Tackling sleepless nights caused by heat

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Tackling sleepless nights caused by heat

Published: 22 Aug. 2024, 20:03

Ban Ki-sung
The author is a senior managing director at K Weather.

“Viper’s Teeth / Dog’s Tongue.” This is a poem titled “Jungbok” by Hong Hae-ri. I’ve never seen such a short poem. After all, the hot summer day does not require a long explanation. The poet described the heat as the panting dog with its tongue out in the heat as fierce as a viper’s teeth. The expression is to the point — and it feels suffocating.

The tropical nights with the lowest temperature over 25 degrees Celsius (77 degrees Fahrenheit) have continued for 31 days since July 21 in Seoul. According to the Korea Meteorological Administration, it easily broke the previous record of 26 days in 2018. The “longest streak of consecutive tropical nights in 118 years” is likely to continue for a while. At this rate, it will likely surpass the most tropical nights in history, 36 days in 1994.

What caused the record-breaking continuation of tropical nights this year? Global warming would be the biggest factor. The U.S. National Oceanic and Atmospheric Administration said that July this year was the hottest month in history and the average monthly temperature broke records for 14 consecutive months from June 2023 to July 2024. The European Centre for Medium-Range Weather Forecasts released a report on the new highest average global temperature of 17.16 degrees Celsius on July 22. This means the temperature of the Earth’s atmosphere is unusually hot this summer.

Tropical nights are more common in the year when the temperature is higher. However, the average daily high in Seoul from July to August 17 this year was about 2 degrees Celsius — or about four degrees Fahrenheit — lower than in 2018, the year of the highest temperature on record. It was hotter than usual, but it was not the worst heat wave in Korea. Nonetheless, tropical nights are lingering longer. Why?

First, there have been so many tropical nights as frequent showers resulted in increased humidity. High humidity keeps the temperature from going down at night, causing hot tropical nights. From July 21 to Aug. 17, Seoul had showers for 20 days. It was about three times more frequent than the seven days with showers in 2018, the previous record for the longest tropical nights.

Second, Seoul’s average relative humidity during the same period was 76.4 percent. It was significantly higher than the previous record of 59.9 percent in 2018.

Third, Seoul’s average cloud cover was 6.5, meaning that clouds covered 65 percent of the sky, during the same period, about 1.6 times more than 4.1 in 2018. Clouds prevent radiative cooling, and more cloud coverage means more tropical nights. The unusual climate conditions this year significantly increased the continuation of tropical nights.

Tropical nights have a great impact on people’s health. When people can’t sleep well due to high temperatures, they feel fatigue and cannot concentrate. A lack of sleep lowers immunity and increases stress. Many people easily get annoyed or complain of having depression. It can be particularly dangerous for people with cardiovascular diseases or respiratory conditions such as asthma.

To tackle tropical nights, the indoor temperature should be adjusted, and drinking enough water at night is important. Light, cotton sleepwear is recommended, and regular sleep patterns should be maintained. Avoid eating too much at night and choose food options that are easy for digestion.

Nine years have passed since the 2015 Paris Agreement, a global agreement to prevent climate change. But greenhouse gas emissions are still increasing. If temperatures rise due to global warming, heat waves or tropical nights will occur more strongly and frequently in the future. As extreme heat waves hit the world this year, UN Secretary-General António Guterres warned that extremely hot weather is making the economy more difficult, widening inequality, undermining sustainable development goals and killing people. He underscored the importance of taking global actions as the number of deaths from heat is about 30 times higher than those from typhoons.

The Yoon Suk-yeol government should also actively participate in efforts to combat the climate crisis. It is necessary to raise socio-economic resilience and the pliability of the ecosystem to cope with future disasters from heat waves.

Translation by the Korea JoongAng Daily staff.