Global temperature

Extreme heatwaves can strike regions that were ‘lucky’ to escape record temperatures so far: Study

 Interventions such as establishing cooling centres or reducing work hours for outdoor workers can help  

By Rohini Krishnamurthy
Published: Wednesday 26 April 2023
Underprepared regions are most vulnerable to heatwave extremes, the findings highlighted. Representative photo: iStock.

Over 31 per cent of the world witnessed record temperatures between 1959 and 2021. These temperature abnormalities were considered ‘statistically implausible’ before they occurred, according to a new study.

Such records can be broken anywhere in the world and at any time and countries should be equipped to deal with extreme heatwaves, warned the study published in Nature Communications on April 26, 2023.

Human-induced climate change is driving an increase in the frequency, intensity and duration of heatwaves. This can potentially increase global excess deaths by thousands, according to the study.

Also read: Heatwaves arrive early in 2023; hit 11 states from March 3 to April 18

No part of the world has experienced the worst possible heatwave they could have, Dann Mitchell, professor in atmospheric sciences at the University of Bristol, told Down To Earth. So, it is technically possible that such heatwave extremes can occur anywhere, he added.

Every country needs to be prepared for an extreme heatwave that is deemed implausible based on the current observational record, Mitchell and his colleagues from the University of Bristol, the University of Edinburgh, the University of Exeter and the University of Oxford wrote in their study.

The researchers focused on regions “lucky not to have experienced higher temperature extremes”. They used the extreme value statistics method to estimate the return periods of rare events. A return period is the estimated average time between events, in this case, between heatwaves.

They also used large datasets from climate models and observations to spot regions where temperature records are most likely to be broken soonest and communities are likely to face the greatest danger from extreme heat.

Underprepared regions are most vulnerable to heatwave extremes, the findings highlighted. Far eastern Russia (with a return period of 70.6 years), Central America (with a return period of 78.1), Afghanistan (83.9), Papua New Guinea (89.6), Central Europe (91.4), northwestern Argentina (91.7), Australia’s Queensland (94.2) and China’s Beijing (99.8) were identified as regions where a record-breaking event is more likely.

Developing countries like Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama, Afghanistan and Papua New Guinea are less likely to have adequate heat plans in place, the researchers highlighted.

Chance of record-breaking heatwave

 A map showing regions where record-breaking heatwaves are most likely to strike. Source: University of Bristol

Regions with a return period of under 100 years were labelled high-risk regions. “Some of these regions have rapidly growing populations, some are developing nations and some are already very hot,” Vikki Thompson at the University of Bristol Cabot Institute for the Environment said in a statement.

Read more: India underestimating heatwave impact, more than 90% of the country at risk: Study

Record-breaking events are likely to overwhelm health services and energy supply in countries with greater projected population growth if they remain unprepared.

The southern part of India was identified as low-risk. “India is very used to extreme heat. Our analysis shows that they have experienced extreme heatwaves consistent with what we expected,” Mitchell explained. They will be better prepared if another extreme heatwave were likely to occur, he added.

Interventions such as establishing cooling centres or reducing work hours for outdoor workers can help.

“Being prepared saves lives. We have seen some of the most unexpected heatwaves around the world lead to heat-related deaths in the tens of thousands. In this study, we show that such record-smashing events can occur anywhere. Governments around the world need to be prepared,” Mitchell said in a statement.

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