In the present paper, we use the term ‘psychological experiences’ to refer to an individual’s interpretation of life events and the temporal narrative relating to the events over one’s life course via cognitive and emotional processes. 
Major theories relating to the wellbeing of individuals (Table \ref{348217}) can be categorised according to two contrasting philosophical positions: hedonic and eudaimonic wellbeing. According to the hedonic standpoint, wellbeing is achieved by focusing on pleasurable experiences in order to enhance positive affect. A major theory is the 'tripartite model of subjective wellbeing', proposed by \cite{Diener_1984}, highlighting a role for life satisfaction, decreases in negative affect and increases in positive affect. Another key model is the 'broaden and build' theory by Barbara Fredrickson \cite{Fredrickson_2001}, which emphasises a role for positive emotions such as joy, interest, contentment, pride and love in broadening individual thought-action tendencies that subsequently build personal resources for individual growth, social connection and psychological resilience. Research has shown that positive emotions increase the perception of social connectedness, enhance vagal function, and facilitate the adoption of positive health behaviours, among other factors \citep{Kok2010,Sin2015,Kok2013}. Recent longitudinal research \cite{Petrie_2018} observed that participants in a low positive affect grouping have a twofold increased risk for mortality, compared to those in the more favourable grouping over a 16.5 year follow-up period. Positive affect has been shown to affect health via inflammation, such that greater trait positive affect is associated with reduced proinflammatory cytokines \citep{Stellar2015}. Interested readers are also referred to major reviews on this topic \cite{Chida_2008,DuBois_2012,Boehm_2012}. Our own work emphasises the role of vagal function over these allostatic systems \cite{Kemp_2017,Kemp2017,ah2018,Kemp_2013,Kemp_2016a}.
In contrast to a focus on hedonia, eudaimonic theories of wellbeing look beyond momentary happiness, focusing on purpose, meaning in life, and flourishing. According to this perspective, Carol Ryff’s Psychological Wellbeing theory \citep{Ryff_1995,Ryff_2014,Ryff_1989} emphasises six elements that contribute to psychological wellbeing including self-acceptance, personal growth, purpose in life, positive relations with others, environmental mastery, and autonomy. As with hedonic wellbeing, psychological wellbeing has also been associated with improved health, including subjective health, chronic conditions, symptoms and functional impairment \cite{Ryff_2014}. Purpose in life reduces risk of developing Alzheimer's disease and mild cognitive impairment \citep{Boyle2010} along with reducing risk of death \citep{Boyle2009}. Postmortem results have even revealed that - among those with high levels of brain pathology - those with greater purpose in life presented with better cognitive functioning whilst they were still alive, highlighting a moderating role of purpose in life on the relationship between brain-based pathology and cognitive functioning \citep{Boyle2012}. A more recent study reported that a stronger sense of purpose is associated with decreased mortality \cite{Alimujiang_2019}, an effect associated with a hazard ratio of 2.43 (95% CI, 1.57-3.75) when comparing those in the lowest life purpose category with those in the highest life purpose category.
However, these theoretical models - especially those focusing on hedonia - have faced criticism. As alluded to above, the focus on 'happiology' has been criticised as lacking in nuance. Positive affect alone is not sufficient for improving wellbeing and over-valuing the need to be happy can actually lead one to feel less happy \cite{Mauss_2011}, and may even be associated with the symptoms and diagnosis of unipolar depression \cite{Ford_2014} and bipolar depression \cite{Ford_2015}. Other writers have criticised the individualistic focus, which ignores the impact of community and wider environmental factors \cite{davies2015,Frawley_2015,Carlisle_2009}. Eudaimonic theories have also attracted criticism for not recognising the importance of positive emotions, leading to proposals such as Seligman's PERMA model \cite{seligman2011,Seligman_2018}, which incorporate aspects of both hedonic and eudaimonic theory. The PERMA model argues for a five-pronged model of wellbeing including positive emotions,  engagement, positive relationships, meaning, and accomplishment (i.e. PERMA). According to this model, all five pillars of wellbeing contribute to flourishing in life. While this field is not short of theories, recent research has shown a large overlap between them. Research by Todd Kashdan and colleagues \citep{Disabato_2016} reported a high latent correlation of .96 between Diener's subjective wellbeing model of hedonia \cite{Diener_1984} and Ryff's psychological wellbeing model of eudaimonia \cite{Ryff_1989} indicating that the discriminant validity of these constructs is negligible. Critically, analyses across 7 geographical world regions revealed similar results. The authors however, noted three exceptions to this trend, which were 'hope', 'meaning orientation' and 'grit', which differentially related to hedonia and eudaimonia, giving some support to the discriminant validity of the two constructs. In another study by the same authors \cite{Goodman_2017}, PERMA was observed to measure the same type of wellbeing as Diener's model of subjective wellbeing with confirmatory factor analysis yielding a latent correlation as high as .98. The authors subsequently criticised PERMA for not offering any further insights into wellbeing beyond the former theory of SWB. In response to this, Seligman has argued that PERMA is not "redundant" simply because different models correlate; rather PERMA presents a model that constitutes the critical elements of wellbeing \cite{Seligman_2018}.
