Elderly heat risk far higher than thought, study says

A US modelling study says rising temperatures driven by climate change could expose many more older people to unsafe heat than previous estimates have suggested.

The study, published in The Lancet Planetary Health and led by researchers at Stanford University, used recent wet-bulb experiments involving people over 60 to estimate how ageing populations could be affected by heat and humidity by 2100.

Previous research used wet-bulb temperature data from young, healthy adults. The new study says that approach did not fully account for older people's greater vulnerability to heat, including reduced sweating, weaker hearts and pre-existing medical conditions.

The researchers estimated that if global warming reaches 1.5C above pre-industrial levels, 22 percent of people over 60 worldwide will be exposed to unsafe heat for at least one month every year.

They said each additional degree of warming would mean about one billion more people experiencing roughly another month of heat and humidity beyond what their bodies can tolerate.

At 3C of warming, older people in the worst-affected regions, including south Asia and the Gulf, could face dangerous heat day and night for three straight months a year, according to the study.

The study identified countries with high poverty and limited access to cooling, including India, Pakistan, Bangladesh, Myanmar and Niger, as facing some of the greatest risks.

The researchers said countries should cut greenhouse gas emissions and make heat plans focus more on vulnerable older people. They also said wider access to air conditioning and other cooling facilities was important because most heat deaths occur indoors.