Nights Getting Hotter: Indonesians Lose the Most Sleep in Southeast Asia

Climate change is causing residents of various Indonesian cities to lose an average of 84 hours of sleep per year due to increasingly hot night-time temperatures, with around 7 of those hours directly attributed to human-caused climate change. This loss of sleep threatens physical health and public productivity.

A report from Climate Central, titled ‘Climate Change is Costing People Sleep’, reveals that globally, the average person lost nearly 56 hours of sleep per year due to high night-time temperatures during the 2020-2025 period. Of that total, approximately six hours, or more than 10 per cent, can be attributed to climate change-driven warming.

In Indonesia, the impact is far more severe, with residents of six major cities losing sleep hours exceeding the global average, making Indonesia one of the countries with the highest rates of sleep loss in Southeast Asia. Specifically, residents of Malang lose 59 hours of sleep per year, Bandung 61 hours, Medan 78 hours, Semarang 83 hours, Jakarta 84 hours, and Surabaya reaches 91 hours.

Courtney Howard, Chair of the Global Climate and Health Alliance, President-Elect of the Canadian Medical Association, and an emergency room physician, explained that adults need 7-9 hours of sleep per night for optimal health. Rising night-time temperatures endanger human sleep, with worse effects for residents of low-income countries, the elderly, and women.

‘Sleeping less than 7 hours per night is associated with impaired immune function and performance, as well as increased errors, pain, and accidents. If sleep deprivation continues regularly, it is linked to weight gain, diabetes, hypertension, cardiovascular disease, and an increased risk of death,’ Howard said, as quoted from a Climate Central statement.

The loss of sleep hours in Indonesia is relatively worse because it is compounded by the urban heat island effect, which amplifies night-time temperatures, especially in large cities like Jakarta, Surabaya, and Medan. High population density and a lack of green open spaces worsen heat accumulation.

Although air conditioning can help protect people from hot nights, access to cooling is strongly linked to income and its distribution is highly unequal in many hot countries, including Indonesia. Only about 35 per cent of global households had air conditioning in 2021, and the ownership rate in Indonesia is far below that figure, particularly among low-income communities.