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Are English Summers Getting Hotter?

August 3, 2016

By Paul Homewood  

 

image_thumb45

 https://notalotofpeopleknowthat.wordpress.com/2016/07/13/project-fear-from-lord-krebs/

 

Are summers in the UK getting hotter?  

It seems to be one of those ideas that are ingrained in the public psyche, fed by headlines like the one above, which was based on the CCC’s latest report claimed:

Heatwaves in the UK like that experienced in 2003 are expected to become the norm in summer by the 2040s. The average number of hot days per year has been increasing since the 1960s.

 

But what do the facts tell us?

 

For the purposes of this exercise, I am only looking at England, as that is where summers are hottest. I have certainly never heard a Scotsman complain that his weather is too hot!

I am also only considering daily maximum temperatures, as it is these which are normally referred to when discussing heatwaves. Also, night time temperatures are less reliable, being affected by UHI.

 

If we look at the Met Office graph below, the trend line seems to have flattened out in recent years. However, trend lines over such a short period of time must be treated with extreme caution.

Nevertheless, this graph tells us more about the relative absence of COLD summers recently, rather than whether summers are actually becoming hotter.

This is a critical consideration. Whether average temperatures are increasing, and whether summers are getting hotter are two separate things.

 

image

http://www.metoffice.gov.uk/climate/uk/summaries/actualmonthly

 

It is readily apparent that the hottest summer by far was 1976, while the second hottest was way back in 1911. The last really hot summer was in 2006, but there was certainly nothing unusual about that one.

In short, there is nothing in the data to show that maximum temperatures in summer are increasing, or that hot summers are becoming more common. Never mind providing evidence that they will in future.

Perhaps the clearest way to appreciate this is to look at the ten hottest summers below:

 

image

http://www.metoffice.gov.uk/climate/uk/summaries/datasets

 

We have:-

  • 1911
  • 1933
  • 1947
  • 1975
  • 1976
  • 1983
  • 1989
  • 1995
  • 2003
  • 2006

In other words, two each in the 1970s, 80s and 2000s.

Contrary to popular myth, it seems that summer temperatures have actually been very stable since the exceptional summer of 76.

 

 

 

image

 

 

Naturally, it is the South East which tends to be hottest and is where heatwaves would be most problematic, so we can do a similar exercise there.

 

In fact, we find a very similar pattern to England as a whole. The hottest summer, again, was 1976, while 1911 was notably warmer than 2003 and 2006.

 

image

http://www.metoffice.gov.uk/climate/uk/summaries/datasets

 

 

The distribution of the ten hottest summers is also nearly the same, with the exception that 1975 drops out, to be replaced by 1949.

 

 

image

http://www.metoffice.gov.uk/climate/uk/summaries/datasets

 

 

I’ll finish with a graph you should all be familiar with, the distribution of days in the CET which were over 30C. After all, average temperatures across the whole of the summer don’t necessarily tell you everything about short bursts of heat.

It does not need a statistician to tell you that daily temperatures have refused to go above those recorded in July 1976 and August 1990 ever since. It is almost tempting to say that there is a ceiling above which temperatures will no go.

As for the claim by Krebs’ committee that temperatures could reach 48C, such nonsense belongs in a comic book, and not a supposedly serious study.

 

image_thumb48

http://www.metoffice.gov.uk/hadobs/hadcet/index.html 

 

There certainly appears to have been a shift change in summer temperatures after 1970, whichever metric you look at. But anybody who claims that “summers are getting hotter”, or that heatwaves in the UK like that experienced in 2003 are expected to become the norm in summer by the 2040s , is selling you snake oil. 

10 Comments leave one →
  1. Joe Public permalink
    August 3, 2016 9:41 am

    Irrespective of frequency, the English ‘summer’ still comprises “two fine days, then a thunderstorm”.

  2. johnmarshall permalink
    August 3, 2016 10:19 am

    UHI is also measurable during the day so it is not just a nighttime phenomenon.

  3. A C Osborn permalink
    August 3, 2016 11:03 am

    Between UHI and coming out of the LIA I don’t think we have warmed up any more or even as much as could be expected.

  4. August 3, 2016 11:17 am

    For some months, I’ve been watching episodes of “Escape to the Country” on my laptop. It has been a lot of fun to see various villages and rural English countryside. Early on I noticed the number of people who had a very positive reaction to the “garden faces south.” That would not bring chortles of glee here where you would find yourself “well done” in short order.

  5. Graeme No.3 permalink
    August 3, 2016 12:09 pm

    Years ago there was a spoof James Bond about some evil enemy attempting to tow the UK to the North Pole but was thwarted by the hero who cut the tow rope. The backlash meant that England finished at the latitude of the Canary Islands. I feel sure that the author must have read this story and not realised its improbability.

  6. Broadlands permalink
    August 3, 2016 12:20 pm

    Have you looked for a relationship with the ENSO or the NAO?

    In the US 48 states the summers (JJA) have been trending warmer since 1998, that El-Nino inspired year. However, the winters (DJF) and falls (SON) are trending colder making the overall annual trend cooler (and consistent with the “pause”.

    Remarkably, the overall warmest months in the US (from 1895-2015) correlate well with the ENSO.

    AUG, 1983, SEP, 1998. NOV. 1999, DEC, 2015.

    All data from NOAA, NCDC.

  7. August 3, 2016 3:29 pm

    The forecast is 30 years out so they don’t have to have any proof.

  8. August 3, 2016 3:57 pm

    So England had what we like to call heatwaves in 1976 and 2003. Where’s the trend?

    The only thing overheating is the imagination of CCC members.

  9. Diogenese2 permalink
    August 3, 2016 7:12 pm

    I remember the summer of 1976 very well. One forgotten incident was how the blocking high resulted in high winds in the Sahara depositing megatons of fine sands over London which had to be washed from car windscreens before starting.On this night the temperature remained about 90f and from a vantage point in Knightsbridge I watched revellers returning from the West End on foot in the small hours (public transport shut down at about 23.00).
    A memorable but sleepless night. But it is worth googling “heat wave 1976″ and reflecting that if ANY of this occurred now you would observe hysterical panic and possibly the return of the Flaggelantes amid cries of the ” apocalypse” .But we survived this and, in time, nothing much changed and the present is nowhere near the extremes I have experienced in my ( nearly complete) lifetime. Hence all such comment just invokes ironic laughter. The miracle of the internet allows anybody to discover almost any historical circumstance they wish.That so few seem to want to experience the past amazes me.If we had this at that time how different my understanding would have been! It teaches me that even what I think I remember is not so, however the scientific method I was taught remains. Seek and verify data and be sceptical of everything.

    • Ben Vorlich permalink
      August 4, 2016 7:33 am

      Summer of 1976, winter 1962/3, Hurricanes 1968 and 1987, numerous wet springs and autumns; one memorable wet autumn in the early 1970s I was unable to dry my walking boots properly for days on end when working as a deerstalking ponyman.

      Then they wonder why older people are the most sceptical.

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