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 21.

    #18 john_cogger

    Can't be bothered please provide the quote....Typical of post normal science the sound bite is king.

    All the papers are listed, dated, with authors and journals of publication.

    This is an example of why climate prediction is so far from reality, models running on a computer in a nice warm office without the need to put any real effort in.

    You should be totally ashamed, I really don't know why I continue with the effort, day in day out, 7 days a week, while you just sit there in front of that computer screen saying 'I can't be bofferred'.

    /sarc :-)

  • rate this

    Comment number 22.

    Ahh I see now. By saying 450 cited papers you don't actually mean 450 papers that rejected global warming. You mean Monckton has referenced 450 different papers in his review.

  • rate this

    Comment number 23.

    He references AR4 (2007)... I can't remember now, was that for or against global warming?

  • rate this

    Comment number 24.

    #22 john_cogger

    Depends on how you play the words really, doesn't it.

  • rate this

    Comment number 25.

    #15 Q'V'

    As per Paul Hudson's info in the body of his opening piece: BBC1 Inside Out, yorks region.

  • rate this

    Comment number 26.

    Another university professor coming up with a theory, remember the hockey stick by another. These chaps need to get out into the real world and then they may learn a thing or so. Give me the University of life any day, Bill Foggitt rest in peace.

  • rate this

    Comment number 27.

    9. QuaesoVeritas wrote:

    "NCDC/NOAA global temperature anomalies for November:
    Global = 0.679c (+0.0578c)...

    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."

    Thanks for that QV.

    Relative to previous November figures this places November 2012 as 5th warmest overall in NOAA's 133 year record. The ten warmest Novembers in the NOAA record have all occurred within the past 12 years. The warming trend for November over the past 30 years is +0.21 C/decade.

    And it makes autumn (fall) 2012 the second warmest in their 133 year global record, behind only 2005. Nine of the top ten warmest autumns have also occurred within the past 12 years. The autumn warming trend over the past 30 years is also +0.21 C/century.

    Adjusted to the 1981-2010 base period, November 2012 is actually slightly *cooler* in NOAA (0.26) than it is in both NASA and UAH (0.33 and 0.28 respectively). The only data set notably 'out of step' so far this month is RSS at 0.10. However, as NOAA points out, 2012 is still shaping up to overtake 2011 as the warmest calendar year on record during which La Nina conditions have been officially declared for any period.

  • rate this

    Comment number 28.

    #25. - chris wrote:
    "As per Paul Hudson's info in the body of his opening piece: BBC1 Inside Out, yorks region."
    Oops, sorry I missed that bit.
    I'll have to watch it on iPlayer.

  • rate this

    Comment number 29.

    #27. - newdwr54 wrote:
    "Adjusted to the 1981-2010 base period, November 2012 is actually slightly *cooler* in NOAA (0.26) than it is in both NASA and UAH (0.33 and 0.28 respectively). The only data set notably 'out of step' so far this month is RSS at 0.10. "
    I make NOAA slightly above UAH after adjustment to 1961-90, but very little difference.
    When I said that NOAA was "out of step", I meant as far as the change is concerned.
    If it is "in step" with UAH & GISS now, then it must have been "out of step" last month, although it was probaly GISS which was "out of step" last month. I haven't compared the revised figures for past months yet.
    "However, as NOAA points out, 2012 is still shaping up to overtake 2011 as the warmest calendar year on record during which La Nina conditions have been officially declared for any period."
    Ah, that's the new criterion is it?
    I can see the MO using that argument when this year fails again to be warmer than 1998 according to HC3, or 2010 based on HC4.

  • rate this

    Comment number 30.

    Actually, the Global State of the Climate report says:

    "If this anomalous warmth continues through the end of the year, 2012 will surpass 2011 as the warmest La Niña year since at least 1950, according to NOAA's Climate Prediction Center."

    I'm not entirely sure why they say "since at least 1950". I would have thought that it would be, as you said, the warmest La Niña year on record.

  • rate this

    Comment number 31.

    I've a question for our warmist brethren that's been puzzling me for a while now, but first I need to set the scene a little

    Given, that I hope we can all agree that the planet hasn't warmed very much since 1998, we can argue over significance or not, but that's not point here. However you try and slice it's not really warmed a lot, and yet C02 had risen significantly since the turn of the century.

    If there are no other really significant forcings or feebacks, then where's the heat?

    There's aparently no significant solar forcing acording to you guys, so a quiet sun cannot explain the lack of heat. You've only really got Aerosols to play with, but with TSI being calculated watts/sq metre at ground level and with that being apparently largely unchanged, these cannot be contributing to a reduced solar input. So again, I'm left with the query where's the heat?

