40°C heatwave may have killed 1000 people in England and Wales

First estimate of extreme heat’s impact suggests that more than half of the deaths are expected to have been in people aged 85 and older

By Adam Vaughan

About a thousand extra people are estimated to have died during the recent three-day UK heatwave, in the first snap analysis of the human toll of record-breaking temperatures.

At least 10 people drowned during the heat, which passed the milestone of 40°C in some areas, but a provisional number has now been put on the wider number of deaths linked to the extreme weather.

Antonio Gasparrini at the London School of Hygiene & Tropical Medicine estimates that 948 people died in England and Wales because of the sweltering conditions between 17 and 19 July. More than half, 495 people, are estimated to have been aged 85 or older, a group that compromises roughly 2 per cent of the nations’ population.

Most of the deaths, 844, are estimated to have occurred on the two hottest days, 18 and 19 July. In a typical year, England and Wales would be expected to see 791 heat-linked deaths. “So it’s higher in just three days than the whole year that you’d expect. So it is severe, that is severe,” says Gasparrini.

The numbers are derived from modelling how many deaths would be expected in different parts of the country depending on how high temperatures go, rather than the observed number of excess deaths during a heatwave. That official process usually takes much longer than the near real-time approach by Gasparrini.

He arrived at his findings, which are being considered for publication in a scientific journal, by extrapolating from research he published earlier this month. That study calculated the risk from heat for different age groups in almost 35,000 small geographical areas across England and Wales between 2000 and 2019.

The estimated 948 excess deaths in just three days is the central estimate of a range of between 618 and 1141 in the worst case. Chloe Brimicombe at the University of Reading, UK, says it looks “in line with expectations” for the anticipated toll from the heatwave.

Some preliminary figures for excess deaths during the heatwave are expected next Tuesday.