Climate change is any systematic change or statistically significant variation in the average state of the climate over an extended period, usually decades or longer.(1) The global average increase in temperature over the last five decades was 0.65°C. However, the South African mean annual temperatures have increased by 1.5 times the global average increase.(2) The extreme weather events and unexpected weather patterns with changes in temperature, rainfall, and wind often result in droughts, floods, storms and heat waves.(3,4) The change in the climate system is a consequence of greenhouse gases mainly originating from human activities, which cause an increase in the biospheric ambient temperature.(5) Extreme weather events may cause disasters, which are sudden, unforeseen events resulting in many fatalities, injuries and significant damage to property and infrastructure.(3,4)
Effects of climate change
Vulnerable groups and communities are most at risk from the effects of climate change.(4,5) This risk is determined by the physical hazard (e.g., floods, extreme heat, storms), the exposure to the hazard (e.g., housing quality, livelihood type, outdoor employment, area of residence) and the vulnerability (e.g., age, gender, access to quality care, socioeconomic status, pre-existing conditions).(4,6) The controls in place to prepare, manage and recover from the effects of climate change are key issues as well.(4) The impact of the climate change risk threatens natural systems such as food and water security and human systems such as health and well-being, displacement of vulnerable populations and damage to settlements and infrastructure.(6)
Temperature increases due to increased greenhouse gases and exacerbated by concrete and black asphalt, which retain heat,(7) have a direct effect on the human body. These effects have been studied in recent years in regions that have experienced abnormal heat waves such as Chicago and Europe.(8,9) The increased heat led to an increased incidence of cardiovascular, cerebrovascular and respiratory illnesses, particularly in the elderly with existing co-morbidities.(7) As temperatures increase, the levels of ground-level ozone also increase.(7) This increase in ozone, combined with the atmospheric pollutants resulting from the increase in wildfires, leads to exacerbations in respiratory illnesses such as bronchitis, asthma and chest pain.(7,9,10)
Poverty, Climate Change and Mental health
As with most public health issues, the populations that bear the brunt of the effects are those in lower socioeconomic circumstances.(11) Rural farmers experience decreased yields due to extreme temperature, too little and too much rainfall and the rising sea levels affecting the salinity of farmable land, and forcing migration, as seen in regions in Bangladesh.(12) In conjunction with the rapidly expanding populations of the developing world, the demand placed on limited food resources leads to increased nutritional disorders, which in turn causes disturbances to mental health.(7,11,13)
As populations grow and migrate to cities for job opportunities, the sizes of cities expand, decreasing the surrounding natural environment and arable land.(11,13) The growing urban population compounds the pressure already placed on the resource constrained healthcare systems and forces a diversion of resources from other important healthcare concerns such as those related to mental health.
The climate change related increases in infectious diseases, especially vector-borne and diarrhoeal diseases, poor nutrition and increases in stress hormones affect our mental health and well-being.(6)
In South Africa, it has been shown that high temperatures are positively associated with aggression, violent behaviour, and homicides which could increase by 18% with temperatures more than 30 degrees.(14) It is predicted that with every one-degree Celsius increase in warming, displacement due to flood events will rise by 50%.(6) A study on climate change migration in an informal urban settlement found that people who migrated due to climate-induced reasons resulting from environmental hazards such as heat waves, droughts and flooding, faced non-economic losses such as their identity, sense of belonging, and honour.(6) Displacement affects psychosocial well-being, livelihood, and access to essential services.(10)
These effects of climate change on physical health are clear, and the impact of physical health on mental wellbeing is well established.(15) Frequent exacerbations of chronic medical conditions as well as the psychological impact of food insecurity and increased risk of infectious disease are expected to have a profound effect on mental health. We discuss the psychiatric disorders that may arise as a result of climate change below.
Post-traumatic stress disorder (PTSD)
Individuals who have been exposed to life threatening situations such as those due to the effects of climate change (rampant floods, droughts and fires), are at a considerable risk of developing acute stress disorder or post-traumatic stress disorder (PTSD). Injuries and loss of residency, as well as deaths of loved ones from increased infection can also lead to the symptoms of PTSD such as flashbacks of the event, increased arousal, and avoidance of cues to the memory of the event. This was borne out in the immediate aftermath of the California wildfires in 1991,(16) as well as after Hurricane Katrina in 2005.(17)
In many cases, symptoms of PTSD may have a delayed onset, months to years after experiencing threatening disaster situations. PTSD is also associated with impairment in the quality of life and significant subjective distress.
