Social determinants of health describe the conditions in which people are born, grow, live, work, and age, and are mediated by environmental factors (Prüss-Ustün et al., 2016). Climate change, an environmental factor, has received significant public health attention over the past 3 decades (Le Treut et al., 2007). Although the Earth's climate has gradually changed throughout millennia, there have been precipitous changes in climate over the past half-century that are extreme and unprecedented. These changes are thought to be accounted for by increased concentration of atmospheric carbon dioxide, secondary to an increase in fossil fuel utilization. Sequelae of climate change include increases in global temperatures of approximately 1.62°F over the past century (Wuebbles et al., 2017), increases in ocean water temperature of approximately 0.5°F over the past 50 years (Levitus et al., 2017), a reduction in mass of ice sheets and glaciers (Gudmundsson et al., 2019; Roe et al., 2017), increases in sea levels (Nerem et al., 2018), and increases in frequency of extreme weather events (Stott, 2016).
It is well established that climate change is associated with myriad public health problems, including increases in heat-related illnesses and death (Wald, 2019); increases in vector-borne diseases, infectious diseases, and respiratory illnesses (Caminade et al., 2019); food and water insecurity (Tito et al., 2018); and health systems deficiencies (Ebi et al., 2018; McIver et al., 2016). Less has been mentioned in public health discourse about the impacts of climate change on population mental health. The purpose of the current article is to provide an overview of the impacts of climate change on mental health, and to discuss opportunities for mental health nurses to reduce health problems related to climate change.
Impacts of Climate Change on Mental Health
Climate change can precipitate acute events, such as extreme weather events or disasters, and chronic consequences, such as the need for migration due to environmental changes, among others. Acute events and chronic consequences of climate change can impact mental health outcomes. Specific populations are at increased risk for mental health problems related to climate change, including gender or sexual minorities, children and adolescents, migrants, indigenous people, or those living in poverty (Berry et al., 2018).
Acute Events Related to Climate Change
Acute events related to climate change include extreme weather events or disasters, such as floods, droughts, tsunamis, hurricanes, tornadoes, or wildfires. The incidence of these types of events has been hypothesized to increase as temperatures increase (Runkle et al., 2018; Tschumi & Zscheischler, 2019). In a 20-year period, more than 2.5 billion individuals were impacted by extreme weather events or disasters globally (United Nations Office for Disaster Risk Reduction, 2015).
Multiple studies have found that individuals exposed to extreme weather events or disasters can exhibit mental health sequelae following the event, including mood, anxiety, and trauma-related disorders. For example, following Hurricane Katrina in 2005, 40% of individuals exposed exhibited posttraumatic stress disorder (PTSD) symptoms (Satcher et al., 2007), and 12 years later, one in six individuals affected by Hurricane Katrina continues to endorse PTSD symptoms (Raker et al., 2019). Following exposure to Hurricane Sandy in 2012, 50% of survivors met criteria for an anxiety disorder, 35% met criteria for a depressive disorder, and 29% met criteria for PTSD (Schwartz et al., 2017). For those who survived Hurricane Sandy, inability to access health care services during the incident, witnessing death or injury, and experiencing physical harm, were factors that most increased risk for development of PTSD (Schwartz et al., 2019). On a broader scale, Beaglehole et al. (2018) published a systematic review and meta-analysis examining mental health issues following exposure to natural disasters. The authors included research on an international scale, and examined natural disasters comprising tsunamis, floods, hurricanes, earthquakes, wildfires, landslides, volcanic eruptions, and typhoons. Rate of any psychiatric disorder in individuals exposed to natural disaster was 38% compared to 28% for those not exposed. For PTSD, specifically, individuals exposed to natural disasters exhibited PTSD symptoms at a rate of 10%, compared to 2% of individuals not exposed (Beaglehole et al., 2018).
In addition to mental health symptoms following exposure to extreme weather events or disasters, survivors may experience grief (Hayes et al., 2019). Cunsolo and Ellis (2018) describe ecological grief as a phenomenon secondary to impact by climate change. Traditionally, grief is defined as a “psychobiological response to [loss] whose hallmark is a blend of yearning and sadness, along with thoughts, memories, and images” (Shear, 2012, p. 120). Complicated grief is described as an “impairing form of grief brought about by interference with the healing process” (Shear, 2012, p. 122), associated with feelings of guilt or anger, ruminative or obsessive thoughts, and excessive avoidance or seeking of reminders of the loss. Ecological grief can be viewed as “disenfranchised grief, or a grief that isn't publicly or openly acknowledged” (Cunsolo & Ellis, 2018, p. 275), and subsequently shares many characteristics with complicated grief. Ecological grief can occur in individuals exposed to extreme weather events or disasters and can persist even after survivors adjust to a new life (Morrice, 2013; Proudley, 2013). However, ecological grief can also occur in individuals who were not exposed to acute events related to climate change, but who witnessed or were impacted by subtle or insidious environmental changes over time. Examples include changes in weather, ecosystems, or landscape over time, which can result in psychosocial issues including food insecurity and forced migration. Furthermore, some individuals may experience anticipatory grief due to concern of environmental changes in the place they call home (Cunsolo & Ellis, 2018; Gifford & Gifford, 2016).
Chronic Consequences of Climate Change
Aside from acute events such as extreme weather events or disasters, climate change results in insidious changes to the environment and subsequent public health consequences. Changes in climate and the subsequent impact on ecosystems globally can result in food and water insecurity, forced migration, economic instability, and violence, all of which may impact the mental health of populations.
