The pathways by which climate change can affect people's mental health and psychosocial well-being are multiple

The direct and indirect pathways by which climate-related hazards, long-term risks, exposure pathways and vulnerabilities interrelate to impact mental health are described in Fig. 1. These factors do not act in isolation. Instead, hazards may overlap (e.g. cascading events such as storms followed by floods). People may be exposed simultaneously to contaminated water and food insecurity while also being exposed to mosquito breeding sites. Existing population vulnerabilities may be exacerbated by climate hazards and long-term climate risks, resulting in aggravated inequities (WHO, 2021b). The resulting effects have considerable implications for mental health and well-being (examples in Box 1).

Fig. 1. Main interlinkages between climate change and mental health.

Box 1. Examples of mental health impacts of climate change and exposure pathways

The Intergovernmental Panel on Climate Change (IPCC), in its 6th assessment report states, with very high confidence, that climate-related illnesses, premature deaths, malnutrition in all its forms and threats to mental health and wellbeing are increasing. It also identifies that, at the global level, health systems are poorly resourced, and their capacity to respond to climate change is weak, with mental health support being particularly inadequate (IPCC, 2022).

The environmental, social and economic determinants of mental health (identified as exposure pathways in Fig. 1) include air quality, water quantity and quality, food security and safety, income and livelihoods, ecosystem changes and a number of other social and economic pathways. They are all negatively affected by climate change. For example, air pollution during periods of high temperatures can cause respiratory diseases that increase demand for health care services, reduce mobility and the capacity to work, and can lead to mental health consequences that range from minimal stress and distress to the development of mental health conditions, particularly in low-income settings (Dodgen et al., Reference Dodgen, Donato, Kelly, La Greca, Morganstein, Reser, Ruzek, Schweitzer, Shimamoto, Thigpen Tart, Ursano, Crimmins, Balbus, Gamble, Beard, Bell, Dodgen, Eisen, Fann, Hawkins, Herring, Jantarasami, Mills, Saha, Sarofim, Trtanj and Ziska2016). The case of prolonged droughts demonstrates a clear example of the impacts of climate change on these determinants. Droughts significantly disrupt agricultural production and lead to loss of livelihood, leaving many communities in poverty, a factor clearly linked with many common mental disorders (Lund et al., Reference Lund, Breen, Flisher, Kakuma, Corrigall, Joska, Swartz and Patel2010). Droughts can also lead to water scarcity and food insecurity, both of which can negatively impact mental health and increase the risk for mental health conditions (Stanke et al., Reference Stanke, Kerac, Prudhomme, Medlock and Murray2013; Vins et al., Reference Vins, Bell, Saha and Hess2015; Pourmotabbed et al., Reference Pourmotabbed, Moradi, Babaei, Ghavami, Mohammadi, Jalili, Symonds and Miraghajani2020), the latter of which is associated with developmental delays, mental health issues and neurological problems that can result from malnutrition (WHO, 2006a, 2006b). Both food and water scarcity can also further contribute to population displacement, which disrupts family relationships and can leave those displaced with fewer resources, services and social support in the new community, all of which exacerbate mental health risks (Vins et al., Reference Vins, Bell, Saha and Hess2015; Cianconi et al., Reference Cianconi, Betrò and Janiri2020). Attention to the influence of climate change on determinants of mental health such as these is crucial for both understanding the impact and for taking climate action.

Climate change may also lead to increased conflict, or aggravated conflict dynamics, particularly in regions dependent on agriculture (Koubi, Reference Koubi2019), and to forced migration for some and forced immobility in challenging environments for others (Wright et al., Reference Wright, Tanzler, Ruttinger, Melde, Milan and Flavell2021). Inevitably, conflict negatively impacts mental health and well-being, with one in five persons exposed to it experiencing a mental health condition (Charlson et al., Reference Charlson, van Ommeren, Flaxman, Cornett, Whiteford and Saxena2019) and countless others enduring distress in the face of adversity. Meanwhile, migration is also commonly viewed as a risk factor for mental health and psychosocial problems, though more research is needed with populations migrating for reasons other than conflict (Meyer et al., Reference Meyer, Lasater and Tol2017).

Certain groups will be disproportionately at risk due to climate change, depending on existing vulnerabilities and inequalities. This is particularly true in low- and middle-income countries, despite the fact that such countries have historically emitted low levels of greenhouse gases (Berry et al., Reference Berry, Bowen and Kjellstrom2010, Reference Berry, Hogan, Owen and Rickwood2011, Reference Berry, Waite, Dear, Capon and Murray2018; Bourque and Cunsolo Willox, Reference Bourque and Cunsolo Willox2014; Hayes and Poland, Reference Hayes and Poland2018; Palinkas and Wong, Reference Palinkas and Wong2019). For instance, indigenous people may be more likely to define well-being in terms of harmony with natural environments, which are significantly disrupted by climate change. As a result, they may be more strongly affected by the loss of even small amounts of land or wildlife or by other climate-related impacts. Children and adolescents are also uniquely affected and can experience strong reactions in response to the scale of the crisis and the lack of action taken (Hickman et al., Reference Hickman, Marks, Pihkala, Clayton, Lewandowski, Mayall, Wray, Mellor and van Susteren2021).

