When the mercury soars, communities can suffer for many reasons: because no one is watching over the elderly living alone, because the poorest do not have air conditionerbecause workers have no choice but to work outside. The new study focuses on a simple reason why societies could be particularly vulnerable to an extreme heat wave: because they have never experienced one before.
Whether it’s heat, floods or epidemics, societies are generally equipped to handle only the most severe disasters they have experienced in recent memory. Immediately after a disaster, people and decision-makers are hyper-aware of the risks and how to respond, said Dann Mitchell, a climatologist at the University of Bristol in England and author of the study. “And then over the years you kind of forget and you’re not that bothered,” he said.
Dr Mitchell and his colleagues looked at daily maximum temperatures around the world between 1959 and 2021. They found that regions covering 31% of the Earth’s land surface had experienced such extraordinary heat that, statistically, it wouldn’t have should not have happened. These places, according to the study, are now prepared to some degree for future intense heat waves.
But there are still many areas that, just by chance, have not yet experienced such extreme heat. So they might not be as prepared.
According to the study, these include economically developed places like Germany, the Netherlands, Belgium and Luxembourg, as well as the region of China around Beijing. But they also include developing countries like Afghanistan, Guatemala, Honduras and Papua New Guinea, which are more likely to lack the resources to keep people safe.
Other areas particularly at risk include the far east of Russia, northwestern Argentina and part of northeastern Australia.
The study was published Tuesday in the journal Nature Communications.
why it matters
In 2021, a heat wave in the Pacific Northwest broken local records by staggering margins. Hundreds of people in Washington and Oregon may have died from the heat. Shrunken crops. A fire destroyed the village of Lyton, British Columbia.
The new study shows that heat waves that fall outside the range of statistical plausibility have occurred all over the world in recent decades. This suggests that they could breed, anywhere, although not all of them are as novel as the recent Pacific Northwest.
Man-made climate change is not helping. As the planet warms, the range of possible temperatures that many places can experience shifts upwards. Scorching heat that would once have been considered unusual is becoming more likely.
But the weather has always varied greatly and the most exceptional events are those which, by definition, people have not experienced very often. Societies must remain “humble” in the face of any climate extremes that may occur, said Karen A. McKinnon, assistant professor of statistics and the environment at the University of California, Los Angeles.
“We are often not even prepared for this baseline level of variability,” said Dr. McKinnon, who was not involved in the new study.
Understand the big picture
The study focuses only on maximum temperatures, which are not the only factor that can heat waves devastating. Humidity is also important, as sweltering night temperaturesthat eliminate opportunities for people to cool off after oppressive daytime conditions.
In general, the removal of heat — in the form, for example, of green or air-conditioned spaces — is less accessible to the poor than to the rich.
Even in places that have already experienced record-breaking heat waves, many residents may still not be preparing for future extremes as average conditions remain largely temperate. In research published last yearDr. McKinnon showed that in the Pacific Northwest, very high summer temperatures occur more often than expected given the region’s generally mild climate.