Extreme heat fueled by climate crisis it is often seen as a problem primarily for vulnerable sections of the population, such as the elderly. But it is people under the age of 35 who will bear the brunt of heat-related deaths as temperatures rise, new research suggests.
Although older people are susceptible to hot flashes, they currently account for the majority of cold-related deaths. As the world warms, younger people will suffer disproportionately as the burden of mortality shifts, with the new study estimating a 32% increase in deaths of people under 35 this century from heat if greenhouse gas emissions are not radically shortened.
“Most discussions of heat vulnerability focus on the elderly, but we found a surprising source of inequality in that the majority of heat mortality is in younger people,” said Andrew Wilson, a researcher at Columbia University who led the the study published in Science Advanceswith a group of nine other scientists. “We didn’t think we’d find this.”
The study is based on data drawn from deaths in Mexico, a country with extensive mortality records and high “wet bulb” temperatures, a measurement that takes humidity into account to determine the level of heat stress on people.
The researchers found that in the two decades to 2019 75% of heat deaths occurred among people under 35, while, conversely, almost all cold-related deaths were among those over 50.
Since most temperature-related deaths in Mexico, as in most countries, currently occur due to cold weather, the growing problem of extreme heat is likely to tip the scales toward more young people dying, the study suggests. This pattern could be replicated in other countries such as the United States and in Europe, Wilson said, because of the fundamental similarities in how different age groups respond to temperature.
“We see that cold-related deaths will decrease, mostly in older people, while heat-related deaths in younger individuals will increase,” he added. “Climate change is here, and how we adapt to it will be a very important factor in human health in the future.” We shouldn’t be shifting resources away from older people, but we certainly need to think more about the risk that younger people face.
There is no clear answer as to why there is an increased risk for younger people, but the researchers said there are likely to be a number of factors, such as physiological differences – for example, babies cannot sweat to produce heat and are dependent on caregivers – as well as occupational risks , as the working-age population that works outdoors while engaged in agricultural labor and construction.
In the US, the Biden administration has spent the past three years crafting the first federal rules to protect workers from intense heatalthough these provisions are likely to be wound back by President-elect Donald Trump.
The higher death rate among young people from the heat in a country like Mexico is influenced by the fact that there are more younger people in the population than older people, as well as risks such as working in the hot sun in the fields, said Christy Eby, an epidemiologist at the University of Washington, who was not involved in the research.
“However, routine exposure to higher temperatures also increases acclimation, which should lead to a lower risk,” Eby said, adding that more research is needed to fully understand this pattern and whether it extends to other countries.
“This study adds more nuance to understanding how different segments of the population may be affected by rising temperatures, and it is possible that, at least in Mexico, climate change will lead to more heat-related deaths in more young people,” said Samed Hattana, a physician and researcher at Penn Medicine whose she found her own job that heat-related cardiovascular deaths will increase in the coming decades due to the climate crisis.
Hattana said younger people are exposed to heat through work, school and recreational activities and “therefore may experience a disproportionate impact from climate change.”
“This highlights the importance of considering targeted measures, such as interrupting work for people working in hot environments or rescheduling sporting events to avoid extreme heat,” he said.
