Metaphors have been used by scientists, political leaders, environmental activists, and journalists (20, 21, 31) to communicate complex issues linked to climate change – and to trigger a response (32). Metaphors offer a way of setting the unfamiliar in familiar terms by carrying over knowledge from past experiences (20, 33). They are relevant to how we make sense of complex problems (27). Metaphors can influence people because they are more emotionally evocative than comparable literal communications (19, 34).

While a metaphorical representation facilitates understanding of certain characteristics of something, metaphors can be misleading if relied upon too heavily, in that by their very nature they create only partial insights (35). Because metaphors are not neutral ways of representing and perceiving reality, one needs to acknowledge the profound implications of commonly using a particular metaphor over another for it promotes particular readings of an event or issue (20, 36, 37). Thibodeau et al. (19) present three main ways metaphors can influence people and thus serve as effective tools of climate change communications: (1) by evoking emotions; (2) by providing a mental model for thinking (i.e. framing) the domain they describe (i.e. referring to the natural world as a complex system – say like globalisation); (3) by being accurate.

Commonly encountered environmental metaphors include ‘the house is burning’, ‘war on warming’, ‘tipping point’, and ‘greenhouse gases’, (see Table 1 for more examples). While these metaphors convey the intended meaning and enhance comprehension of climate change (33), their anxiety-inducing nature may have unintended consequences as they impact our ability to respond. For ‘alarmist’ metaphors may reduce our ability to engage collaboratively on sustainable solutions due to neurophysiological processes involved in associative learning linking thoughts with autonomic states (24). Metaphors that rely on an alarmist or ‘risk reduction’ framework (19) may be useful in the short term to capture people’s attention, but can become detrimental by maintaining people in a state of vigilance from which they will grow fatigued (38), as they did with prolonged covid-19 precautionary measures.

Researchers (18, 27) have observed a tendency to overuse risk reduction metaphors, instead of more relational (hopeful/optimistic or ‘co-benefit’) ones, providing a reductionist representation of climate change and/or a separation between humans and nature – as if unrelated. The overuse of such risk reduction metaphors feeds narratives which tend to reduce the complexity of climate change and the richness of the human-nature relationship to a single dichotomous impacted/not-impacted scenario, reinforcing the economic principles of cost–benefit analysis. “This representation undermines public understanding of and engagement with climate change by marginalising subordinate policy framings which do not align with the prevailing dichotomous framing” (27, p. 34).

Although fear-based messaging is used to promote pro-ecological behaviour from the general public (39), one may wonder about its medium and long term effectiveness – especially among young people who feel more directly impacted, leading to feelings of eco-anxiety, paralysis or depression (10). How can anyone feel calm or relaxed in his/her own home while constantly being reminded that ‘the house is burning’ outside (e.g. while listening to the news)?

According to Rucińska & Fondelli (40), humans can be influenced by metaphors not only due to their intellectual ability to understand the conceptual implications (20), but also because metaphors can be defined and operationalized in more dynamic (i.e. embodied, enactive, and ecological) ways (41). For metaphors can convey many subtle and complex emotions. Table 1 summarizes the commonly encountered climate metaphors and possible related eco-emotions in scientific literature. While not exhaustive, this list provides a brief overview which shows that “negative” climate metaphors and eco-motions are far more prominent than the “positive” ones.

Interesting new advancements have recently been made in the fields of emotions studies, environmental psychology, climate emotions and eco-emotions. Works by Albrecht (42) and Pihkala (22) Pihkala (30) both acknowledge the wide scope, complexity, depth, and diversity of climate emotions, as well as the need to embrace the coexistence of their darker side (undesirable, negative, painful) and brighter side (pleasant, positive, desirable) with regards to our current natural environment. Based on their proposed typologies, both researchers propose a higher ratio for unpleasant (“negative”) versus pleasant (“positive”) eco-emotions (about 3:2 for 22; and 2:1 for 42). This seems to make sense: when things are difficult, stressful or problematic, the human mind may search for answers to explain such lack of coherence or clarity, in order to calm the state of activation (triggered by such problem) and find peace of mind (43, 44). In sum, people dealing with climate anxiety (or eco-anxiety) can experience a wide range of affects and respond differently, from high distress and even clinical symptoms (45) to finding meaning in times of adversity (46), the latter observed in terms of “practical eco-anxiety” (i.e. engaging in adapted and healthy ways despite feeling anxious about climate change, 47).

