When a 40 degrees Celsius heat wave threatened the U.K. for the first time in 2022, officials were caught flat-footed.
This was uncharted territory for British people, whose typical summer is dreary gray interspersed with flashes of welcome sunshine. Top temperatures in July in the U.K. barely graze 20C on average, even in our modern, warmed-up climate. Now 40 C heat was set to affect the whole of Europe, cutting a swath through the U.K. that would put millions of people in danger.
"What happened back then had never happened before,” says Candice Howarth, head of climate adaptation and resilience at the Grantham Research Institute on Climate Change and the Environment. "The U.K. doesn’t have much experience of these types of risks. So the severity of the issue is quite difficult to convey.”
To prepare for the high temperatures, the Met Office — the UK’s official weather forecaster — issued its first ever "red” warning for a heat event. Fortunately, the most intense temperature spike lasted a single day, and emergency services were able to cope. But the heat wave still killed an estimated 1,200 people in the UK, and sparked a conversation on how to handle the next one.
Unlike hurricanes, wildfires or floods, the problems caused by heat are often invisible until it’s too late. It’s hard to illustrate why "feeling hot” — a routine human experience — can easily become dangerous, and even harder to tell people when and how to react. As academics and governments debate the most effective tactics, there are growing calls to mobilize around one: giving heat waves names. Very preliminary results suggest there might be benefits.
"Heat waves are a weather event that should be treated with the severity that other weather events are treated,” says Andrew Mackenzie, associate director of strategy and external relations at the Physiological Society, a global group of experts in how the human body works.
The Physiological Society is among several organizations calling on meteorologists to start naming heat waves as a way to raise awareness of the dangers they pose. Doing so would follow the long-established convention of giving hurricanes names, which began in the mid-20th century as a way to help meteorologists, emergency services and the media avoid confusion.
Heat is much less visible than a looming hurricane, and can be a far more nuanced threat. Specific groups are especially vulnerable to overheating, including children; the elderly; anyone with diabetes, high blood pressure, heart or lung disease; and those dealing with mental health issues. Dying from extreme heat can also seem like a nebulous threat: Heat deaths often occur at home or in a hospital days after temperatures spike, rather than right away.
In that same summer of 2022, the Spanish city of Seville became the first to put the naming idea in motion. A pilot program geared at raising public awareness dubbed a six-day stretch of high temperatures in July as "Zoe.” Hurricanes are given names in alphabetical order; Seville decided to go in the opposite direction, though it too would alternate names between male and female.
"Everything should be on the table to save lives,” says Kathy Baughman McLeod, chief executive officer of the nonprofit Climate Resilience for All and co-author on a study about the Zoe experiment published in Scientific Reports this year.
Among the first peer-reviewed academic papers to assess the value of naming any weather phenomenon, the study found that two months after the heat wave, some 6% of people across southern Spain remembered the name Zoe without being prompted. That cohort was also more likely to have taken steps to avoid overheating, more likely to have warned others about the heat, and more likely to trust their government’s response to heat waves.
In the wake of Zoe, other countries have tried similar measures. Last year, the Greek, Israeli and Cypriot weather authorities jointly named a particularly brutal heat wave "Cleon.” In India, Ahmedabad uses color coding to grab people’s attention, ranking hot days on a scale of yellow to red. Baughman McLeod says naming heat waves is just "one tool among many.”
But for all of the momentum, many meteorologists aren’t sold on naming heat waves — including those at the United Nations’ World Meteorological Organization and the U.S. National Weather Service. In 2022, the WMO released its own paper arguing that there isn’t sufficient evidence to support the idea, adding that it could even be counterproductive. A WMO spokesperson said that the organization’s view hasn’t changed since.
The Met Office, which academics and even some lawmakers have called on to introduce a Seville-like pilot program, says it’s following the WMO’s lead, though it’s keeping the topic under review.
Ironically, the arguments against naming heat waves aren’t so removed from the arguments in favor: Heat is complicated, and its threat level tricky to generalize. Differences in climate mean that there is no universal definition for a heat wave; experiencing one in Finland is different than in Spain or India.
Even within countries, one jurisdiction deciding not to name a heat wave might cause confusion or promote a false sense of security. And for the most vulnerable, heat risks increase well before an actual heat wave threshold is crossed, says Adeline Siffert, a senior climate policy adviser at the British Red Cross.
The WMO report also pointed to the risk of "warning fatigue.” Even in a world of rising climate threats, it said, too many pleas, instructions and cautions coming from authorities can cause people to simply stop listening.
"Why spend this money ... in order to make the people understand, was it Romeo or was it Juliet?” quips Andreas Matzarakis, a professor in biotechnology and environmental meteorology at the University of Freiburg, who was until earlier this year responsible for Germany’s heat health warning system. "More important is having actions. Not only having actions, but also how to communicate the actions that we have.”
Indeed, one takeaway from the U.K. in 2022 was a gap in the availability and uptake of practical advice, says Howarth, who earlier this year published a research paper on the government’s heat wave response. Many people who are vulnerable to heat — especially older people — don’t see themselves as vulnerable. And offering tips and tricks to individuals doesn’t solve structural problems that make heat more dangerous, including unsuitable housing and poor workplace protections.
"There’s a lot of research that shows that if you just give people information, it doesn’t lead to behavior change,” Howarth says. "It needs to come alongside practical information, so people don’t only know what to do, but they understand the risks to themselves.”