Study highlights regions most susceptible to harm due to heatwaves

A new study has highlighted under-prepared regions across the world most at risk of the devastating effects of scorching temperatures.

The research, led by University of Bristol, UK, showed that unprecedented heat extremes combined with socioeconomic vulnerability puts certain regions, such as Afghanistan, Papua New Guinea, and Central America, most in peril. It is published in the journal Nature Communications.

In this study, the researchers used extreme value statistics - a method to estimate the return periods of rare events - and large datasets from climate models and observations to pinpoint regions globally where temperature records are most likely to be broken soonest and the communities consequently in greatest danger of experiencing extreme heat.

The researchers also cautioned that statistically implausible extremes, when current records are broken by margins that seemed impossible until they occurred, could happen anywhere.

These unlikely events were found to have transpired in almost a third, or 31 per cent, of the regions assessed where observations were deemed reliable enough between 1959 and 2021, such as the 2021 Western North America heatwave.

In light of the findings, the researchers are calling for policy makers in hotspot regions to consider relevant action plans to reduce the risk of deaths and associated harms from climate extremes.

"We identify regions that may have been lucky so far - some of these regions have rapidly growing populations, some are developing nations, some are already very hot.

We need to ask if the heat action plans for these areas are sufficient," said lead author, climate scientist Dr Vikki Thompson at the University of Bristol Cabot Institute for the Environment.

Countries yet to experience the most intense heatwaves are often especially susceptible, as adaptation measures are often only introduced after the event. A high chance of record-breaking temperatures, growing populations, and limited healthcare and energy provision, increase the risks.

Beijing and Central Europe are also on the list of hotspots, as if record-breaking heatwaves occurred in these densely populated regions millions of people would be adversely affected.

Human-induced climate change is causing an increase in the frequency, intensity, and duration of heatwaves, which have the potential to lead to thousands more excess deaths globally.

Improving our understanding of where society may not be ready for climate extremes can help prioritise mitigation in the most vulnerable regions.