro-environmental behaviors (PEBs). Students are expected to participate in both direct and indirect impact PEBs. Direct impact PEBs include the acts that directly contribute to environmental improvements such as reuse and recycling behaviors and energy-saving behaviors; however, indirect impact PEBs refer to the acts that have no direct effects on better environmental change, but potentially shape the way how the environment is managed [1
]. Indirect impact PEBs are include supporting environmental policy and preference to work with environmentally responsible organizations. Students could take an important role in bringing sustainability to the society by participating in both types of PEBs. Formal environmental education, such as providing environmental courses, has been used as one of important channels to educate students with environmental values and significance of environmental conservation and protection in order to promote environmental citizenship among university students [2
]. The study of Pizmony–Levy & Michel [4
] found that learning about environmentalism and sustainable issues in class and being a member of campus-based environmental groups could promote student’s participation in PEBs. Similarly, the study of Borchers et al. [5
] found that environmental education could enhance people’s environmental knowledge and attitudes towards nature. Jurdi–Hage et al. [6
] suggested that to promote environmental literacy and students’ sustainable life styles, students should learn about environmental knowledge, awareness, and critical thinking skills. Educating students with environmental knowledge that could promote positive ecological attitudes and students’ engagement in PEBs is an important goal of environmental education [7
], but it remains challenging. Though environmental knowledge is provided, students are still reluctant to engage in PEBs. Therefore, environmental education research that could support the development of effective environmental education is currently required [10
With regard to value belief norm theory, environmental attitudes—defined as an individual’s environmental worldviews—significantly influence PEBs [1
]. Environmental attitudes represent people’s beliefs about the interconnection between humans and the environment; thus, having positive environmental attitudes allow people to identify the negative consequences of behaviors for the environment. Consequently, they will construct a sense of obligation to act in an environment-friendly manner, which can, in turn, lead to a decision to engage in PEBs. Many previous studies affirmed that having positive environmental attitudes eventually leads to a decision to participate in PEBs [12
], and most of those studies applied the New Ecological (Environmental) Paradigm proposed by Dunlap et al. [15
] to measure individuals’ environmental attitudes. The study of Abun & Aguot [16
] revealed that eco-centric concern attitude could promote people’s engagement in environmental movement activism and conservation behavior. Similarly, the study of Kim et al. [17
] and Kukkonen et al. [2
] revealed that if they have greater emotional empathy toward nature, people are more likely to participate in PEBs. However, some studies also found a weak relationship between environmental attitudes and PEBs [18
]. Vermeir and Verbeke’s [21
] study demonstrated that environmental attitudes alone were a poor predictor of PEBs. Manaktola and Jauhari [20
] discovered that though having positive attitudes toward environment-friendly practices in the hotel industry, customers did not translate their attitudes into a willingness to pay more for taking services from green hotels. However, PEBs can be predicted by diverse factors. Literature review suggests diverse viewpoints of PEB predictors. Many scholars indicated that PEBs were strongly predicted by social factors such as social relationships and social network [22
]. Some scholars strongly believed that participation in PEBs was predicted by normative goals, intention, and gain [1
]. For instance, the study of Heeren et al. [26
] revealed that environmental knowledge was not as important as social norms, attitudes toward PEBs, and perceived capability to perform PEBs to promote American students’ participation in PEBs. Many studies also revealed significant roles of socioeconomic characteristics in predicting PEBs. Those socioeconomic factors included gender [27
], age [28
], educational level [29
], and income [30
Regarding students’ participation in PEBs, environmental knowledge could play an important role in cultivating students’ positive environmental attitudes and PEBs [12
]. Environmental knowledge can be generally defined as any information that constitutes the formation of environmental attitudes and people’s participation in environmental behaviors [18
]. Put differently, environmental knowledge can be defined as people’s capability to identify numerous ecological symbols, concepts, and characteristics of behavior concerning environmental protection [34
]. Hines et al. [35
] defined two types of environmental knowledge, including knowledge of environmental phenomena and knowledge of environment-friendly action strategies. Several studies referred environmental knowledge as knowledge of environmental issues [33
] and problem-solving actions and strategies [18
]. Fryxell and Lo [39
] defined environmental knowledge as environmental issues and general environmental knowledge about the facts, concepts, and relationships in the surrounding environment and ecosystems. Mostafa [36
] also conceptualized environmental knowledge as people’s understanding of environmental influence, environmental values and appreciation, negative relationships potentially destroying the environment, and collective responsibility.
