Impact of extreme heat ‘underestimated’ on those 60 and older: Lancet study

The impact of extreme heat on people 60 years or older has been “underestimated” a new study published in The Lancet suggests.

Heat limits were evaluated in young (18–39 years), middle-aged (40–59 years), and older adults (60 years) to evaluate how global warming impacts different age groups as the planet continues to warm up.

Health academics from Stanford University estimated that if the planet gets 1.5°C warmer, 22 per cent of the world’s older adult population will experience “frequent and widespread exceedance of heat-compensability limits,” which means their bodies will no longer be able to cool them down to compensate for extreme heat levels.

Currently, Earth’s 2025 average temperature sits at 2.14 degrees Fahrenheit (1.19°C), according to NASA . However, 2024’s temperatures (2.30 degrees Fahrenheit, 1.28°C) were “the warmest on record.”

“As the planet warms, understanding where, when, and to what extent environmental conditions will exceed human heat tolerance becomes crucial,” the study states.

“Intolerable heat will be experienced at much larger scales and for longer durations, affecting far more people than previously thought.”

India was found to have the largest population in the world exposed to at least 180 hours of “uncompensable heat stress” per year on average at 3°C warming, at 648.4 million people.

“India, Pakistan, Bangladesh, Myanmar, and Niger warrant particular attention, exceeding both the absolute and proportional exposure thresholds,” the study states.

It was also found that at least 10 million older adults (at least 80 per cent of the older adult population) experiences 180 hours or more of “heat limit exceedance annually.”

In addition, older adults in south Asia and the Persian Gulf “could face sustained, day-and-night exposure for three consecutive months at 3°C or more warming.”

The study states that “the number of people aged 60 years and older is projected to double from one billion in 2020 to 2.1 billion in 2050, representing 21 per cent of the world’s population.”

Therefore, as the population continues to age, older adults will face “disproportionately severe and imminent risks” to their health.

The study also estimates that more than two-thirds of this population is “expected to reside in low-income and middle-income countries,” many of which “are also on the frontline of emerging uncompensable heat stress.”

“By overlooking the ageing population and heat vulnerability of older adults, previous projections based on limits for young adults might have seriously underestimated the frequency, geographical extent, and imminence of uncompensable heat stress with climate change.”