Global warming already affects daily life worldwide, study finds

by Mike Gawrecki

• Recent studies have shown that the constraints on people’s daily lives imposed by climate change are already extensive and may increase as global temperatures rise. Elderly people are the most affected.
• The researchers used a “physically grounded” thermal model to analyze 75 years of global climate data.
• The global average number of hours per year that people are exposed to heat that severely limits their activity has doubled for young adults since the 1950s, while for older adults, it has increased from about 600 hours to about 900 hours per year.
• Parts of Southwest and South Asia, South America, and Australia have already experienced what the study researchers call “extreme habitability constraints,” which is also true for young adults.

As the terrible heat wave of March American West Bats With dangerous temperatures, and what the world braces itself for may be Another dazzling record-breaker for Super El Niño, a team of researchers has revealed a Study Seeing how global warming is already disrupting people’s regular daily activities.

Using 75 years of data spanning 1950 to 2024, the scientists identified a clear trend and concluded that while climate change is already severely limiting people’s daily lives, those effects are now widespread and likely to worsen as temperatures rise. Older adults and people in tropical regions are particularly affected.

The research team found that the global average number of hours per year people are exposed to heat that severely limits their activity has doubled for young adults since the 1950s, while it has increased from about 600 hours to about 900 hours per year for older adults.

However, these effects are not evenly distributed: parts of Southwest and South Asia, South America, and Australia have already experienced what researchers call “extreme habitability constraints” even for young adults.

The research team behind the study, led by Luke Parsons, an applied climate modeling scientist at The Nature Conservancy, said it used a “physiologically grounded” heat model to analyze 75 years of global climate data that researchers perceived as a gap in our understanding of the effects of ongoing and expected heat on people’s daily lives.

“There are all these different thermal metrics,” Parsons told MangaBay. “They’re very useful tools, but they carry these hidden assumptions about who’s being exposed. They often don’t differentiate between younger and older people,” for example. They are often more focused when it is too hot to work outdoors or when extreme heat threatens human survival.

Parsons continued: “We wanted to think about what we call a physiologically grounded approach here, ‘Can a person do (normal) daily activities? How does extreme heat outside affect or limit our daily lives?'” In other words: “Is this place livable?”

Instead of using a traditional heat index to answer this question, Parsons and his team used the Human/Environmental Adaptation and Threshold Limit Model (HEAT-Lim Model), developed by study co-author Jenny Vanoss of Arizona State University and her lab. That model was first applied by Vanos et al. on a paper published Nature communication In 2023.

Combining the output of the Heat-LIM model with global climate data over the past 75 years allowed researchers to determine what level of activity people can sustain without an uncontrolled rise in body temperature threatening their well-being.

“We looked at how hot and how wet it was from 1950 to the end of 2024,” Parsons said. “And we asked, for each hour of the day, if you’re a young adult who can sweat (efficiently) or an older adult who can’t cool down easily, when is it dangerously hot for you to participate in basic daily activities?” Young adults are defined in the study as those aged 18-40, while older adults are those aged 65 and over.

The team found that there are already places on Earth where it sometimes gets so hot and humid that it makes it unsafe for young or older adults to do more than lie down or sit outside. There are parts of Southwest and South Asia, South America, and Australia where even young adults are already experiencing what scientists call “extreme habitability limits.”

For older adults, the team found extreme limitations that make human life “unsustainable,” where in parts of southwestern and eastern North America, it is impossible for the human body to naturally compensate for environmental heat load; Tropical South America; West Saharan Africa; Southwest, South and East Asia; and Australia. They wrote: “Temperature and humidity severely limit the life expectancy of older adults across large parts of the tropics and subtropics.”

The researchers also looked at the global average number of hours per year that heat and humidity severely limit human activity and found that it “doubled for young adults from the 1950s to recent decades,” Parsons said. “And for older adults, it went from about 600 hours a year to about 900 hours a year.”

The estimate of 900 hours per year of livability limitations for older people is a global average, Parsons noted, combining averages for cool places and hot places. In some parts of the world, the restrictions are much worse.

“We’ve seen places in the Persian Gulf or sub-Saharan West Africa or South Asia or Southeast Asia, and some of these places, (see) about 2,000 to about 3,000 hours of the year (that are) so hot and humid that older adults can’t go about their daily lives safely if they don’t have access to indoor air.”

Data indicates that a large portion of humanity is already being affected by global warming, Parsons explained. “About 35% of the current world population lives in areas where annual maximum heat already severely limits what young adults can safely do outside. And for older adults, that number jumps to about 78%, (affecting) nearly four in five older adults. When it’s the hottest time of the year, (they’re) going to be really limited in what they can do outside.”

Parsons was particularly impressed that, even when considering young adults, about 1% of the world’s population already lives in places where it is hot enough during the hottest part of the year to make it unsafe to do any outdoor activity. “And that number increases to about 25%, or one in four, among older adults. That’s about 2 billion people.”

Duke University earth sciences professor Drew Schindel, who was not involved in the current study, said the study shows how “potentially damaging” global warming that has already occurred could be. “I’d say potentially,” he noted, “the kind of changes we’ve seen so far can be accommodated in most cases, at least in well-functioning countries.”

But, he added, “adaptation has limits, and as warming continues, it will become more difficult and more vulnerable to adapt, as we become more dependent on artificial cooling.”

It’s not hard to imagine conditions getting so hot that overtaxed electrical grids fail in very hot climates, Schindel said, meaning people would lose their cooling systems and therefore their ability to adapt to the “uninhabitable” conditions they’re experiencing.

“This is a risk not only for poorer tropical countries, but even for places like Texas or Arizona, where the grid may fail under the pressure of high AC demand in very hot summers,” he said. “So adaptation carries the risk of failure that may be small but (may) still have potentially huge consequences.”

Research like the current study is important because it can help countries, local governments and communities determine where vulnerable people are most exposed to heat so their adaptation resources can be directed, according to Cascade Tuholsk, assistant professor of human-environment geography at Montana State University.

“While numerous studies have documented how climate change is driving a rapid increase in extreme heat globally, this study expands our understanding of how the actual livability of locations for different populations is changing due to increased outdoor heat stress,” said Tuholske.

He continued: “This is really important because it shows that actual outdoor activities, such as farming or construction, should be limited due to exposure to rising heat and which populations live in these warming regions. Middle Eastern countries, (for example) where large numbers of migrant workers work outdoors, really stand out as areas of concern.”

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Quote:

Parsons, LA, Baldwin, JW, Guzman-Echavarria, G., Jay, O., Kalmas, P., Stoudemire, H., … and Wolff, NH (2026). Global warming threatens the livelihoods of young and older adults. Environmental Research: Health, 4(1), 015013. doi:10.1088/2752-5309/ae3c3a

Vanos, J., Guzman-Echavarria, G., Baldwin, JW, Bongers, C., Ebi, KL, & Jay, O. (2023). A Physiological Approach to Assessing Human Survival and Survivability to Heat in a Changing Climate. Nature communication14(1), 7653. doi:10.1038/s41467-023-43121-5

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Previously published with news.mongabay Creative Commons Attribution

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