The record heat wave in the UK was “statistically impossible”

The Climate crisis made extreme heat in the UK over 40 degrees 10 times more likely

(Sustainabilityenvironment.com) – The climate crisis has made 4 ºC more intense and 10 times more likely than the heat wave that hit the UK in mid-July. Even in a climate that, globally, is almost 1.2 degrees warmer than the pre-industrial era, such an event remains exceptional. There would be a 1% probability that the heat wave in the UK will recur with such virulence every year.

This is supported by the World Weather Attribution, a body that brings together scientists from South Africa, Germany, France, Switzerland, New Zealand, Denmark, United States and United Kingdom to assess the extent to which human-induced climate change alters the probability and intensity of extreme weather events, such as the heat wave in the UK.

The role of the climate crisis in extreme heat in Britain

On July 19, many London weather stations scored 40°C or more, surpassing the previous (2019) record of 38.7 degrees. The absolute record during the heat wave in the UK was 40.3°C.

“While in Europe heat waves have been more and more frequent in recent years, the recently observed heat in the UK has been so extreme that it is a rare occurrence in the current climate,” explain the 21 authors of the study. “Temperatures observed on average over 2 days have been estimated with a return period of about 100 years in the current climate. For maximum temperatures of 1 day, the return time is estimated at 1 per 1000 years in the current climate“.

To get an idea of how exceptional it was to exceed the threshold of 40 degrees in Great Britain, just consider that on 19 July the temperature values recorded by 2 out of 3 units throughout the country are considered “statistically impossible“. That is, they are so extreme that they fall far outside the bell curve that describes the probability of recording a certain temperature, based on the reference climatological average.

Heat wave in UK caused almost 1000 deaths

Meanwhile, up-to-date and more likely figures are coming in on the excess deaths directly attributable to the heat wave in the UK. The government, in the days immediately following, had spoken of just 13 deaths, all caused by drowning, mostly young people. Using more standardized criteria to count the lethality of heat waves, Antonio Gasparrini of the London School of Hygiene & Tropical Medicine arrives at very different figures. And in line with those of other European countries.

According to the scientist, at least 948 people died between England and Wales because of the extreme heat between 17 and 19 July. More than half are 85 years old or older. To put the figure in perspective, in a normal year, the excess mortality from heat in the two regions reaches 791 deaths. In practice, in just 3 days the standard value over 12 months has been exceeded. In the previous days, Portugal had faced the same heat wave, touching temperatures of 47 degrees and recording over 1000 deaths only on days of more intense heat.