New heatwave study maps ‘significant exposure increases’ threatening vulnerable populations in global South

Heatwaves have become more frequent and intense with climate change “and have serious and potentially life-threatening impacts on human health, particularly for people over 65,” a new open-access study published earlier this month found. 

Few existing studies of exposure to heatwaves cover the whole world and “very few” cover key areas in Africa, South America, and East Asia, says Global and cross-country analysis of exposure of vulnerable populations to heatwaves from 1980 to 2018.

But using global data going back to 1980 on climate, population, ageing and health, Jonathan Chambers – a scientist at the Institute for Environmental Sciences of the University of Geneva – finds that vulnerable populations “are experiencing up to five times the number of heatwave days relative to the global average”.

The study says there is a “clear trend” of more heatwaves globally, which are known to affect the elderly more severely, and the combined effect of this and an ageing population in China and India, for example, has led to increased heatwave exposure of an average of just over half a billion person-days a year over the last decade.

‘We recommend healthcare be fully engaged
in climate mitigation and adaptation
for this growing risk factor’

“These results are significant in that they are produced from observational data of the recent past, rather than…future projections, and therefore highlight the reality of climate change impacts that have already happened,” the study says.

“Ongoing work aims at maintaining updates of these indicators as new data becomes available.”

The study, published in Springer Nature and supported by the University of Geneva, also flags “large disparities in health and wealth relative to heatwave trends”.

It says some countries are at additional risk from heatwave impacts on human health because of a combination of “high heatwave exposure, low medical staffing, and low income. These factors exacerbate inequalities between countries with respect to climate change impacts.”

The study argues for greater consideration climate impacts in healthcare, in national planning and international development.

“We recommend that healthcare entities be fully engaged in climate mitigation and adaptation efforts to address this growing risk factor.”

The Climate Centre recently developed a series of podcasts with a detailed look at heatwaves, while new Red Cross Red Crescent guides to heatwave precautions in cities were published in two
parts this year and last aimed at National Societies and municipalities respectively.

North Korean Red Cross personnel using mobile pumps to help farmers trying to keep maize alive during the intense 2018 heatwave that triggered a national state of emergency and caused human casualties. (Library photo: IFRC)