Currently, climate change (CC) and its linkage to global change, is one of the most important challenges that our world is facing. Such is the seriousness of the problem that in a recent study conducted in 50 countries and involving more than half of the world’s population, 64% of the participants considered that CC remains a global emergency despite the COVID-19 health crisis [
1]. There is widespread consensus among the scientific community that there is a causal relationship between human activities and CC [
2], with a convincing body of evidence that CC is the result of a combination of an increase in greenhouse emissions and land-use changes [
3]. The negative effects of global warming on natural and human systems make it necessary to mobilize society in general, and every individual in particular, to create a coherent and coordinated response to solve the problem. Societies are faced with the urgency of transforming the energy model and their citizens’ way of life. To this end, there is a pressing need to educate people in an effective manner, so that they can act and make decisions, both in the present and in the future, in an educated and informed way. In such a challenge, the major role of preparing skillful, competent, and motivated teachers with all the fundamental pedagogical and content knowledge is undeniable.
The remainder of the introduction section develops as follows: first, the concept of climate change education (CCE) is described, followed by a review of studies focusing on educational gardens and their benefits; second, the matter of gardens and connectedness to nature is approached; subsequently, the importance of teacher training in CCE is analyzed; finally, the more specific aims and research questions of the study are presented.
1.1. Gardens and Climate Change Education
Climate change education is addressed in the context of education for sustainable development [
4]. Specifically, it is aligned with Goal 13 (Climate Action) of the 2030 Agenda and the Sustainable Development Goals [
5], Target 3 “Improve education, awareness-raising and human and institutional capacity on climate change mitigation, adaptation, impact reduction and early warning”. CCE must provide students with a set of transversal skills and abilities that enrich their cognitive and affective domains [
4]. Moreover, it must be an interdisciplinary task that encompasses scientific, socio-economic aspects, and possible solutions [
6], and it must educate for climate and for change [
7]. CCE aims to develop individuals’ capacities for climate literacy, which can be defined as the ability to understand, comprehend, and analyze climate concepts in depth, understanding people’s influence on climate and climate’s influence on them and society, so as to develop attitudes of respect towards the environment and people [
8]. From this perspective, schools should encourage participation, information management, and free and conscious decision making [
9]. These skills are part of what is known as critical thinking, another of the key competences for the 21st century [
10], which again links to the 2030 Agenda (Goal 4, Quality Education). Specifically, CCE and the development of critical thinking are related to Targets 4.6 and 4.7 since the development of scientific literacy and critical thinking skills must be considered to achieve a literate population. These, in turn, include the theoretical knowledge, skills, and attitudes necessary to promote sustainable development.
The construct of CC competence was recently introduced with the purpose of creating a framework to develop understanding, awareness, and abilities related to CC through education [
11]. It is composed of three dimensions: knowledge, skills, and attitudes. Knowledge is founded on evidence-based science and current scientific consensus, and should serve to understand what CC is, its causes, and its consequences [
11]. The skills dimension connects the capacities that a student should acquire to learn what can be done to face CC. Nevertheless, it should be noted that a person being aware of a problem and knowing what can be done to avoid it does not necessarily imply that this person will take action and apply such knowledge (i.e., people may know what recycling is (knowledge) and may know how to recycle (skill), but that does not necessarily mean that they will do it). Therefore, competence is incomplete without the attitudinal dimension, whose objective is to raise awareness and mobilize society to address this important challenge, and to enable citizens to freely exercise their knowledge and skills. In this context, educational gardens have proved a suitable strategy in the frame of the current European educational model based on teaching and learning by competences, because they are capable of mobilizing the cognitive, procedural, attitudinal, and relational dimensions of learning [
12].
The COVID-19 crisis has brought to light the need for green cities and schools. The results of the project carried out in France, Germany, Poland, the UK, and the USA [
13] show that during the COVID-19 pandemic, urban gardens and farms adapted to become more resilient and address the challenges and opportunities that arose. Lessons should be learned for long-term planning to enable urban and school agriculture to respond to future public health, economic or other crises, as was the case in the past. All over the world, community gardens are being developed as living green welfare infrastructures in response to CC and global change, the loss of biodiversity, and the loss of the sense of community resulting from rapid industrialization and urbanization [
14,
15,
16]. According to Zinia and McShane [
14], green adaptations make communities more resilient to pressure from demographic change and CC, which makes them increasingly relevant in industrialized countries.
