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The Met Office & Prince Charles

January 25, 2017

By Paul Homewood

 

image

https://blog.metoffice.gov.uk/2017/01/24/looking-hard-at-the-accumulated-evidence-of-climate-change/

 

From the Met Office blog:

 

HRH, the Prince of Wales, who has co-written the forthcoming Ladybird Expert Series Climate Change book – wrote a guest editorial in the Mail on Sunday in which he suggested a ‘focus on looking hard at the accumulated evidence’ of climate change.

Professor Stephen Belcher is the Met Office Chief Scientist. He said: “Last week, climate scientists reported on the fact that during 2016, the world had marked yet another record-breaking year for global temperature, so the comments by HRH, the Prince of Wales on climate change are extremely timely.”

flooding-image-scaled-for-blog

The natural variability of weather means that extreme weather events have always occurred. The challenge for climate scientists is to be able to attribute extreme weather events to a changing climate.

Climate scientists around the world, including colleagues at the Met Office are thus striving to understand the links between the natural variability of extreme weather events and climate change. This is a developing science and increasing understanding will be vital to decision makers when planning policies to avert the worst effects.

Professor Peter Stott is the Acting Director of the Met Office Hadley Centre, and is a world authority on attribution science – the study of ‘attributing’ weather events to climate change. He said: “The frequency of many weather extremes, such as heatwaves and heavy rainfall events, has been increasing worldwide. This is in line with predictions from climate models and well established understanding of how the climate responds to increasing greenhouse concentrations in the atmosphere.”

As temperatures rise the frequency of hotter temperatures increases and with more moisture in the air there is a greater chance of very intense rainfall.

“A wealth of evidence has now shown that increasing greenhouse gases from human emissions have caused the planet to warm. Global temperatures for 2015 and 2016 were over 1 degree Celsius warmer than late 19th century temperatures. The dominant contributor to the warming seen over the past century is from human activity through burning of fossil fuels.” But does that mean we can link recent extreme weather events – like Storm Desmond that brought flooding to Cumbria in December 2015 or like the heatwave over large parts of England in September 2016 – to human-induced climate change?

It can be all too easy to put the entire blame of weather-related disasters on anthropogenic climate change. Floods, droughts and heatwaves have happened many times in the past in our variable climate, but given that natural climate variability can also lead to extremes in our weather, misattribution can easily lead to bad policymaking about how to adapt to climate change.

Peter Stott added: “Now scientific research is showing that we can address the attribution of extreme events by calculating how the probability of particular types of events such as floods and heatwaves have changed as a result of human induced climate change. To do this we compare what actually happened with what might have happened in a world without climate change. Climate models are used to determine how the world could have evolved without greenhouse gas emissions and other human factors on climate.”

Such studies have shown that many heat-related events observed in recent years have been made much more likely by climate change. The chances of the record annual mean UK temperatures seen in 2014 have become about 10 ten mores likely as a result of climate change.

Peter Stott added: “But attributing extreme rainfall events such as occurred in Storm Desmond in December 2015 and which led to extensive flooding is much more difficult. This is because rainfall is much more variable than temperature and climate models can still struggle to simulate some of the fine details of how rain forms in weather systems. But as models improve new research is beginning to emerge showing that for some events at least anthropogenic climate change is playing a significant role.”

More research needs to be done before such attribution analyses become as routine as our familiar weather forecasts. But researchers at the Met Office are collaborating with international partners to develop an operational attribution system for extreme weather and climate events. Such a system would deliver regular updates putting recent extreme events into the context of climate variability and change. This would enable people to better understand how climate change has affected them and help them prepare better for the future.

https://blog.metoffice.gov.uk/2017/01/24/looking-hard-at-the-accumulated-evidence-of-climate-change/

 

Peter Stott is called “a world authority on attribution science, the study of ‘attributing’ weather events to climate change”. Now what could go wrong with that?

If he fails to blame weather events on climate change, he will end up out of a job!

And of course it is very easy to programme the computer models to assume that a warmer climate leads to more extreme weather. Then, Bob’s your uncle, the model says that climate change is to blame every time there is a bit of bad weather!

