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Honey, I Shrunk The Jet Stream!

November 27, 2019

By Paul Homewood


 Jaime Jessop has an excellent put down of the latest piece of junk science:



In the Times yesterday, we read the following:

The jet stream — the powerful transatlantic wind that dominates British weather — is being shrunk by climate change, scientists say.

Climate change shrinks many things: the US economy, fisheries, fish, chips, Salamanders, wasps, tropical moths, plankton (could they get much smaller?), mountain goats, the Winter snowpack, the Sahara Desert, oyster habitat in California, the ranges of Adelie Penguins and bumble bees and Sweden’s tallest mountain. In fact, probably the only thing which climate change doesn’t shrink is hurricanes, which are becoming ginormous and threatening to gobble up huge areas of the US. Note also how climate change obligingly shrinks mountain goats and mountains – meaning the poor dimininutive critters won’t feel so overwhelmed by their environment because as they shrink, it shrinks also. How sweet. I guess that’s what you call #ClimateJustice for small(er) furries. But anyway, we can now add the Jet Stream to that long list above, courtesy of research scientist Tim Woollings:

Tim Woollings, associate professor of atmospheric physics at Oxford University, who has published a new book, Jet Stream, said: “The planet is warming rapidly due to humanity’s greenhouse gases. It means the whole of the Earth’s tropical belt is likely to expand, pushing the jet stream north so it shrinks in size and accelerates.”

The warning comes as greenhouse gas levels in the atmosphere hit a new high, keeping Earth on track for global temperature rises of 4C-5C by 2100. This weekend CO2 levels reached 410 parts per million (ppm) at one global reference laboratory in Mauna Loa, Hawaii, and 414ppm at another in Alaska. Such figures are a huge rise on the 350ppm seen in 1990.

Apparently, this “means that Britain is at growing risk of more violent storms in winter and searing heatwaves in summer”.

Woollings suggests that, as the world warms, the jet stream will spend more of the winter across the British Isles and go further into Europe, letting storms keep their power as they reach the UK.

In summer it is likely to shift further to the north than now, opening Britain to hot air from the tropics.

Scientists have long been reluctant to link weather events to climate change but, said Woollings, the number of extremes means connections can be made. He cited the stormy winter of 2013-14 as the first evidence that the jet stream was altering.

Reluctant? Who is he kidding? They’re falling over themselves to attribute extreme weather to climate change. They can’t get in there quick enough!

Now this is all very well but what the Times doesn’t tell you in its eagerness to convince readers that heatwaves in summer and storms in winter are heading their way is that this is just another hypothesis about what might happen to the jet stream due to GHG warming and it is a hypothesis which relies upon a predicted consequence of GHG warming which has not been observed, despite the best efforts of scientists to torture the data in order to claim that it has been observed. The predicted consequence is accelerated warming in the tropical troposphere, the so called tropospheric tropical ‘hot spot’, which has remained annoyingly elusive.


Full story here.

As Jaime goes on to explain, Woollings’ theory of an accelerating jet stream is the total opposite of Dr Jennifer Francis’ theory that the jet stream has grown weaker and more meridional, as a result of Arctic warming.

She naturally claims this is the cause of more frequent and severe extreme weather as well.

In reality, it has been well understood for decades that global warming leads to an expansion of the tropical zone, in turn pushing the weather belts polewards. HH Lamb explained this phenomenon well in his books.

During global cooling in the 1960s and 70s, it was this movement of weather belts back towards the Tropics which was responsible for the catastrophic droughts which beset a wide swathe from the Sahel right across to India at the time.

The current shift back to the poles should result in the jet stream shifting north of the UK during winter.

What is transparently obvious from all of this alarmist claptrap is that neither Woollings or Francis has actually bothered to check the actual data about the jet stream.

Instead they have alighted on a few random weather events and developed a theory around them.


But if they studied the history of the Little Ice Age, they would have discovered that the weather was a lot worse then, as the renowned historian Geoffrey Parker elaborated on in his book, “Global Crisis: War, Climate Change and Catastrophe”.

