The Links Between Climate Change and Mental Health
Patricio V Marquez
November 11, 2023
“Let’s stop putting our heads in the sand like ostriches, pretending that problems don’t exist. If you don’t address them individually and collectively, eventually they will overwhelm us.”
Nouriel Roubini, Professor Emeritus of Economics, Stern School of Business, New York University
As the UN Climate Change Conference, COP28, which is scheduled to take place in Dubai, United Arab Emirates, on November 30-December 12, 2023, draws near, it is important to keep in mind that climate change is one of the most pressing global challenges of our time.
As pointed out in a new report, in the past 12 months, the world experienced record-breaking temperatures, affecting around 7.3 billion people for at least 10 days. Global warming played a significant role in these high temperatures, particularly in tropical regions across South America, Africa, and the Malay archipelago, with approximately one-quarter of the global population being exposed to dangerous levels of extreme heat across land and sea during this period. Overall, the report estimates suggest that the average global temperature over the past 12 months was 1.32 ºC above that during the pre-industrial baseline period of 1850 to 1900, surpassing the previous increase of a record 1.29 ºC that was set from October 2015 to September 2016.
The record high temperatures and suffocating heat that we experienced this past summer, along with smoke-filled days from wildfires that sprang unannounced in different regions of the world, and the sheer destructive power of hurricanes, cyclones, and flooding that we witnessed, are vivid reminders that climate change is not a hoax. Rather, the evidence continues to mount showing that human activities are responsible for global warming. Indeed, the 2023 U.N. climate change report that assessed the causes and consequences of rising temperatures, concluded that:
“Global greenhouse gas emissions have continued to increase, with unequal historical and ongoing contributions arising from unsustainable energy use, land use and land-use change, lifestyles and patterns of consumption and production across regions, between and within countries, and among individuals.”
In a recent book, Megathreats, the economist Nouriel Roubini explains that climate change is part of a web of overlapping, interconnected, and serious threats that ominously face humanity. Illustrating the syndemic or interrelated nature of these threats, a growing body of evidence points out that climate change stands to have far-reaching consequences for the environment, the economy, and the well-being of people, contributing significantly to human suffering.
While the physical impacts of climate change are well-documented, the relationship between climate change and mental health is still a growing area of study. Here we offer a summary of an initial exploration about the connection between climate change and mental health, focusing on the various ways in which climate change can affect our psychological well-being and how we can adapt and mitigate its impacts.
How is Climate Change Negatively Impacting the Mental Health and Wellbeing of Populations?
In an influential paper published in 2011, Susan Clayton and Thomas J. Doherty argued that climate crisis is “as much a psychological and social phenomenon as a matter of biodiversity and geophysics.” They highlighted in the paper three broad types of possible mental health impacts: the acute trauma of living through climate disasters; the corroding fear of a collapsing future; and the psychosocial decay that could damage the fabric of communities dealing with disruptive changes.
A recent scoping review of available literature suggests that climate change is expected to impact mental health via a range of direct and indirect pathways. Direct pathways include exposures to several climate-related events—heat, humidity, rainfall, drought, wildfires, and floods. Indirect pathways largely operate through a range of social, political, and economic drivers of poor physical and mental health such as poverty, unemployment, and housing. Vulnerable people and places, especially in low-income countries, are at risk of being badly impacted.
Overall, climate change-related events have been associated with psychological distress, worsened mental health (particularly among people with pre-existing chronic conditions), increased psychiatric hospitalizations, higher mortality among people with mental illness, and heightened suicide rates. The effects of pressures on migration need to be considered as well (Lolas, F, GMHP Review 2022).
Anxiety, Depression, and Grief Come with Climate Change
One of the most immediate and direct impacts of climate change on mental health is the anxiety it can induce. Anxiety disorders are typically characterized by feelings of tension, intrusive thoughts or concerns, and persistent, intense worry and fear. The increasing frequency and severity of extreme weather events, such as hurricanes, wildfires, and floods, can leave individuals and communities living in fear of impending disasters. Uncertainty about the future, including concerns about personal safety, property damage, and economic stability, can lead to heightened levels of anxiety. This is particularly true for people living in vulnerable areas, such as coastal regions prone to sea-level rise and flooding.
