In recent years, various regions, including Europe, have been hit by heatwaves. Among the concerns raised by scientists are high-humidity heatwaves. In May to June 2022, a heatwave in South Asia recorded a maximum wet-bulb temperature (temperature with 100% humidity) of 33.6°C in Pakistan.

According to a 2010 study, a wet-bulb temperature of 35°C is considered the safe limit beyond which the body cannot effectively regulate its temperature. Exceeding this limit leads to continuous rise in body temperature, increasing the risk of heatstroke with prolonged exposure. Furthermore, not only physical health but also mental health effects are worrisome.

In the United States, many cities have set up cooling centers to provide relief from the heat, but some people still don’t have access to these facilities. Additionally, high energy costs and frequent power outages due to heatwaves and wildfires leave some people unable to use their air conditioners.

Climate change is not a future issue; it is happening right in front of us. Understanding the risks we face is crucial to finding solutions.

“Heat is an invisible killer,” says Dr. Maharankal, head of the Indian Public Health University. He refers to the fact that more than 300 million people in India are exposed to the risks of extreme heat due to a lack of cooling devices. This situation is also relevant to us living in Japan, given the recent scorching temperatures.

Heatwaves threaten not only individual health, with risks of heatstroke, cardiovascular diseases (heart failure, etc.), and respiratory illnesses, but also impact access to healthcare services.

So, what does the future hold for heat and health? For instance, the CDC points out that in recent decades, heatstroke and related death rates have decreased in the United States, attributed partly to the widespread use of air conditioning.

However, we need to take a longer-term perspective. Measures such as increasing green spaces with cooling effects and promoting green buildings that balance livability and environmental performance at the municipal and national levels may help.

We stand at a major crossroad between heat and livability.

The sweltering heat has arrived again this year. Under the scorching sun and clinging humidity, I, who should enjoy summer, feel drained of energy.

And it’s no wonder; there seems to be a significant connection between heatwaves and mental health. The increase in suicide rates from spring to summer is said to be particularly pronounced during heatwaves. In certain regions of the United States and Mexico, every 1-degree increase in average temperature leads to a 1-2% increase in suicides.

Heatwaves can have mild to moderate effects on mental health, causing increased depression, anxiety, irritability, and anger.

Furthermore, some people experience “eco-anxiety,” a vague sense of anxiety and fear about the future due to recurring extreme weather events. Personally, after studying abroad in Northern Europe where heat was not an issue until I returned to Japan and faced consecutive scorching days at 38 degrees Celsius, I felt worried about what the future might hold.

So, how should we address mental health in the face of these environmental factors? Of course, health maintenance is a top priority. Adequate sleep in an appropriate environment is essential, as heat can inhibit deep sleep and lead to daytime stress. Additionally, summer nights with longer daylight hours can lead to insomnia. Properly using air conditioning and adjusting room temperature are crucial for quality sleep.

Yet, we should not be shortsighted in dealing with the current situation and focus on what we can do to reduce both future and personal burdens.

The energy used for air conditioning in the United States is roughly equivalent to the energy used by over 1 billion people in Africa throughout the year. However, the unstable power grid presents a challenge to air-conditioning-dependent communities, particularly those with Black and Latinx working-class populations.

The World Health Organization (WHO) highlights the need to include mental health support in national responses to climate change in a new policy outline presented at the Stockholm+50 environmental summit.

Climate anxiety, or environmental anxiety, may be seen as our minds raising alarm about climate change. Cherish moments of feeling in control by spending time with family in nature and taking small actions within reach.