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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  • rate this

    Comment number 41.

    I wonder if these 'EXPERTS' are the same ones who said that increases in carbon dioxide in the atmosphere causes global warming. Remarkable that over the past 12 years carbon dioxide has doubled, but world temperatures have remained the same, in fact slightly decreased. Suddenly global warming has been renamed climate change, which is totally different and has happened since the world began.
    My theory is the bad summers and wet winters are caused by the delay in sunspot activity and my forecast is next year will be wet, but the following year will be a good summer. Trust me, it's as accurate as you so called experts.

  • rate this

    Comment number 42.

    Not quite sure what these people are saying apart from climate models are not representing what is actually taking place and that the Northern Hem is going to get colder in the 21st Century. Might mean a little more to others:-

    “UMass Amherst Climate Model is First to Study Climate Effects of Arctic Hurricanes”

    “…Results point to potentially cooler conditions in Europe and North America in the 21st century than other models predict….”

    “Before polar lows were first seen by satellites, sailors frequently returned from the Arctic seas with stories of encounters with fierce storms that seemed to appear out of nowhere,” says Condron, a physical oceanographer. “Because of their small size, these storms were often missing from their weather charts, but they are still capable of producing hurricane-force winds and waves over 11 meters high (36 feet).”

    “He and Renfrew say that despite the fact that literally thousands of polar lows occur over the Arctic region of the North Atlantic Ocean every year, none are simulated by even the most sophisticated climate models. To understand the importance of these storms on climate, Condron and Renfrew therefore turned to a new, state-of-the-art climate model to simulate the high wind speeds associated with these “missing” storms.”

    Read it all:-

  • rate this

    Comment number 43.

    Wow all the petrol heads of the earth on one site here it seems - no doubt few of you even spend a few minutes in the open air every day. Certainly few of you show any sense of responsibility for future generations but I guess that is par for the course in our times. Anyway I will leave you to carry on as you are regardless .....

  • rate this

    Comment number 44.

    #38. - theelasticjesuz wrote:
    "I love the way you GENUINE flat-earthers have twisted this so the IPCC appears to be a group of misguided religious fascists who refuse to listen to the OVERWHELMING evidence that is 24 dissenting articles - out of a staggering 13,950. Truth is not a democracy, especially a democracy that advocates minority rule. "

    "The only peer pressure here - as the overwhelming majority of people know - is that which comes from the multi-trillion dollar fossil fuel industry. End of. But if you think a climatolgist on 40k a year has more to lose than Fossil Fue Inc...?"

    What about those who have something to gain from the renewables industry?

    You seem to blame the fossil fuel industry for "climate change". They are only meeting a demand. If anyone it is the billions of motorists who use petrol who are to blame. Do you drive a car?
    Do you want the fuel companies to make less profit, by reducing the price of fuel?
    Surely if you are correct, that would only make things worse?

  • rate this

    Comment number 45.

    #39. - greensand wrote:
    "Mind, there seems to be some other issues in that direction, clear as mud at present but I am sure clarity will come through eventually"

    Thanks for the link, but I am afraid that most of the terminology is unintelligible to me.
    What I do think is that trying to make the model "hindcasts" match reality may be futile, because even if they do, that doesn't guarantee that "forecasts" will be correct.

  • rate this

    Comment number 46.

    #43. - KeithJ wrote:
    "Wow all the petrol heads of the earth on one site here it seems "
    Who are you referring to?

  • rate this

    Comment number 47.

    #43. - KeithJ

    Why do you think that we're all petrol heads? Not that I post much these days, so maybe i shouldn't consider myself part of the collective we, but I'm certainly not a petrol head, you could call me a thorium head if you'd like.... it's not really got the same same sort of ring to it though......

    It's attitudes like yours and a those of a certain elastic religous figure that lead to me no-longer wishing to think of myself as being green.........

  • rate this

    Comment number 48.

    #37 - QuaesoVeritas

    "However, isn't the "missing heat" supposed to be in the deep ocean, i.e. below 700m, although how it got there I have no idea."

    Yep, I'm with you. How it managed to pass through the top 700m with no appreciable effect I've no idea - Still that's a two box model for you..... sorry couldn't resist..... but it is a bit of a conundrum, isn't it?

    And, that's the general problem with climate science as it stands today, far too many conundrums and not very much joined up thought...... but all done in the name of saving the planet, so that's alright then................

  • rate this

    Comment number 49.

    I don't know what you're all going on about, some other experts say the world is going to end in 3 days time, so I wouldn't worry, that's rubbish as well.

  • rate this

    Comment number 50.

    @ elastic

    "I love the way you GENUINE flat-earthers have twisted this so the IPCC appears to be a group of misguided religious fascists who refuse to listen to the OVERWHELMING evidence that is 24 dissenting articles - out of a staggering 13,950. Truth is not a democracy, especially a democracy that advocates minority rule. "

    I think you'll find that the person in question wasn't actually looking too hard, I think you'll find that Pielke Snr has produced more papers than that on his own, add in Richard Lindzen and just 24 papers is looking ridiculous rather than just dodgy.