In terms of knowledge measurement, environmental knowledge is divided into two types, including subjective and objective knowledge [31
]. Subjective knowledge refers to people’s own perception of understanding about the environment, whereas objective knowledge refers to actual knowledge that people possess [40
]. Martin and Simintiras’ [41
] study found no correlation between these two types of knowledge. People’s misunderstanding of their actual knowledge might cause ineffective decision making to take environmental actions. In terms of scale, environmental knowledge can be classified into two types: general environmental knowledge and specific knowledge [12
]. General environmental knowledge is defined as “general knowledge of facts, concepts, and relationships concerning the natural environment and its major ecosystems,” while specific environmental knowledge means knowledge relevant to particular environmental issues such as knowledge and behavioral consequences related to particular environmental behavior [39
]. Taufique et al.’s [42
] study measured levels of general knowledge by analyzing the degree to which people are familiar with contemporary pressing environmental issues, such as “climate change,” “greenhouse gas,” etc. Previous studies revealed diverse findings regarding the impact of both general and specific environmental knowledge on PEBs. Ellen [43
], Frick et al. [10
], and Ogbeide et al. [44
] found in their studies that specific environmental knowledge has a more significant impact on environmental behavior. The study of Polonsky et al. [12
] revealed that both general and specific environmental knowledge levels assist US consumers in making environment-friendly consumption decisions. A more recent study by Taufique et al. [42
] found that both general environmental knowledge and issue-specific environmental knowledge (e.g., eco-label knowledge) positively influence consumer attitudes toward the environment in driving ecologically conscious consumer behavior.
In universities, several environmental knowledge-related subjects are taught to students to cultivate their understanding of ecological values, problems, awareness, and preferred environmental practices, but the actual contribution of that educated knowledge to positive environmental attitudes and engagement in diverse types of PEBs is not clear. While many previous studies have investigated the relationship between environmental knowledge and attitudes, as well as association among environmental knowledge, attitudes, and behaviors, it was noticed that environmental knowledge explored by those studies was mostly investigated based on measurement of subjective knowledge, which may not reflect their actual knowledge (objective knowledge). Kaiser and Fuhrer [38
] also added that the influence of environmental knowledge on pro-environmental behavior has been underestimated because the underlying structure of environmental knowledge has not been addressed adequately. They suggested that it is necessary to consider different forms of environmental knowledge to understand their effects on pro-environmental behavior.
This study aims to investigate how several types of environmental system knowledge taught in a university are essential to promote students’ environmental attitudes and PEBs including both direct and indirect impact PEBs. The study also explores whether positive environmental attitudes are associated with students’ participation in both types of PEBs and investigates types of environmental system knowledge that correlate with environmental attitudes and PEBs. Objective environmental knowledge of students will be measured based on the evaluation of actual knowledge acquisition. Namely, students will be taught environmental knowledge, and their knowledge will be tested. Types of environmental knowledge included in this study are knowledge of political ecology, sustainability, natural characteristics of the environment and ecology, and knowledge of environmental situations. The results of this study clearly indicate whether environmental knowledge could affect students’ environmental attitudes and PEBs and provide an implication for developing an effective environmental education.