Furthermore, the study of eco-emotions is relevant to experiences of psychological resistances in the context of climate change (15). By responding to the messages conveyed by emotions − which, etymologically speaking, refer to the adaptive function of “setting in motion” (42)−, humans can better guide and direct behavior to better meet their needs in order to move forward. This requires a deep understanding of eco-emotions enabling us to transcend the psychological barriers of inaction (48).

Comparing various approaches for understanding social behavior and adaptive responses to stress, we can also draw parallels with climate emotions. Alarmist (risk reduction) climate metaphors (e.g. ‘our house is burning’) correspond to the classic ‘fight or flight’ response to threats (49), while “co-benefit” metaphors (e.g. ‘our common home’) resonate with the Tend and Befriend theory (50). Since the quality of attachment informs the level of safety and satisfaction within human relationships, Hlay et al. (51)’s findings suggest that secure attachments are linked to prosocial reactions to stress, namely tending to and befriending others (50).

Amidst an ongoing debate regarding the relevance of using fear-based messages versus hope-based messages in order to motivate people to adopt a more sustainable lifestyle (39), some research points in favor of using more hope-based (and/or less fear-based) messages (52–56). In short, “constructive hope” can promote pro-environmental behavior (57), policy support and political engagement (58), especially when it is understood in terms of trusting that climate change can be mitigated by solution-oriented individual and collective action (59). After all, climate messages without negative emotional content (i.e. fear-based) tend to be better received by people in general (60).

Socio-cultural contexts can influence people’s ability to use as well as respond to metaphors, which both in turn impact their effectiveness (35). Furthermore, given that polyvagal theory can help shed light on various autonomic states within threatening versus safe relational contexts (23, 24, 61), we thus argue the following: this conceptual framework − which provides a neurological and physiological grounding − can support the use of positive metaphors in climate communications, particularly via climate metaphors.

In the case of relational (or “co-benefit”) environmental metaphors which may be seemingly less dire from an intellectual point of view, from the perspective of Polyvagal Theory (23, 24), such environmental metaphors may lead to greater collective involvement. Especially, if these metaphors are delivered within trusted communities and in ways that support co-regulation so as to engender feelings of safety that are maintained within individuals’ ventral vagal systems (24). Indeed, “Polyvagal Theory provides an innovative scientific perspective … of safety that incorporates an understanding of neuroanatomy and neurophysiology” (24, p. 1). Autonomic states can be regulated to promote a feeling of safety from within, which in turn leads to collaborative behaviour and social engagement (23, 24). Polyvagal Theory also validates collective involvement in promoting opportunities to experience co-regulation that contributes to feelings of safety as a reciprocal process (23, 24).

Polyvagal Theory stipulates that bidirectional pathways connect the brain’s motor cortex to the autonomic nervous system through the ventral vagal system, a “family of neural pathways” that wander (‘vagus’ is latin for ‘wanderer’) throughout the body (23). Whereas the dorsal vagal system regulates organs below the diaphragm, including the digestive system, and the sympathetic nervous system regulates blood circulation, heart rhythms and body temperature, providing energy to the system, the ventral vagal system oversees the entire autonomic nervous system, “holding the sympathetic and dorsal vagal systems in a warm embrace” (62, p.11). When the ventral vagal system is engaged as a person’s autonomic state, a feeling of safety is created.

From the perspective of Polyvagal Theory, “life is experienced from the inside out”, and these “experiences are carried in autonomic pathways” (62, p. 33). Perceptions of emotional and/or physical threats are experienced as sympathetic and dorsal vagal dysregulation, whereas feelings of safety and connection, of collaboration, creativity, and openness to possibilities are experienced in the ventral vagal autonomic state. It is important to note that in response to the same environmental context, individuals may experience differing autonomic states (24).

As Dana (62) points out, one can learn to regulate autonomic threat responses by bringing explicit awareness to previously implicit experiences. In doing so, one can interrupt the usual adaptive survival responses that typically prevent the autonomic nervous system from finding safety in connection, and thus effectively engage the “ventral vagal safety circuit” (62, p.36). Social connection is perceived as a result of ventral vagal involvement through co-regulation, but also as a “neuromodulator” that reciprocally supports the individual’s ability to maintain ventral vagal involvement, with its resulting positive effects of connection, mutual help, and cooperation (24). “Polyvagal Theory emphasizes that resilience reflects a physiological state, which is sufficiently resilient to recover from disruptions, support feelings of safety, and connect with others via an active social engagement system” (24, p. 11).