Anxiety / Psychosis / Sleep Disorders
An anxiety response in relation to an external stressor is not always accompanied by negative outcomes. The anxiety response may be viewed as a warning signal. “Anxiety is an alerting signal; it warns of impending danger and enables a person to take measures to deal with a threat.”(18)
In the context of climate change concerns, the manner in which a person responds to this anxiety may produce beneficial or harmful outcomes. A beneficial outcome is one where the response encompasses greater awareness of individual choices and actions and their impact on the environment. This then leads to individual action that is aimed at reducing harmful effects. A harmful outcome is one where there are increased levels of anxiety experienced in the face of feelings of helplessness and gloom and concerns about the future. This anxiety may worsen over time.
As individuals become more aware of climate change, they may become involved in climate action, which may improve wellbeing through an increased sense of coping with the crisis. It may also increase distress when confronted with the enormity of the crisis.(19) The impact of climate action at the individual level may therefore be an increase or decrease in anxiety symptoms.
Climate change and acute climate events may be a direct and immediate cause of anxiety. Anxiety disorders (such as generalized anxiety disorder, panic disorder with or without agoraphobia, social anxiety disorder) may present after an acute climate event. Anxiety may also develop more chronically in response to reported or experienced climate change and might lead to anxiety disorders indirectly in the short or long term.(20)
Anxiety related to the destruction of the environment and resultant climate change is on the rise. This anxiety has been referred to as ‘eco-anxiety’. There may be other emotional reactions associated with this anxiety. These include anger, guilt, despair and grief.(21)
The collective trauma of loss has been referred to as solastalgia (loss of solace).(22) Berry et al describes this as the distress, the loss of solace, caused by degradation of the environment, home and sense of belonging.(23) “It is manifest in an attack on one's sense of place, in the erosion of the sense of belonging (identity) to a particular place and a feeling of distress (psychological desolation) about its transformation.”(22)
As part of an anxiety response individuals may experience changes in sleep patterns. This can have a further negative impact on mental health outcomes. In addition, acute traumatic climate events can precipitate acute psychiatric outcomes, including psychotic episodes. This may be especially relevant in individuals with a pre-existing history.
Acculturation (how people adapt to their new cultural environment) has been studied in its relation to psychotic disorders such as schizophrenia and psychotic like experiences (PLEs). One research study by DeVylder et al. (24) showed that acculturative stress is associated specifically with hallucinatory symptoms among immigrants to the United States, particularly those from Asian countries. Hence the stress from forced migration due to climate change effects might be implicated in the onset of PLEs and psychotic disorders.
Obsessive-compulsive disorder (OCD)
Akhtar et al. displayed the socio-cultural impact on OCD symptoms as far back as 1978.(25) As anthropogenic climate change dominates present day culture through youth movements, legislature, media, global health summits etc., it is likely to influence OCD symptomatology. Unfortunately, to date, there are relatively few studies on the effects of climate change on OCD (26) and none in South Africa. In 2008, Jones et al. found that 28% of 50 patients with OCD in Australia had symptomatology related to climate change.(26) Obsessions revolved around increasing temperatures causing evaporation of pets’ water, depleting power and water sources by leaving lights and taps on and global warming leading to infrastructural damage.
Environmental factors can impact OCD symptoms and the COVID-19 pandemic has demonstrated this. Even prior to COVID-19, Lindahl et al. (2015) cautioned of climate change as a promoter of emerging infections, especially viral infections.(27) The estimated lifetime global prevalence of OCD prior to COVID-19 was 2%–3%.(28) A systematic review by Guzick et al. in 2021, demonstrated that the prevalence of OCD in multiple countries was significantly higher post COVID-19, for example in Wuhan, China it was 18.0% and in Germany it was 21.5%.(28) A worsening of OCD symptoms related to contamination fears, such as an increased demand for handwashing, reinforcement of ritualistic handwashing, media exposure to sources of contamination, normalisation of hand-washing compulsions and stocking of personal protective equipment and sanitisers in the context of hoarding was also noted in this review.
