Greenland’s pronounced glacier retreat not irreversible

English: Retreating calving front of the Jacob...

Retreating calving front of the Jacobshavn Isbrae glacier in Greenland from 1851 - 2006. Image via Wikipedia

Via the AGU weekly highlights:

In recent decades, the combined forces of climate warming and short-term variability have forced the massive glaciers that blanket Greenland into retreat, with some scientists worrying that deglaciation could become irreversible. The short history of detailed glacier observations, however, makes pinning the ice loss to either short-term dynamics or long-term change difficult. Research by Young et al. detailing the effects of two bouts of sudden and temporary cooling during an otherwise warm phase in Greenland’s climate history could help answer that question by showing just how heavy a hand short-term variability can have in dictating glacier dynamics.

Along the western edge of Greenland, the massive Jakobshavn Isbræ glacier reaches out to the coast, its outflow dropping icebergs into Baffin Bay during the summer months. Flanking the glacier’s tongue are the Tasiussaq and Marrait moraines-piles of rock marking the glacier’s former extent. Researchers suspected the moraines were tied to two periods of abrupt cooling that hit Greenland 9,300 and 8,200 years ago, and the association was reinforced by the authors’ radiocarbon and beryllium isotope analyses of the area surrounding the moraines. Beryllium-10 forms when cosmic radiation travels through the atmosphere and strikes the Earth’s surface, with surface rock concentrations indicating how long it has been ice-free.

The authors’ analyses show that the moraines were laid down 9,200 and 8,200 years ago, corresponding with periods of sudden cooling. They suggest that the Jakobshavn glacier, which had been retreating prior to the sudden temperature changes, started to grow. At the end of each cold phase, the glacier deposited a moraine before it resumed its retreat. In detailing the sensitivity of the Jakobshavn glacier to short-term temperature change, the study suggests that while the Greenland glaciers’ current retreat is not necessarily irreversible, their extent is tightly bound to the variability of our warming world.

Source: Geophysical Research Letters, doi:10.1029/2011GL049639, 2011

Title: Response of a marine-terminating Greenland outlet glacier to abrupt cooling 8200 and 9300 years ago

Authors: Nicolas E. Young, Jason P. Briner, Beata Csatho and Greg S. Babonis: Department of Geology, University at Buffalo, Buffalo, New York, USA;

Yarrow Axford: Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois, USA;

Dylan H. Rood: Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California, USA, and Earth Research Institute, University of California, Santa Barbara, California, USA, and Scottish Universities Environmental Research Centre (SUERC), East Kilbride, UK;

Robert C. Finkel: Department of Earth and Planetary Sciences, University of California, Berkeley, California, USA.

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47 Responses to Greenland’s pronounced glacier retreat not irreversible

  1. David L says:

    Why do people lament the loss of glaciers? Do people complain when winter is over and all the snow and ice melts and all the flowers and gardens start to bloom? So a lot of ice melts in some remote location. Who cares?

  2. Skeptic Tank says:

    … with some scientists worrying that deglaciation could become irreversible.

    It’s not clear to me why it has to be revered.

  3. Matthew W says:

    From looking at the photo, about half of the retreat occurred between 1851 and 1950.
    Does the glacial melt mirror the decline of the British Empire???


  4. John Marshall says:

    These scientists claim that Be^10 is formed when cosmic rays strike the surface. I was always taught that it was cosmic rays strike nitrogen atoms in the upper troposphere. Be^10 analysis can indicate past cosmic ray intensity and variability over time.

    How many Greenland glaciers are actually monitored? To claim that all are retreating could be wildly wrong. Also glacial retreat can also be a measure of precipitation since all glaciers need this to continue to flow. To claim that glacial calving is a temperature measure can also be wrong. When a glacier ends up as an ice shelf, floating, a good storm will aid calving, nothing to do with temperature.

  5. Caleb says:

    Interesting, however these massive glaciers scour all evidence of earlier warm periods away, each time they advance. Of more interest are the less mighty glaciers, or simple snow fields, that don’t scour so much, and in some areas press stuff down as they advance, and then reveal the stuff they pressed down, as they retreat.

    These lighter glaciers and snow fields give ample evidence of earlier warm periods, where the glaciers retreated even farther than they have retreated today. Off the top of my head I recall reading of A.) dead brush being revealed in East Greenland, where no brush or shrubs grow today, that dated from the MWP. B.) A fairly large log being revealed in Alaska where not a twig grows today, also dating from the MWP. C.) A Roman road, dating from the Roman Climate Optimum, being revealed; the road apparently, according to very old written documents, led to a Roman lead mine, which is still covered with ice.

