A recent study published in The Lancet highlights alarming findings regarding the effects of extreme heat on individuals aged 60 and above, suggesting that the risks have been significantly underestimated. Researchers from Stanford University evaluated how escalating global temperatures could impact various age groups, with a particular focus on the vulnerabilities of older adults as climate change intensifies.
Extreme Heat and Its Consequences
As global temperatures rise, the study projects that if the planet’s temperature increases by 1.5°C, a staggering 22 per cent of the elderly population worldwide will face “frequent and widespread exceedance of heat-compensability limits.” This means that their bodies will struggle to regulate heat, leading to severe health risks. Current data indicates that the global average temperature is already about 2.14 degrees Fahrenheit (1.19°C) above pre-industrial levels, with 2024 recorded as the hottest year to date at 2.30 degrees Fahrenheit (1.28°C).
The study emphasises the necessity of understanding the geographical and temporal aspects of heat exposure. “As the planet warms, understanding where, when, and to what extent environmental conditions will exceed human heat tolerance becomes crucial,” the research asserts. It warns that the experience of intolerable heat will likely affect a far broader demographic than previously anticipated.
Regions at Risk
India has been identified as having the highest number of residents exposed to at least 180 hours of “uncompensable heat stress” annually, with an estimated 648.4 million people at risk under a scenario of 3°C warming. Other countries, including Pakistan, Bangladesh, Myanmar, and Niger, are also highlighted as facing significant heat exposure challenges.
The study reports that over 10 million older adults globally—representing at least 80 per cent of the older demographic—experience 180 hours or more of heat limit exceedance each year. Notably, older individuals in South Asia and the Persian Gulf may be subjected to extreme heat for sustained periods, potentially facing continuous exposure for three months at temperatures exceeding 3°C.
The Growing Elderly Population
The global population aged 60 and over is projected to double from one billion in 2020 to 2.1 billion by 2050, constituting 21 per cent of the world’s total population. This demographic shift underscores an urgent need for increased awareness and proactive measures, as older adults are likely to encounter “disproportionately severe and imminent risks” related to extreme heat.
Moreover, the study indicates that two-thirds of this growing elderly population will reside in low- and middle-income countries, many of which are already grappling with the challenges posed by rising temperatures and inadequate infrastructure to cope with heat stress.
Implications of Underestimating Vulnerability
The research points out a critical oversight in previous studies, which often relied on data pertaining to younger adults and consequently underestimated the frequency and geographical spread of uncompensable heat stress among older populations. “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,” the authors caution.
The 2025 report from the Lancet Countdown on Health and Climate Change, in collaboration with the World Health Organization (WHO), further reveals that heat-related mortality has surged by 23 per cent since the 1990s, resulting in an average of 546,000 deaths each year. In 2024 alone, the average person experienced 16 days of dangerous heat that would not have occurred without climate change, with vulnerable populations, including infants and older adults, facing an alarming total of over 20 heatwave days each.
Why it Matters
As climate change continues to escalate, the health risks associated with extreme heat for older adults become increasingly urgent. This demographic shift towards an ageing population, coupled with the rising incidence of heat-related illnesses, necessitates immediate attention from policymakers and health professionals alike. Addressing these vulnerabilities is critical to ensuring the well-being of one of society’s most at-risk groups, as the frequency and severity of heat events are set to increase in the coming decades.
