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Whatever Happened To Our Heatwaves?

November 24, 2012

By Paul Homewood



The UK government continues to warn us that we can expect hotter summers and more intense heatwaves. In their Climate Change Risk Assessment, issued earlier this year, DEFRA forecast :-

  • By 2080, average summer temperatures would have increased by between 1C and 8C.
  • Heatwaves would become more severe due to a changing climate.
  • By 2050, premature deaths due to hotter weather would increase by between 580 and 5900 pa. (Interestingly, they acknowledge that night time temperatures during the 2003 heatwave in London were 9C higher than the surrounding countryside.)

Met Office data shows that summer mean daily maximum temperatures have barely increased in the last 80 years, and the trend has been downhill since the warm summer of 2006. Even that year was not as hot as 1976 and 1995.





The last six summers have averaged 18.3C, well below the 1981-2010 average of 18.6C. Talking of UHI though, it is worth noting that minimum trends have shown a larger increase in recent decades.




But are the average numbers disguising an increase in extreme hot weather events?

Sheffield is a pretty representative part of the UK, lying in a fairly central position. (It’s also where I live!)

Daily temperature data from the Met Office for the town shows no upward trend, either in the number of days over 30C, or in the temperatures for such days.






The record temperature of 34.3C was set in 1990, and 1995 set the record for most days with six. The consecutive summers of 1975 and 1976 probably still stand out as the longest and hottest summers of all, with 1976 topping the averages with 23.1C. And there have been no days over 30C at all since 2006.

So once again we see that the modelling and the forecasts bear no resemblance to what’s actually been happening.



DEFRA warn us in this report that premature deaths due to hot weather will increase by between 580 and 5900 pa. They also inform us on the same page that, under their projections, premature deaths due to cold weather will decline by between 3900 and 24000 pa.

Apparently this is a bad thing.

  1. TinyCO2 permalink
    November 24, 2012 8:03 pm

    Interesting work. It’s funny how the Met Office detail never matches the headline.

    I once downloaded temperature figures for Armagh, Durham, Oxford, Sheffield, Stornaway and the CET – as a good cross section of UK temps that go back to 1892. I noticed that Sheffield and the CET were very similar.

    I theorised that Stornaway might be the least polluted by UHI even though the monitoring station is down wind of the town and at an airport. I suppose it’s essentially a sea surface measurement. Subtracting Stornaway from the other station data showed interesting trends. Armagh shows the least warming trend compared to Stornaway. Sheffield and CET were next and very similar. Durham was next and then Oxford. The last two showed significant warming trends compared to Stornaway, possibly reflecting rapid growth.

    I’m sure there are a lot of clues to our climate that are lost when looking at the annual (and maybe even the monthly) data. I’ve always wondered how much time is given to looking for patterns in the fine detail rather than the broader picture.

    Of course everything is lost under the heading of climate change because it explains everything and there’s no need to look further.

    • Brian H permalink
      November 25, 2012 7:09 am

      The very act of looking for detail is subversive. You will be dealt with in due course.


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