    Seriously, if you can't have an informed or sensible discussion just keep quiet, Trolls like you do not help your cause.

  • rate this

    Comment number 51.

    31. blunderbunny wrote:

    "I've a question for our warmist brethren... Given, that I hope we can all agree that the planet hasn't warmed very much since 1998..."

    Let me stop you right there bunny. The evidence that the planet has warmed (i.e. gained heat energy) since 1998 is overwhelming.

    Most of this energy has been absorbed by the oceans and, as we now know, the deep oceans also.

    This energy uptake arises from the observation that more solar energy is being retained in the earth energy system than is being released at the top of the atmosphere.

  • rate this

    Comment number 52.

    45. QuaesoVeritas wrote:

    "I am afraid that most of the terminology is unintelligible to me."

    Same here, though it would appear all is not well. When launched DePreSys came with:-


    "Retrospective forecasts have been made from numerous dates in the past. Some of these are shown in the top global annual temperature forecast figure (white curves and red uncertainty regions from 1985, 1995 and 2005). Generally, the forecasts predict rises in temperatures similar to those observed (black curve). Many facets of the variability, such as the record warming caused by the large 1997-1998 El Niño and the cooling caused by the 2008 La Niña, are within the range of the predictions (red shading). An exception is the cool period after the large volcanic eruption of Mount Pinatubo in 1991, which could not have been forecast years in advance."

    I have no doubt normal service will be resumed shortly.

  • rate this

    Comment number 53.

    #51. - newdwr54 wrote:
    "Most of this energy has been absorbed by the oceans and, as we now know, the deep oceans also."

    Although evidently not predicted in the climate models?

    What is the mechanism for the absorbtion of heat by the deep oceans?

    Presumably CO2 heats the atmosphere, then that heats the sea surface, then that heats the lower ocean depths?

  • rate this

    Comment number 54.

    #52. - greensand wrote:
    "Retrospective forecasts"
    Surely a contradiction in terms?

  • rate this

    Comment number 55.


    Firstly, didn't say it hadn't warmed... so sorry about that.... as i understand it there's a set of results that unreliably show that the deep ocean may have warmed, but the top 700m has not really warmed.

    So, please try a little harder and really dont use the word "overwhelming" at the end of a point that no-one, well at least me, was disputing.

    The planet has warmed, but only a little and not by anyway near enough to lend any weight at all to your case.

    So, solar constant, aerosols negligible, CO2 massively increased, sea temp increased a little, but not much and not the top 700m.... So I ask again, where's the heat?

    If the theory as espoused by both the team and the IPCC is in anyway accurate, there should be a lot more of it and it's simply not there and is continuing to be not there. As I said it's not supposed to be complicated.

  • rate this

    Comment number 56.

    54. QuaesoVeritas wrote:

    "Retrospective forecasts"
    Surely a contradiction in terms?

    Yup, after a few discussions with the MO I got confirmation that they are "hindcasts"

    Figure 1 on the same page has "...Previous predictions starting from June 1985, 1995 and 2005 are shown as white curves...".

    The MO person agreed that this was misleading and said they would talk to the people responsible for the page. Heard no more.

  • rate this

    Comment number 57.


    Not to invoke old Albert, but I'm afraid I cant help myself.

    Einstein, said "No amount of experimentation can ever prove me right; a single experiment can prove me wrong"

    I'm just pointing out that currently, this extra large thermodynamic, physics and chemistry experiment that we all inhabit, is not playing ball or even oblate spheriod ;-)

    Personally, I find that very interesting

  • rate this

    Comment number 58.

    #50 blunderbunny

    It's the way they tell 'em!

    You will probably find that the statement is in fact correct that only 24 articles were found against 'global warming' in the sense that the planet has warmed.

    That obviously is not the intention of the headline grabbing statement that infers 'global warming' to anthropogenic release of CO2 as the reason that temperatures have risen.

    The clarity of definition between the two being obscured, some would say intentionally to provide sensationalism, much in the same manner of my earlier posts about Lord Moncktons 450 papers as an example of such but with reverse intention.

  • rate this

    Comment number 59.

    #58. - ukpahonta wrote:
    "You will probably find that the statement is in fact correct that only 24 articles were found against 'global warming' in the sense that the planet has warmed."

    Yes, taken literally, that would imply denial of the data which supports the premise that global temperatures have increased. In fact, I think it is remarkable that as many as 24 articles would deny actual warming. That would suggest some sort of belief that ALL of the datasets were either wrong, or had been manipulated in some way, which would be an extreme viewpoint.
    While there is some evidence that terrestial data may have been manipulated, either by "adjustment" of the figures, or careful selection of sampling locations, that is not the case for satellite data.

  • rate this

    Comment number 60.

    Oops, that was obviously oblate spheroid

    Mea Culpa


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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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