 

But let’s look at some of his specific claims:

1) “The frequency of many weather extremes, such as heatwaves and heavy rainfall events, has been increasing worldwide

 

On the face of it, a slightly warmer climate will mean that heatwaves also get slightly hotter. But the whole concept of a heatwave is relative.

What someone living in Edinburgh might regard as a heatwave would be a cold day for a Bedouin Arab!

Indeed, heatwaves and temperature extremes can only be defined with regard to a typical, average temperature. As this average gradually rises in a warmer world, so too does the threshold that makes a heatwave.

 

But is there actually any evidence of record breaking summer temperatures or more frequent heatwaves?

Certainly not in the UK, where no summer since has come close to the scorcher of 1976.

 

image

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

 

image_thumb48_thumb

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

 

 

And certainly not in the US either:

 

high-low-temps-figure1-2014

https://www3.epa.gov/climatechange/science/indicatorsEPA-2-24-2016/weather-climate/high-low-temps.html

 

And not even in Australia:

 

HD40.29208

http://www.bom.gov.au/climate/change/index.shtml#tabs=Tracker&tracker=extremes-timeseries&tQ=graph%3DHD40%26ave_yr%3D0

 

When we do see record temperatures quoted, they are often in the middle of large cities, or next to busy airport runways.

 

2) What about extreme rainfall?

The frequency of many weather extremes, such as heatwaves and heavy rainfall events, has been increasing worldwide

There is precious little evidence for this statement, although it is easy to cherry pick a few sites where it is true.

The UK Met Office don’t publish much in the way of daily rainfall data, but we know that monthly data shows no such trends.

 

image_thumb52

https://notalotofpeopleknowthat.wordpress.com/2017/01/13/england-wales-precipitation-annual-stats-2016/

 

 

In the US, it is fair to say that a step up in extreme rainfall occurred in the 1990s, since then the trend is flat. (For the definition of the graph, see here.)

There is an argument, of course, that much of the 20thC was a period of severe drought.

 

multigraph

https://www.ncdc.noaa.gov/extremes/cei/graph/us/4/01-12

 

And again, in Australia the facts don’t support Stott’s contention of a worldwide increase.

 

R99p.9192

http://www.bom.gov.au/climate/change/index.shtml#tabs=Tracker&tracker=extremes-timeseries&tQ=graph%3DR99p%26ave_yr%3D0

 

And other scientists who have studied the issue in great detail state that :

In part because of large intrinsic variability, no evidence was found for changes in extreme precipitation attributable to climate change in the available observed record.

https://notalotofpeopleknowthat.wordpress.com/2016/09/10/new-study-finds-no-evidence-of-global-warming-increasing-extreme-rainfall/

 

3) The chances of the record annual mean UK temperatures seen in 2014 have become about 10 ten mores likely as a result of climate change.

To which I can only reply – “So what?”

We are also much less likely to see a really cold year like 1963.

This tells us nothing at all about extreme weather.

 

 

The Met Office blog begins by applauding Prince Charles’ ridiculous Ladybird book. It is a pity they did not use the opportunity to provide a few home truths.

But still, if they had, they might have missed out on a few gongs.

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55 Comments
  1. January 25, 2017 7:31 pm

    I have been following Peter Stott for years, including a series of email exchanges with him many years ago. He can best be described as a propagandist rather than a scientist. He didn’t get to his current position by being a genuine scientist, pursuing the scientific truth. To use modern terminology – he is a creator of fake news.

  2. markl permalink
    January 25, 2017 7:44 pm

    “A wealth of evidence has now shown….” care to share the “evidence” or will you keep repeating it ad nauseum without any proof?.

    • stewgreen permalink
      January 25, 2017 9:04 pm

      Fallacy of “Argument by assertion” I guess

  3. AlecM permalink
    January 25, 2017 7:45 pm

    UKMO is allegedly quietly dropping the fake IPCC CO2 science in order to eliminate the ‘Warmng Tendency’.

    Stott’s job appears to be to hide that information from the Public so, perhaps, we can be proud of his inconvenient stalling.

    • CheshireRed permalink
      January 25, 2017 9:02 pm

      Where’ve you heard that little beauty from Alec? If true it should signal the end of the scare because without CO2 ‘pollution’ AGW theory is deader than Monty Python’s parrot. C’mon, spill the beans.