Educational gardens can be defined as any context in which to implement garden-based learning approaches, which, in turn, can be defined as instructional strategies that use gardens as a context for integrated learning through active and real-world experiences [
17]. Thus, educational gardens encompass several types of green spaces, mostly in outdoor settings, such as community gardens, allotment gardens, school gardens, university gardens or any other type of space where vegetables or fruit can be grown. In recent years, these spaces are experiencing a resurgence and an increase in popularity; one of the possible reasons for this being the current environmental crisis that is driving them to go “from leisure to necessity” [
18]. Although community and allotment gardens are not formal educational spaces, they can provide opportunities for environmental education and for Education for Sustainable Development (ESD) that lead to a more sustainable society since they are spaces where people could both explore and learn, and share and experience natural processes, for example, how vegetables grow [
19]. The literature includes studies that show their educational value, sometimes as service-learning projects/community service projects in higher education [
20] or as intergenerational learning opportunities [
21]. In addition to promoting the development of the aforementioned SDGs related to CCE, gardens also contribute to the achievement of many other goals. They can undoubtedly be seen as a connecting link for Goal 2 (Zero hunger, target 2.4 ensure sustainable food production systems and implement resilient agricultural practices), Goal 3 (Good health and Well-being, target 3.4 promote mental health and well-being), 11 (Sustainable cities and communities, target 11.7 green and public spaces, in particular for women and children, older persons and persons with disabilities), Goal 12 (Responsible consumption and production, target 12.2 achieve the sustainable management and efficient use of natural resources) and Goal 15 (Live on land, target 15.9 integrate ecosystem and biodiversity values into national and local planning, development processes, poverty reduction strategies and accounts).
For several decades now, school gardens have become established as interdisciplinary tools to engage students in experiential, real-world, problem-based, and outdoor learning for health, science, environmental education, and many other disciplines. Studies have shown that gardens promote healthy nutritional habits by encouraging children to eat more vegetables [
22,
23,
24,
25], provide the health benefits of outdoor environments, such as well-being, and physical and mental health [
26], and engage students in food production and consumption models [
27]. Regarding emotional associations, their benefits to mental health are related to the fact that they are places where emotion can flow (they involve teamwork, physical work, controlling frustration, wondering about life processes, etc.). Gardens are also useful tools for the teaching of science across educational stages since they are used as natural laboratories that arouse students’ interest and motivation towards learning [
12,
28] and promote inquiry-based methods [
29]. In fact, previous research has shown an overall positive impact on direct academic outcomes with the highest positive impact on science followed by math and language arts [
30]. Ruiz-Gallardo et al. [
31] also demonstrated that garden-based learning programs could influence personal behavior and lead to a substantial decrease in dropout rates. In addition, their results showed that this approach creates a better classroom atmosphere, with a significant reduction in disruptive behavior throughout the experience. School gardens must also be a mirror of traditional allotment gardens, where nature and culture are inextricably linked, thereby everybody benefits from including diverse backgrounds and perspectives in field experiences that include human-influenced ecosystems as well as more conventional natural habitats [
32].
Educational gardens also seem ideal settings to integrate the global perspective of environmental education and CCE into local action. In this regard, according to Stevenson et al. [
6], CCE “cannot be confined to traditional structures and formal curriculum spaces of education but needs to draw on new informal and hybrid (e.g., school/community) spaces offering alternative possibilities for learning and action. Such spaces that provide opportunities for students to engage in inquiry/project-based and action-oriented learning include community and school gardens that allow for learning about alternative paths of food production and security, as well as creating community” (p. 70). As examples, during instruction, teachers should work on and reinforce the ideas that growing plants favors carbon sink enlargement, that a healthy soil also contributes to carbon sequestration, or that compost activities and eating local food products are a way to reduce “food miles” and carbon footprints.