Long-term droughts can impact food and water supply, leading to subsequent food or water insecurity (Hayes & Poland, 2018). Gender minorities, children and adolescents, and indigenous individuals are most likely to be impacted by food or water insecurity (Cooper-Vince et al., 2018; Durkalec et al., 2015; Ford, 2012; Nicholas & Breakey, 2017). In addition to physical health problems, such as gastrointestinal disease, dehydration, malnutrition, and cardiovascular problems, food and water insecurity can also precipitate mental health issues. Individuals experiencing food and water insecurity are more likely to experience anxiety symptoms; emotional distress; shame, stigma, or embarrassment; and social isolation (Adams et al., 2020; Bisung & Elliott, 2017). Water insecurity has also been shown to increase risk of anxiety and depression across genders and ages (Maxfield, 2020), in addition to somatic symptoms (Tallman, 2019). A recent meta-analysis revealed that food insecurity was associated with increased risk for anxiety disorders, depressive disorders, PTSD, psychosocial stress, and poor self-reported mental health outcomes (Tribble et al., 2020).
Individuals may be forced to migrate secondary to the impacts of climate change. It is estimated that over the next 30 years, >200 million individuals will be displaced due to the effects of climate change (Rechkemmer et al., 2016), with other estimates exceeding 1 billion displaced individuals (Hayes et al., 2018). Forced migration can precede physical and intangible losses, including loss of one's home or loss of one's support system, respectively (Shultz et al., 2019). Social connectedness can mediate outcomes related to forced migration, with social loss precipitating mental health symptoms, whereas preparing for migration by strengthening social ties and preparing for distance may act as a protective factor (Torres & Casey, 2017). Furthermore, during migration, individuals may be exposed to interpersonal violence (Levy et al., 2017). Forced migration can precipitate anxiety, mood disorders, and trauma-related disorders (Gleick, 2014). Migration can precipitate safety and security concerns, further increasing psychosocial stress and anxiety (Schwerdtle et al., 2018). Individuals who experience forced migration are at risk for substance use problems and issues with acculturation (Horyniak et al., 2016). Forced migration can precede and follow economic instability and violence.
Economic instability secondary to climate change is likely to impact countries that are already vulnerable. It is estimated that the poorest one third of countries globally will experience economic losses as high as 20% of country income related to climate change (Hsiang et al., 2017). It has been well established that economic instability can contribute to deleterious mental health issues across the lifespan (Bøe et al., 2017; Higashi et al., 2017; Martin-Carrasco et al., 2016). On a global scale, economic instability is often associated with interpersonal and collective violence. Interpersonal violence associated with climate change can include death and non-fatal injuries due to riots or civil unrest considering food insecurity and economic volatility (Levy et al., 2017). Alternatively, collective violence includes armed conflict, state-sponsored violence, and violent organized crime. For example, it has been hypothesized that climate change intensified the civil war in Syria, after a 3-year drought resulted in loss of land, produce, and employment, and subsequent civil unrest between disadvantaged citizens and the government (Levy et al., 2017). Furthermore, it has been predicted that climate change will foster conflict and increase the demand on government to maintain infrastructure, assure adequate food and economic supply, and respond to natural disasters (Agnew, 2011). The effects of interpersonal and collective violence on mental health can include depressive, anxiety, and trauma-related disorders that are sustained for years following exposure.
There is some emerging, preliminary evidence that climate change and subsequent increases in temperature can contribute to inpatient mental health service use and suicidality. A recent study reported that, over 35 years, an association was found between increases in monthly temperatures and rates of suicide, and reported that suicide rates rose by more than 2% for the hottest months on record in the United States (Burke et al., 2018). Similar findings were reported in Japan, with increases in temperatures resulting in a greater risk for suicide in men, specifically (Takahashi, 2017). Acute increases in temperature, or heatwaves, have been associated with increased inpatient mental health service use, self-injurious behavior, and suicidality (Carleton, 2017; Williams et al., 2016). Although more research is needed, these findings have implications for mental health nurses in assuring patient safety.
Implications for Mental Health Nurses
Because climate change has direct impacts on patient outcomes and patient care, nurses should engage in patient and public education regarding the impacts of climate on mental health (Kreslake et al., 2018; Sarfaty et al., 2016). Nurses should be able to provide evidence-based, accurate information regarding the effects of climate change on mental health, ways to mitigate risk factors, and individual and collective ways to reduce environmental footprints (Kreslake et al., 2016).
Nurses can be instrumental in responding to the mental health needs of those impacted by climate change. This response includes the implementation of standardized, universal trauma-informed care, and through evidence-based interventions to address trauma-related mental health issues. For individuals who were forcibly displaced, nurses should be able to provide culturally competent care as indicated. Finally, it is important to note that those with mental health issues related to suicide may be at increased risk for suicidality. Nurses should implement suicide risk assessments and necessary interventions to reduce death by suicide in this population.
Nurses should also be prepared to engage in disaster response, and professional organizations should develop curricula and continuing education opportunities pertaining to climate change and disaster preparedness (Leffers & Butterfield, 2018). The American Nurses Association (ANA; 2015) has included competencies that reflect nurses' professional role in climate change in the environmental health domain of the ANA scope and standards (McDermott-Levy et al., 2019). Furthermore, the International Council of Nurses and the World Health Organization developed the Framework of Disaster Nursing Competencies for educational use (Hutton et al., 2016). Despite this, inclusion of climate change information in nursing curricula, including disaster preparedness, is neither robust nor standardized (Veenema et al., 2017). Finally, nurses generally report feeling poorly equipped to implement psychological care during disaster response (Said & Chiang, 2020).