    • Tom Dowter permalink
      January 25, 2017 9:31 pm

      There is nothing fundamentally wrong with the basic physics behind the idea that higher concentrations of carbon dioxide in the atmosphere will, other things being equal, lead to higher earth surface temperatures.

      The trouble is that other things are not equal. Not only are the feedbacks more complicated than the various climate models suppose, but there are also other factors that can, and do, lead to changes in global temperatures.

      One has only to look at the inter-annual variability to see that this must be the case.

      Obviously, there can be no direct empirical evidence for the effect of CO2 on temperatures – we would need to have sharp changes in CO2 concentrations, both up and DOWN for us to be able to obtain such evidence. Hoiwever, there is some real evidence that water vapour does indeed act as a greenhouse gas.

      This evidence comes from the “triangle” of temperatures, specific humidity and outgoing long wave radiation. As one might expect, there is a correlation between temperatures and OLR. Hiowever this correlation is not perfect. There is a strong NEGATIVE correlation between the excess, or deficit in OLR as predicted by temperatures and specific humidity. This is true whether or not one uses specific humidity or the excess or deficit of it as with OLR.

      The basic physics for CO2 and H20 acting as greenhouse gases is the same.

      • January 25, 2017 10:58 pm

        Water rises and contains latent heat which is dissipated way up in the clouds, before returning to earth. Some of this get up to the top of the troposphere in the cirrus clouds. This energy is huge in comparison with the so called Greenhouse Effect and is the prime mechanism for cooling the earth.

      • AlecM permalink
        January 26, 2017 8:30 am

        The 1.2 K x 3.5 CO2 CS claimed by the IPCC is based on an assumption that Earth’s emissivity (ratio of OLR to mean surface exitance) is 0.6. This basic radiative physics’ mistake appears in R D Cess J Atmos Sci 1976 and created G = (exitance – OLR) result; 40% extra energy than reality.

        To offset this, the 1976 GISS 1-D modelling paper used ‘negative convection’, copying Manabe’s 1964 paper. Negative convection cannot exist because it breaches the 1st Law.

        In 2000, Hansen admitted to an AIP interviewer that this was ‘a fudge’, but the 3-D models were fine. Not true: the Kirchhoff’s Law of Radiation approach devised by UKMO is in turn based on Sagan and Pollack’s 1967 aerosol optical physics mistake, and creates imaginary ‘positive feedback’.

        In reality CO2 CS in a cloud free atmosphere would be ~0.85 K but the water cycle restores it to near zero. This is why we have for 20 years had no net warming, albeit with two big El Ninos. These result from the real AGW, Asian industrialisation decreasing cloud albedo (reduction of apparent area from 67% to 63% from 1983 – 1997. Since then albedo has stabilised and revised ocean currents are shifting the energy to Space via the N. Pole.

        The IPCC is bloody well wrong.

      • Rowland H permalink
        January 26, 2017 9:22 am

        In a tropical country with high humidity, you bake by day and bake by night. In a desert country, you roast by day and get somewhat chilly by night. To my simple mind, that makes water vapour the most potent greenhouse gas.

      • richard verney permalink
        January 26, 2017 11:28 am

        Phase changes and latent heat are radically different between that of H2O and that of CO2.

      • johnmarshall permalink
        January 26, 2017 12:35 pm

        TomD,
        What “physics” are you talking about? The idea that backradiation from a cold atmosphere can heat the warmer surface is clueless rubbish. Calling any gas a “greenhouse” gas does not make it a source of new energy or do anything that is claimed within the GHE theory.

      • dennisambler permalink
        January 27, 2017 3:46 pm

        There is a demolition of the “basic physics” here:

        “The Shattered Greenhouse: How Simple Physics Demolishes the “Greenhouse Effect””

        http://greenhouse.geologist-1011.net

        Greenpeace et al always claim the basic physics was settled by Fourier, Tyndall, Arrhenius, but this analysis shows them to have misinterpreted what they found and to be misinterpreted by those pushing the AGW theory.

  4. Athelstan permalink
    January 25, 2017 8:43 pm

    What is he on, whatever it is it must be strong.

