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Temperatures, Sunshine & The Clean Air Acts

September 24, 2018

By Paul Homewood

h/t Kelvin Vaughan


UK Mean temperature - Annual


We are all doubtless familiar with the Met Office’s UK temperature chart, showing a clear rise during the 1990s and early 2000s, but one that has levelled off since.

You may be less aware, however, of a very similar increase in sunshine hours, which began at around the same time, and which has also since levelled off.


UK Sunshine - Annual


Coincidence? Maybe.

But in their recently published State of the UK Climate 2017 Report, the Met Office show that the rise in land temperatures was also very closely matched by a similar rise in sea surface temperatures in near-coastal waters:



FIGURE 20 UK annual mean temperature over land 1910–2017 and UK annual mean sea surface temperature across near-coastal waters around the UK 1870–2017, expressed as anomaly relative to the 1981–2010 long term average. The table provides average values (C) 

GHGs certainly cannot account for such a rise in SSTs, but the sun definitely can. And warmer seas will then have a knock on effect on land temperatures.

It is worth recalling what the late Philip Eden wrote in 2015:



In particular:



He also wrote about the topic the month before:



All of this raises the very real question, is the recent rise in UK temperature the result of cleaner air and therefore more sunshine?

  1. Ian permalink
    September 24, 2018 11:59 am

    There’s an article on the subject in today’s DT:

    Early comments are largely sceptical, which is nice.

    There’s also a puff piece by Ovo on smart meters. Nothing new. Answers none of the regularly put questions. I saw it on the smartphone app but can’t find it on the website. A search on that brings up a lot of criticism, which is also nice.


  2. saparonia permalink
    September 24, 2018 12:14 pm

    I remember when there was thick red smog around the industrial area outside Sheffield. My father was a turner in the steelworks and he suffered terribly for many years with chest complaints that eventually killed him. He took early retirement but wasn’t compensated for his injuries. It took years for them to put in a proper filter, and the filter was designed by the father of a friend of mine. The smog was red, rancid and choking. I’m not surprised it interfered with sunshine levels.

  3. Phoenix44 permalink
    September 24, 2018 12:18 pm

    Perhaps the later part of the Little Ice Age, from the mid 19th century onwards, was the result of increasing air pollution?

    • September 24, 2018 12:28 pm

      But the Little Ice Age never existed. Neither did the Medieval Warming. Michael Mann told us so.

      • Broadlands permalink
        September 24, 2018 1:27 pm

        Neither did the slowdown and leveling off of temperatures… NOAA’s team of “adjusters” has told us so…it’s all an artifact?

      • September 25, 2018 12:04 pm

        No, Broadlands, it is all an artifice.

  4. Chris, Leeds permalink
    September 24, 2018 12:37 pm

    A good number of years ago I was working on pollution research at Manchester University. One of the pieces of research was looking at the substantial increases in sunshine from the late 1950s onwards in the Manchester conurbation – smoke and SO2 pollution declined as smokeless zones spread across the city and sunshine rose rapidly. The rise was modest in summer – just a few percent, but substantial in winter. The same would probably be true for most cities and urban areas in the UK and probably NW Europe. Could this impact temperatures? The likely mechanism would be this – in winter anticyclonic conditions the weather was often foggy or smoggy in earlier decades and these ‘inversion’ conditions often persisted all day and led to low daily maxima. In recent years in such anticyclonic conditions the weather would now be sunny and temperatures would be a few degrees higher in urban areas. This could have an impact on mean winter temperatures.
    However, I am not sure this would be the reason for the change in sunshine totals in the 90s and 2000s because most of the effect of clean air legislation had worked through by the 1980s…. we may have to look at whether atmospheric circulation changes have meant sunny conditions are more likely, or whether cloudiness has decreased. Either way there would appear to be a correlation, at least, between increases in UK sunshine and UK temperatures, as Paul suggests.

  5. September 24, 2018 1:28 pm

    I believe that weather patterns may be a more likely explanation for the increase in sunshine hours in the UK, a shift in the 1990s from mostly westerly weather (cloudy) to easterly weather (relatively cloudless), based on a general perception of wind direction when out walking.

    This year in Southern England has been dominated by easterly weather, from the winter Beast to the summer heatwave, and now hopefully an Indian summer.

  6. September 24, 2018 1:47 pm

    David Archibald’s chart of Beryllium-10, which is related to the Sun’s magnetic field strength.

    See also the Wikipedia page for Beryllium-10.