Nevertheless, while there are several examples in the literature dealing with environmental education and gardens, just a few focus specifically on CC. Trott [
33] documented a collaborative, multisite participatory action research project in collaboration with 10-to 12-year-old children to act on CC in Northern Colorado (USA). Her findings showed that children who participated in the garden program perceive themselves as competent and effective change agents in their families and communities because of their engagement with CC. Thus, it can be concluded that gardens favor positive environmental attitudes and climate action. A study conducted in Spain with PSTs, found that a garden-based learning program had a positive impact on students’ cognitive domain regarding certain CC-related topics [
34]. Finally, in a study conducted in Germany, Sellmann and Bogner [
35] demonstrated that a one-day intervention involving CC in a botanical garden was an effective learning experience that led to short- and long-term cognitive achievements in the area of CC. Hence, they concluded that botanical gardens provide a unique opportunity to educate about the complexity of climate change and its consequences for ecosystems and plants in concrete terms.
1.2. Gardens and Connectedness to Nature
The increase in indoor activities, the use of video games, and online relationships, which are more pronounced among young people and children, are causing a worrying lack of connectedness to nature [
36,
37]. This detachment is a matter of concern, given the evidence of health and well-being benefits that human interaction with nature provides and its contribution to addressing sustainability challenges, particularly the need to embed them within ecological limits and become aware of them, and, most importantly, changes in behaviors. Some researchers have shown that connectedness to nature is associated with satisfactory early experiences, especially those linked to adventure and pleasure, such as leisure time in the wild nature [
37,
38] or fieldwork [
32]. It is therefore necessary to offer opportunities to enjoy nature or naturalized spaces such as school gardens, even though domesticated nature experiences have a weaker effect on connectedness to nature [
38]. Furthermore, promoting connectedness to nature should be made one of the goals of environmental education programs [
38,
39]. However, as Ives et al. [
40] point out, a connection to nature must be drawn together through a transdisciplinary methodological approach and go beyond individual, local, Western scales to help guide the transformation of societies towards sustainability. Connectedness to nature is a material, experiential, cognitive, emotional, and philosophical association, and this demonstrates the importance of using multidimensional strategies to promote conservation behaviors, as we think educational gardens are [
41].
Although there are quantitative studies that have questioned whether environmental behaviors consistently improved with gardening [
24], it is widely assumed that experiences in outdoor settings can be significant in developing environmental sensitivity, knowledge, affective connection to nature, pro-environmental attitudes, and protective actions, and can thus contribute to the current sustainability education agenda [
42,
43]. Moreover, many studies have shown that using gardening made the achievement of environmental awareness relatively high, both in formal [
34,
44] and non-formal educational contexts [
45]. Direct contact with nature cultivates bonds with it [
46,
47], which means, as stated by [
48], that by offering experiences in nature, environmental education interventions in outdoor learning settings may not only affect knowledge and environmental attitudes but could also influence an individual’s degree of connectedness to nature. Schultz [
49] first defined connectedness to nature as “the extent to which an individual includes nature within his/her cognitive representation of self” (p. 67). This construct was formulated on the basis that, according to the extent to which the construction of the self includes nature, it could determine both the type of environmental awareness and behaviors of a person. In fact, previous research has demonstrated the relationship between nature connectedness and pro-environmental behaviors [
47], and the positive results derived from the latter, such as happiness and well-being [
49]. In addition to these findings, Pérez-López et al. [
34] also demonstrated that educational gardens could promote sustainability by increasing participants’ connection to nature. Sellmann and Bogner [
48] pointed out that connectedness to nature only increased directly after a one-day intervention in a botanical garden, but not in a long-term perspective. In line with this argument, [
50] suggested that contact with nature can act as a way to communicate the urgency of CC to young people. Wang et al. [
51] suggested that individuals with a higher degree of connectedness to nature are more concerned about the natural environment, more aware of the dangers of CC, and believe more strongly that CC is a reality. In other words, since CC acceptance has been found to be deeply determined by an individual’s environmental values, to effectively face CC and increase awareness of it requires a reconnection between people and nature. As stated by Galway et al. [
52], connectedness to nature has a direct positive association with individual-level climate action.
Therefore, this theoretical framework can lead to the assumption that a relationship, similar to a chain reaction, could exist between the use of educational gardens and a connection to nature, allowing the possibility to improve CCE and promote climate action.