    Peter Stott added: “Now scientific research is showing that we can address the attribution of extreme events by calculating how the probability of particular types of events such as floods and heatwaves have changed as a result of human induced climate change. To do this we compare what actually happened with what might have happened in a world without climate change. Climate models are used to determine how the world could have evolved without greenhouse gas emissions and other human factors on climate.”

    He Stott is, either totally insane or he fancies himself as some half baked cartoon science fiction nerd pseudo blog artist.

    “To do this we compare what actually happened with what might have happened in a world without climate change.”

    Right?! I wonder, what is their sample area, size etc? Or, does, is he preposterously claiming that the drips in the wet office know about and concerned with “extreme events”…….. “what actually happened” right across the globe?

    “in a world without climate change” a ‘world without climate change’ – er wot? and or, does he mean the myth of man made carbon dioxide causing [by somehow unknown mechanism as yet unrevealed]………….’warming’?

    What a load of old tripe it all is. I don’t know what he is trying to say on a third reading.

    Though, a known known is that; Stott is a tosser. And the wet office is stuffed full of warmunist advocates and Marxist propagandizing nutters, move over ladies, HRH chuckleman wants to join in.

    Cue calls for, another bigger, better MORE powerful bank of servers :-((( oh no!

    • John Palmer permalink
      January 25, 2017 9:30 pm

      Take yer blood pressure pills Athel… he’ll be Sir Fake Scientist very soon!

      But come on… given the offer of the (probably very well paid) post of “World Authority on Attribution Science (??? – really, science???) for waffling-on to the fawning media a few hours a week – what’s a man to do?

      • Athelstan permalink
        January 25, 2017 9:47 pm

        OK John – I do hear you and you are quite right:-)

        But! I am loathe to cut them any slack, the green blob, the taxpayers sink called the wet office, the government ….dear God my government!….. there is no much shit being told here.

        And the rot goes deep, my old mam worries no end about paying the bills and fretting about blackouts, I can do something about the former – if she’ll allow me to but to the latter I want to assuage her concerns but find that, I cannot.

        Stott is not to blame for an energy policy, Stott is not to blame for the only reason the grid keeps the lights on – fossil fuels and that our engineers used to be some of the very the best but Stott is part of the green ‘thing’ and his lies perpetuate the myth, thus he is complicit and guilty by association.

        He is supposed to work for us, he is paid by us, why can’t he search his conscience and recant, once one does – the whole house of cards collapses, all I ask is for, a bit of personal probity.

  5. January 25, 2017 8:45 pm

    Nice post. Another game of whack-a-mole. The official 2014 US National Climate Assessment made the same claims as Stott for the US. Essay Credibility Conundrums was able to deconstruct and disprove every single one.

  6. January 25, 2017 9:04 pm

    Reblogged this on WeatherAction News.

  7. John Palmer permalink
    January 25, 2017 9:34 pm

    You just hope that, one day, we’ll wake up and find that it’s all been declared as b*****it and the funding’s being cut from these leeches.
    Oh.. I just heard that, apparently, there’s a new President across the pond!

  8. The Old Bloke permalink
    January 25, 2017 11:04 pm

    I didn’t know space had weather. Does it rain or snow up there then?

  9. Derek Colman permalink
    January 25, 2017 11:43 pm

    What heat wave in 2016? A few hot days do not constitute a heatwave, and I certainly never experienced those nights we used to get when the heat made it hard to get sleep. All we had in 2016 was a few pleasantly warm days.i well remember1976. That was a heat wave, so hot the ground dried up and cracked. The company where I worked treated every worker on afternoon shifts to ice cream to help us keep cool in unbearable heat, as we struggled to keep production going. The room I worked in had no humidification and we had to flood the floor with water from a hose to keep going. All we had in 2016 was a few pleasantly warm days.

    • John F. Hultquist permalink
      January 26, 2017 1:23 am

      “… those nights we used to get when the heat made it hard to get sleep.

      Mid-1950s in western Pennsylvania
      At the time I did not think to check how widespread that was.