Building on strong theoretical foundations and an extensive body of research, our previously published models \cite{Kemp_2017a,Kemp_2017} argue that healthy vagal nerve function underpin and are impacted on by positive psychological moments, facilitating longer-term improvements in health and wellbeing. These insights are based on a strong body of evidence. For instance, Todd Kashdan and Jonathan Rotenberg \citep*{Kashdan_2010} argued that vagal function is an index of psychological flexibility (PF) that is fundamental for psychological health. Psychological flexibility is an important component of resilience, facilitating ones capacity to assess and adapt to demands, alter mindset and behaviour when necessary, and for commitment to behaviours that are congruent with deeply held values \citep*{Kashdan2010}. Conversely, psychological inflexibility has been associated with worsened mental health and an exacerbated stress \citep{Masuda_2011,Kato2016,Chawla2007,White2013,Smeekens2007}. An inflexible response style - characterised by withdrawal of the vagal brake - plays a key role in the development of and symptomatology of depression \citep*{Nolen_Hoeksema_2008}, along with explanatory inflexibility (applying the same attribution style cross different situations) and inflexible coping behaviours \citep{Fresco_2006,Moore2007}. According to \citet*{Kashdan_2010}, vagal function underpins the capacity for psychological flexibility. Intriguingly, Bethany Kok and Barbara Fredrickson \citep{Kok_2010,Kok_2013} demonstrated that change in vagal function - following training in loving kindness meditation - is associated with increases in positive emotions and enhanced perception of social connectedness, suggesting that positive emotions facilitate physical health via the vagus nerve. The link between individual and community is a topic that we turn to following our discussion of positive health behaviours.

3.1.2: Health behaviours 

Whilst health behaviours are typically thought of with respect to their impact on physical health , there is now compelling evidence that health behaviours impact on both physical and mental health. Accordingly, and in contrast to many other models of wellbeing \cite{Ryff_1989,Diener_1984,seligman2011a}, we have proposed a key role for health behaviours in facilitating individual pathways to health, wellbeing and longevity \citep*{Kemp_2017}. Moreover, we proposed a critical mediating role of the vagus nerve in explaining why both physical and mental health are improved as a function of positive health behaviours. We propose the vagal nerve is the structural link between physical and mental health and plays a critical role in mediating the relationship between positive health behaviours, and physical and mental health. In this section, we present some key studies highlighting the importance of health behaviours in physical and mental health outcomes. An exhaustive review is beyond the scope of this paper however, and interested readers are referred to \citet*{Kemp_2017}. Given the number of health behaviours, for brevity, we focus specifically on physical activity, diet and sleep.  
Impact of health behaviours on physical health: A summary of public health guidelines relating to physical activity, diet and sleep is provided in Table XXX.
XXX JESS TO INCLUDE TABLE HERE SUMMARISING GUIDELINES FOR IDEAL NUMBER OF MINS PER WEEK OF PHYSICAL ACTIVITY, NUMBERS OF FRESH FRUIT AND VEG, AND NUMBER OF HOURS SLEEP... OR OTHER ASSOCIATED RECOMMENDATIONS XXX
Research on over 20,000 participants analysed the impact of four key positive health behaviours on mortality risk - non-smoking, physical activity, consumption of less than 14 units of alcohol per week and a diet rich in fruit and vegetables. Participants who adopted all four health behaviours at baseline had a mortality risk that was equivalent to being 14-years younger at follow-up (average of 11-years later), compared to those who adopted none of the positive health behaviours (Khaw et al., 2008). A more recent study focused on six health behaviours: non-smoking, physical activity, healthy diet, sleeping 7 to 8 hours a night, inactivity less than 8 hours a day, and daily social contact (Martínez-Gómez et al., 2013). Results again highlighted a mortality risk that was equivalent to being 14-years younger for those who adopted these behaviours relative to those who adopted none of them. Wen et al. (2011) conducted a prospective cohort study with over 400,000 individuals between 1996-2008. Surprisingly, even those individuals in a low physical activity group (average of 15 mins a day or 92 mins per week) had a 14% reduced risk of all-cause mortality. Moreover, every additional 15 minutes of daily exercise beyond this minimum amount, reduced all-cause mortality by further 4%. The authors argued that less exercise is easier to achieve for those who do not engage in any physical activity at all, and yet it may still be sufficient to achieve health benefits. Moreover, Lee, Pate, Lavie, Sui, Church, and Blair (2014) concluded that running 5-10 minutes a day at slow speeds (less than 6mph) is even associated with reduced all-cause risk of mortality, providing further evidence that exercising below current minimum guidelines is sufficient for mortality benefit. Once a routine is established individuals may then be able to be motivated to exercise at higher levels. 