    I always get the feeling this evidence is hushed up. When I do read about it, it always is amidst an article which attempts to prove the evidence shows that recent glacial retreat is “unprecedented,” when in fact it shows exactly the opposite.

  6. Hector M. says:

    irreversible = not to be reversed, unable to change direction. Nothing to do with being revered (from “reverence”).

  7. M.A.Vukcevic says:

    The Reykjavik long term temperature forecast for both winter and annual temperatures forecast shows (with a good degree of certainty) that Arctic cooling is on the way
    This is based on my Arctic/North Atlantic research.

    BTW: Does anyone know where the GISS temperatures database (station.number)/station.txt
    has moved to?

  8. Zac says:

    Seems that Richard Black thinks plants caused the Ice age.

  9. GregO says:

    There are already a couple of comments along the lines of “who cares about ice melt in some utterly remote location?” Add me to the list. So what if glaciers shrink a bit? I mean, it’s mildly interesting, but so what?

    Nice map of Greenland:

    I mean these questions sincerely – does anyone care to elaborate on why ice melt/sublimation in Greenland makes any difference at all outside of:

    A proxy for CAGW and we know that ice status is tons of fun arguing about even though from a purely logical viewpoint it isn’t anything more than a proxy for, well, ice. Ice and glaciers form or melt for any number of reasons we simply do not fully understand, but we all like to cheer for the ice every year and for gosh sakes, I don’t want to spoil the fun.

    Sea-level rise. Ahem, that doesn’t seem to be working as predicted by CAGW doom sayers but I suppose if enough land-based iced did manage to get itself melted and find its way to sea, the sea-level would go up a bit faster. Here’s an interesting exercise. Google a couple of busy seaports, like Boston Harbor. See if you can find anything on their sites about CAGW sea-level rise. You won’t find much. Lesson: They are commercial enterprises making plenty of money – they will deal with it as they have for hundreds of years. But a direct link from CAGW to sea-level rise is sadly lacking in empirical evidence – CO2 goes up compared to recent history , sea-level not so much.

    Ecology/wildlife/etc. Somebody will have to help me here. Not my field at all – I recycle, drive a small car, use non-polluting stuff – but to be honest, I just don’t even think about wild animals, plants, ecology and stuff like that. I am open to being schooled as to why melting ice is so bad for Gaia and her creatures – note: the polar bear thing hasn’t worked out too well for the CAGW crowd either.

    Sorry for the longish post, but I am serious – who cares if some ice melts other than earth scientists? (And I don’t mean to slight you guys and gals out there that are into this stuff…I’m glad you are interested in it so you can watch out for all of our best interests.) In the mean time I’m back to work at my profession, building machinery.

  10. John Marshall says:

    How did Richard Black get here? He is well known for producing all sorts of rubbish to prove CAGW. He is the one who did a series of in-house lectures as to how best to promote climate change and the best ways to ignore climate skeptics who complain to the BBC about some preaching about CO2 etc..

    Also he is a journalist not a scientist.

  11. richard verney says:

    Zac says:
    February 1, 2012 at 5:18 am
    The Daily Mail is carrying this story.

    Of course it is simply based upon model projections which in turn are based upon the underlying assumptions (including forcings their strength and effectivenss) held by the person who wrote the model. As such, models prove nothing and are a complete waste of time.

    Climate science will not mature until it gets away from its dependence upon model projections.

  12. geoprof says:

    Fewer glaciers hogging all the water on the planet, more water in the atmosphere, more rain in TX… In a drought, we aren’t missing these glaciers.
    It is mind-boggling that they think they know what is going to happen hundreds of years from now, and state that they know exactly what happened thousands of years ago.

  13. Bloke down the pub says:

    John Marshall says:

    February 1, 2012 at 5:52 am

    ” Also he is a journalist not a scientist.”
    I think if there are any true journalists left out there, they may dispute the first part of that statement.

  14. SandyInDerby says:

    richard verney says:
    February 1, 2012 at 5:56 am

    Zac says:
    February 1, 2012 at 5:18 am

    So to prevent another ice-age we have to get rid of the tropical rainforests as a starting point. Who’s going to tell Prince Charles?

