SAMS in major scientific finding: Antarctic Circumpolar Current shows only limited change in 1000s of years

antarctica © mike meredith

Scientists have been surprised to discover that the strength of the world’s largest ocean current has remained similar over tens of thousands of years, despite vast differences in the world’s climate during that time.

The current circumnavigates the Antarctic and, when analysed, it showed that its strength in comparatively recent times matched its strength during the last ice age.

This was unexpected because ocean circulation – a network of interconnected currents – is affected by climate, winds, the amount of heat entering the ocean and the size of the sea ice field, some of which factors were considerably different between the times studied.

This new information has given researchers a better insight as to how the current has responded to changes in its driving forces – and in to how it might change in the future.

antarctic circumpolar currentKnown as the Antarctic Circumpolar Current (ACC), this connects the Atlantic, Pacific and Indian Oceans. It flows from west to east between about 45° and 70° south and is driven by westerly winds and exchanges of heat and freshwater at the ocean surface. With no landmasses to impede its flow, it circulates continuously around Antarctic, connecting back to itself.

UHI Professor Mike Meredith of the Scottish Association of Marine Science’s [SAMS] Physics, Sea Ice and Technology explains the importance of the ACC: ‘The Antarctic Circumpolar Current is the biggest current system in the world, and plays a huge role in controlling planetary-scale climate.

‘These new results show that its strength during the last ice age was surprisingly similar to more recent times, with the exception of where more extensive sea ice blanketed the ocean.

‘As well as helping us understand how much the winds that drive the current might have changed over thousands of years, this gives us new insight into how the current actually works and therefore how it might change in future.’

Because of its very strong flow and its huge reach, the ACC plays a major role in moving heat, salt and climatically-important chemicals around the globe, so any changes in its flow could have planetary-scale implications.

jcr © mike meredithThe ACC is also an important site for ocean mixing – a key process in the conversion of dense water to light water and vice versa, and hence the vertical flow of the water [see previous information from SAMS on this matter]. This process is termed ‘overturning circulation’, and has implications for the drawdown of carbon from the atmosphere and, consequently, for the global climate.

Although the overall picture was of minimal change in the ACC, the researchers did find significant change in ACC flow in the region where sea ice has changed since the last ice age. This hints at changes in the overturning circulation over this time scale. But, as ever, the research team see there is more work needed to verify and to understand this better.

The paper ‘Minimal change in Antarctic Circumpolar Current flow speed between the last glacial and Holocene” is published on Nature Geoscience’s website as linked – available form 18.00, 22nd December, at which point the news embargo is lifted.

Mike Meredith, a physical oceanographer, is one of the authors of this paper, working both for SAMS and for the British Antarctic Survey and inevitably spending a lot of time in the Southern Ocean.

Note: SAMS – near Oban in Argyll,  a partner of UHI and founded in 1884, is Scotland’s oldest oceanographic research institution.

The image above of the Antarctic Circumpolar Current is in the public domain. The other two images of Antarctica – of the research ship, RRS James Clark Ross, in the Antarctic and the generic shot of Antarctica at the top, are © Professor Mike Meredith.

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42 Responses to SAMS in major scientific finding: Antarctic Circumpolar Current shows only limited change in 1000s of years

  1. “‘These new results show that its (Antarctic Circumpolar Current) strength during the last ice age was surprisingly similar to more recent times, with the exception of where more extensive sea ice blanketed the ocean.”

    Does this mean the Southern Hemisphere has been exempt from “global” warming?

    Or does it mean, as many “scientists” now suggest that we are heading for a period of global cooling?

    Like or Dislike: Thumb up 7 Thumb down 6

  2. I’m slightly puzzled about the Australian vessel en route to East Antarctica that has been trapped in dense pack ice since Tuesday:
    “The vessel is being used by the Australasian Antarctic Expedition to follow the route explorer Douglas Mawson travelled a century ago.”
    Does this mean that the route used 100 years ago is now much colder?

