Climate Change and Mental Health: The Impact of Extreme HeatClimate Change and Mental Health: The Impact of Extreme Heat Introduction Climate change is increasingly recognized as a significant threat to both physical and mental health. Recent discussions have primarily focused on climate anxiety, but research reveals a broader impact, particularly from extreme heat. Impact of Extreme Heat on Mental Health The Intergovernmental Panel on Climate Change (IPCC) has concluded that rising global temperatures are negatively affecting mental health. Heatwaves have been linked to increased hospital admissions and emergency psychiatric visits, especially among individuals with pre-existing mental health conditions. Moreover, suicide rates have shown a correlation with rising temperatures, although the connections are complex. Additionally, poor sleep, a common consequence of extreme heat, can exacerbate mental health issues. Consequences of Extreme Heat Extreme heat can disrupt social behavior and interactions. Research indicates a link to increases in violent acts, which can further negatively impact mental health. Factors such as poverty, social isolation, and certain medications can amplify the vulnerability of individuals with mental health conditions to extreme heat. Research Gaps and Policy Lag Most research on climate change and mental health has been conducted in developed countries, leaving substantial gaps in understanding for the Global South. Policymaking has also lagged, with only 3% of climate pledges under the Paris Agreement addressing mental health. Policy Recommendations Integrating mental health into climate change policies, such as heat action plans, is essential. Nature-based policies that expand access to green spaces and transport policies that promote active modes of transport can simultaneously benefit mental health and the environment. Conclusion Extreme heat poses a significant threat to mental health. A comprehensive understanding of the impact and mechanisms linking heat to mental health is crucial for developing climate-resilient solutions and effective mental health interventions. Researchers, policymakers, and practitioners must prioritize this neglected area to promote a world where everyone can thrive, regardless of the impacts of climate change.
In recent years, discussions about the impact of climate change on mental health have focused primarily on climate anxiety.
However, this concern about the future of the Earth and humanity in the face of global warming is not the full picture.
Research contributes to a better understanding of the damage that climate change, particularly extreme heat, can cause to mental health.
The latest climate impact assessment report from the Intergovernmental Panel on Climate Change (IPCC) concluded with very high confidence that rising global temperatures are having a “negative impact” on mental health in regions around the world.
Research shows that heatwaves can lead to an increase in both hospital admissions of people with mental health problems and emergency psychiatric visits. People with pre-existing mental health problems are also at increased risk of dying during periods of high temperatures.
Furthermore, suicide rates have been shown to increase with rising temperatures and are expected to increase in a warmer world, although the links with climate change are complex and exacerbated by other factors.
Despite these research findings, there are still significant gaps in understanding the biological, psychological, social, and environmental interactions between mental health and heat.
And policymakers have a huge amount of catching up to do, as mental health barely figures into climate-related policies and commitments around the world.
How heat can affect mental health
Being in the middle of a heatwave can feel overwhelming. In general, being hot and uncomfortable can affect a person’s mood, causing some to feel more irritable and stressed. This can have a knock-on effect on behavior. For example, research shows that people are more likely to tweet negative comments during a heatwave.
Extreme heat can have an even greater impact on sleep. Research shows that warmer nights affect human sleep worldwide – and the effect is three times greater for people living in lower-income countries.
While poor sleep in hot and humid conditions is unpleasant for anyone, poor sleep can actually make the situation worse for people with mental health problems.
However, not all heat is bad for mental health. Many people believe that they are happier on sunny days and some studies confirm this.
For example, a 2023 study in Switzerland found that mood among the general population improves as temperatures rise. However, the study also found that the opposite is true for people with anxiety, depression and psychosis, who more often experience low mood.
Consequences of extreme heat
The impact of extreme heat on a person’s mood has implications for social behavior and interactions.
There is a growing body of research linking extreme heat to increases in violent behavior, such as homicide, sexual assault and sexual assault, which in turn can negatively impact mental health.
For example, a study conducted in India, Nepal and Pakistan found that for every 1C increase in annual temperature there was a 4.5% increase in violent acts. This finding alone is an indicator that heat affects a person’s psychology, but there are so many other factors to consider.
There are other possible social factors that could explain this link. People who already live with mental health problems may be more vulnerable to the impact of extreme heat because of social factors that put them at greater risk.
Because of the link between mental health problems and poverty, people with mental health conditions are more likely to live in less energy-efficient homes, have less access to adaptation mechanisms such as air conditioning, be more socially isolated, or have occupations that expose them to greater exposure to extreme heat.
Finally, certain medications for mental health conditions – such as some antidepressants or antipsychotics – can interfere with the body’s ability to regulate temperature, meaning people who take these medications may be more vulnerable in high temperatures. This may explain why people who take these medications are at higher risk of hospitalization or death during heat waves.
A patient in the UK who takes antipsychotics – medications for mental health problems where symptoms include psychotic experiences – was quoted in the BMJ last year explaining how he was affected by extreme heat. He said:
“(Many) summers I had also noticed that I was struggling to cope with the heat as the weather in the UK became more extreme. I would sweat profusely, my skin would feel clammy and I would feel very tired, irritable and have difficulty thinking… I had no idea that this was related to my medication.”
Prescribing appropriate medications for specific mental health conditions and protecting people taking these medications from the potential adverse effects of heat are major clinical and policy priorities.
Research gaps
To date, most studies on climate change and mental health have been conducted in Europe, North America and Australia. This means there are huge gaps in research for the Global South, which is facing some of the worst impacts of climate change.
A new Wellcome-funded project called Connecting Climate Minds aims to develop a research and action agenda on climate change and mental health. As part of this project, 900 people shared their experiences of the impact of climate change on mental health around the world.
One of them is Laila, a teacher working in Jordan. She suffers from stress, anxiety and depression. At her worst, she admits that she struggles to teach and finds it hard to communicate with the children.
In recent years, these episodes have become more frequent and severe. Her psychologist noted that Laila’s mental health seemed to deteriorate during the country’s extreme heat waves — something that is becoming increasingly common in the region.
Watch the full interview below.
Wellcome will also launch a call for funding later this year, focusing on uncovering the mechanisms underlying the link between heat and mental health in the world’s hardest-hit communities.
The aim is to gain a global understanding of the biological, psychological, ecological and social connections surrounding extreme heat, which will in turn lead to better climate-resilient solutions and mental health interventions.
Policy making is lagging behind
As with research, there are gaps in policymaking on mental health and climate change.
Most countries currently do not consider mental health in climate change policies, such as heat action plans. Currently, mental health is only mentioned in 3% of climate pledges that national governments submit under the Paris Agreement.
South Australia is one of the few states that is already doing this. South Australia’s warning system includes public heat warnings, health advice and targeted support for at-risk groups, including people with mental health conditions, so they can get help if they need it. In Athens, a city that is more frequently and severely affected by heatwaves, psychologists are being deployed to support older people who feel lonely in the heat.
Research has shown that nature-based policies that improve access to green and blue spaces, and transport policies that encourage active modes of transport, also have positive effects on mental health and the environment.
But right now, climate change is one of the biggest threats to physical and mental health worldwide. Extreme heat is more deadly than hurricanes, floods and tornadoes combined. Heat stress can worsen underlying conditions – such as heart disease, diabetes, asthma – and can increase the risk of accidents and the transmission of some infectious diseases. And that’s not to mention the huge hidden costs of rising rates of poor mental health.
Research into the impact of climate change on mental health remains limited and inconsistent. A better understanding of how and why extreme heat negatively impacts mental health is essential to achieving a world where no one is held back by mental health issues, even in the context of a changing climate.
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