Climate Change Has Doubled Heat-Related Sleep Loss Over the Last 50 Years: Study
New Climate Central analysis finds the average person now loses nearly 56 hours of sleep annually due to high temperatures, with climate change responsible for more than 10% of that loss
A new global analysis by Climate Central has found that climate change has at least doubled temperature-related sleep loss in nearly every major city worldwide since the early 1970s, highlighting a growing but often overlooked public health consequence of global warming.
The study, which analyzed 1,338 major cities across the globe, estimates that the average person lost nearly 56 hours of sleep annually between 2020 and 2025 due to high ambient temperatures. More than 10% of that sleep loss was directly linked to climate change, largely driven by greenhouse gas emissions from burning fossil fuels and deforestation.
According to Climate Central, this is the first study to quantify the number of sleep hours lost specifically because of climate change by combining climate attribution science with research on the impact of heat on human sleep.
Heat Disrupting Sleep Worldwide
Researchers found that rising nighttime temperatures are becoming increasingly common as global temperatures climb. Unlike daytime heat, hot nights prevent the human body from cooling down, making it difficult to achieve restorative sleep.
The study concludes that climate change has at least doubled heat-related sleep disruption in nearly every one of the 1,338 cities examined since the early 1970s.
Middle East and South Asia Among Worst Affected
The highest climate change-related sleep losses were recorded across the Middle East.
Residents in cities across Saudi Arabia, Oman, and the United Arab Emirates lost between 55 and 87 hours of sleep each year due to elevated nighttime temperatures, with 12 to 16 hours directly attributable to climate change.
Southern India and several Southeast Asian countries also experienced severe impacts, where people lost 78 to 91 hours of sleep annually, including 8 to 9 hours linked specifically to climate change.
Cities across West Africa, including parts of Niger, Nigeria, and Burkina Faso, recorded annual sleep losses exceeding 65 hours, with approximately **10 to 11 hours attributed to climate change.
Health Risks Extend Beyond Fatigue
Scientists warn that rising nighttime temperatures pose significant health risks beyond sleep deprivation.
Poor sleep is associated with:
- Reduced immune function
- Higher risks of cardiovascular disease
- Increased incidence of diabetes and hypertension
- Cognitive impairment
- Lower workplace productivity
- Greater risk of accidents and injuries
- Negative effects on children’s brain development and learning
The study notes that infants, older adults, pregnant women, and low-income communities are particularly vulnerable because of limited access to cooling technologies and poorer housing conditions. Urban heat island effects further intensify nighttime temperatures in cities.
Scientists Call for Urgent Action
Dr. Kristina Dahl, Vice President for Science at Climate Central, said the findings demonstrate that climate change is affecting people’s daily lives in measurable ways. “This analysis reveals how climate change is translating into measurable hours of lost sleep for people around the world. Across more than 1,300 cities, climate change has at least doubled temperature-related sleep loss since the early 1970s.”
Dr. Courtney Howard, Emergency Physician and President-Elect of the Canadian Medical Association, emphasized that adults require 7 to 9 hours of sleep each night for optimal health.
She warned that chronic sleep deprivation caused by increasingly hot nights can contribute to obesity, diabetes, hypertension, cardiovascular disease, impaired immunity, workplace errors, and even increased mortality.
Health experts say the findings strengthen the case for both climate adaptation measures, including improved urban cooling and access to air conditioning, and rapid reductions in greenhouse gas emissions to safeguard public health and productivity.
The writer of this article is Dr. Seema Javed, an environmentalist & a communications professional in the field of climate and energy
