How the Arctic may be impacting UK summers

Monday 17 December 2012, 12:48

Paul Hudson Paul Hudson

We may have to get used to wet summers like we've seen recently across the UK, according Dr Edward Hanna from Sheffield University in an interview which you can see on Inside Out and Look North tonight.

According to Dr Hanna and an international team of scientists, melting summer Arctic ice may be weakening the jet stream, leading it to meander and become slow moving.

This effectively means that weather patterns become locked in for long periods of time.

The jet stream is a ribbon of strong winds high up in the atmosphere, a result of the temperature contrast between northern latitudes towards the Arctic, and latitudes further south.

Because the Arctic is warming faster than any other region on earth, this temperature contrast is getting weaker, leading to a less powerful jet stream in summer.

Crucial to the UK and Northwest Europe is Greenland, a huge mountanous land-mass which can act as a barrier to the jet stream.

If the jet stream is weaker than normal, two things can happen.

It can either split, with one arm going northeastwards, with the other travelling southeastwards towards the UK.

Or the whole jet stream can be deflected southeastwards towards the UK.

The result in both cases would be wet, cool, unsettled conditions as we have seen since 2007.

Not every summer is likely to be poor.

The slow-moving jet stream may become positioned to the north of us, leading to warm settled conditions.

But because of our position relative to Greenland, these summers are likely to be the exception to the rule.

Dr Hanna says if this theory is correct and summer Arctic ice melt continues, there is also likely to be a higher risk of extreme rainfall events such as we have experienced in 2007 and again this year.

The research, which was carried out jointly by experts from NOAA (National Oceanic and Atmospheric Administration), Rutgers University, University of Washington, and the University of Sheffield, was published in the journal Geophysical Research Letters.

You can see more on this on BBC Look North from Leeds, on BBC1 at 6.30pm, (Sky channel 956, Freesat 966) or on BBC1's Inside Out at 7.30pm (Sky 956 & 957, Freesat 966 & 967).

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Comments

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  • rate this
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    Comment number 1.

    Didn't we recently hear of something similar from the solar experts, (low activity influences jetstream) or am I getting this mixed up with Stephen Wilde's ideas?

  • rate this
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    Comment number 2.

    As far as I am concerned, there is a new theory, every time the weather refuses to follow the predictions from the previous theory.
    We were told that "global warming" would result in mild/wet winters and hot/dry summers, until we got the opposite, so a new theory is produced to match the latest weather pattern.
    We will go back to the old theory as soon as we have a hot summer.
    One day they will realise that there is no pattern and it's all just random.

  • rate this
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    Comment number 3.

    @2, QuaesoVeritas wrote:

    “ As far as I am concerned, there is a new theory, every time the weather refuses to follow the predictions from the previous theory. “

    This is a modest improvement on the behaviour of the true AGW hard-liners who claim the real-world data must be wrong if it doesn't agree with their models.

  • rate this
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    Comment number 4.

    #1 lateintheday

    Is this what you were thinking of?
    http://www.bbc.co.uk/news/science-environment-15199065

  • rate this
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    Comment number 5.

    Looks like it ukpahonta. Thanks

  • rate this
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    Comment number 6.

    James Lawrence Powell of the National Science Board looks at 13,950 peer reviewed climate articles published between 1991-2012. 24 reject Global Warming. In other words, a whopping 0.017%.

    Strange then that those 0.017% should keep reminding us that 0.040 ppm is negligible.

    BTW Paul Hudson. Good article tonight. There's hope for humankind yet.

  • rate this
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    Comment number 7.

    My bad - 0.17%. Still?

  • rate this
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    Comment number 8.

    #6. - theelasticjesuz wrote:
    "James Lawrence Powell of the National Science Board looks at 13,950 peer reviewed climate articles published between 1991-2012. 24 reject Global Warming. In other words, a whopping 0.017%. "
    Which proves absolutely nothing.
    If you had asked most astronomers at the time of Galileo, whether the Earth went around the sun, the vast majority would have said that was not the case.
    Have you heard of "peer group pressure"?

  • rate this
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    Comment number 9.

    NCDC/NOAA global temperature anomalies for November:
    Global = 0.679c (+0.0578c)
    N.H. = 0.7653c (+0.1088c)
    S.H. = 0.5951 (-0.0024c)

    The changes are relative to the October figures published last month, although in the case of global and N.H. figures, they have been revised upwards since last month.
    The N.H. increase is similar to that in GISS, which showed a fall in S.H. compared to little change in NCDC/NOAA, resulting in a global increase in the latter, which means it is out of step with the other datasets so far published.
    The overall increase seems to be the result of an increase in NH and SH land surface temperatures, while sea surface temperatures have fallen in both hemispheres, at least according to the revised figures in the files.

