By Abbas Nazil
Climate change has at least doubled heat-related sleep loss in major cities around the world over the past five decades, with rising nighttime temperatures increasingly threatening public health, according to a new report by Climate Central.
The analysis, which examined 1,338 major cities globally, revealed that between 2020 and 2025, the average person lost nearly 56 hours of sleep each year due to elevated nighttime temperatures.
More than 10 per cent of those lost sleep hours were directly linked to climate change caused largely by greenhouse gas emissions from fossil fuels and widespread deforestation.
The report described the findings as the first to quantify the number of sleep hours lost because of climate change by combining climate attribution science with scientific evidence on the impact of heat on sleep patterns.
According to the analysis, climate-related sleep disruption has at least doubled since the early 1970s in almost every city studied.
The highest levels of climate-driven sleep loss were recorded across cities in the Middle East, while southern India, Southeast Asia and parts of West Africa, including Nigeria, Niger and Burkina Faso, also experienced significant declines in sleep quality due to warmer nights.
Researchers estimated that residents of some West African cities lost more than 65 hours of sleep annually because of high nighttime temperatures, with approximately 10 to 11 hours directly attributable to climate change.
Climate experts warned that warmer nights make it more difficult for the human body to cool down after exposure to daytime heat, limiting recovery and increasing the risk of cardiovascular diseases, stroke, poor mental health, lower workplace productivity and premature death.
The report identified infants, older adults, pregnant women and low-income communities as the groups most vulnerable to heat-related sleep disruption because they often have limited access to cooling systems, quality housing and other protective measures.
Climate Central’s Vice President for Science, Dr. Kristina Dahl, said the findings expose another overlooked consequence of global warming.
She said the analysis demonstrates how climate change is translating into measurable hours of lost sleep across more than 1,300 cities worldwide, adding that climate-driven temperature increases have at least doubled heat-related sleep loss since the early 1970s.
Chair of the Global Climate and Health Alliance, Dr. Courtney Howard, warned that inadequate sleep weakens the immune system, increases the likelihood of chronic diseases and accidents, and reduces productivity in workplaces.
She called on governments to strengthen climate adaptation measures while intensifying efforts to reduce greenhouse gas emissions to protect public health.
The researchers also noted that nighttime temperatures are rising faster than daytime temperatures as global warming accelerates, making sleep disruption an increasingly serious public health challenge that requires urgent climate action and improved urban adaptation strategies.