Climate change also contributes to depression and grief. The loss of natural environments, biodiversity, and ecosystems can be deeply distressing for individuals who have a strong connection to nature. Additionally, as people witness the destruction caused by climate change, they may experience a sense of helplessness and despair, leading to depressive symptoms. These emotions can be particularly pronounced in communities that have experienced the loss of livelihoods due to environmental changes.
Post-Traumatic Stress Disorders (PTSD) after Extreme Weather Events and Natural Disasters
Case studies from climate-hit communities in Africa, Asia and the Pacific Islands suggest that the ‘not easily quantified and often overlooked’ non-economic loss and damage impacts cause significant human harm. The loss of traditional ways of living, cultural heritage, and biodiversity triggers the erosion of community cohesion and resilience and causes trauma, displacement, and danger, especially for the most vulnerable people and groups.
The consequences of extreme weather events and natural disasters can trigger symptoms of PTSD. Survivors of hurricanes, wildfires, and other disasters may suffer from flashbacks, nightmares, and heightened anxiety, impacting their overall mental health. Recovery from such events can be long and arduous, and the associated trauma can persist for years.
Forced Displacement and Migration Negatively Impact Mental Health
Climate change-induced forced migration can have profound psychological effects before, during, and after migration occurs, including loss of family connections and social support networks, cultural dislocation, and the stress of adapting to a new environment. Displaced individuals often face discrimination and challenges in accessing essential health and other social services, finding stable housing and employment, all of which can contribute to mental health problems. For example, it has been observed that Central American migrants at the North American border (Ponce de León, C, GMHP Review 2022), show violence-related symptoms and the impact of family loss on mental health. Children and adolescents are particularly vulnerable, requiring age-specific interventions to address psychological symptoms, substance abuse, and interpersonal difficulties.
Air Pollution and Mental Health
As wildfires raged across Canada in the summer of 2023, covering entire parts of the United States with smoke that reached as far as Norway, they became in the words of Angel Hsu, the "visible link between climate change and air quality”.
Climate change is associated with increased air pollution, which has been linked to a range of mental health issues. Studies have shown that exposure to air pollution is correlated with cognitive decline, mood disorders, and an increased risk of psychiatric hospitalizations. The fine particular matter (PM) in polluted air, a complex mixture of solid and liquid particles suspended in the air from smokestacks, fires, or cars, can penetrate the bloodstream and affect the brain, potentially leading to mental health problems among populations in different age groups. For example, a study in China showed that long-term exposure to ambient PM was associated with greater odds of screening positive for childhood attention deficit hyperactivity disorder (ADHD). Another study found that older adult populations, particularly in high income countries, have a higher risk of depression related to hazardous environmental pollutants exposure due to their pulmonary and neural vulnerability to inflammatory triggers (e.g., air pollutants) and have a higher chance of developing related physical comorbidities associated with worsened psychiatric health. In the United States, a related study at JAMA, involving a nationwide Medicare cohort with late-onset depression diagnoses, observed statistically significant harmful associations between long-term exposure to common levels of air pollution and increased risk of depression diagnosis after age 64 years, controlling for climate co-exposures, neighborhood greenness, socioeconomic conditions, health care access, and urbanicity level.
Although most studies have focused on urban pollution, it has been noted that many of the same toxic chemicals in city air can also be found in wildfire smoke (e.g., nitrogen dioxide, a harmful gas that can also react with other compounds in the air to produce secondary pollutants, such as ozone and PM), and often in far larger quantities. All of these compounds have been found to negatively affect mental health. The above-mentioned study in JAMA showed, for example, that across the United States, the more people are exposed to ozone, the higher their risk of developing depression. A study in Britain showed that people who routinely breathe air with PM2.5 levels of at least 10.6 micrograms per cubic meter have 15 percent higher risk of depression than those who live in areas with less than 9.3 micrograms of that pollutant per cubic meter, a number that pales when compared to the PM 2.5 level of 196 micrograms per cubic meter measured in the air in New York City on June 7, 2023, caused by the Canadian wildfire haze that spread at that time.