  10. JabbaTheCat permalink
    January 25, 2017 11:49 pm

    Interesting to note that Stott is listed as a mathematician, which in the alarmist world makes him 100% qualified for his position but if someone of similar qualification were to take the opposite position they would be dismissed out of hand by the alarmists as being unqualified to comment as a “climatologist”, wtf that is in the real world…

  11. January 26, 2017 2:29 am

    very interesting post, paul.
    thank you.
    i printed this out.
    i am doing some work in this area and will post a link when done.
    cheers

  12. January 26, 2017 2:52 am

    “Looking hard at the accumulated evidence of climate change”
    i think they mean “Looking hard for anything that could be presented as evidence of climate change”
    and the problem is that they look a little too hard.

  13. tom0mason permalink
    January 26, 2017 5:57 am

    O/T but readers here may be interested in “Just How Much Does 1 Degree C Cost?” at https://co2islife.wordpress.com/2017/01/25/just-how-much-does-1-degree-c-cost/

  14. Athelstan permalink
    January 26, 2017 7:53 am

    Thanks to my strong disapprobation of everything ‘wet office’ – what I should have said and again, another, quite clinical and very able refutation of Stott et al. and a good read.

    Nice one Paul.

  15. January 26, 2017 8:21 am

    Ron Clutz has pointed out that recent warming has been mainly in the overnight temperatures, not in the daytime, an entirely non-scary, and in fact benign picture, one major problem faced by all lifeforms (except modern man and her pets) is coping with the diurnal temperature variation:

    https://rclutz.wordpress.com/2016/09/16/its-not-hotter-its-milder/

  16. Tim Hammond permalink
    January 26, 2017 10:11 am

    Talk about begging the question!

    So to “prove” that CO2 is responsible, they build a model without CO2 – that just means that they build a model without the thing they are trying to prove!

    If you assume that additional CO2 has no effect in your first model, then it will be identical to your second model. The idea that the first model shows warming all on its own, without the basic assumption(s) that additional CO2 will warm the world embedded in it somewhere, is sheer nonsense.

    As for probabilities, that is more nonsense. It assumes that we know all the possibilities that could happen for any given time period. But where is the evidence for that? A model? Seriously? Are they really claiming that they can model all the possibilities of what our weather (since this is extreme events, not trends) would be if we hadn’t produced extra CO2?

    • Jack Dawkins permalink
      January 26, 2017 10:33 am

      If I understand the methodology correctly:

      1. Accept that human induced climate change is happening. as shown by climate models..
      2. Use climate models to show how the world could have evolved without this change.
      3. The difference between 1 and 2 is therefore the result of human induced climate change.

      And that’s science?

      • Gerry, England permalink
        January 26, 2017 1:41 pm

        It would also be helpful if your model actually worked but unlike Stott’s delusion it doesn’t.

  17. Dung permalink
    January 26, 2017 10:18 am

    Athelstan

    I remember at Bishop Hill some helpful soul extracted from our own parliament the fact that they had no idea what difference our money would make to global temperature.
    Can anyone think of any other area of government that would get funded on that basis?

    • Gerry, England permalink
      January 26, 2017 1:42 pm

      A railway line from London to Birmingham?

  18. January 26, 2017 10:25 am

    Re this: “The frequency of many weather extremes, such as heatwaves and heavy rainfall events, has been increasing worldwide. This is in line with predictions from climate models and well established understanding of how the climate responds to increasing greenhouse concentrations in the atmosphere.”

    They ignore that many of these ‘weather extremes’ are due to unusual jetstream behaviour e.g. blocking patterns. There’s no known correlation between jetstreams and trace gases comprising 0.04% of the atmosphere. Maybe they should study solar wind strength

    Re ‘predictions from climate models’ – they would be better off keeping quiet about those, given their massive and ongoing divergence from observed reality.

  19. Dung permalink
    January 26, 2017 10:35 am

    As Donald Trump gets his real life feet under the table at the White House and his mataphorical hands on the levers of power, how long can our government maintain the illusion of the world acting in unison to fight climate change?

    • Dung permalink
      January 26, 2017 10:37 am

      Because only as long as that illusion is maintained can parliament justify a single penny of expenditure purporting to help fight climate change.