6. Discussion and Conclusions
First, the results of this investigation clearly revealed that there was significant difference in environmental attitudes and the engagement in indirect impact PEBs between students participating in the environmental course and students not participating in the course. A significant difference in students’ engagement in direct impact PEBs was not found. Particularly, students who participated in the environmental course for seven weeks did not engage in direct impact PEBs at a significantly higher level than students who did not participate in the course. It is possible that a decision to act in an environment-friendly manner can be based on other more influential and diverse factors (e.g., infrastructure, motivation, sense of responsibility, and social norms) and require some time for students to act upon. Vicente–Molina et al. [62
] suggested that motivation and perceived effectiveness of PEBs were very powerful to predict university students’ engagement in PEBs. Heeren et al. [26
] also indicated environmental knowledge was important, but not as important as social norms, attitudes toward PEBs, and perceived capability to perform PEBs to encourage American students in PEBs engagement. Based on this study’s finding, formal environmental education can greatly bring some positive change to students’ environmental attitudes and influence them to partake in indirect impact PEBs. The engagement in indirect impact PEBs such as supporting environmental policy in organizations and supporting goods and services from responsible business sectors may require fewer efforts and greatly rely on one’s cognitive judgment based on self-awareness. Therefore, the role of environmental knowledge in influencing indirect impact PEBs could be sufficiently influential. For the engagement in direct PEBs, environmental knowledge provided through a formal environmental education might not be strong enough to bring a positive change. This finding can be supported by the study of Varoglu et al. [66
], which reported a moderate relationship between environmental knowledge and environmental attitudes of students in secondary school level in North Cyprus and found a weak relationship between environmental knowledge and PEBs.
However, this study did not find significant relationships between environmental attitudes and both of types of PEBs including direct and indirect impact PEBs. This means that students might not act in an environmentally responsible manner despite having high positive environmental attitudes. This result is consistent with the study of Mifsud [67
], which investigated several types of environmental knowledge, environmental attitudes, and direct impact PEBs of students attending postsecondary institutions in Malta. The results revealed that students exhibited strongly positive toward the environment but reported their engagement in few positive environmental actions. Similarly, Paço and Lavrador [68
] also reported a weak relationship between environmental attitudes and PEBs of students from the University of Beira Interior. Unlike the study of Mifsud [67
] and Paço and Lavrador [68
], an investigation carried out by Heyl et al. [69
] revealed the potentiality of positive environmental attitudes in predicting PEBs of engineering students in a Chilean university.
For this study, it can be concluded that environmental knowledge provided through a formal environmental education can constitute students’ environmental attitudes, but it is uncertain that the attitudes would turn to PEBs. Knowledge may influence PEBs through other variables such as motivation, social norms, and perceive self-efficacy, according to the suggestion of Vicente–Molina et al. [62
]. The study of Mtutu & Thondhlana [70
] and Heberlein [71
] also exhibited that though having a positive environmental attitude, people may not always decide to participate in PEB because of external factors which are beyond the control of individuals. External factors, for instance, include infrastructure condition or access to relevant infrastructure. Students will engage in waste separation, if they can access to recycling bins. This study found that the result of t
-test analysis demonstrated that students participating in the environmental course reported a significantly higher level of engagement in indirect impact PEBs than students who did not participate the environmental course, but a significant relationship between environmental attitudes and indirect impact PEBs was not found. It could imply that knowledge might influence indirect impact PEBs through other attributes. This finding contradicts with the study of Oreg and Katz–Gerro [72
], which stated that environmental knowledge potentially fosters an environmental attitude, which in turn influences any environmental behaviors.
In consideration of types of environmental contents that potentially foster environmental attitudes and contribute to students’ engagement in both types of PEBs, it is hard to find relevant works of literature that investigate roles of specific environmental content in promoting types of PEBs. Therefore, the discussion in this part will be made based on only the results found in the study. This study has revealed that students having a high level of knowledge related to environment and ecology relatively reported a high level of positive environmental attitudes; on the other hand, other types of environmental contents were not significantly correlated. While studying about environment and ecology, students would be taught about interactions among organism in environmental system, ecosystem function, and environmental services. Therefore, having this basic knowledge, students would have the potential to evaluate environmental values and susceptibility of the environment and ecological systems to human behaviors; thus, a positive attitude toward the environment could be formed. For the knowledge relevant to students’ engagement in direct PEBs, the result displayed that knowledge of environmental situations (e.g., the potential impact of climate change, pollution, ozone depletion, and ecological degradation) and knowledge of political ecology were positively and significantly correlated with such PEBs. It is possible that by understanding these issues, students could understand the seriousness of the current environmental problems and their root causes.
