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Slingo Admits Floods Mainly Due To Natural Variability

December 31, 2015

By Paul Homewood




Has Julia been listening to me? For once, there is a slightly more balanced explanation for our bad weather from her!


This is a quick post, I’ll be doing a fuller job when all the month’s data is in.


December 2015 will go down in meteorological history as one of the wettest – and warmest – on record. It will also be remembered for the devastating floods in Cumbria, Lancashire, Yorkshire and Scotland. The extensive flooding of homes and businesses, loss of electrical power, major damage to roads and bridges, and disruption to the rail network have caused great misery and incurred huge losses.

In this blog our Chief Scientist, Professor Dame Julia Slingo, discusses what factors may have influenced the record breaking weather we have seen in recent weeks.

As with all high-impact weather, the meteorological set-up was critical in defining the severity of these events. Throughout the month, the winds have come from the south or southwest, bringing both extreme warmth but also very high levels of moisture.

There has been a lot of debate whether this has been associated with El Nino – an intermittent warming of the equatorial Pacific Ocean which has been very strong this year – or whether this is a sign of a changing climate. The links to El Nino are certainly very clear in the set up of large waves (troughs and ridges) in the atmospheric circulation, which we expect to see in these events.


I’ll not reprint the rest, but it is worth a read. The main points that stand out though are:-



1) They have already declared record breaking wet weather for December on their news page here. This is based on provisional data up to 29th Dec, but crucially only compares back to 1910. The longer running England & Wales Rainfall Series dates back to 1766, and usually the monthly numbers are not out for a few days after the end of the month.

One wonders why they have not simply waited a week before declaring “records”. My interpretation of the data is that this month certainly won’t be the wettest in the longer  series, and may not even make the Top 10.


2) However, beggars can’t be choosers! Slingo actually makes a few sensible points, ones that I have been pointing out for a few weeks!

For instance:

As with all high-impact weather, the meteorological set-up was critical in defining the severity of these events. Throughout the month, the winds have come from the south or southwest, bringing both extreme warmth but also very high levels of moisture.

With this sort of set up for the whole of the month, it was always going to be unusually mild and wet.


3) She also refers to the “river of moisture”, which, as I have pointed out, has targeted the North West, not only during Storm Desmond.

Storm Desmond in early December was associated with a strong west-south-westerly flow around the ridge over the eastern seaboard of the US, reaching far back across the Atlantic, as far as the Caribbean. With ocean temperatures well above normal in the southern part of the North Atlantic (see above) – possibly due to the much weaker than normal hurricane season this year associated with the current El Nino – the air was primed with more moisture than normal. This river of atmospheric moisture fed the storms that formed on a stronger than normal jet stream, and as the air impinged on the mountains of Cumbria, large quantities of rainfall were released.


4) In discussing the importance of the jet stream in all of this, she speculates that it may be connected to El Nino, and also the warm water in the North East Pacific. But she also mentions the contribution played by the cold pool of water in the North Atlantic, increasing the temperature gradient and strengthening the jet stream:

Later in the month the southerly flow intensified, with a high pressure system to the east of the UK over continental Europe providing a block to the normal passage of the westerly jet. With colder than usual ocean temperatures over the northern part of the North Atlantic (see above), a strong temperature gradient formed which acted to strengthen the jet and set up the conditions for the formation of rapidly deepening cyclones, such as Storm Frank. These cyclones drew in warm, moist air from far south leading again to heavy rainfall and further flooding on already saturated ground. And the southerly winds on the eastern flank of Storm Frank, and strengthened by the high pressure to the east, enabled extremely warm air to penetrate, temporarily, the deep Arctic leading to very high temperatures.


5) Finally, she says:

As for whether climate change has played a role, we know that the overall warming of the oceans increases the moisture content of the atmosphere by around 6% for every 1°C warming. This extra moisture provides additional energy to the developing weather system, enabling even more moisture to be drawn in to the system, so that the overall enhancement of rainfall when the moisture-laden air impinges on the mountains of Wales, northern England and Scotland may be even more significant. So from basic physical understanding of weather systems it is entirely plausible that climate change has exacerbated what has been a period of very wet and stormy weather arising from natural variability.

We have heard a lot about how the floods have been the result of climate change, but Slingo makes clear that, at most, higher atmospheric temperatures have only exacerbated what would have been extremely wet and stormy weather, caused by natural factors.

Assuming the numbers are correct, the half a degree or so of warming recorded in the last half century should only add 3% to the moisture content of the atmosphere. UK rainfall in December has been around 200mm, so, according to theory, rainfall might be 6mm more than otherwise. In other words, the difference would actually be barely noticeable.



Perhaps we should now expect apologies from David Cameron, Rory Stewart, and all of the other politicians and commentators who have jumped on the bandwagon, and blamed the floods on climate change.