  15. Karen says:

    Pardon me for asking, but it seems to me that the whole thing about ages of rock piles–not only this report but also, frex, the crater in California (Ubehebe??) rest upon the assumption that beryllium isotopes are a clock. Yet on looking at the discussion, it’s never that the steady drumbeat of radioactive decay is measured. It’s always that the “rain” of beryllium isotopes down from the sky is measured. The *assumption* here seems to be that the beryllium rains down steadily, year after year, at the same exact pace and nothing else can add to or dilute it after it has fallen and the rate of accumulation never changes. Has anyone ever actually studied whether this assumption of clocklike steadiness is true? Because if the rate of beryllium accumulation changes, or if small creatures like ants can knock it off or pile it up…not to mention the scrubbings of floods…
    You see what I mean? I begin to wonder if much of the “knowledge” gained from rockpile dating is essentially the proverbial house built on sand, and one day the storm tide will roll in and wash out the foundations from under it altogether. (I live near a barrier island. Can you tell?)
    –just an interested reader!

  16. Sal Minella says:

    So, glaciers have been retreating since the end of the LIA, who knew? We had snow yesterday and then it melted. Two examples of snow/ice melting after forming. I didn’t shed a tear for yesterday’s snow and I won’t for the melting glaciers.

    The Sun is burning up it’s fuel, shouldn’t we worry about that? Maybe, if we start now, we will be prepared for it’s inevitable exhaustion. Why be proactive about eradicating climate cycles while being oblivious to the certain doom of a zero-degree-Kelvin future?

    A thought: How about more CO2 to keep us warm post-sol.

  17. John Marshall says:


    Yes I did make a mistake Black acts like a yob not journalist. I do hate to revert to name calling.(sarc. off).

  18. Glaciers come and go.

    The great Aletsch Glacier has been going since 1860. Before that time it was coming, and eating up precious pastureland. The Catholic church held ceremonies to stop its advance.

  19. M.A.Vukcevic says:

    in the South Atlantic SST 60 year record
    data: link

  20. Owen in GA says:

    I really hate this “irreversible” language (I was going to use an expletive but decided against). It is generally accepted that the Earth was once ice-free from pole to pole, so how did the glacier get there in the first place? It obviously isn’t “irreversible” as evidence indicates that it “reverses” all the time on geological time scales! WHAT UTTER RUBBISH!

  21. kathy says:

    Hey what’s with the Obama 2012 ad showing up on this post? Really?

  22. Edim says:

    The myth of the cursed glaciers:

    “The details differ but the general structure of the myth is very similar: A long time ago there existed a rich city surrounded by fertile pastures where today is the glacier. Unfortunately the wealth corrupted the inhabitants and they wasted the fortune, one day they decided to use milk and bread to clean the streets of the city. When a beggar asked for a piece of bread the presumptuous inhabitants denied him this humble request. So he cursed the city, dark clouds covered the sky and heavy and persistent snow started falling in the mountains. When the sun reappeared, the city and pastures were gone, lost forever under the glacier.
    Some historians suggest that this myth is based on observations of advancing glaciers during the period of the “Little Ice Age“, a period of cooling extending in the Alps from the 16th to the 19th centuries.”

  23. Owen in GA says:

    Kathy: Funny thing about ads, if you click on them they have to pay a small amount to keep Anthony’s site running. Isn’t it wonderful to force the Obama campaign to keep this fine establishment going?

  24. Robertvdl says:

    Imagine that today would be 11,500 years ago, how would the IPCC react to the “irreversible” glacier retreat and sea rise flooding coastal towns because of global warming ?

  25. TomT says:

    We already know that according to map makers Greenland glaciers can shrink and then grow back in just a few years.

  26. Don Easterbrook says:

    Beryllium is producted at the surface of rocks exposed to atmospheric radiation. The amount of beryllium formed is determined by the length of time that the rock has been exposed to atmospheric radiation, so the age of a moraine is the time since the rock was first exposed to radiation when the glacier dumped it on the moraine.
    Glaciers seldom retreat at constant rates–they oscillate back and forth with climate changes and thus make good paleothermometers. The most interesting thing about the ages of the glacier terminius shown on the photo is how the 1964 and 2001 positions almost overlap. Off hand, I’d bet that’s because the glacier probably stopped retreating during the climatic cooling of 1945 to 1977 and very likely advanced until the warming after 1978.

  27. G. Karst says:

    What is more alarming:

    Retreating ice
    Advancing ice

    One thing for sure – it will always be doing one or the other. GK

  28. Molon Labe says:

    I don’t understand how the glacier has retreated when the photo clearly shows a glacier reaching well past the oldest indicated line of advance?

