Heatwave Update

As predicted by the UK Met Office, the recent heatwave ended on Tuesday 19th July after some record-breaking temperature maximums all over the UK including the first record of >40 ℃ temperatures. Maximum daily temperature records were set for England (40.3 ℃), Wales (37.1 ℃) and Scotland (35.1 ℃) along with the highest UK minimum (night) daily temperature of 25.8 ℃ in Greater London. For our American friends, 40.3 ℃ is 104.5 ℉.

UK temperatures above 38 ℃ have only been recorded in this (21st) century - a clear sign of a warming planet. And the high temperatures were widespread not only in the UK but also in Europe.

BBC Reality Check did a reasonable summary along with a comparison to our 'most-remembered' heatwave of 1976. One aspect of the BBC summary I was not impressed with was the bar-graph labelled 'Hottest day of the year since 1970'. Who in their right mind puts up a graphic for maximum summer temperatures in the UK with the temperature axis starting at 0 ℃!! If you are showing annual differences in maximum annual temperatures then a range of 25 to 40 ℃ would have been appropriate - at least until this year when the upper limit would need to be even higher.

A minor contrarian blog did complain about this BBC report saying it was just opinion even though the BBC clearly presented its evidence and gave its data sources (albeit the source links should have been clearer). For the contrarian to opine most people thought the 1976 heatwave was more intense (it was longer-lasting but not as hot) than the 2022 version (no evidence provided to support that claim) does seem a tadge hypocritical! I lived through both heatwaves and I certainly found the recent one more debilitating; albeit I was obviously younger in 1976!

Our contrarian then compares June/July daily maximum temperatures, from the Central England Temperature (CET) series, for 1976 and 2022 which just confirmed what we already knew. The former was longer and not as hot as the latter. To see a better statistical analysis of the CET data with respect to the recent heatwave, go here.

Finally, our contrarian takes issue with the UK Health Security Agency issuing its highest level 4 heat alert with a warning of increased risk of illness and death even among the fit and healthy. This is where our contrarian friend resorts to cherry picking and red herring fallacies by:

• using total deaths rather than 'excess deaths' as the BBC report does
• showing a couple of bar charts to demonstrate summer death rates for England & Wales are lower than in other seasons, especially winter. This supports one of the contrarian memes that global warming is good because the reduction in cold weather deaths will outweigh the increase in hot weather deaths. Of course, it is far more complicated than that. As global temperatures rise, the much faster increase in heat-related deaths will surpass the slowly decreasing cold weather deaths leading to higher overall temperature-related deaths.
• ignoring the point of the heat alert that temperatures over 38 ℃ come with a significant health risk, yet providing irrelevant information about summer death rates in sub-38 ℃ conditions (a red herring fallacy).
• playing down the effect of such high temperatures. Temperatures of 38 ℃ and above were seen on 10th August 2003, 25th July 2019 and, most recently, 18th & 19th July 2022. The August 2003 heatwave resulted in 2139 (+16%) excess deaths. Below, I have plotted total deaths in England and Wales during the summer months of 2018 (selected by our contrarian friend as a hot summer) and 2019. Do I need to tell you which of these 6 months contained a daily maximum above 38 ℃ despite occurring in a relatively cool summer?

• hiding the spike in deaths resulting from hot periods with/without a >38 ℃ daily maximum by trying to 'blend it away' in seasonal (summer) data rather than showing what actually happened in the month where the daily maximum of 38 ℃ was exceeded.
• not including the part of the BBC Reality Check report that clearly shows the 2022 heatwave was widespread and more intense than the 1976 version.

Finally, as a point of interest, my Davis weather station reported its highest temperature (38 ℃) on the 18th July, a day before the new record 40.3 ℃ temperature maximum for England was set.