  1. BLACK PEARL permalink
    December 31, 2015 5:34 pm

    Re MetOff
    ” it is entirely plausible that climate change has exacerbated what has been a period of very wet and stormy weather arising from natural variability.”
    “Plausible” Plausibility is the bedrock of any big con and there’s been plenty scams financial or otherwise, but this Climate Change one is a bute and has got to be one of the biggest

    Don’t you miss all those BBC reporters walking up and down dried up river beds … chanting over an over …. “because of climate change ….”
    Where are they now ?

    • David Richardson permalink
      December 31, 2015 6:35 pm

      Yes Black Pearl we need a “go to” website for links to BBC reporters swinging both ways – but of course that is why we have “climate change” so that they can change horses in a flash.

      I don’t know whether you have seen this website

      If I am in need of good laugh I have a read here. I first came across it when someone pointed me to their “Hardest Hit” section and that is worth a read, but I think my favourite is the “Having it both ways” section.

      AND from time to time I cheer myself up by re-reading this wonderful piece by farmer Charlie Flindt back in 2012

      Looks like they now need to dig out the PowerPoint slides from 2001 !!!??

  2. David Richardson permalink
    December 31, 2015 6:13 pm

    I had a read when craig posted the comment earlier – not much to disagree with and not much to add to what we already knew.

    Looking forward to seeing your round up in the fullness of time Paul

  3. December 31, 2015 6:56 pm

    Thanks, Paul, for the crazy news.
    Yes, incredibly enough, El Niño is playing with the planet.
    Known since Pizarro was conquering what is now Perú this mischievous child has been toying with Earth. And we have not been able to understand the thing.
    By corrupting science we are surely not helping.

    Happy New Year!
    May 2016 be a better year!

  4. December 31, 2015 7:41 pm

    Slingo got a stinging rebuke from the Met Office itself over her climate change claims about the Somerset Levels floods in 2012. Perhaps she did not want another. Part of the tale told in essay Somerset Levels.

    • David Richardson permalink
      December 31, 2015 8:15 pm

      A contradiction maybe, rather than rebuke I would say – the person who told the truth was probably down the Job Centre pretty smartly or their head will be well below the parapet. These are political appointments now ristvan, you have to tell the correct story. Imagine the Met Office now saying “well we are beginning to think we might not be totally correct”! Politicians would hang them out to dry because they will not take the drop and scapegoats will be needed.

      Climate Scientists have ruled the roost in the last decade – you wouldn’t have been selected as Chief Scientist if you displayed any tendency to scepticism at interview – all you would have heard would be “next”.

      Many in climate science must be doubting the theory by now (certainly the cAGW end especially), but expressing that is career limiting and many of the leading climate science outfits just recruit in their own image – express the idea of doing true sceptical science and you will be working in McDonalds.

      A couple of years back the Met Office finally found the Sun – so perhaps things are looking up. I really do hope so

  5. December 31, 2015 7:51 pm

    Reblogged this on Climatism.

  6. December 31, 2015 11:12 pm

     So from basic physical understanding of weather systems it is entirely plausible that climate change has exacerbated what has been a period of very wet and stormy weather arising from natural variability.

    So what explained the 1870’s or the weather in the WW1 period or even the 1970’s? This reeks of the opportunism evident during the droughts of 4-5 years ago or the snows when it was “[insert latest weather episode] is what we’d expect from climate change”.

    Piers Corbyn has been warning of these type of extremes for years too with an entirely different mechanism (the sun affecting the jetstream). It’s also what scientists in the 70’s during the last cooling episode expected from a meridional jetstream.

    Why do the MetO limit the final explanation – after what is a mainly balanced and informative piece – to climate change? Can nothing else be considered or as I commented on their site “today we are at war with Oceania etc…”.

    I really find that final paragraph quite disturbing.

  7. John Peter permalink
    January 1, 2016 8:19 am

    Can anyone explain how you get tax payers money first to a £30 million and then a £200 million computer to explore “climate change” (meaning cAGW) without dramatically demonstrating the dire effect of “climate change” at every given opportunity. Surely Slingo could not press for such funding if there was nothing to investigate (man made CO2’s dramatic effect on the climate). Her main problem appears to be that the Met Office still seem to have a few scientists remaining dedicated to do some actual science.

  8. January 2, 2016 9:25 pm

    They need natural variability to explain the 18+ year Pause & they know their public aren’t buying the implausible Pause Fiddling going on at NOAA & NASA with eg. @climateOfGavin & Karl et al., so it is strategic to cool the Global Warming hype & talk some sense for a while.

    Apart from that the December storms were forecast over 2 months before by sun watchers to within a day or two, so NV & El Niño may be effects but solar factors may have been a cause & a predictable one, as the Prime Minister has been advised.

    Click to access WANews15No30.pdf

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