Porges (24) entertains the hope that spontaneous social engagement can emerge from communities which foster co-regulated feelings of safety, and states that “introduction of cues of safety would be a functional antidote to threat reactions by reducing the associative links between feelings of threat and thoughts and actions” (24, p.4). Furthermore, Polyvagal Theory links self-regulation and co-regulation of autonomic responses to affective experience, emotional expression, facial gestures, vocal communication, and social behavior (23). Thus, cues of safety need to be understood from the perspective of pro-social cues and social cognition.

Given the complexity and plurality of people’s emotional, behavioral and adaptive responses, according to Wright (61), Porges’ model seems useful since it provides a conceptual framework with promising heuristic potential for accounting for and/or categorizing diverse behavioral and emotional responses related to perceptions of climate change. Wright (61) suggests that in the context of climate change, people’s responses, thoughts, and feelings can be mapped following some nervous system responses. For example, social engagement responses may relate to any regulated state involving a sense of safety, curiosity, calmness, compassion and presence. However, under initial stress (or nervous activation), individuals enter into the fight or flight mode, where anger, rage or frustration are related to the fight mode, and the panic, fear, anxiety, worry, dread may echo the flight mode. Finally, feelings of hopelessness may relate to the freeze mode, and so forth (61).

Let us apply the Polyvagal Theory perspective to the two aforementioned types of opposing (i.e. alarmist/”risk reduction” versus relational/”co-benefit”) environmental metaphors. When a communicator uses a more relational metaphor such as “The earth is our home”, listeners may subjectively associate his message with the calm autonomic state which is regulated by the ventral vagal pathway, supporting homeostatic functions (i.e. health, growth, restoration) (24). This in turn activates the social engagement system which sends back signals of security (non verbal cues and facial expressions) among them and to the speaker that functionally regulate (via neuroception) autonomic states of calmness (24). Through this co-regulation, potential threat reactions can be neutralized in favor of establishing and nurturing trusting relationships (24). Furthermore, these feelings of safety not only allow sociality but can also foster problem solving and creativity, by enabling efficient access to the cortical regions (i.e. higher brain structures), optimizing health and performance (24), two important determinants of well-being (63, 64).

Another framework well-known in positive psychology may support this overall argument: the so-called “Broaden and Build theory” of positive emotions (65, 66). This theory, by adding an evolutionary dimension, may further support the psychophysiological grounding proposed by Porges (24). In brief, negative affect (emotions) narrow attentional scope, draw on existing skills and resources and arise in relation to threats which, from an evolutionary perspective, usually demand immediate attention and response (66). By contrast, positive affects (joy, pleasure, interest, etc.) broaden attentional scope, fostering the use of a wider repertoire of thoughts and actions (66). This allows for creative exploration and innovation leading to developing new skills and capabilities (such as self-regulation and emotional regulation). One may see a potential link with the ventral vagal system being the anatomical-functional instantiation of this evolved set of tendencies. Incidentally, this also echoes research on “play”, or how the creative and adaptive skills development that comes from the “playful approach” (not only for children) requires a secure, low threat “relaxed field” (67) and non-stressed frame of mind (68, p. 140).

By contrast to fostering such a secure (and thus engaging) social response via positive emotions, if someone decides to use a popular alarmist climate metaphor (i.e. “our house is burning”) with the same audience, people may feel somehow threatened, thus stressed and/or anxious, due to a subjective interpretation activating shared autonomous states of defense which disrupt homeostatic functions (24). In sum, from a psychophysiological point of view, aforementioned, we argue that the use of frequent relational (or inclusive “co-benefit”) environmental metaphors would lead to greater collective involvement if delivered within trusted communities and in ways that support co-regulation (i.e. fostering feelings of safety that are maintained within individuals’ ventral vagal systems, 24). Thus, not only the wording, but the context and manner of delivery will be important to incite greater collective engagement (24). Table 2 summarizes this by contrasting two different environmental (or climate) metaphors using similar semantic terms, house/home. Let us underline that for most people, the notions of ‘home’ or ‘house’ refer to that of a refuge (i.e. a nocturnal symbol, 70): a place where one feels safe, can rest and enjoy life in a peaceful way, as opposed to daytime struggles linked to work, performance, achievement and so on (70).