The relationship between diet and physical health has been widely reported in the literature. For example, the vegetarian diet has been associated with a reduced risk for disease development, including coronary heart disease and type 2 diabetes, compared with a diet containing red and processed meat (McEvoy, Temple, and Woodside, 2012), while insufficient fibre has been associated with colon cancer, high blood cholesterol, diabetes, coronary heart disease and obesity (Jefferson and Cowbrough, 2005). Diet is also associated with all-cause mortality, with one study reporting findings based on a sample of 2000 individuals, finding that those adhering to a Mediterranean diet had an all-cause mortality risk that was 34% lower than those who did not adhere to the diet (Limongi et al., 2017).  
Watson et al. (2015) concluded that 7 hours or more sleep per night produces optimal health in adults. Sleeping less than 7 hours a night is associated with obesity diabetes, hypertension, heart disease, stroke, depression and increased mortality. Moreover, a recent prospective twin study (Åkerstedt 2017) found that both short (defined as <6.5 hours) and long (defined as ≥9.5 hours) sleep were linked to increased mortality. However, it is important to note that these statistics are generalisations, with small groups of people fully able to function healthily on shorter periods of sleep (Pellegrino et al., 2014; He et al., 2009).  
 
Impact of health behaviours on physical and mental health: Focusing on health behaviours - including exercise, diet and sleep - typically involves consideration of one’s physical health, however there is now convincing evidence that demonstrates the impact of positive health behaviours on mental wellbeing, supporting declarations that there is 'no health without mental health' \cite{Prince_2007}. In a study on over 4,500 adolescents, health behaviours were measured across several domains; diet, specifically consumption of carbonated soft drinks and fast food, tobacco use and physical activity. Participants were then allocated a number ranging from zero to "four or more" depending on the number of unhealthy behaviours they engaged in (Rao et al., 2015). Results highlighted that participants with a score of four or more were significantly more likely to be anxious, experience suicidal ideation and have been involved in a physical fight, compared to those who scored zero. Analysis of over 2,400 Chinese college students found those who frequently consumed alcohol, had disturbed sleep, poor dietary behaviour and internet addiction disorder. This was associated with significant increased risk of depression and anxiety (Ye et al., 2016).  
With respects to phsyical activity, research on a sample of 49 unique prospective studies (N=266,939), showed that physical activity protected against depression, irrespective of age and geographic region \cite{Schuch2018}. In a cross-sectional study of more than 1 million individuals in the U.S. \cite{Chekroud2018}, exercisers displayed 43% fewer days of poor mental health than non-exercisers. The authors further reported that all exercise types were associated with a lower mental health burden (from 11.8% to 22.3% reduction), and the activities associated with the largest associations included popular team sports (22.3% lower), cycling (21.6%  lower), and aerobic and gym activities (20.1% lower). Exercise duration of 45 minutes and frequencies of  three to five times per week were associated with the lowest mental health burden. 
With respects to diet, the Mediterranean diet has received a large focus in regards to its link with health conditions, for example, combined data from four longitudinal studies found a risk estimate of highest vs. lowest adherence to the Mediterranean diet of 0.67 (95% CI 0.55-.82) for incident depression \cite{Lassale_2018}. The Mediterranean diet has proven useful in slowing age-related deterioration, including improvements in cognitive function and reducing risk of cognitive impairment and dementia (Petersson 2016, Aridi 2017), with B-vitamins and antioxidants playing a key role (Moore et al., 2018; Castelli et al., 2018). The Mediterranean diet has also proven effective in reducing depression symptomology (according to an RCT) (Parletta et al., 2019). Based on the evidence, dietary recommendations for the prevention of depression have been proposed; adopting "traditional" diets, such as the Mediterranean diet, increasing consumption of fruits, vegetables, legumes, wholegrain cereals, nuts, seeds, foods rich in omega-3 polyunsaturated fatty acids and limit consumption of processed foods (Opie et al., 2017). We note here that socio-structural factors (e.g. inequality and poverty) will impact on individuals capacity to follow such advice.
 
With regards to sleep, a systematic review and meta-analysis of 14 studies found sleep disturbances significantly predicted the risk of suicidal ideation; an effect not moderated by depression \cite{Liu_2019}. Poor sleep is also associated with common mental disorders, while improving sleep in these patients can lead to mental health improvements (Freeman et al., 2017). Analyses on nearly 100,000 adolescents in Japan found a U-shaped association between mental health status and sleep duration (Kaneita et al., 2007). The authors also reported a positive correlation between mental health status and subjective sleep assessment. Similarly, among an elderly population, sleep problems were associated with worsened mental and physical health-related quality of life (Reid et al., 2006).