    Aerosols have been used to pin back and restrain the largely CO2 and largely positive feedback based models, yet in reality there's been no appreciable solar dimming in terms of energy in, so again where the heat?

    Following on from that you could explain, where's the extra water vapour and again where's the heat that should be generated from this?

    If as is oft claimed, it's all simple science and simple physics, this is not a difficult question - so where is it?

    And, is it as Trenberth said "A travesty that you can't explain it"

    I'm just curious... those of you of a warmist persuasion, with a modicum of intelligence and scientific expertise, must be starting to realise that some of the more outlandish claims for C02 sensitivity are just that...... outlandish.....

    As I said, I'm just curious.

  • rate this

    Comment number 32.

    You SAY: 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:

    I SAY: WOW! I'm absolutely staggered by your naivete. Then again...

    So remind us: who Monckton DOESN'T WORK FOR; what qualifications regarding AGW he DOESN'T HAVE; what office he NEVER held under Thatcher; all the connections he DOESN'T HAVE with Heartland and every other spurious organisation set up by either Exxon or Koch to rubbish the science behind AGW.

    Monckton has been thoroughly investigated and his spurious claims re AGW have been found wanting in every dept. That said, Monckton is a master of the vernacular and that's why he continues to mesmerise the stupid. Amen.

  • rate this

    Comment number 33.

    Blunderbunny the great insight is that science has little to do with the output of computer models. The great shame is that the vast amounts of money that have been spent on computer modelling of climate could have been spent on alleviating poverty and providing clean water and electricity to the billions on our planet that do not have such luxuries. The great crime is that we have leaders taken in by this nonsense.

  • rate this

    Comment number 34.

    There are two major problems with such proposals:

    i) In the 1950s and 60s the jets behave in a similar fashion to current observations yet Arctic ice was much more extensive than now.

    ii) Despite Arctic ice having decreased for up to three decades since the mid 70s the change in jet stream behhaviour didn't happen until recently. I noticed it start to change around 2000 but the so called 'experts' have only just picked up on it.

    The correlation with the level of solar activity is far more compelling.

    I find it very puzzling that neither Dr Hanna nor his international team are apparently unaware of such obvious facts.

  • rate this

    Comment number 35.

    #32 theelesticjesuz

    Just love the sophistication of your post although you did miss out on Satan in association. He must really get under your skin to compel such a fascinating response in the true vernacular. Thoroughly expected you to quote by Chapter, House of Lords position but I expect that will follow at some stage.

    A word of advice if your paths ever cross, don't attempt to debate him, the experience would probably stunt your growth.

  • rate this

    Comment number 36.

    #34 Stephen Wilde

    Don't know how involved you may be with this but found it fascinating, not too far away from me:

  • rate this

    Comment number 37.

    #31. - blunderbunny wrote:
    "If there are no other really significant forcings or feebacks, then where's the heat?"

    A good question, I hope we get a reply from a "warmist".

    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.
    Also, if correct, this would confirm that the climate models are wrong, since they didn't predict that the heat would end up in to the deep ocean.

    Another interesting question is, assuming CO2 emissions caused what warming there has been, how cold would it be if there had been no increase in CO2 emissions.
    I think the answer is about 0.75c colder.

  • rate this

    Comment number 38.

    ATTN: QV
    YOU SAY: 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"?

    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...?

  • rate this

    Comment number 39.

    29. QuaesoVeritas wrote:

    “I can see the MO using that argument when this year fails again to be warmer than 1998 according to HC3, or 2010 based on HC4.”

    Now that would be interesting to see how they could square that with their DePreSys “ENSO” included forecasts?

    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

  • rate this

    Comment number 40.

    QV - I can understand your perspective on events but I think your interpretation isn't completely correct. You're absolutely right the climate science in the early 1990s was pointing to hot dry summers and wet winters. Indeed the period from November 1988 to October 1990 looked like a very good template and I think there was a review commissioned by the then DOE entitled the hot summers and mild winters of 1989 and 1990. In fact there was a repeat exercise for the period November 1994 to October 1995 again commissioned by the DOE.

    Likewise the computer models must have been far too simplistic of the treatment of the Greenland ice cap with adiabatic cooling maintaining the low temperatures but look what has happened since 1998.

    I recall reading a book on atmospheric chemistry by PW Atkins in 1985. In it he mentioned the tantalising prospect of an ice free Arctic summer by 2100.

    The response to an increasing signal whether from increasing CO2 or from the other greenhouse gases is likely to be complex as we are still influenced by the last Ice Age. And you're quite right there are still many factors in the mix. The aim should be to measure, and review theory accordingly. That was the 'crime' of Climategate.
    To accept that there was good correlation between tree ring data and temperature up to about 1960 but then dismiss thereafterwards poor correlation as an inconvenience. It could be telling us something important or even useful to us not to be dismissed.


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