Affective/ mood disorders
The relationship between mood disorders and climate has been established, with a “seasonal pattern” specifier, for both bipolar and related disorders and major depressive disorders (MDD), appearing in the Diagnostic and Statistical Manual of Mental Disorders (DSM)-5.(29) Traditionally, seasonal patterns have typically been associated with autumn or winter months,(29) but a recent scoping review by Charlson et al. published in 2021 identified multiple studies where an increase in temperature was associated with mental illness.(30) A study in Taiwan, included in the review, found a 7% increased incidence of MDD per 1°C rise in regions with an annual average temperature above 23°C. Fifteen studies in the review demonstrated the association between heat waves and psychiatric hospital admissions, including mood disorders. Wildfires have also been significantly associated with MDD, with a Californian study identifying 33% of victims having symptoms of MDD.(20)
Rotge et al. (2014) compared the lifetime prevalence rates of mood disorders from 17 countries and found a statistically significant association between mood disorders and average annual rainfall (p=0.003), as well as monthly rainfall differences (p=0.02).(31) The systematic review of Cianconi et al. (2021) found that 20% of flood victims were clinically depressed.(20) The consequences of climate change, such as loss of life, abode, resources, communities etc. also place individuals at risk for mood disorders.(20)
Substance use disorders
Substance use has been associated with both the direct and indirect effects of climate change in a review by Ramadan et al. in 2021; however no South African studies were included.(32) The direct effects refer to reactions following acute weather events while indirect effects relate to financial loss, displacement, forced migration, a lack of resources, collective violence and homelessness. One consequence of homelessness in youth populations abusing substances are drug overdoses requiring hospitalisation. Kidd et al, in a Canadian based population survey, found that 35% of homeless youth reported at least one drug overdose requiring hospitalisation.(33) Charlson et al. found that patients with substance misuse were victims of significantly higher heat-related mortality, and air pollution also has the potential to exacerbate cardiorespiratory illnesses in patients with substance use disorders who smoke.(30)
Climate change has been linked to suicide via air pollution, rising temperatures and drought.(34) A review by Dumont et al. in 2020 found that daily poor quality air increased suicide rates by 1%–2%.(34) The pathophysiology of air pollution and suicide risk is theoretically neuroinflammatory, with air pollutants acting as irritants. Studies in India, Finland, Italy, the United States of America and Mexico have all found an association between higher temperatures and increased suicide rates.(30) In Finland, temperature changes contributed to the variance in suicide rates by more than 60%. If climate change continues at its current rate, it is expected to result in an additional 21 770 suicides by 2050 in the US and Mexico alone. Studies demonstrating the association between drought and suicide are mostly Australian.(34) One study done between 1964 and 2001, demonstrated an 8% increased risk of suicide for every 300 mm decline in rainfall.(34)
Going forward for better Mental health
South Africa is in the process of drafting a new Climate Change Bill [B9- 2022] into legislation in 2022. This new Bill will provide an overarching response to ensure the protection of lives and property and tackles the control of greenhouse gas emissions to prevent further harm. The Bill highlights a National Climate Change Adaptation Strategy to undertake climate needs and a response assessment for every region, coastal and inland. The recent COVID-19 pandemic taught us the importance of building resilient health systems, which include health workforce, financing, information systems, and governance structures.(6) Like COVID-19, the climate change crisis is expected to amplify health system weaknesses and inequalities. Mental health, a key component of health will be severely impacted. To safeguard against this, in 2020 the World Health Organization described six prescriptions for a healthy and green recovery to preserve human health (Table 1).(35)
|1.||Protect and preserve the source of human health: Nature.|
|2.||Invest in essential services, from water and sanitation to clean energy in healthcare facilities.|
|3.||Ensure a quick and healthy energy transition.|
|4.||Promote healthy, sustainable food systems.|
|5.||Build healthy, liveable cities.|
|6.||Stop using taxpayers' money to fund pollution.|
Countries, such as South Africa, with developmental constraints, render themselves more vulnerable to the effects of climate change. The risk posed by the effects of climate change together with South Africa's high poverty, inequality, crime, and political turmoil will significantly exacerbate mental health challenges in the country. It is hoped that the proposed new Climate Change Bill will be far reaching in tackling some of the serious challenges posed by climate change to health. In addition, we suggest following the six prescriptions for a healthy and green recovery as proposed by the WHO, in mitigating the substantial risks posed by climate change.