Critically, each of these health behaviours - physical activity, diet and sleep - have a powerful impact on vagal function \cite{Kemp2017}. Thus, focus on positive health behaviours is a powerful means to promote health and wellbeing. As with physical activity \cite{SANDERCOCK_2005,Raffin_2019} and diet \cite{Young_2018}, changes in sleep are associated with changes in vagal function, such that reduced vagal function (combined baseline and reactivity measures) is associated with sleep disruption (El-Sheikh, Erath, and Bagley, 2013). Intriguingly, increases in resting state vagal function have been shown to predict better subjective and objective sleep quality (Werner et al., 2015; Grimaldi et al., 2016). By contrast, reduced HRV (as measured over a 24-hour period) has also been detected early during early stages of sleep-related breathing disorders (Aeschbacher et al., 2016)
 
In summary, we highlight a role for positive psychological experience and positive health behaviours in health and wellbeing, abd by emphasising the beneficial effects of both on vagal function, we seek to highlight the importance of integrating interventions that combine principles from positive psychology and a focus physical activity, diet and sleep  when considering how wellbeing in populations might be improved. We now turn our attention to the impact of social relationships and community on health and wellbeing. Before doing so however, it is instructive to point out the importance of building individual wellbeing for achieving community and environmental wellbeing. While it may be argued that such a relationship is obvious and intuitive, one could counter such arguments by highlighting that inituition is not evidence-based, and that there are many examples that could be provided in which research has led to counter-intuitive findings. Take for example, findings that  XXX GOOD EXAMPLE ANYONE? JT?? XXX Furthermore, scholars now emphasise that community resilience is underpinned by the individuals within it, highlighting the role of a positive outlook and individual strengths, which underpin a community's capacity for resilience and agency \cite{Berkes_2013}. A greater appreciation of the interconnectedness between individuals, and the communities and environment in which they reside is important for considerations relating to how we might improve the wellbeing of current and future generations.

Focus on Community

In this section we focus on the relevance of community to individual wellbeing, a major focus of our original GENIAL model \cite{Kemp_2017}. The Japanese have a word to describe "lonely death"  -  ‘kodokushi’ - which refers to people dying without friends or family, and sometimes these individuals are not found for many weeks... or months. ("Dead people don't pay their bills"). Tragically, these experiences characterise the modern world,  and especially individualistic cultures. Social ties are deteriorating and loneliness is on the rise \cite{Kushlev_2017,Twenge_2013,twenge2014,putnam2001}, the reasons for which are complicated, but may involve a host of interconnected societal issues including generational shifts in narcissism \cite{Twenge_2013,twenge2014}, increasing individualism (versus collectivism) in western society \cite{Heu_2018,Brewer_2007}, and inequalities \cite{Scheffer_2017,scheidel2017,r2010,Nolan_2019}. Critically, loneliness has important impacts on health and wellbeing. For instance, a meta-analysis of studies on more than 300,000 participants reported that a lack of social ties are associated with a 50% increased risk of premature mortality over a 7.5 year follow-up period, an effect that was stronger than physical activity, smoking (15 cigarettes daily) and body mass index \cite{Holt_Lunstad_2010}. In a more recent study on 48,673 participants, the same researchers \citep*{Holt-Lunstad2015} observed that social isolation (29%), loneliness (26%), and living alone (32%) increase risk for premature mortality, reporting no differences for objective and subjective measures. Furthermore, greater impacts on mortality were observed among those under the age of 65 years.  
Social isolation and loneliness may lead to ill-being via a host of behavioural, psychological and physiological factors. Associated behavioural factors include physical inactivity and smoking \cite{Shankar_2011}, substance use and hazardous drinking \citep*{Stickley2014}, while psychological factors include decreases in self-esteem, increased risk of depression, and feelings of hopelessness \citep*{Steptoe_2004}, contributing to a dysregulation of cardiovascular, metabolic, and neuroendocrine processes \citep*{Grant2009}, higher systolic blood pressure, independent of several factors such as age, gender, cardiovascular risk factors, medications, social support and perceived stress \citep*{Hawkley_2010}The NIACT \cite{Kemp_2017a} and GENIAL \cite{Kemp_2017} models integrate these behavioural, psychological and physiological factors into innovative frameworks within which pathways to health and ill-health may be understood, bridging the gap between psychological moments and mortality. 
Further to our original GENIAL model \citep{Kemp_2017}, the relationship between social ties and health was recently comprehensively reviewed in a book titled 'The New Psychology of Health: Unlocking the Social Cure' \citep{2018}. Social identity theory helped to contextualise the research that was discussed, emphasising that people conform to the norms of the group to which they identify. Therefore, the actions and thoughts of the group become the reference point for the individual. If an individual's perception of others in a representative group is positive, individuals of that group will think and behave similarly. Peer modelling has proven to be an effective intervention to increase fruit and vegetable intake \cite{Horne_2008}, although only when modelled by someone that shares the same group identity \cite{Cruwys_2012}. By contrast, if an individual was to identify with a group whose health behaviours are risky, they are more likely to participate in negative health behaviours. Research has shown there is a relationship between strength of group identification and smoking status when smoking is a normal group behaviour \citep{Schofffild_2001}. Intriguingly however,  the more group identities an individual has, the less likely they are to engage in negative health behaviours, such as cigarette smoking, alcohol consumption, and use of illicit drugs \citep{Miller_2016}.            