    The above are equivalent to 0.541c, 0.675c and 0.419c, after adjustment to 1961-90.

    Still waiting for HadSST2 figures for November, but the MO site seems to have problems at the moment.

  • rate this
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    Comment number 10.

    Sorry, the full global figure should be 0.6795c.

  • rate this
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    Comment number 11.

    "According to Dr Hanna and an international team of scientists, melting summer Arctic ice may be weakening the jet stream . . . . . Dr Hanna says if this theory is correct".

    Is this 'looking for correlation to something . . . anything' or is there some really hard evidence - I rather doubt it is the latter the key word is IF - if only my lotto numbers would all come up at once!

  • rate this
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    Comment number 12.

    "Not every summer is likely to be poor. ..."

    In other words - we'll get mainly wet summers, with the occasional warm, dry one - or pretty much like the weather we've had for the last 100 years or so.

    My observations: (a) The long range weather forecasts (by the Met Office) are so vague and cover-any-possibility as to be worthless. (b) The times when researchers like these are bang on the nail are as rare as a hot British summer. The AGW fanatics have been so hopelessly out, these last few years that just about every alarmist headline now, is followed by a qualification such as that above - meaning the whole prediction could have just as accurately have been made by a five year old.

    I'll make my own forecast now: In future, every report of the dire consequences of predicted global warming (sorry - not used any more, is it?) 'climate change' will end with the qualification "... But much more research needs to be done...."

    Cui bono ...

  • rate this
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    Comment number 13.

    On the recent CH4 "propumentary" (I wonder if I can get that name to be popular?), Dr. Simon Boxall of Southampton University mentioned a theory that in the U.K., we might get "colder, harsher winters", as a result of increasing global temperatures, due to the changes or "wobbles" in the gulf stream as a result of melting arctic ice. This would result in a "scandanavian" climate, rather than a "tropical" one. However, immediately after this, the narrator said "Dr Boxall is keen to point out that this is by no means a certainty".

  • rate this
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    Comment number 14.

    Enjoyed and rather go along with #12 & 13

    Thought the inside out feature was mainly a review of 2012/2007 - didn't let the camera linger too long on the upper air charts!

  • rate this
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    Comment number 15.

    #14. - chris wrote:
    "Thought the inside out feature was mainly a review of 2012/2007 - didn't let the camera linger too long on the upper air charts!"

    Are you referring to "Inside Out" on BBC t.v.?
    Different subjects in different regions.

  • rate this
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    Comment number 16.

    'James Lawrence Powell of the National Science Board looks at 13,950 peer reviewed climate articles published between 1991-2012. 24 reject Global Warming.'

    Wow, I'm impressed with the depth of authority and the extreme effort employed by that well payed individual.

    Lord Monckton cites 450 papers in his role as voluntary IPCC reviewer:
    http://o.b5z.net/i/u/10152887/f/AR5_Expert_Review_Lord_Monckton_Foundation_20121216.pdf

    Perhaps Dr Powell wasn't looking in quite the right places?

  • rate this
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    Comment number 17.

    OVER THE LAST 14 YEARS WE HAVE BEEN CAMPING WITH A TENT.BEFORE WE BOOK OUR SITES WE HAVE TAKEN INTO ACCOUNT WHERE THE GULF STREAM IS GOING.WE FIND IT HARD TO BELIEVE THAT IT'S TAKEN A UNIVERSITY TO COME UP WITH THIS SOLUTION.
    JACKY
    Rotherham

  • rate this
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    Comment number 18.

    @16 ukpahonta

    Where does Monckton cite 450 papers? Can't be bothered to read through 79 pages to find the quote!

  • rate this
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    Comment number 19.

    If I have to make a choice between taking advice from Dr Edward Hanna and his international team of scientists on the one hand and Jacky from Rotherham on the other hand, to inform my choice on summer holiday destination, Jacky wins every time.

  • rate this
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    Comment number 20.

    #17. - finnerja wrote:
    "OVER THE LAST 14 YEARS WE HAVE BEEN CAMPING WITH A TENT.BEFORE WE BOOK OUR SITES WE HAVE TAKEN INTO ACCOUNT WHERE THE GULF STREAM IS GOING.WE FIND IT HARD TO BELIEVE THAT IT'S TAKEN A UNIVERSITY TO COME UP WITH THIS SOLUTION."

    Did you mean jet stream rather than gulf stream?

 

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Hello, I’m Paul Hudson, weather presenter and climate correspondent for BBC Look North in Yorkshire and Lincolnshire. 

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I worked as a forecaster with the Met Office for nearly 15 years locally and at the international unit, after graduating with first class honours in Geophysics and Planetary physics at the University of Newcastle upon Tyne in 1992. I then joined the BBC in October 2007, where I divide my time between forecasting and reporting on stories about climate change and its implications for people's everyday lives.

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