Consequently, a sense of urgency to take some actions can be constructed, and it can potentially affect students’ decisions to perform environmentally. However, the result of t
-test revealed no significant difference in the level of direct impact PEBs reported by students participating in the environmental course and students not participating in the course. This could be because knowledge of environmental situations and relevant knowledge of political ecology such as environmental politics were generally available in other informal sources such as media, public demonstrations about the environment, and environmental activities carried out by universities. The study of Zhang et al. [73
] revealed positive relationships between news media use and people’s engagement in two types of PEBs including environmental activism and consumerism. Similarly, Yu at. al. [74
] indicated that people’s understanding of environmental problems and media exposure significantly and positively contributed to the engagement in PEBs. However, to drive a significantly positive change in students’ direct impact PEBs, other types of potential determinates should be further investigated, and environmental education should cooperate with those potential determinants.
Regarding indirect impact PEBs, the result revealed that knowledge of SD was moderately and significantly correlated with students’ engagement in indirect impact PEBs. Knowledge of political ecology and environmental situations were also significantly correlated with such PEBs, but the relationships between them were weak. However, it could suggest that the combination of these environmental contents could allow students to recognize ultimate goals and benefits of SD in term of sustainably solving current environmental problems. Educated with knowledge of political ecology and environmental situations, students could understand several causes of environmental problems generated from political and socio-economic systems along with their seriousness. Students could, therefore, understand and recognize the significance of their roles in promoting sustainability goals through the support of environmental actions at an organizational level and regional level.
In conclusion, this study confirms a significant role of environmental knowledge and formal environmental education in fostering students’ environmental attitudes and promoting indirect impact PEBs. However, students’ engagement in direct impact PEBs (e.g., waster separation, energy-saving behavior, and reuse and recycling behaviors) cannot be enhanced by only students’ participation in an environmental course. As found in the study of Geiger et al. [75
], though people had a high level of both general and environmental knowledge such as knowledge of ecological systems, sustainability issues, effective actions and environmental situations, their engagement in PEBs was merely average. Several studies indicated the influence of other factors on PEBs engagement. Those are such as situational conditions [76
], current behavior patterns [77
], and also socioeconomic characteristics including gender [27
], age [28
], educational level [29
], and income [30
]. Students’ engagement in direct PEBs can be also influenced by internal factors (e.g., awareness, personal norms, motivation, and perceived efficacy) and external factors (e.g., social norms and availability of infrastructure) [62
However, it does not mean that environmental knowledge is not essential. This study demonstrated that students who possessed a high level of environmental situations and knowledge of political ecology relatively reported a higher engagement in direct PEBs, even though their relationships were not strong. Therefore, it could be suggested that both formal and informal environmental education should be provided in order to promote students’ engagement in direct impact PEBs. This study also confirms that different types of environmental knowledge have distinct influence on each kind of PEBs. This conclusion is also supported by the work of Barber et al. [31
], which also indicated that different types of environmental knowledge contributed to different types of environmental behavior. This study revealed that knowledge of environmental situations was the most significant in promoting direct impact PEBs, whereas knowledge of SD was most significant in supporting indirect impact PEBs. However, no single knowledge can totally influence students’ PEBs; therefore, a combination of diverse environmental knowledge is suggested. This study found that knowledge of political ecology, SD, and environmental situations positively correlated with indirect impact PEBs. Therefore, providing diverse environmental contents is suggested to develop an environmental course for promoting student’s attitudes and environmental behaviors.
Finally, there is a limitation in this research which should be addressed. Majority of participants in this study were in third and fourth year of bachelor’s degree, and all of them were studying in the field of sciences and technology. Therefore, the results might not be proper to generalize for all university students. For the recommendations for future research, it can be suggested that students’ participation in PEBs can be influenced by diverse factors which should be comprehensively and deliberatively investigated. In addition, it is also important to develop effective strategies for organizing environmental courses which can finally encourage students to engage in PEBs. Therefore, research on environmental education with respect to content structure and learning tools for university students are heavily essential.