Study: Changing winds cause melting of coastal Antarctic glaciers

From the AGU: Anthropogenically induced changes in winds in the Southern Hemisphere are playing a key role in recent warming of subsurface waters around Antarctica, according to a new study by Spence et al. The warming water increases melting of coastal glaciers and thus could affect sea levels in the future.

Since the 1950s, westerly winds in the Southern Hemisphere have been picking up and shifting poleward, due to anthropogenic global climate warming. The authors combined half a century of atmospheric data with a model of the coastal currents that shuttle water around Antarctic glaciers. Easterly winds create surface currents that pump cool fresh water downward, the authors demonstrated, keeping the temperatures at the bases of glaciers cool and pushing warm water away. But the westerly winds reduce these currents, and as a result, warm water creeps inward and upward toward the shore, where it heats up glaciers. Warm temperatures along grounding lines—where the glacier meets the ocean floor—especially increase melting.

The authors found that the changing westerly winds are responsible for an increase in water temperature of 2.5 °C on the western side of the Antarctic Peninsula, at critical depths of 200–700 meters. They calculated that the total heat increase in that region was enough to cause a sea level rise of 5.5 mm over the past 50 years (assuming that the grounded ice remains stationary). Based on the strong relationship between temperature increases and these winds, the authors think that current projections for sea level rise may be significantly underestimated.

Rapid subsurface warming and circulation changes of Antarctic coastal waters by poleward shifting winds

Abstract

The southern hemisphere westerly winds have been strengthening and shifting poleward since the 1950s. This wind trend is projected to persist under continued anthropogenic forcing, but the impact of the changing winds on Antarctic coastal heat distribution remains poorly understood. Here we show that a poleward wind shift at the latitudes of the Antarctic Peninsula can produce an intense warming of subsurface coastal waters that exceeds 2°C at 200–700 m depth. The model simulated warming results from a rapid advective heat flux induced by weakened near-shore Ekman pumping and is associated with weakened coastal currents. This analysis shows that anthropogenically induced wind changes can dramatically increase the temperature of ocean water at ice sheet grounding lines and at the base of floating ice shelves around Antarctica, with potentially significant ramifications for global sea level rise.

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92 thoughts on “Study: Changing winds cause melting of coastal Antarctic glaciers

  1. So the changing wind patterns have moved more heat polewards where it can more readily radiate out into space. Sounds like yet another negative feedback to me.

    • Yes, I’ve been pointing out that the high temps reported at the south pole would be the best negative feedback possible: dark for 6 months, and virtually no water in the atmosphere to absorb the emitted IR.
      If warming is really an issue, then it seems nature is doing a great job or mitigating it.

      • “Anthropogenically” altered winds, no less. Is there no limit to our powers? I’m calling BS on this one, too.

  2. “We can’t think of anything else it could be so we’re going to go with ‘climate change’ so we can secure another grant.”

  3. Hmm I wonder how much energy that consumes from global warming – another energy ignorant paper. Why is it that climate modellers never sanity check their work by calculating the radiative flux necessary to fuel their particular version of armageddon.

    • I doubt if 5% of them ever took or much less passed Thermo 101. Why would you expect them to even think of radiative heat flux.

  4. Since the 1950s, westerly winds in the Southern Hemisphere have been picking up and shifting poleward, due to anthropogenic global climate warming.
    And the supporting evidence for this blanket statement is? Yet another computer model that is programmed to show whatever they want it to show. Are they going to claim that, unlike other scientists who studied things like “water memory” & other alleged “properties” in Wholistic medicine, climate scientists don’t suffer from bias?

    • The use of the word ‘model’ brings a tired yawn. Pertinent question is that they used 50 years data – so how do they know that this wind change hasn’t happened before?

    • Yeah Id love to see proof that a fraction of a degree of warming changed wind patterns. Especially since this shift started in the 50s before we potentially had co2 driven warming.

  5. No mention of those volcanoes under the ice on coastal Antarctica that WUWT reported on a short time ago?

    • Dave
      October 22, 2014 at 4:28 am
      No mention of those volcanoes under the ice on coastal Antarctica that WUWT reported on a short time ago?