    • Gerry, England permalink
      January 26, 2017 1:43 pm

      Donald has already signaled the end of funding for the UNFCCC as US law requires. He will obey the law unlike Obummer.

  20. Reasonable Skeptic permalink
    January 26, 2017 12:24 pm

    My kid who is in Grade 5 now has a science test about CC. It teaches them that extreme weather is caused by CC.

    Get them young and never doubt who they will support once they get the vote.

    • Harry Passfield permalink
      January 26, 2017 1:06 pm

      RS: You & your son/daughter have my sympathy. What happens when he/she questions the syllabus? Does the teacher ignore sites like this with its contradictory stats?

  21. NeilC permalink
    January 26, 2017 12:43 pm

    Unfortunately, Stott’s nonsence is listened to by MPs on the CCC. He is one who should be added to the list of misinformation “experts” to lose, not only their funding but also their positions.

    It is a crime that our governments, since adoption of the CCA, have messed up electricity production by forcing the National Grid to give priority to unreliable wind and solar. And the closure of coal power stations. Of course this is all based on bad science from the like of Stott and Slingo.

    It is time the government started to open their eyes to what is going on and spend the money taken from wind and solar subsidies to build new coal fired power stations, CCGTs and start fracking. After all it is their duty to provide inexpensive electricity for both industry and the poor people (JAMS) of this country.

  22. Ex-expat Colin permalink
    January 26, 2017 12:48 pm

    Cheers to Global Warming apparently…the wine growing variety. (Camilla at Clarence House)

    http://www.thegwpf.com/camilla-salutes-global-warming

    Ladybird books at dawn?

    • John Palmer permalink
      January 26, 2017 3:01 pm

      To quote from Monty Python… “Always look on the bright side of death!”

  23. CheshireRed permalink
    January 26, 2017 3:23 pm

    Just when you thought the green blob’s shenanigan’s couldn’t get any lower….

    http://www.bbc.co.uk/news/science-environment-38745937

    Literally re-defining their start dates this time, and of course it suits their agenda. A blatant cherry pick that amazingly makes things ‘worse than previously thought’. Honestly, who’d of thought it?!

  24. Svend Ferdinandsen permalink
    January 26, 2017 7:53 pm

    human-induced climate change?
    If they could just define how much of the warming we have seen could be human induced it would help a lot.
    We would still have the problem to figure out what kind of “climate changes” the temperature change could induce. For the time being not even IPCC knows that.

    • CheshireRed permalink
      January 27, 2017 1:05 pm

      Dana Nuccitelli claims it’s….wait for it…110%! Yep, I know what you’re thinking. The 10% is then knocked off by natural forcings leaving, amazingly! – ALL the ‘warming’ as being caused by mankind. Every last bit of it. How neat and tidy is that, eh?

  25. Tom Dowter permalink
    January 26, 2017 10:47 pm

    There have been many responses to my earlier post. I do not have the time to respond to all of them. However, here are some relevant thoughts:-

    Those who deny the possibility of the greenhouse effect by arguing that back radiation cannot cause warming are missing the point. All the warming is caused by the sun. What greenhouse gases do is reduce the cooling – especially at night. Virtually the whole scientific community, and not just climate scientists, accept the possibility of CO2 induced warming. I find it extraordinary that anyone can believe that they are all wrong or engaged in some sort of hoax.

    The effect of clouds is important. They hinder heat and light transfer in both directions. Higher cloud cover leads to cooler days and warmer nights, and, because nights in winter are longer than days, they cause a net warming in winter and a net cooling in summer. Overall, they result in a net cooling on an annual basis. All this is clear from the statistics.

    The cold desert nights and warm desert days are more an effect arising from the absence of clouds than any greenhouse effect – although I agree that water vapour is a powerful greenhouse gas. Molecule for molecule, it is slightly less potent than CO2. However, because it is more plentiful than CO2, the net effect from water vapour is somewhat larger.

    Those who claim that there has been no warming for 20 years are not supported by the statistics. In fact, none of the temperature series, (HadCRUT4, GISS, NOAA UAH or RSS), shows any period greater than18 years between 1979 and 2016 where there has not been some warmiing. Indeed, none of the surface data shows any warming for periods longer than 13 years!