Moreover, several studies have indicated that short-term exposure to air pollution is associated with increased risk of hospitalization or emergency department visits of depression as well as anxiety. Similarly, the results of a recent study at JAMA Psychiatry suggest an association between long-term exposure to low levels of multiple air pollutants and depression and anxiety.
As climate conditions actively interact with hazardous pollutants in the air that we breathe every day, it has been suggested that living in areas with higher levels of air pollutants and higher ambient temperature could contribute to additional risk of being admitted to a hospital for individuals with psychotic disorders (e.g., false beliefs, delusions, hallucinations, and disorganized thoughts). A related study found evidence of a positive association between exposure to ozone and fine particles and mental health-related emergency department in California, with increased risks for sub-categories of mental health including neurotic, mood, and affective disorders, depression, bipolar, self-harm/suicide, and homicide/inflicted injury outcomes.
Food Insecurity, Undernourishment, and Mental Health
Climate change is disrupting agricultural systems, negatively impacting global agricultural productivity growth, causing food shortages and raising concerns about food insecurity. Climate extremes, economic downturns, and armed conflicts and violence are raising the prevalence of undernourishment, which had been decreasing for years. FAO data show that in 2022, an estimated 735 million people faced chronic hunger, marking an increase of approximately 122 million since 2019. This issue has significant implications for mental health, as poor nutrition and hunger can lead to mood disorders, anxiety, and reduced cognitive functioning, particularly in children.
Climate Activism is a Positive Coping Mechanism
Across the world, as noted in a World Economic Forum article, climate fear has taken hold in younger generations. A The Lancet study shows that among the 10,000 16–25-year-olds surveyed in ten countries, almost 70 percent reported they were either extremely worried or very worried about climate change. This number was even higher on average in developing countries that are expected to bear the brunt to climate change-related destruction—for example, 84 percent of youths in the Philippines, 78 percent in India, 77 percent in Brazil, and 51 percent in Nigeria. Likewise, the results of a 2022 survey in the United States indicate that 64 percent of adult population responders are worried about global warming.
While people worry about the negative impact of climate change, growing climate activism and engagement in climate change mitigation efforts can have a positive impact on mental health. Many individuals find meaning and purpose in advocating for environmental sustainability. Taking action to address climate change can provide a sense of agency and hope, counteracting some of the negative emotions associated with this issue.
Resilience and Adaptation
While the international community has up to now placed particular attention on mitigation of climate change (i.e., human interventions to reduce emissions or enhance the sinks of greenhouse gases), building resilience to impacts of climate change is also crucial. Indeed, as Asif Saleh, a Non-resident Fellow at the Center for Global Development, has noted, mitigation should not preclude focusing on adaptation to current conditions, since much of the world, especially billions of people in low-income countries, are already bearing the brunt of its devastating impacts. Dealing with the mental health impacts of climate change will need to involve developing adaptive strategies at the individual, community, and societal levels. Indeed, developing, strengthening, and promoting access to and use of integrated mental health services under universal health coverage arrangements, support networks, and coping mechanisms can help individuals better handle the psychological challenges associated with climate change.
The effects of global warming are progressively more severe, with a potential to have major disruptive social and economic impacts globally. The 2023 U.N. climate change report has reminded us that every increment of warming will come with more frequent, extreme, hazardous, and destructive weather events. As discussed above, climate change-related events are also a significant threat to mental health and wellbeing.
Going forward, efforts to mitigate and adapt to climate change should also include mental health support and resilience-building to help individuals and communities navigate the emotional toll of a changing world. And, as suggested in a study in The Lancet, future research is also needed to understand the unequal effects of climate change on the mental health of vulnerable and marginalized groups to inform better prevention, planning, response, and adaptation tools and efforts.