Climate change could deny the human race sleep.
Scientists have predicted that rising temperatures could take away between 50 and 58 hours of sleep per person per year - just under 10 minutes per night - by the year 2099.
The study claims that sleep loss will be significantly larger for people from lower-income countries as well as for older adults and females.
Higher global temperatures will cause a lack of sleep as the body's core temperature needs to drop before humans can begin their slumber - which is difficult to achieve in hot surroundings.
Study author Kelton Minor, from the University of Copenhagen in Denmark, said: "Across seasons, demographics, and different climate contexts, warmer outside temperatures consistently erode sleep, with the amount of sleep loss progressively increasing as temperatures become hotter.
"We show that this erosion occurs primarily by delaying when people fall asleep and by advancing when they wake up during hot weather."