    Like or Dislike: Thumb up 3 Thumb down 2

  3. This is the verification phase of the climatic computer models’ predictions – the “observation” phase and just as the computer models have failed to predict the present 17-year pause in global warming, we see that their predictions of melting ice in the Antarctic have also failed, spectacularly.

    Is this the global warming catastrophe we are spending hudreds of billions on wind turbines and solar panels to prevent?

    Like or Dislike: Thumb up 3 Thumb down 2

  4. There’s an update with lots of wonderful pictures of the global warming research ship now hopelessly trapped in ice during the Antarctic midsummer with penguins marching out in droves to view the quixotic band which includes an Australian Green Party senator and – the icing on the cake – a Guardian reporter!

    Apparently, two ice breaker ships were unable to reach the trapped ship to effect a rescue and became stuch themselves but expedition leader Prof Chris Turney, climatologist, University of New South Wales, insists the ice is melting … Oh, well, that’s alright then, they won’t be needing fossil-fuelled helicopters and ships to rescue them from their fossil-fuelled expedition?

    Asked to comment, Santa boomed, “Ho, ho, ho, global warming ships? Just goes to show, you can’t beat “reindeer-power!”

    Like or Dislike: Thumb up 4 Thumb down 2

  5. Back at your old nonsense again Andrew?

    Try reading

    Here is a quote from one of the scientists involved in the above report, which succinctly deals with all your posted drivel:

    “Sceptics may also point to the ‘hiatus’ of temperatures since the end of the 20th century, but there is increasing evidence that this inaptly named hiatus is not seen in other measures of the climate system, and is almost certainly temporary.”

    Get it?

    Like or Dislike: Thumb up 2 Thumb down 6

    • No Kass, I don’t get it, global warming as a major threat, that is.

      This is a newly-constructed model the authors of which claim answers the conundrum of what would happen to the level of cloud cover with global warming.
      They say cloud cover will decrease as the world warms, causing further acceleration of the warming via a ‘positive feedback’ effect.

      Their study is interesting since it goes against the IPCC position that warming will cause cloud cover to increase, not ‘decrease’, and suggests the world will warm at the top end of the range of computer model predictions which, as we know, are already performing unconvincingly versus observed reality.

      The leader of the study, Professor Steven Sherwood, University of New South Wales is, of course, a colleague of climatologist and ‘carbon entrepreneur’ Professor Chris Turney who is currently having to be rescued from his Mission to prove Antarctic sea ice is melting by a combination of helicopters and powerful ice breaker ships which themselves became stuck in ice and had to retreat, this being the middle of the Antarctic summer!

      On 31st December, global sea ice measured its highest EVER-recorded level for that day of the year.

      MWAH, MWAh, mwah!

      Like or Dislike: Thumb up 4 Thumb down 4

      • Well, if you don’t get it I’ll repeat it: “this inaptly named hiatus is not seen in other measures of the climate system”
        That is to say that the current lack of warming in the Antarctic is NOT reinforced by any other measure of global warming. Again: temporary downturns at any given time do NOT negate the overall average increase in temperature worldwide. Also – weather is Not climate!!!
        And finally:
        William Blum – Published December 3rd, 2013
        “we can proceed in one of two ways:
        . We can do our best to limit the greenhouse effect by curtailing greenhouse gas emissions (carbon dioxide, methane, and nitrous oxide) into the atmosphere, and if it turns out that these emissions were not in fact the cause of all the extreme weather phenomena, then we’ve wasted a lot of time, effort and money (although other benefits to the ecosystem would still accrue).
        . We can do nothing at all to curtail the emission of greenhouse gases into the atmosphere, and if it turns out that these emissions were in fact the cause of all the extreme weather phenomena (not simply extreme, but getting downright freaky), then we’ve lost the earth and life as we know it.
        So, are you a gambler?
        PS “MWAH, MWAh, mwah!” makes you sound as if you are just out of primary school – not a good image.

        Like or Dislike: Thumb up 4 Thumb down 3

        • Re gambling, here’s a fine quote from Richard Lindzen:

          “When Ban Ki Moon says life as we know it will change forever, what does he mean?