For those who have not read it, my review of it here offers a glimpse of the weather disasters the poor souls had to put up with in those days.

  1. Curious George permalink
    November 27, 2019 8:00 pm

    “Climate change shrinks many things: the US economy … ” After a growth of around 2% a year in Obama years, it is now growing at around 4%. The link is to a projection for year 2100 by people with the best crystal balls.

  2. Mike Turner permalink
    November 27, 2019 8:46 pm

    If you have not seen this before, please observe when windy and then when not so windy..and when the temperature drops…..

    Illustrates that what Paul says is true!


    • dave permalink
      November 27, 2019 10:28 pm

      The jet stream in both hemispheres is ACTUALLY tending to move Equatorward*, therefore getting loopier because necessarily longer, and generally “wilder,” in the sense that the polar vortexes of winter break down more often and air masses spill out. Weather extremes will be seen more often.

      For example, in the Southern winter just gone the jet stream moved away from Antarctica and as a result the “ozone hole” was aborted halfway through its seasonal development. And just in the last few days there has been a deep penetration of cold into North America from the Arctic. Slightly less frigid air was pulled in to the Arctic from elsewhere to replace the exiting air, and here is the result according to the DMI:

      You just have to look at Climate Reanalyser’s global maps every day – especially the 500 hPa Geopotential Height:

      *Because of solar influences on the stratosphere, according to one theory.

  3. swan101 permalink
    November 27, 2019 9:51 pm

    Reblogged this on ECO-ENERGY DATABASE.

  4. November 27, 2019 10:24 pm

    The Times says: ‘hurricanes, which are becoming ginormous and threatening to gobble up huge areas of the US.’

  5. November 27, 2019 10:27 pm

    …so how does it explain the total lack of major hurricanes affecting the US in the Obama years?

  6. Bruce of Newcastle permalink
    November 27, 2019 10:28 pm

    Weird how the last episode of jet stream hysteria was back in 2010.
    Which was right at the bottom of the solar cycle.
    Recall the UK winter white out? And the great Moscow heat wave?
    We’re back in similar solar conditions.

  7. jack broughton permalink
    November 27, 2019 11:52 pm

    The scientists who believe in AGW are almost fanatical in their religion. Tonight there was one on ITV news who spouted the most amazing drivel about how the world was doomed unless we reduce CO2 immediately: would certainly terrify any gullible kids watching.
    The 1.5 deg K above the 1800 temperature is going to be a disaster apparently: where do they come from?

  8. john cooknell permalink
    November 28, 2019 12:12 am

    We didn’t know there was a jet stream till 1930’s and then it wasn’t widely scientifically recognised till much later.

    So we must look for a proxy on historical changes, how about tree rings?, bet MM would get a correlation and a hockey stick!

    • dave permalink
      November 28, 2019 7:53 pm

      It was actually found, with the aid of balloons, at the end of the 19th Century, that there was

      (1) A general tendency in the upper atmosphere for a West to East movement such that the gross kinetic energy of the upper atmosphere was six times that of the lower;


      (2) a phenomenon existed of localised air streams of very high velocity within the general tendency (a Frenchman found a speed of over a hundred miles an hour from a ballon-sondes experiment in 1891);

      However it was, indeed, several decades before it was fully appreciated that the waving nature of the jet stream was caused by instabilities resulting from the fact that the vector of vorticity of air moving from the equator did not correspond to the vector of the vorticity of the air flowing back towards the equator.

  9. John of Cloverdale, WA permalink
    November 28, 2019 3:27 am

    ”Scientists are however increasingly confident that important changes are afoot in the tropics. Driven by the vast quantities of energy pouring in from the Sun directly overhead, these are the great powerhouses of Earth’s climate”, says Woollings. Is it solar or CO2 driving Climate?

  10. martinbrumby permalink
    November 28, 2019 7:06 am

    I keep pointing out that it’s all caused by those naughty witches.
    My scientific evidence is just as good as theirs and I have thousands of years of cultural history to back me up.

