Are Hot Days Becoming More Frequent In England?
By Paul Homewood
I want to take a closer look at one particular claim made in the CCC’s UK Climate Change Risk Assessment report:
The average number of hot days per year has been increasing since the 1960s
I have analysed the daily CET maximum data since 1878, looking at days which were over 29C. There are 92 of these, so it is not dissimilar to a 99th percentile.
It would certainly be true to say that the number of days over 29C have increased since the 1960s. But it would be equally true to say that the number has declined since the 1970s.
The statement is effectively meaningless, and certainly does us nothing about what might happen in future.
The two years which are anomalous are 1976 and 1995, and both can now be regarded as being “in the past”, rather than “current”.
Certainly since 1995, no year has had a frequency of hot days that had not occurred prior to 1976.
The statement by the CCC, which is headlined under their Key Messages, is grossly misleading. Worse still, in the detailed section (p34), they state the average number of hot days per year is increasing.
Note they say “IS”, and not “HAS BEEN”.
They then use this statement as a way of reinforcing their message:
High temperatures are associated with mortality and wellbeing impacts across all regions of the UK. The average number of hot days per year is increasing as is the chance of a severe heatwave – both are projected to rise further with climate change.
A more honest, and accurate, statement, that the average number of hot days per year is not increasing, would, of course, have removed any credibility from the rest of the sentence.
And that would not have done!