          I don’t know. People retire to the SUN BELT, not to the north West Territory of CANADA! If you want something serious to worry about, two miles of ice on top of your head could be problematic.

          I’d say that applies to your quote from you Mr Blum, too.

          Like or Dislike: Thumb up 3 Thumb down 4

  6. Aw, Kass, do me a favour!

    “Well, if you don’t get it I’ll repeat it: “this inaptly named hiatus is not seen in other measures of the climate system”

    Are you for real? Two examples:

    1. Global temperature – e.g. HADCRUT4, HADCRUT3, the products of our own ‘Great British’ Met Office Hadley Centre and the University of East Anglia Climate Research Unit, formerly headed by the redoubtable Phil Jones of ‘Climate-gate’ notoriety, both clearly show, depending on the timescale, a dramatic slowdown in the rate of rise or even falling temperature over the last 10-20 years.

    The computerised climate models almost universally predicted a continuing rapid rise in temperature during the same period. They have now been found wanting.

    2. We have already discussed both Antarctic and global sea ice extent, the latter having recorded its highest level since records began for 31st December, on Hogmanay, 2013.

    Sorry about the onomatopoeic sound effects in my last post – you were obviously hurt by that – I just couldn’t think of anything more aptly succinct to sum up the situation.

    Like or Dislike: Thumb up 3 Thumb down 5

      • So what, if the global average is down on past years then other places must have had colder weather to pull down the average?

        How far back do Australian records go?

        Like or Dislike: Thumb up 1 Thumb down 0

      • The new Government in Australia, due to concerns for its citizens having to face ever increasing electricity bills has abolished the carbon tax and may be considering doing the same with windfarm subsidies. But what do they know Eh ?

        Like or Dislike: Thumb up 2 Thumb down 0

        • If they know as much as you and AA then we can assume that they know very little, but they do know what their prejudices are and they mean to stick to them. You will notice that in neither your comment or mine are there any concrete arguments – because despite all the factual evidence you have been pointed to, you two seem impervious to reason, so I give up on the reasoning process as far as you both are concerned.

          Like or Dislike: Thumb up 1 Thumb down 1

          • Come on, Kass, you’re starting to sound like the wee guy outside the pub on Sarurday night shouting at the bouncers who’ve just thrown him out for crying into his pint – “See yus, yese know nuthin!”

            You said there were no measures supporting the ‘pause and I gave you some of the most readily available – HADCRUT3/4 and both Antarctic and global sea ice and now you’re blustering, all red-faced and puffed-cheeked.

            I didn’t make up HADCRUT 3 and 4, Phil Jones and the met Office did – your own beacons of climate wisdom and truth!

            Like or Dislike: Thumb up 0 Thumb down 2

  7. You’re like one of those “knock-me-down” dolls with semi-circular bases, but you are still on a hiding to nothing AA. Try reading: for a multitude of links which will indicate that your crackpot theories are exactly that.
    I’m getting bored with this now – it’s like banging one’s head off a brick wall. With regard to your “sound effects they had no effect on me except to excite a vague feeling of pity for you. So here’s another Mark Twain quote for you which describes my situation re you:
    “Never argue with a fool, onlookers may not be able to tell the difference.”

    Like or Dislike: Thumb up 3 Thumb down 5

    • What’s this, ‘abusive personal comments’?

      Next we’ll know, Longshanks will be telling you to ‘take it like a man’!

      After effects of festive over-indulgence, if you ask me – I should know, I’ve got the T-shirt!


      Like or Dislike: Thumb up 4 Thumb down 2

    • Kassandra – don’t you have any work to go to of a day, or indeed have anything of value in your life. Spending your hours spouting absolute balderdash on this, and no doubt other forums, really is going to turn you into a basket case. Oopps sorry wrong tense !

      Like or Dislike: Thumb up 3 Thumb down 2

  8. @Andrew Argyle says:
    January 3, 2014 at 6:53 pm

    That’s your faulty strategy – to look at one or two isolated examples and extrapolate a whole ecosystem. Any one experiment or study can be wrong, or merely a short term position – try looking at the overall picture – the whole picture – the majority of informed opinion – which points only in one direction.

