A new research analyzing 1,338 major cities across the world says that sleep loss due to increased temperature linked to climate change has at least doubled globally since the early 1970s. India is among the places most vulnerable to such sleep loss.
According to the study by global climate research organisation Climate Central, an average individual in cities in South India currently experiences 78–91 hours of annual sleep loss, out of which 8–9 hours are the direct outcome of climate change. The figure placed South Indian cities among the most affected globally outside West Asia.
Globally, according to Climate Central, the average person loses nearly 56 hours of sleep every year due to high temperatures. More than 10% of that sleep deprivation was due to climate change.
“This analysis reveals how climate change is translating into measurable hours of lost sleep for people around the world. By combining the latest climate attribution science with research on how heat affects sleep, we can now quantify a hidden but growing consequence of rising temperatures,” said Kristina Dahl, vice-president for science, Climate Central.
Southern Indian states among most affected
The report analyses the experience of Indian cities in detail.
In India, the southern states have recorded the highest overall temperature-related sleep loss, according to the study. Puducherry, the union territory in South India, records the highest annual sleep loss at 92 hours per person, followed by Andhra Pradesh at 88.6 hours and Kerala at 88.3 hours.
“This suggests that persistently hot and humid nights are not only reducing sleep but that climate change is increasingly amplifying these losses across some of India’s hottest regions,” says Climate Central.
Tamil Nadu and Karnataka, among Indian states, show the strongest climate change trends. Tamil Nadu appears to be the state most affected by climate change, where an average of 7.9 additional hours of sleep loss per person occurs annually due to climate change-related temperature rise, the highest in the country.
Rajasthan, Maharashtra, Uttar Pradesh show sleep loss
Rajasthan at 7 hours also record very high climate change-induced sleep deprivation, though it records lower overall sleep loss than southern coastal states.
“Maharashtra has the largest representation in the dataset (22 cities), indicating that heat-related sleep disruption is widespread across the state. Residents lose an average of 76.3 hours of sleep annually, of which 5.8 hours are attributable to climate change,” says the Climate Central release.
“Uttar Pradesh, despite having 11 cities in the dataset, records a comparatively lower climate change signal (4.9 hours), although people still lose nearly 69 hours of sleep each year due to high night time temperatures,” it adds.
West Asia is the global topper, West Africa follows
India is close to West Asia, which experienced the highest levels of climate change-attributed sleep loss between 2020 and 2025, says the analysis. “Cities in Saudi Arabia, Oman, and the United Arab Emirates lost between 55 and 87 hours of sleep annually due to higher night time temperatures, with 12 to 16 of these lost due to climate change,” says a Climate Central release.
“…in some cities across West Africa, including cities in Niger, Nigeria, and Burkina Faso, people lost 65 hours of sleep or more per year, including about 10 to 11 hours linked to climate change,” it adds.
Night time heat spike
Quality sleep is critical for health and well-being. Climate change is shooting up night-time temperatures globally, affecting sleep and leading to a range of serious physical and mental health impacts.
“Adults need 7 to 9 hours of sleep per night for optimal health. Increases in night-time temperatures harm human sleep, with a larger effect seen in residents from lower-income countries, older adults, and in women,” observed Courtney Howard, managing director, emergency physician, chair of the Global Climate and Health Alliance and President-Elect of the Canadian Medical Association.
“Sleeping less than 7 hours per night is associated with impaired immune function and performance, and increased errors, pain and accidents. If poor sleep continues on a regular basis, it is associated with weight gain, diabetes, hypertension, cardiovascular disease and increased risk of death,” added Howard.
“As climate change drives more frequent and intense hot nights, sleep disruption should be recognised as a growing concern for both public health and human productivity,” Howard said. “These findings reinforce the need for adaptation measures that address inequities, and urgent decreases in greenhouse gas emissions to protect health and prosperity.”