      No mention of extreme snowfalls offsetting sea level rise. Here is what they say in the press release.

      They calculated that the total heat increase in that region was enough to cause a sea level rise of 5.5 mm over the past 50 years (assuming that the grounded ice remains stationary).

      Do they mean just over 1mm every decade! Now take a look at what else has been happening recently. Why worry over a non-problem?

      Abstract – 2 NOV 2012
      Snowfall-driven mass change on the East Antarctic ice sheet
      An improved understanding of processes dominating the sensitive balance between mass loss primarily due to glacial discharge and mass gain through precipitation is essential for determining the future behavior of the Antarctic ice sheet and its contribution to sea level rise. While satellite observations of Antarctica indicate that West Antarctica experiences dramatic mass loss along the Antarctic Peninsula and Pine Island Glacier, East Antarctica has remained comparably stable. In this study, we describe the causes and magnitude of recent extreme precipitation events along the East Antarctic coast that led to significant regional mass accumulations that partially compensate for some of the recent global ice mass losses that contribute to global sea level rise. The gain of almost 350 Gt from 2009 to 2011 is equivalent to a decrease in global mean sea level at a rate of 0.32 mm/yr over this three-year period.
      http://onlinelibrary.wiley.com/doi/10.1029/2012GL053316/abstract
      =================
      Abstract – 7 JUN 2013
      Recent snowfall anomalies in Dronning Maud Land, East Antarctica, in a historical and future climate perspective
      Enhanced snowfall on the East Antarctic ice sheet is projected to significantly mitigate 21st century global sea level rise. In recent years (2009 and 2011), regionally extreme snowfall anomalies in Dronning Maud Land, in the Atlantic sector of East Antarctica, have been observed. It has been unclear, however, whether these anomalies can be ascribed to natural decadal variability, or whether they could signal the beginning of a long-term increase of snowfall. Here we use output of a regional atmospheric climate model, evaluated with available firn core records and gravimetry observations, and show that such episodes had not been seen previously in the satellite climate data era (1979). Comparisons with historical data that originate from firn cores, one with records extending back to the 18th century, confirm that accumulation anomalies of this scale have not occurred in the past ~60 years, although comparable anomalies are found further back in time. We examined several regional climate model projections, describing various warming scenarios into the 21st century. Anomalies with magnitudes similar to the recently observed ones were not present in the model output for the current climate, but were found increasingly probable toward the end of the 21st century.
      http://onlinelibrary.wiley.com/doi/10.1002/grl.50559/abstract
      =================
      Abstract2014
      High-resolution 900 year volcanic and climatic record from the Vostok area, East Antarctica
      …..The strongest volcanic signal (both in sulfate concentration and flux) was attributed to the AD 1452 Kuwae eruption, similar to the Plateau Remote and Talos Dome records. The average snow accumulation rate calculated between volcanic stratigraphic horizons for the period AD 1260–2010 is 20.9 mm H2O. Positive (+13%) anomalies of snow accumulation were found for AD 1661-1815 and AD 1992-2010, and negative (-12%) for AD 1260-1601. We hypothesized that the changes in snow accumulation are associated with regional peculiarities in atmospheric transport.
      http://www.the-cryosphere.net/8/843/2014/tc-8-843-2014.html

  6. The authors combined half a century of atmospheric data with a model…..
    Stop! No more, I have heard enough. Another bunch of quacks presenting a hypothesis as validation of their own hypothesis. I label this scientific fraud.

  7. As I discuss in Don’t Sell Your Coat, the “forcing” attributed to AGW appears to have certain characteristics of magic: the South Pole has been cooling for decades, Antarctic sea ice has been increasing over the same span, and yet everything is getting hot, hot, hot. Pure magic!

  8. “The authors combined half a century of atmospheric data with a model of the coastal currents “.
    Yeah? And just what bloody good would that do. WHat would that tell you apart from sketch a cartoon around a tiny data set.
    This sounds like more Hockey Schtick Science. Ice Hockey Schtick!
    LOL

  9. Well, well well – ‘the model simulated warming events………’ For a moment I thought they had factual evidence of recent warming at the 200 – 700m depth, do they?

