2.4 billion people are exposed to high nighttime temperatures every
Due to climate change caused by the use of fossil fuels, about 2.4 billion people around the world are exposed to high night temperatures for at least 2 weeks a year.
Climate change caused by the use of coal, oil and natural gas has resulted in a global increase in nighttime temperatures, while extreme heat and related sleep disorders have serious public health impacts.
Scientists from the international research organization Climate Central analyzed how climate change is increasing night temperatures around the world and how many people are affected by high night temperatures and face health problems every year between 2014 and 2023.
According to the analysis, around 2.4 billion people a year experience at least two weeks with minimum temperatures above 25 degrees Celsius due to climate change. As nighttime temperatures increasingly rise above comfortable and safe levels, health experts warn of climate change-induced sleep deprivation, acute and chronic diseases and mental health problems.
According to the analysis, high nighttime temperatures are particularly dangerous because they prevent the body from cooling down and recovering from daytime heat. While this increases the risk of stroke, other cardiovascular conditions and death, warm nights also reduce the quality and duration of sleep. Yet this in turn has a wide range of negative effects on physical and mental health, cognitive functioning and children's brain development and learning. Short and poor quality sleep is also likely to shorten life expectancy and increase the risk of accidents and injuries.
The impacts of high night-time temperatures vary between and within countries, with low-income groups disproportionately affected by temperatures due to differences in housing quality and access to air conditioning.
Michelle Young, Climate Impacts Research Fellow at Climate Central, stated that climate changes in many parts of the world have led to an increase in nighttime temperatures:
"In the last decade, 2.4 billion people have experienced at least 2 more weeks a year of nights above 25 degrees Celsius due to climate change. These findings once again show the human impacts of a warming world, with many lives disrupted by climate-induced nighttime heat, sleep deprivation and the physical and mental health impacts that come with it. With this year set to be the hottest on record, it has never been more important to stop burning fossil fuels like oil, coal and gas and protect forests to prevent global temperatures from rising further."
Nick Obradovich, Chief Scientist for Environmental Mental Health at the US-based Laureate Institute for Brain Research, said that scientific research shows that higher nighttime temperatures harm sleep.
Emphasizing that the world is experiencing increasingly warmer nights due to climate change, Obradovich said, "This rise in nighttime temperatures, along with the associated loss of sleep, brings with it a range of physical and mental health risks. Some demographic groups, such as low-income people and the elderly, are particularly hard hit. Sleep is a critical component of well-being, and to protect it we will need to help people adapt to warmer nighttime temperatures, while seeking to reduce the degree to which these temperatures increase over time in the future."
