Though they are unfolding simultaneously, the heat events in the U.S. and U.K. are independent, said Ben Zaitchik, a professor in the Earth and planetary sciences department at Johns Hopkins University who studies extreme heat. But both are made more likely by climate change, which is raising temperatures worldwide as humans pump heat-trapping greenhouse gases into the atmosphere.
“What are the odds you’re going to have two major things happening at the same time?” Zaitchik said. “The probability of these compound events is increasing. … The baseline has shifted.”
Zaitchik added that some scientific evidence suggests that changes in the jet stream could be, in part, to blame for the intensifying heat waves in Europe.
A recent study in Nature Communications identified Europe as a heat wave hotspot and suggested that heat waves were accelerating there at three to four times the rate of other northern regions.
In recent years, the jet stream has shown a tendency to split for longer periods of time, trapping hot weather over Western Europe and allowing it to linger there, the study found.
Petteri Taalas, head of the World Meteorological Organization, said Tuesday that he hopes the heat wave unfolding in Europe this week is a “wake-up call” for governments and voters to address the climate crisis.
In Europe, the risks from heat have been apparent for years. As many as 70,000 more people died than expected during a 2003 heat wave that roiled the continent.
Countries with generally cooler climates such as the United Kingdom are often among those most at risk.
“People are not physically acclimated, they’re not structurally acclimated,” Zaitchik said.
Officials in the U.K. have urged people to avoid travel, stay home from work and avoid the brutal temperatures. Some hospitals halted elective surgeries during the hottest days, expecting an influx of patients.
“We have got a quite good heat-wave plan. There’s a lot of behavior change and messaging so people know what to do with heat,” said Sari Kovats, an associate professor of public health, environments and society at the London School of Hygiene & Tropical Medicine.
But plans can only go so far. About 20 percent of U.K. homes are overheating in normal summer conditions, Kovats said, adding that the country’s committee on climate change has “failed to change the building standards.”
It’s another example that suggests humans are struggling to adapt as quickly as the climate — and its risks — are shifting.
“There’s only a little you can do with behavior if the infrastructure isn’t particularly cool,” Kovats said.