  10. … water temperature of 2.5 °C on the western side of the Antarctic Peninsula, at critical depths of 200–700 meters. They calculated that the total heat increase in that region was enough to cause a sea level rise of 5.5 mm over the past 50 years (assuming that the grounded ice remains stationary).

    But the Antarctic Peninsula is only 1.7% of the whole continent, and – because it sticks out INTO the strong westerly currents always flowing around Antarctica, it WILL BE always affected differently than the remaining 98% of the land mass and the remaining 98% of the continental ice mass!
    What did they model – how much of the continent? How far out to sea? How did they “model” these grounding lines of the glaciers – themselves only a very, very small part of the total continental coast? In other words, are they treating the entire 45,300 kilometer coastline like a single huge Pine Island Glacier?
    Length of Antarctic Peninsula = 1,340 km.
    West Coast of Antarctic Peninsula = ~1600 km (it curves significantly)
    Thus, “Glaciers across the entire North Slope of Canada will melt faster based on wind studies modeling the Newfoundland Coast that show the Gulf Stream might go faster near Cape Cod in the future.”

    • Isn’t the peninsula the area that has the subsurface volcanoes? Is that why there is warming in that area of Antarctica?

    • The northern end of the Antarctic peninsula seems to have been the place where the sea ice extent was closest to average most of this past winter anyway. If their model predicts ice should be increasing along the peninsula, it would seem to be a failed forecast.

  11. This analysis shows that anthropogenically induced wind changes can dramatically increase the temperature of ocean water at ice sheet grounding lines and at the base of floating ice shelves around Antarctica, with potentially significant ramifications for global sea level rise.

    I’m gonna go way out on a limb here, and guess that the temperature of ocean water at an ice sheet grounding line is 271 K… or exactly the same as it has been for quite a while, now.

  12. Three degrees required to become a “climate scientist”:
    BS = self-defining
    MS= More of the Same
    PhD= Piled Higher and Deeper
    ‘Nuf said.

  13. Well let’s see the actual data and sources for their alleged changes. Then they can show us……
    1. What was the strength, at various latitudes, of the westerly winds in the Southern Hemisphere in 1950?
    1a. What is the data for each year up to the present?
    2. What was the temperature of the subsurface waters around Antarctica in 1950?
    2a. What is the data for each year up to the present?
    3. What was the temperature of the subsurface water on the western side of the Antarctic Peninsula at depths of 200–700 meters in 1950?
    3a. What is the data for each year up to the present?
    Until this is shown, everything they say and their alleged ‘Model’, is absolute bollocks.
    Don’t hold your breath!
    Alan

    • Don’t forget to ask for proper error analysis with the measurements. Exactly how accurate do you think the temperature measurements in 1950 were for the entire ocean around the Antarctic Peninsula? My bet is that proper error analysis wipes out any ability to claim any change.

      • You are putting in much more thought that this paper deserves. Although your questions are correct, I feel it is giving that model based paper much more credibility than it warrants.

  14. “Since the 1950s, westerly winds in the Southern Hemisphere have been picking up and shifting poleward, due to anthropogenic global climate warming. ”
    During the 50s and 60s it was an equatorward shift.
    From the mid 70s to 2000 it was indeed a poleward shift.
    From 2000 it has been an equatorward shift.
    Only by cherry picking the start and end points can one say what they did.
    The shifts were caused by variations in solar activity:
    http://www.newclimatemodel.com/new-climate-model/

    • Once again Stephen, tell me which system invades the Stratosphere, the top down “needs to be amplified to work” unobserved mechanism you propose, or the bottom-up invasion of Rossby Waves observed to be the source of such disturbances in the Stratosphere over the poles (especially the Arctic).
      Here is a link to a very cool demonstration of such events, that are not only random in the short term, but such invasions have oscillations over longer time scales. They are easily identified in measures of atmospheric pressure systems via satellite.
      http://geosci.uchicago.edu/~nnn/LAB/DEMOS/RossbyWave.html
      Sometimes the old papers are the best source. They are pre-debate and untainted with AGW versus solar hysteria. These waves (generated by teleconnected systems here are Earth) are well understood and you seem all too eager to ignore them. Between your hypothesis and known observations, I will side with known observations.
      http://www.pmel.noaa.gov/pubs/PDF/kess1113/kess1113.pdf

      • Stephen, you know very well that paper does not state that the top-down mechanism has been observed. The only thing observed was the well known diminution of the ozone layer as a result of the solar cycle, especially at the poles. This does not in any way explain the rising trend nor the pause in temperature data.