Social identity theory provides a useful context within which to understand the influence of community on the health and wellbeing of the individual. For example, social identity provides meaning, purpose and worth to an individuals life \cite{de_Vroome_2013,Nakamura_2013,Peterson_2005}, the importance of which was highlighted above in our discussion of positive psychological experiences. Social identities also facilitate the extent to which others are likely to provide social support \cite{Cohen_2004,Levine_2002,Levine_2005,Platow_2006}, and provide a sense of efficacy, agency and power to an individual (the agency hypothesis), contributing to the sense that 'the whole is greater than the sum of its parts' \cite{Haslam_2018}. Strikingly, research has demonstrated that cardiac and respiratory patterns synchronise when members of a choir sing in unison, compared to when singing independently \citep*{Timmons2015}. This phenomenon of 'physiological linkage' may help to explain relationship connectedness \citep{Timmons2015} and the vagus nerve underpins ones capacity for such connectedness, regulating downstream allostatic systems that are no doubt also involved such as the hypothalamic-pituitary-adrenal axis\cite{Porges:2011wv,Kemp_2017,Kemp_2017a}
To conclude, community is important for individual health and wellbeing as it provides the environment in which individual health and wellbeing may be achieved. A supportive community will therefore contribute to the health and wellbeing of individuals within that community, and this relationship will be a bidirectional one such that improved health and wellbeing of individuals will also foster community wellbeing. Community resilience is a social-ecological system, nested within different levels of a complex system - the 'symbioment' (see fig \ref{881013}) - which is (perhaps over-) simplified in the present paper to levels that include the individual, community and the environment. In this regard, it is interesting to observe that research not only highlights the importance of eating less meat for individual health and wellbeing [REF RE MEAT - CANCER ASSOCIATION], it also highlights the impacts of eating less meat to reduce adverse impacts on the environment \cite{Poore_2018}, reinforcing this concept of the 'symbioment' (Fig \ref{881013}) which emphasises symbiotic coexistence of all life at various scales. It is perhaps prudent to note however, that although this article led to much fanfare in the media on the need to 'go vegan' \cite{earth}, other research \cite{Peters_2016} reports on findings from modelling that shows that the diets with low to modest amounts of meat (the 'omnivore diet') actually outperformed a vegan diet in regards to the "carrying capacity" of an agricultural land base. The authors noted that the carrying capacity of the vegan diet fell between the 60% and 40% omnivore diet options, which reflect the percentage of vegetarian food consumed. These findings highlight - as always - that one should be always mindful of evidence-based nuance. Finally, and in closing this section, we further note the importance of context in regards to the relationship between individuals and community. For instance, among Western cultures, positive feelings are associated with individual success, high self-esteem, and good health \citep{Heine_1999,Kitayama_2000,Taylor_1988}. In Japan however, for example, individuals are more likely to associate happiness with negative social consequences, such as jealousy and disharmony among relationships \citep*{Uchida_2004}. We now turn our attention to the wider environment in which individuals live and work, focusing on a major societal challenge to human health and wellbeing: the climate crisis.

Focus on the Environment

Psychological science has been criticised for a blinkered focus on the individual while ignoring wider, systemic issues issues \cite{Carlisle_2009,Frawley_2015}. Critics have argued that the construct of wellbeing is a socio-cultural construction of western individualism that places importance on wealth, fame and materialistic pursuits, while neglecting neglecting our shared environment \cite{Carlisle_2009}. These criticisms in combination with an ever-increasing body of peer-reviewed literature on ‘happiness’ and ‘wellbeing’ were, in part, reason for proposing our original GENIAL framework \cite{Kemp_2017}, which extended theoretical frameworks of individual wellbeing to community wellbeing. Here we focus on contributions from the wider environment to individual wellbeing, and implications for tackling greatest societal facing mankind: the climate. We use the term ‘environment’ in a very general sense, encompassing natural as well as human-built environments, although we place emphasis on the relationship between individual wellbeing and the natural environment given the sheer scale of the challenge associated with the climate crisis.
It is now accepted in scientific circles \cite{change2007,change2014} that humanity will face catastrophic climate change should we fail to commit to climate action. An increase in the frequency, duration and intensity of extreme weather events increases risk of population distress and psychiatric disorders through disruption to food supply and damage to community wellbeing \cite{Berry_2009,Hayes_2018}. Extreme weather events have even been shown to influence the future health and wellbeing of an unborn child with implications for brain development and metabolic outcomes \cite{Dancause_2015,Dufoix_2015}. Other research has also shown that climate change has increased global economic inequality by ~25% over the last 50 years, with wealthy countries benefiting disproportionally \cite{Diffenbaugh_2019}. Specifically, this research concluded that there is more than 90% liklihood chance that per capita GDP of the most poor countries is lower today than if changes to the climate had not occurred. Rising inequality has been linked to the middle-class squeeze, intergenerational immobility, erosion of trust, more divided societies, rising populism, poverty, crime, ill-health and ill-being. Interested readers are referred to the excellent recent review by Brian Nolan and Luis Alenzuela \cite{Nolan_2019}. Critically, ratings of peer-reviewed climate-science and self-ratings by climate change scientists themselves has indicated that there is 97% endorsement that humans are contributing to the warming climate (i.e. anthropogenic climate change) \cite{Cook_2013,Cook_2016}. Unfortunately, this finding remains under appreciated in a brave new world of alternative facts and disinformation \cite{Lewandowsky_2013,Lewandowsky_2017}.