    Finally, on latent heat transfer. This probably happens and is the underlying theory behind the so-called, but mis-called, “tropospheric hot spot”. This theory claims that upper tropospheric temperatures should be an amplified version of what happens near the surface. The effect should be strongest over the sea and in the tropics. Indeed, this is the only place where the theory appears to hold. Over land, especially in the Northern hemisphere, the theory doesn’;t appear to work at all. Elsewhere, the situation is too confused to be certain.

    • richard verney permalink
      January 27, 2017 12:58 am

      The cold desert nights and warm desert days are more an effect arising from the absence of clouds than any greenhouse effect – although I agree that water vapour is a powerful greenhouse gas.

      I spend a lot of time in Southern Spain, and I can assure you that cloudy nights in summer means a cold night (in relative terms) and a cloud free night means a warm night (in relative terms). Typically, on a cloudless day it may be say 33degC during the day, and on a cloudless night still 30 degrees at midnight, by about 2 am, it may be down to 27/28 degC. Very often the night does not cool off until about 3am to 4 am. We frequently think about going to bed between 4 am to 5 am and sleep in till 10am/11am. That is the coolest period, so easier for sleeping. In the sun, it is very warm at 10am/11am, but in the shade, it is still not that warm.

      It is a question of humidity. When humid, there is a lot of energy in the atmosphere and therefore it takes a long time to cool; it has a lot of energy to give up and dissipate. When there is little humidity, the atmosphere has little energy and therefore loses this small amount of energy very quickly.

      The reason that deserts are cold at night is that the air is dry with little humidity. Over deserts, the air has little energy stored within it; it therefore heats up quickly, and cools down quickly.

      On the Northern shores of the Med (ie., Southern Spain) the air is humid and therefore has a lot of energy entrained within it; it therefore takes a long time to cool, and much longer to warm.

      Both the deserts in Northern Africa, and the shores of Southern Spain normally have cloudless nights all summer long, but in Spain the night time temperature remains high. It is nothing to do with clouds, but rather humidity.

      Of course, clouds hinder convection and therefore the presence of clouds will tend to slow down heat loss, but that is a secondary factor; the main one being how much energy is entrained within the atmosphere due to its humidity.

      • Tom Dowter permalink
        January 27, 2017 6:31 am

        Basically I have examined the effects of cloud cover on every single 5X5 degree grid for which we have sufficient data. The conclusions on cloud are very strong.

        Spain is only a small part of the world. My results are much more global.

        I do not deny that humidity plays a part. In fact my original post, (way back), makes this very point.

      • AlecM permalink
        January 27, 2017 9:23 am

        Your comment that clouds hinder convection is wrong. Clouds transport latent heat from the surface, converting it to IR to Space at different altitudes for different wavelengths.

        The key wavelengths are 16 – 25 microns, all of which goes to Space from about 2.6 km. Because of the unique self-absorption properties of H2O IR, this mechanism reduces CO2 CS to near zero.

        So, clouds are the key part of the control system, but ocean currents and convective clouds plus Hadley cells are also important

  26. Dung permalink
    January 27, 2017 8:46 am

    Tom Dowter

    What you do not seem to understand is that you and all other ‘scientists’ are little better than single cell organisms when considering what knowledge you (jointly) have amassed about how the world works.
    There are some scientists who have earned a higher level of respect because they deal only with the real world and amongst those I would include mathematicians and engineerers.
    The rest of you need to show some humility.

  27. January 27, 2017 11:19 am

    I’m with Richard Verney on this ‘not so cold’ desert nights thing, there’s more to it than the basic theory that heat disappears quickly in deserts at night. In Southern Spain you can go May to September wthout seeing a cloud and it seems to get stuck in a loop, the coolest part of the day being between 8.00 and 9.00 in the morning with sun already up. I can vouch for the same effect from Morroco to Egypt and on though Jordan and Syria. Same goes with the Sahara, of course these are very hot days where the max T in the range 40 – 55º C.

    I don’t know why, but I suppose there’s just too much heat to dissipate.

  28. JasG permalink
    January 29, 2017 10:49 am

    The modern trend is to call people ‘experts’ despite a history of being wrong all the time.

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