      • Pamela,
        The ozone layer is supposed to decrease when the sun is inactive and increase when it is active.
        The paper shows that in fact it decreases above the stratopause when the sun is active and the effect is transmitted down through the polar vortices to change tropopause height above the poles and thereby influence tropospheric circulation patterns.
        That is the essence of my 2010 hypothesis.

  15. “The ‘model’ simulated warming results from a rapid advective heat flux induced by weakened near-shore Ekman pumping and is associated with weakened coastal currents.”
    “This analysis shows that ‘anthropogenically induced’ wind changes can dramatically increase the temperature of ocean water…”
    Are any comments necessary?

  16. What amazes me is how the Australian Government still allows public expenditure on this C@@@ (ie boat in Antarctica too measure how acidity will affect ocean in 100 years due to AGW). Its about time they actually terminated ALL AGW funding in Government, CSIRO, Universities ect. Abbott needs to move faster on this.

    • Yep – unfortunately there are too many warmists in Abbott’s government to push things as quickly as we would like. (Sadly)

  17. ‘the model simulated warming events………’

    There’s a typo: a ‘t’ is missing from the third word.

  18. I would love to actually read a paper that proves “anthro” induced wind changes in the antarctic.

  19. Isn’t this another rehash of the discredited missing heat hiding theory. We know from the recent work by Bob Tisdale as shown by Paul Homewood that the SSTs down there were level and falling. So how did the heat get into the lower layers without warming the top ones?

      • Barry:
        Water cools as it moves toward higher latitudes, but there is no poleward current in the SH. The model invents one. This paper is garbage.

      • Actually it is the very cold and saline water that is “frozen out” when sea-ice forms that sinks and moves outwards from Antarctica as AABW (AntArctic Bottom Water). This is the main reason the deep ocean is so very cold, so it will take some very advanced Climate Science™ to explain it away.

      • And ‘The Science is Settled’.
        We know – we’ve read it in/on the warmist organs, so it must be true. [Ummm. /Sarc.]
        The catastrophic increase of deadly CO2, from three parts in ten thousand to – now, fasten your seat belts & take a deep breath – as much as four parts in ten thousand, has been the cause of many unwanted changes in the biosphere.
        I didn’t see a hawk in my garden yesterday – fifteen years ago I did. Bull-gore warming.
        Giant chamois extinct; slightly smaller chamois thrive. Boll-goure warming.
        Urban heat islands expand with temperature: Gull-bore effect.
        Plant crops improve wholesale. Gure-Boll happenstance.
        [Mod – I’m not sure if any of this is /sarc, given that the science has been oh-so-firmly settled . . . . . .]
        Am I getting warm?
        No – it’s autumn [fall for N America] in the UK.
        Decidedly not – on the station this morning.
        But that, I am positive, is merely [Merely??] weather – ‘cos the ‘science is settled’.
        So I read, folks.
        Auto

      • Barry: The Ekman pumping in those waters is pure invention, found only in the model.
        The whole study is a hypothetical premise, from the “anthropogenically” induced change in the wind to the warming of the waters. In short, it is another alarmist invention with _no_ observational basis. It is garbage, not even fit for the CAGW propaganda mill.

  20. From the article:
    “Anthropogenically induced changes in winds …”
    ??!?!!?
    Everybody in the Southern Hemisphere needs to walk around hunched over so they don’t affect the wind so much? Lower all flags to half staff? Cut down power poles and only use underground cable? Ban kite flying?
    I’d like a little evidence that there is an anthropogenic component changing the winds, perhaps a few centuries of observations that show there were no changes prior to the last 50 years or so.