In our original GENIAL model \cite{Kemp_2017}, we described an important role for positive social ties and community on health and wellbeing. Interestingly, others \cite{Beery_2015,Nurse_2010} have argued that the boundaries of ‘community’ should be extended to the environment including soil, water, plants and animals, in order to facilitate love and respect, and a commitment to environmental sustainability. Human beings have a strong, innate affiliation with the biological world, a phenomenon captured by the ‘biophilia hypothesis’. Recent research indicates that people who spend at least two hours a week in nature are more likely to report good health and high levels of wellbeing than those who spent no time in nature \cite{White_2019}. Furthermore, these findings were consistent across a variety of demographic variables including sex, age-group, occupational social grade, presence of chronic illness and whether or not individuals met physical activity guidelines. Prior research had indicated that spending time in nature over a 2-week period boosts hedonic as well as eudaimonic wellbeing \cite{howell2014}, and that effect sizes are larger (ds from .37 to .63) than those reported for other positive psychology interventions (ds from .20 to .34) \cite{Bolier_2013}. Exposure to nature can lead to transcendent emotions \cite{Bethelmy_2019}, peak experience \cite{1964} and psychological flow \cite{Csikszentmihalyi_2014}. Interestingly, transcendent emotions - including compassion, gratitude and awe - foster healthy social relationships \cite{Stellar_2017} and such relationships are facilitated by spending time in nature \cite{Mayer_2008,Richardson_2016}. Research also reports that exposure to nature is associated with stress reduction \cite{Hansmann_2007,Ulrich_1991}, feelings of restoration \cite{White_2013,Wyles_2017}, subjective wellbeing \cite{Johansson_2011,LUCK_2011,White_2017}, and improved cognitive functioning \cite{Berman_2008,Berto_2005}. Human beings also have a strong affiliation with the local environment (‘place’), driven by cultural experience \cite{Beery_2015,s2012}. This is known as the 'topophilia hypothesis'; the word topophilia combines topos (place) with philia (love). 
The biophilia and topophilia hypotheses provide a foundation on which to understand the distress, pain or sickness associated with environmental degradation of home or territory. Glenn \citet{albrecht2019}, an Australian environmental philosopher coined the term ‘solastalgia’ after reflecting on the environmental impacts of open cut coal mining and pollution of local power stations on the residents of the Upper Hunter Region of NSW in Australia. He wrote that ‘solastalgia’ reflects a: 
“specific form of melancholia connected to a lack of solace and intense desolation” associated with place-based distress \cite{albrecht2005a}
Feelings of guilt, shame, fear, emotional discomfort and solastalgia have been associated with motivation to engage in environmental sustainability behaviours \cite{Albrecht_2007,DICKERSON_1992,Kaiser_2008,Malott_2010}. In order to encourage such behaviours, scholars have proposed an ‘aesthetics of elsewhere’, which involves encouraging a double aesthetic judgment of ‘here’ and ‘elsewhere’ to induce an aesthetic melancholia to influence consumption decisions \cite{maskit2011}. However, researchers have also begun to investigate the value of positive psychology in encouraging pro-environmental behaviours. The positive psychology of sustainability \cite{Corral_Verdugo_2014,Corral_Verdugo_2012,obrien2016} is a strategy that may help to foster what has been described as sustainable wellbeing \cite{Kjell_2011}. In a study on 606 undergraduate students in Mexico \cite{fraijo-sing2011}, researchers reported that pro-ecological, altruistic, frugal and equitable behaviors reflect the sustainably-oriented person, and that these behaviours have positive psychological consequences. A major goal of positive psychology should now be focused on developing interventions that promote such behaviours, an effort that would have substantial benefits for the wellbeing of current and future of generations. In this regard, prior research has shown that individuals engaging in pro-ecological behaviours – such as resource conservation – report greater happiness \cite{Brown_2005}, that altruism leads to greater long-term happiness \cite{ja1995}, and that frugality predicts greater psychological wellbeing, satisfaction and motivation \cite{Brown_2005}. Notably however, equitable individuals have been reported to be less happy due to the ‘negative hedonic impact of inequality in society’ as climate change exacerbates existing inequities \cite{Hayes_2018}, highlighting a need for sociostructural reforms. Indeed, in their review of inequality and its discontents, \citet*{Nolan_2019} concluded that we now have a window of opportunity for designing and implementing sociostructural changes through strategies and policies to halt and reverse rising income and wealth inequality.
