Climate Change is Taking Away Your Sleep... Quite Literally

Rising heat is reducing sleeping hours, especially in lower-income countries, says new study.

(Photo: iStockphoto)

You're still sleeping and someone turns the fan off. You're too sleepy to realise, so you continue sleeping till it gets really really hot and you wake up annoyed. This is a scenario we have all woken up to at some point. So we all know how precious is a good night's sleep.

And if the heatwave, floods, forest fires etc have not made you take climate change seriously, maybe this well. Climate change is reducing your sleep, according to a new study titled 'Rising temperatures erode human sleep globally,' published in a science journal, 'One Earth'.

The study has analysed data of over 47,000 people in 68 countries for two years.

"By 2099, suboptimal temperatures may erode 50–58 hours of sleep per person-year, with climate change producing geographic inequalities that scale with future emissions."

Four Highlights of the Study

• Warmer temperatures reduce sleep globally, amplifying the risk of insufficient sleep

• The elderly, women, and residents of lower-income countries are impacted most

• Those living in warmer climates lose more sleep per degree of temperature rise

• Climate change is projected to unequally erode sleep, widening global inequalities

Global temperatures are rising across the globe, and this temperature rise is not limited to the day, night-time temperatures are rising as well. The impact is higher on low-income country where access to electricity and cooling is also difficult.

The alarming thing is if we don't take adequate adaptation measures to deal with climate change and fail to stabilise emissions of green house gasses by 2100, "each person could be subjected to an average of 2 weeks of temperature-attributed short sleep each year."

Sufficient sleep is crucial for a good mental and physical health. "A lack of sleep has been associated with reduced cognitive performance, diminished productivity, compromised immune function, adverse cardiovascular outcomes, depression, anger, and suicidal behavior," said the study.

Indian Heatwave and Loss of Sleep

Indian and Pakistan saw a record breaking heatwave that started in March 2022. The heatwave resulted in loss of human life, impacted the global wheat supplied and caused forest fires and floods.

While the direct impact of this was experienced by the most vulnerable even in the two countries, the more widespread impact felt by almost everyone was heat-- higher temperatures during the day and the night.

Kelton Minor, from the University of Copenhagen, Denmark, who led the research, told The Guardian that night-time temperatures above 25 C in a city with a million people would mean 46,000 extra people will suffer from shorter sleep.

“And if you look at the heatwave that’s transpiring right now in India and Pakistan, we’re talking about billions of individuals exposed to conditions expected to result in considerable sleep loss,” he told The Guardian.

Parts of Delhi had touched 49 C during the heatwave.

Climate Change will Exacerbate Sleep Inequality

Developing, low-income countries will face loss of sleep far more than developed, rich countries. While all will be impacted, the "amount of sleep loss per degree increase may be disproportionately larger for people in lower-middle-income countries," found the study.

The negative effect of nighttime temperature on sleep duration is 2.8 times greater in lower-middle-income countries compared with those from high-income countries.

This is primarily because access to electricity, infrastructure, cooling technologies etc are critical to determining the extent to which temperature impacts sleep.