    Here’s a quote from Hadcrut 3/4:
    “Also, the warmest year on record, which was 1998 with HadCRUT3, is now 2010 with HadCRUT4″
    If that doesn’t tell you something, you must be looking the other way.

    Like or Dislike: Thumb up 0 Thumb down 1

    • 1. Look at the trend, not the points on the graphs. It’s quite clear that the rising trend of the 1990s has slowed or reversed, depending on the timescale chosen, over the last 10-20 years.

      2. Doesn’t it surprise you that every new version of the data from these people suggests a faster rate of warming than before? (HADCRUT4 shows a higher level of pause than HADCRUT3)

      It’s a bit like the government changing the definition of fuel poverty or unemployment to make the total number suffering appear lower, isn’t it?

      But even HADCRUT4 clearly shows the ‘pause’.

      And even the EU has seen the folly of its ways and is now ordering a stop to wind and solar subsidies in the UK. That’s because they are not seeing any evidence of past alarmist predictions coming true and they now fear the collapse of EU industry due to excessive energy prices caused by their own ‘green’ energy fantasies.

      The EU says onshore wind and solar are now’mature industries which no longer require subsidy to support them. If so, fine, if not, they should be allowed to fall,mthey’ve had a damn good crack of the whip!

      Like or Dislike: Thumb up 1 Thumb down 1

  9. AA – You remind me of a christian – you have a dogged faith in nonsense.
    There is no point in me giving you any more counter examples. Look – in simple terms – if you care to examine the situation with an open mind there are something like 500/1000+ articles/graphs/studies etc. out there on the internet which say global warming is a reality, for every 1 that you can produce against. Additionally, most anti-warming sources have been revealed to have external motives for their stance, or to be crackpots.
    Kindly explain that – (without bringing in blue shape-shifting lizards which rule us all in secret).

    Like or Dislike: Thumb up 0 Thumb down 1

    • I have no recollection of ever denying that there has been warming, nor do I recall ever denying that human actions have some effect on the climate – all that is well established and in the absence of other effects – known as ‘feedbacks’- doubling of CO2 level is expected to produce about 1.1C of warming.

      The question is, what are the ‘other effects’ i.e. will they amplify or damp any initial change of temperature and if so, by how much?

      The climate is an incredibly complex system and climate science is in its infancy, as has been clearly demonstrated by the failure of the models to predict the pause in warming which you are in ‘denial’ about, so until we see the computer model predictions being reasonably close to observed temperatures and global sea ice, there is no evidence that these theories are any more than guesses based on extrapolation of the 1990s temperature trend.

      BTW Science isn’t actually a democracy, you have to show that your theories are valid by making predictions and observing the results – QED!

      Like or Dislike: Thumb up 0 Thumb down 0

  10. Gentlemen, what’s the ice-bound ship got to do with the research reported at the top of the page?
    Also, allow me to point out that 20-30 years, even 100 years, is as nothing to the hundreds of thousands of years of climate history documented in ice cores –
    Epica C found alarming increases – lines going off the charts (see, exactly as also documented in Al Gore’s documentary, An Inconvenient Truth.
    Here’s the link to a clip of a slide show presented by Al Gore in a TED show in 2008:
    Sadly, perhaps because we’ve been distracted by the big financial crash, things have got a great deal worse since then. Let me quote from the 2013 IPCC Working Group I Summary for Policymakers, p 2:
    “Warming of the climate system is UNEQUIVOCAL [my emphasis], and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased.”
    And from p. 6: “Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010 (HIGH CONFIDENCE) [my emphasis].
    It is VIRTUALLY CERTAIN [my emphasis] that the upper ocean (0−700 m) warmed from 1971 to 2010 (see Figure SPM.3), and it LIKELY [my emphasis] warmed between the 1870s and 1971.”
    Let’s get serious and push our policy makers to pull out all the stops to diminish the impacts of global warming. Let us all “do our best to limit the greenhouse effect”, as Kassandra quoted William Blum on 2 January!

    Like or Dislike: Thumb up 0 Thumb down 0

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