The grave threat of anthropogenic climate change may help to inspire a variety of positive feelings such as altruism, compassion, optimism as well as a sense of purpose “as people band together to salvage, rebuild, and console amongst the chaos and loss of a changing climate” \cite{Hayes_2018}, feelings that reflect ‘active hope’ \cite{c2012}. The concept of ‘sustainable happiness’ \cite{2016} has been defined as “happiness that contributes to individual, community, and/or global well-being without exploiting other people, the environment, or future generations”\cite{obrien2010} thus differentiating it from phrases typically used in positive psychology such as “sustaining happiness” or “sustainable increases in happiness” \cite{s2007}. More recently, a structural model of the relationships between character strengths, virtues and sustainable behaviours has been presented such that all 24 character strengths \cite{p2004} are associated with all four sustainable behaviours (i.e. altruistic, frugal, equitable and pro-ecological behaviours) \cite{Corral_Verdugo_2015}. The knowledge that pro-environmental behaviours provide opportunities to promote happiness and build resources for resilience, in addition to much-needed environmental benefits provides a useful foundation on which psychological scientists could address environmental challenges through targeted interventions focusing on the individual \cite{Clayton_2016,fraijo-sing2011,Corral_Verdugo_2012}. Recommendations included the need for psychological scientists to incorporate a contextualised or 'place-based' approach - including aspects of the built environment and different cultures - into initiatives designed to facilitate pro-environmental behaviours and to engage in more interdisciplinary research.
Unfortunately, the vast majority of people do not engage in pro-environmental behaviours, a result of helplessness and low self-efficacy \cite{Salomon_2017}. The difficulty in comprehending problems associated with climate change, and the intangibility and invisibility of such change may lead individuals to 'sit on their hands and do nothing', a phenomenon known as ‘Giddens Paradox’ \cite{a2009}. Recent qualitative research \cite{langen2017} has investigated the psychological processes that foster pro-environmental behaviours. Findings were interpreted in the context of ‘salutogenesis’ \cite{ANTONOVSKY_1996}, which emphasises a role for a ‘sense of coherence’ for managing and overcoming stress. This ‘sense of coherence’ reflect feelings of confidence that stimuli in the (internal and external) environment are comprehensible, manageable and meaningful. The researchers reported that grassroots activists relied on values and attitudes, emphasising that the problems are so vast that limits are imposed on knowledge (i.e. comprehensibility), arguing that emotions are a key mediator between the appraisal of a situation and motivation to take action. A sense of personal responsibility for change was associated with an improved perceived quality of life, attributable to empowerment and social cohesion, which provides a sense of meaning and purpose in life. Concrete and collective action was also observed to enhance positive emotions and mastery experiences subsequently enhancing beliefs about self-efficacy (i.e. manageability) \cite{langen2017}.
In summary, we have observed emerging research interest in the concepts of sustainable happiness and wellbeing, directly linking positive psychology to concepts relating to sustainability and pro-environmental behaviours. Although much work remains to be done, these efforts serve to combat criticisms of psychological science relating to a blinkered focus on personal happiness that ignores important societal challenges. Spending time in and caring for for the natural environment may provide an under-appreciated means to promote  wellbeing that is over and above the beneficial impacts of outdoor physical activity \cite{Franco_2017,Capaldi_2015,Bowler_2010} and may even promote commitment to pro-environmental behaviours, serving to support efforts to combat the climate crisis. 

The Updated GENIAL model: GENIAL 2.0

”Models, of course, are never true, but fortunately it is only necessary that they be useful”.
– George Box, 1979, Journal of the American Statistical Association, 74:365, 1-4
The GENIAL framework illustrates common pathways to ill-health and ill-being versus health and wellbeing. The evidence-base for these pathways - including a key regulatory role for vagal function - have been described previously \cite{Kemp_2017,Kemp2017,ah2018}. While our original GENIAL model highlighted the importance of positive social ties for individual health and wellbeing \cite{Kemp_2017}, our updated model (see Fig \ref{div-162276})  provides an important update to our original GENIAL model, emphasising individual, community and environmental contributors to personal wellbeing. In doing so, our model characterises the relationships between individuals, communities and their environments, as well as the impacts of sociostructural factors (e.g. inequality) and their impact on the health and wellbeing of the individual. Key features of the individual, community and environmental domains are now briefly described with a particular focus on vagal function.