    • You got to be kidding, you want evidence? Evidence, really? This is a climate science paper, which means it is self-re-enforcing, the evidence is in the claim itself. You start with the premise AGW is causing x and then you conclude that AGW is causing x because the premise is AGW is causing x. Circular logic like you find in debating intelligent design proponents.

      • “You got to be kidding, you want evidence? Evidence, really?”
        People in hell want ice water, Alx. I hadn’t planned on holding my breath until evidence was provided.

    • Models don’t do volcanoes except maybe as a constant used as a factor that climate scientists tweak as necessary to arrive at a pre-defined conclusion.
      Too bad modelers don’t do the double blind test.

  21. the warming water increases melting of coastal glaciers
    See the WUWT article “John Cook’s claim of a ‘warmer southern ocean’ is proven wrong”.

  22. Sea surface temperatures, 700 meter temperatures, over generalizing for the entire Antarctic using localized data of unknown consistency, warming causing cooling here, cooling causing warming there, warming causing warming someplace else, sea ice, surface land ice – who cares, it doesn’t matter. Understanding climate is not the purpose of papers like these, especially the ones that start with the assumption that AGW is as well established as gravity.
    The purpose is to enforce the idea that modern Civilization is coming to an end because we do not have enough windmills, solar panels and most importantly global taxes.

  23. How do you handle the ever-shifting temperature record? GISS pushed the mid 1930s record high down because they saw the big 1998 el Nino as possibly the last chance in many years to be able to report new high records because of global warming. If this study had been done in 1997, it would have the southern polar seas cooling relatively. The price to be paid for jiggering the temperature record is it makes research essentially impossible. eg.: the models with the older thermometric measurements would have the wind blowing the other way!

  24. Haven’t we just argued in WUWT that there has been NO warming of the Antarctic water and ice-top temperatures (other than that from sub-ice volcanism)?

  25. Science 12 September 2014:
    Vol. 345 no. 6202 pp. 1354-1358
    DOI: 10.1126/science.1256697
    REPORT
    Boundary condition of grounding lines prior to collapse, Larsen-B Ice Shelf, Antarctica
    Abstract: Grounding zones, where ice sheets transition between resting on bedrock to full floatation, help regulate ice flow. Exposure of the sea floor by the 2002 Larsen-B Ice Shelf collapse allowed detailed morphologic mapping and sampling of the embayment sea floor. Marine geophysical data collected in 2006 reveal a large, arcuate, complex grounding zone sediment system at the front of Crane Fjord. Radiocarbon-constrained chronologies from marine sediment cores indicate loss of ice contact with the bed at this site about 12,000 years ago. Previous studies and morphologic mapping of the fjord suggest that the Crane Glacier grounding zone was well within the fjord before 2002 and did not retreat further until after the ice shelf collapse. This implies that the 2002 Larsen-B Ice Shelf collapse likely was a response to surface warming rather than to grounding zone instability, strengthening the idea that surface processes controlled the disintegration of the Larsen Ice Shelf.
    =============================================
    note the last sentence of tis report abstract. Warm water melting at the depth of the glacier grounding lines is a myth.

  26. I suppose we have to disregard some inconvenient facts.
    1) The only place glaciers are melting is around the West Antractic Peninsula where presumably the geothermal heat sources discovered there have no effect at all since not being in the model they do not really exist.
    2) There is no proof or even indication that the wind direction change is at all anthropgenic.
    3) We have essentially no historic data to establish a baseline that can be called ‘normal’
    4) We have no data to indicate any of this is real, just a computer model that says it MIGHT happen and that is based on a bunch of fact free assumptions.
    This is not science its an exercise in misusing simulation. They appear to have started with the desired result and designed a model to reproduce it without bothering with trivial stuff like ACTUAL water conditions.
    Sheesh

  27. Whenever you think they are getting a bit more serious about this debate they come up with a bit of nonsense like this and you know they aren’t. They are just taking the mickey.