However, vulnerability is context-dependent and understanding who is vulnerable and in what way requires targeted assessment to identify contextual factors (WHO, 2021c). Any single factor may not necessarily determine vulnerability. However, in the case of different vulnerability factors, often interacting, the effects are multiplied (Gamble et al., Reference Gamble, Balbus, Berger, Bouye, Campbell, Chief, Conton, Criminis, Flanagan, Gonzalez-Maddux, Hallisey, Jantarasami, Khoury, Kiefger, Kolling, Lynn, Manangan, McDonald, Morello-Frosch, Hiza Redsteer, Sheffield, Thigpen Tart, Watson, Powys Whyte, Fun, Wolkin, Crimmins, Balbus, Gamble, Beard, Bell, Dodgen, Eisen, Fann, Hawkins, Herring, Jantarasami, Mills, Saha, Sarofim, Trtanj and Ziska2016; Hayes et al., Reference Hayes, Blashki, Wiseman, Burke and Reifels2018; Cianconi et al., Reference Cianconi, Betrò and Janiri2020). For example, someone may be older in age, or of lower socioeconomic status, or living in a water-stressed zone or living with a chronic disease, but may not be as vulnerable as someone who experiences all these factors simultaneously.

Mental health and climate change: emerging concepts and concerns

There have been increasing efforts to better understand the mental health impacts of climate change. Individuals and communities may experience many intense emotions in the face of a changing climate, including sadness, fear, despair, helplessness and grief. Various terms have emerged to describe these responses, particularly among youth affected by climate change, including climate change anxiety (Clayton and Manning, Reference Clayton and Manning2018), solastalgia (Albrecht et al., Reference Albrecht, Sartore, Connor, Higginbotham, Freeman, Kelly, Stain, Tonna and Pollard2007), eco-anxiety (Cordial et al., Reference Cordial, Riding-Malon and Lips2012), environmental distress (Higginbotham et al., Reference Higginbotham, Connor and Baker2012), ecological grief (Cunsolo and Ellis, Reference Cunsolo and Ellis2018) and climate-related psychological distress (Bourque and Cunsolo Willox, Reference Bourque and Cunsolo Willox2014). Further research is needed to better understand these concepts, including what risk factors predispose people to these experiences and whether specific prevention and response actions are necessary. In any case, it must be noted that many of these reactions may represent understandable and congruent responses to the scale of the crisis the world faces (Hickman et al., Reference Hickman, Marks, Pihkala, Clayton, Lewandowski, Mayall, Wray, Mellor and van Susteren2021). In any emergency, including the global climate crisis, the terminology used to describe mental health and psychosocial problems can either support or stigmatise those affected. Care should be taken to ensure the use of terminology that normalises reactions to difficult situations and reinforces people's abilities to overcome adversity, rather than assuming the need for clinical intervention for all or labelling everyone affected as ‘traumatised’.

The potential beneficial mental health outcomes resulting from engaging in climate action have been described (Augustinavicius et al., Reference Augustinavicius, Lowe, Massazza, Hayes, Denckla, White, Cabán-Alemán, Clayton, Verdeli and Berry2021), such as increased well-being resulting from actively coping with the situation through climate action (Lawrance et al., Reference Lawrance, Thompson, Fontana and Jennings2021). However, others have discussed the potential distress experienced by people when confronting the scale of the problem (Sanson and Bellemo, Reference Sanson and Bellemo2021), indicating that climate action can also be harmful for mental health and well-being in some cases. Further research is required to develop a clear understanding of how climate action may promote and protect mental health and wellbeing and how better mental health can support increased action to address climate change.

Recommendations to MHPSS and climate change actors

Approaches to address the mental health and psychosocial impacts of climate change must be implemented with urgency. We propose five recommendations to MHPSS and climate change actors.

Integrate MHPSS within policies and programmes dealing with climate change and health

Key strategies in any response to climate change are mitigation and adaptation. There are important co-benefits to be gained from actions that contribute to climate change mitigation. Interventions related to active transport, for instance, are positive for physical health and can be positive for mental health too (WHO, 2016). Transport can also be important for access to services and social interaction, which have positive effects on mental health (WHO, 2011). Urban design that is environmentally friendly can provide green spaces for communities, with mental health benefits and stress reduction in different settings (WHO, 2016).

Regarding adaptation interventions, WHO recommends a systematic approach to strengthening the climate resilience of health systems. This is outlined in the WHO Operational Framework for Building Climate Resilient Health Systems (WHO, 2015). Mental health considerations and MHPSS approaches should be integrated within this health systems strengthening approach to build resilient health and mental health systems (Table 1). Both for mitigation or adaptation strategies, indicators, metrics and monitoring mechanisms are required to better understand the linkages between climate change and mental health.

Table 1. Integrating mental health considerations with climate change actions: examples of integrated mental health and climate change actions

Concluding remarks

We must increase the visibility of the problem: The mental health consequences of climate change have until recently been an invisible problem. However, there is growing evidence of the various mechanisms by which climate change is affecting mental health. Countries need to dramatically accelerate their responses to climate change, including efforts to address its impacts on mental health and psychosocial well-being.

We must continue the research and debate on this emerging problem: The systemic, global and potentially irreversible effects of the crisis have given rise to emerging concepts such as climate change anxiety, solastalgia, eco-anxiety and ecological grief. In many cases, these reactions may represent understandable and congruent responses to the crisis the world faces, and yet their impact can be significant. Although there is a need for further research, the world has sufficient experience and evidence to guide immediate action.

We must act now to protect mental health: Strengthening the link between mental health and climate change is an opportunity to create a more holistic and coordinated response. Effective interventions are available and can be implemented immediately. With further support from policy-makers, researchers and MHPSS and climate actors, other interventions will be developed and a holistic response can be implemented.

We must ensure mental health is included in the climate change agenda: Given the human impacts of climate change, mental health and psychosocial well-being need to be one of the main focuses of climate action. There needs to be a commitment both politically and financially and across all sectors to make MHPSS and climate action a priority. This is the only way to achieve justice for all those who are affected.