  7. Gerry, England permalink
    September 24, 2018 1:56 pm

    But the air can’t be clean or we wouldn’t have all these stupid taxes on diesels and money wasted on EVs! Oh, hang on – it depends on who sets the limits of air pollution and whether they are honestly done. Government agency says things are bad – government must do something.

    • BLACK PEARL permalink
      September 24, 2018 2:09 pm

      Confirming EVERYTHING we are told is just opinion / half truth or just plain bullshit.
      The more you read the more you disbelieve

      • MrGrimNasty permalink
        September 24, 2018 5:41 pm

        What makes me laugh is that even though all this ‘pollution’ is absolutely ‘lethal’, the same scare pieces often admit that the benefits of exercising in this toxic fug, far outweigh the risks, ergo the risks are infinitesimally small (or fake)!

        The latest scare in the DM was that soot particles cause Alzheimers. Two seconds research shows that there is actually a higher % of sufferers in predominantly rural areas, and very low rates in big cities, central London for example. Also whereas soot levels are at a fraction of their levels in 1990s and projected to improve, Alzheimers has grown, and is expected to climb. So there is clearly no, or a minuscule correlation.

  8. TinyCO2 permalink
    September 24, 2018 2:07 pm

    I can’t help feeling that clean air particularly affects fog in the colder months. On a winter’s day, walking from a sunny area to one in fog is striking. You see the effect most around Bonfire Night if it’s cold enough for fog to form and if the majority of fires are on the same night. Might a lack of fog enhance the UHI effect above and beyond fog reduction due to warming itself?

    • September 24, 2018 3:40 pm

      Maybe I don’t get out enough, but fog seems to be much less prevalent that it was 20-30 years ago.

  9. tom0mason permalink
    September 24, 2018 3:42 pm

    The Clean Air Act was not just Britain, throughout Europe, USA, and even the USSR (to a lesser extent) similar laws were being enforced over this time period. So generally over the Northern Hemisphere the skys cleared a lot.
    Now there is less debris, less particulate in the NH sky compared to before the 1990s. Today when planes pass overhead contrails are more evident in the clearer sky; when a dirty volcano throws up its ash, smoke, and climate changing gases it is seen better visually, and in the weather/climate records.

  10. bobn permalink
    September 24, 2018 4:09 pm

    A major change in summer air quality in rural and urban areas occured at the end of the 1980s. Thats when stubble and straw burning across the arable fields of UK and Europe was banned. In the 1980s on a sunny summers day the air filled with smog rapidly from all the field fires across Europe. As a pilot I saw the whole of europe blotted out below a stubble smog inversion within 3 days of a high pressure system settling. Flying at 5,000ft you couldnt see the ground through the smog blanket that was held below 3000ft. It was so extensive it covered Uk through to East Germany (i couldnt fly further east!) in a total blanket. When they banned this wholesale biomass burning the summer skies cleared dramatically. I hadnt thought about the weather effect of this horrible smog but it certainly reduced the sunlight hitting the ground. I remember landing through this haze and cursing that it wasnt sunny in my garden when i had been in the sun 3000ft above it. Of course they didnt burn on rainy or windy days (when sunlight was often hidden by cloud), but did burn as soon settled blue (soon to be brown) cloud free skies arrived. The whole of western europe was blanketed through the summer months greatly reducing the sunlight and heat reaching the ground.

    • Chris Martin permalink
      September 24, 2018 11:18 pm

      Bobn … a really good point. I had forgotten about stubble burning. As a child in the East Midlands I remember the mid to late summer skies hazy with smoke and often seeing great columns of smoke rising from fields. This must have been a very significant factor in weakening sunlight compared to today that I had completely forgotten about.

  11. September 25, 2018 6:33 am

    Reblogged this on Climate Collections.

  12. September 25, 2018 2:48 pm

    Years ago I wrote an article on Tallblokes Talkshop on CET max temperatures vs Bright sunshine. I did not have the digital data so I used the average trends as deduced by Paul. I found 2 curious cycles through time from 1930 to 2010. The cycles appeared to be a combo of the oceanic cycles. There was a very small linear temperature rise component that I agree could be anthropogenic – or not.

    The cycles are simply seen when the datapoints are colour coded.

    I suggest a redo: get those trend cycles and plot them, delta T max vs delta Bright Sunshine Hours., with colour coded times of datapoints.

    What I did was crude but effective. Cloud cover has increased and decreased over central Britain and accounts for a lot of the temp changes. The AMO and PDO account for more. The interaction of both creates most of the CET temp rise since 1930. A-CO2 and delta TSI are probably up for the rest, but it is too small to worry about.

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