Individual wellbeing is promoted through positive psychological experiences and positive health behaviours. Meta-analyses have demonstrated that positive psychological interventions (PPIs) are effective for people with or without diagnosed disorders \cite{Bolier_2013,Hendriks_2019,Chakhssi_2018,Sin_2009,White_2019a}, with effect sizes ranging from small to large. Meta-analyses have further demonstrated the effectiveness of specific positive psychological interventions (PPIs) on increasing SWB, PWB, optimism, positive affect and life satisfaction, including the practicing of gratitude \cite{Davis_2016}, the ‘best possible self’ intervention \cite{Malouff_2016}, savouring positive emotions \cite{Smith_2014}, mindfulness-based interventions \citep{Simpson_2019}, and performing acts of kindness \cite{Curry_2018}. The three main models of wellbeing \cite{Seligman_2018,Diener_1984,Ryff_1995} provide a theoretical foundation for developing new and novel interventions for enhancing positive psychological experience. Importantly, research demonstrates that despite the different theories that have been proposed for wellbeing, each of these contributes to the same higher order construct of wellbeing \cite{Goodman_2017,Disabato_2016}. In other words, there are many strategies through which positive psychological experience may be enhanced. Other meta-analyses on health behaviours have emphasised the role of physical activity \cite{Chekroud2018}, diet \cite{Firth_2019} and sleep \cite{Baglioni_2016} on our mental lives. Our recent review on vagal function \cite{Kemp_2017a} concluded that higher resting state vagal function is associated with positive mood states, highlighting the utility of positive psychology interventions for enhancing a critical regulator of health and wellbeing. Our work further emphasises the structural link between the vagus nerve, and physical and mental health \cite{Kemp_2017,Kemp2017,ah2018,Kemp_2013,Kemp_2016a}. It is interesting to note here that purpose in life has been shown to predict allostatic load ten years later \cite{Zilioli_2015} as measured by the sum of seven scores across multiple physiological systems including cardiovascular, lipid, glucose metabolism, inflammation, autonomic function, and hypothalmic-pituitary-adrenal risk scores. Unfortunately however, this study did not distinguish between upstream and downstream systems driving increases in metabolic risk. as we do here. Critically, vagal function plays a known regulatory role over inflammatory processes, as demonstrated previously: \citealt{Tracey_2002}
In addition to focusing on positive psychological experience and health behaviours, recent developments in psychological science have highlighted a key role for social relationships for the health and wellbeing of the individual. Therefore, individual wellbeing may also be promoted by focusing on community, the focus of our original GENIAL model \cite{Kemp_2017}. The implications of social relationships for the health and wellbeing of the individual were recently summarised in the recent publication of 'The New Psychology of Health: Unlocking the Social Cure' \cite{2018}\citet{Haslam_2016} evaluated a new intervention that targets social isolation and disconnection, "Groups 4 Health" (G4H). Results highlighted the intervention to improve mental health, wellbeing, and social connectedness up to 6-months post intervention. In addition to this, improvements in depression, anxiety, stress, loneliness, and life satisfaction correlated with heightened identification with the G4H group and with multiple groups. The work by Barbara Fredrickson and colleagues is also relevant here, emphasising the upward spiral of positive emotions, social connectedness and vagal function \cite{Kok_2010,Kok_2013}. Other well established theories of vagal function, such as the polyvagal theory \citep{Porges:2011wv,PORGES_1995,Porges_2001,Porges_2003,Porges_2007} highlight a role for the vagus in promoting capacity to engage with others and regulating our emotions during such encounters. 
Finally, our updated model emphasises the environmental context within which individual health and wellbeing is promoted and communities reside. Glenn \citet{albrecht2019} provides a solid foundation for understanding the link between human emotion and the environment, coining numerous words to emphasise the negative and positive 'psychoterratic' states that have important implications for the health and wellbeing of individuals, communities and nations now and into the future. Environmental contributors include negative and positive psychoterratic states such as solastalgia (chronic place-based distress) and soliphila (a neutral political term for combatting solastalgia) \cite{albrecht2019}. A review of the literature on potential mechanisms linking nature to health identified 21 potential pathways empirically linked to nature \cite{Kuo_2015}. These pathways included environmental factors including phytoncides - antimicrobial volatile organic compounds with physiological effects - and vegetation filtering of pollutants, physiological factors such as elevation of vagal function and immune function, psychological factors involving positive emotions and attention restoration, and behavioural factors including positive health behaviours such as the promotion of physical activity and social ties. Interestingly, this paper suggested that enhanced immune functioning might reflect a central pathway for mediating the beneficial effects of nature on health. It is apparent however, that vagal function plays a regulatory role over immune function via the cholinergic anti-inflammatory response \citep{Pavlov_2003}.  Other research has shown that vagal function may be facilitated by spending time in nature. For instance, a recent review of the literature \cite{Kondo_2018} on the impacts of spending time outdoors on stress reported that of 17 studies reporting on measures of HRV, 14 reported significant findings. Measures of the high frequency (HF) component - a commonly reported measure of vagal function - increased for participants spending time outdoors. It is relevant to note here that measures of HF HRV are generally negatively correlated with with meaures of heart rate. That is, high levels of vagal function  - as is typically indexed by HF HRV - are associated with a low heart rate. Thus, it is against this background of findings that we suggest that vagal function both affects and are affected by the effects of psychological experience, health behaviours, social ties, as well as the environment.
In conclusion, our updated GENIAL model (fig \ref{div-162276}) summarises individual, community and environmental contributors to human health and wellbeing. Our model also characterises the major targets for potentially improving wellbeing in people including those living with chronic conditions and disorders. Targets include psychological experience, health behaviour, social connections and outdoor nature-based activities to which the tools from positive psychology and behaviour change may be applied.