  11. Ian Wilson permalink
    November 28, 2019 8:07 am

    The BBC inevitably splashed as lead item over several bulletins the 2 ppm increase in CO2 over two years. It’s interesting to see from your post that the recorded variation between two sites is double that.

  12. November 28, 2019 8:51 am


    Lamb’s theory of shifting weather belts during 1960s/70s cooling as an explanation for the Sahel drought, appears to be borne out by research in 2008:

    “The influence of the large‐scale ocean circulation on Sahel rainfall is elusive because of the shortness of the observational record. We reconstructed the history of eolian and fluvial sedimentation on the continental slope off Senegal during the past 57,000 years. Our data show that abrupt onsets of arid conditions in the West African Sahel were linked to cold North Atlantic sea surface temperatures during times of reduced meridional overturning circulation associated with Heinrich Stadials. Climate modeling suggests that this drying is induced by a southward shift of the West African monsoon trough in conjunction with an intensification and southward expansion of the midtropospheric African Easterly Jet.”

    Interestingly. they don’t find that the observed pattern of rainfall is solely explained by a simple shift in the ITCZ. The actual reasons for rainfall variability in the Sahel are more complex, so Woollings’ simple explanation of the tropical troposphere expanding and ‘squeezing’ the NH polar jet is probably just that – simplistic.

    “Evidence in marine sedients from off‐shore Senegal, submitted to Paleoceanography, 2008] interpreted drought in the tropics by a southward shift of the Intertropical Convergence Zone (ITCZ). Our experiments indeed suggest a southward shift of the ITCZ (i.e., monsoon trough) during AMOC slowdown by a few degrees latitude over West Africa. It is however problematic to explain the widespread nature of drought exclusively with an ITCZ shift. Today, the ITCZ seems to be effectively independent of the system that produces most of the rainfall. The tropical rainbelt (which is often confused with the ITCZ) is in fact produced by a deep core of ascent lying between the axes of the AEJ and the TEJ, some ten degrees of latitude south of the ITCZ [Nicholson and Grist, 2003]. Interestingly, a southward shift of the ITCZ has been rejected as a cause of the multidecadal Sahel drought during the second part of the last century [Citeau et al., 1989].”

  13. November 28, 2019 10:05 am

    Piers Corbyn on the Jetstream

  14. bobn permalink
    November 28, 2019 10:17 am

    Mr Woolly Woollings seems to have everything 180degress wrong. The Jet (as observed and not modelled) is getting less intense and more oscillatory. It is moving away from the Poles in both hemispheres. In the last two months the northern Jet has spent considerable time over Spain and hammering the Med (hence major floods in south France and North Italy). The position of the North AtlanticJet is driven by the ITCZ which is the line of collision of the Azores High with the Arctic High. This is determined by heat expansion and contraction of the Azores (the Arctic is marked by a lack of heat!). Therefore the Azores must be cooling (by ocean heat transfer and/or direct radiation) for the Jet to move south. Looks like we are about to revisit the 1960’s climate phase. And Valentina Z (building on Svensmark) has given a good explanation of why this is happening. A few years of white xmas’s are on the cards.

  15. dearieme permalink
    November 28, 2019 12:05 pm

    In honour of Clive James, Quadrant has rerun this fine piece.

  16. November 28, 2019 12:25 pm

    What “Little Ice Age?” Didn’t Michael Mann dissolve it, so to speak? And to disagree with Michael Mann is to risk a law suit……

  17. Patrick Harcourt permalink
    November 28, 2019 3:36 pm

    Tim Woollings is quoted by The Times as saying that “The planet is warming rapidly due to humanity’s greenhouse gases.”

    Does he look at the data? The UHI satellite data shows that the earth has cooled from +0.86C in Feb 2016 (a very strong El Nino year) to 0.46 for Oct 2019. This means a cooling of 0.4C over the last almost four years.

    I despair!!

    Patrick Harcourt

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