  28. You know that if glaciers stopped calving and ice bergs stopped happening it would be ascribed to anthropogenic global [fill in the blank] and that we should stop [fill in the blank] so that ice bergs can once again break free of glaciers and ice shelves to float free and wild.

  29. So, if the warmunists know that the trends of the past half century mean that there should be more sea ice, then why did they go to Antarctica last year looking for less ice, only to get themselves and their wives & kids stuck in the more ice that was actually there and that they claim their theories say was supposed to be there in the first place?

  30. Since climate science proved that a model is as good as a measurement I began showing prospective sex partners a model of my endowment. Sure enough, 97% preferred the model. :^(

  31. As soon as I read “model” I reflect on well other “models” have predicted things in the past and are trying to predict in the future. I then stop.

  32. With apologies to the “Few”of the “Battle of Britain”
    Climate warming model science;
    “Never has so much hot crap been produced by so few for so little benefit to so many”

  33. “The warming water increases melting of coastal glaciers ”
    Er … didn’t Bob Tisdale just present data that shows the Southern Ocean is cooling?

    • No, but this paper shows warming in the Antarctic…
      Increasing Antarctic Sea Ice under Warming Atmospheric and Oceanic Conditions
      JINLUN ZHANG
      Polar Science Center, Applied Physics Laboratory, College of Ocean and Fishery Sciences, University of Washington,
      ABSTRACT
      Estimates of sea ice extent based on satellite observations show an increasing Antarctic sea ice cover from
      1979 to 2004 even though in situ observations show a prevailing warming trend in both the atmosphere and
      the ocean.
      http://psc.apl.washington.edu/zhang/Pubs/Zhang_Antarctic_20-11-2515.pdf

      • Martin,
        Not exactly. This is a highly technical 2006 paper from which singular conclusions are impossible. Zhang writes, “Although satellite observations over 1982–98 show a cooling over parts of the Antarctic continent, a general warming occurred in the surface temperature of the peripheral seas (Kwok and Comiso 2002).”
        The first two sentences in Zhang’s Conclusion are:

        To investigate the seeming paradox of increasing Antarctic sea ice and increasing atmospheric and oceanic temperatures for the Southern Ocean during 1979–2004, a global POIM that includes a POP ocean model and a multicategory TED sea ice model was forced by the NCEP–NCAR reanalysis data that include increasing SAT, SDLR, and P and decreasing SDSR. There are many uncertainties with both the model and the reanalysis data, and the results must be viewed with caution.

        In other words, a little bit of this, a little bit of that.

  34. So…the surface waters are now warmer than before? Is that why the sea ice is spreading to record extents?

  35. Have you noticed that compulsive liars never stop talking?
    Why cant they just give themselves a rest and wait and see whether rapidly growing Antarctic ice really does mean catastrophic warming, or something else.

  36. An annotated graph taken from Paul Homewood’s page on Roy Spencer’s comparison of the two main satellite records. Interesting double hump shows up, which suggests that global temperatures will likely drop in 2015/2016. No scientific reason, simply looking at the wave shape of the 1979 to 2014 satellite record. Of no scientific predictive value whatsoever; but it will interesting to see what happens:
    https://www.dropbox.com/s/8rgl0l86ivfgxtb/Yearly-global-LT-UAH-RSS-thru-Sept-2014_MU.gif?dl=0

  37. “They calculated that the total heat increase in that region was enough to cause a sea level rise of 5.5 mm over the past 50 years”
    I hope they are right. At that rate, sea level will rise a foot in 2,770 years. The next ice age might come before that time.

  38. Anthropogenically induced changes in winds in the Southern Hemisphere???
    Is this evidence of just how low today’s pseudo-scientists have sunk? Humans cannot affect factors such as the winds, the ocean currents, the jet stream, the clouds, or anything else climatic as a consequence of emitting carbon dioxide into the atmosphere.
    How can the AGU even allow such papers to be published? Doesn’t the AGU have quality control procedures to prevent such outlandish claims that humans can influence the winds in the southern hemisphere? It’s a disgrace.
    Unbelievable!!!!!!!

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