  29. Matthew W says:

    Owen in GA says:
    February 1, 2012 at 7:29 am
    . It is generally accepted that the Earth was once ice-free from pole to pole,
    Not only that, but at one time almost the entire earth was iced over.

  30. crosspatch says:

    “Did plants gobble all the CO2 and begin the Ice Age sequence 450-odd million years ago”

    Possibly. The Carboniferous Period probably accounted for the loss of a lot of atmospheric CO2 starting around 350 million years ago. There wasn’t enough oxygen for decay as we know it today so the dead biomass simply piled up to become great beds of coal and oil. A lot of CO2 was removed by animals which created the absolutely huge deposits of limestone, too. All of that limestone is CO2 that came out of the air. Same with the shale and marble and alabaster and gypsum. All of that drywall in all of the houses in the world is made from CO2 that came out of the atmosphere.

    As for the glacial retreat, what should absolutely amaze them is the LACK of retreat from 1964 to 2001 when the majority of the “global warming” happened. That should completely discredit their hypothesis right there. There was practically no retreat when temperatures were warming the fastest and retreat picked up only when temperatures stabilized. I think they would be better off looking for a precipitation cause, not a temperature cause.

  31. adolfogiurfa says:

    @Vukcevic: BTW: Does anyone know where the GISS temperatures database (station.number)/station.txt
    has moved to?

    To Dante´s Inferno? :-)

  32. Many other studies show the Greenland glaciers began advancing about 5000 yrs ago, and their advance culminated in the LIA.

  33. tim maguire says:

    Anytime I hear the word “irreversible” regarding planetary systems, I think “careless thinker.” All of it is reversible, all of it will be reversed. There is only one thing that can (will) make the glacier melt irreversible: when the sun becomes a red giant and burns off all the water. Even continental drift towards warmer climes will be reversed eventually.

  34. Eric Huxter says:

    NASA quotes a total retreat of over 45 kilometers in 159 years, 10 in the past deacde. With a ruler and the satellite image, plus a little calculation using EXCEL, this is distributed as follows per decade:

    Decade Retreat (km)
    1850 – 1860 2.08
    1860 – 1870 2.08
    1870 – 1880 4.48
    1880 – 1890 4.09
    1890 – 1900 2.89
    1900 – 1910 3.67
    1910 – 1920 2.17
    1920 – 1930 2.54
    1930 – 1940 3.09
    1940 – 1950 2.05
    1950 – 1960 3.35
    1960 – 1970 1.74
    1970 – 1980 0.30
    1980 – 1990 0.30
    1990 – 2000 0.30
    2000 – 2010 10.25

    The trend of this is
    y = 0.2576x – 474.93
    R2 = 0.9711
    suggesting a consistent rate of retreat since 1851.

    The rapid retreat over the past decade merely makes up for the pause from 1964 – 2001.

  35. Edim says:

    When I first got interested in AGW, sometime in the late 1990s, one of the most important factors that made me skeptical was the retreating glaciers. My first reaction was:

    -What? Did these people go to school?

    My impression was that the AGW proponents were uneducated. I learned in the elementary school (geography) that glaciers are always retreating or growing. ALWAYS! Never still. That’s why the Alps for instance look the way they do. I used to joke that I might start believing in AGW if glaciers stop retreating/growing. Now, that would be unprecedented.

  36. David L. says:

    GregO says:
    February 1, 2012 at 5:48 am
    Well said! Excellent points! The only downside to melting ice, as you point out, might be sea level rise. So my advice: if you live in a flood plain you might take some precautions now and sell before the panic happens, and move to higher ground. I personally lived in a flood plain for a number of years and finally moved, not because it wasn’t beautiful and had great canoeing and fishing, but because I got tired of getting flooded and being forced to evacuate every spring and then come home to clean up.

  37. It seems that the illustration at Wiki is different from that at NASA. The latter (at ) is a TIFF image and gives problems in IE9, but if you make a download first and open it in an image program, it works fine. Here you can see it as .jpg file:

    The Wiki image probably is from RealClimate and shows some differences, mainly for the year 1953: in the NASA image, the 1953 line is where the 2001 line is in the Wiki image, quite a difference. It may be that between 1953 and 2001 the glacier advanced, because of colder temperatures in Greenland. The temperatures during summer in the period 1935-1950 were higher than in the period 2000-2006 (but I need to make an update for the past years):

    Further, this is a floating glacier for its tongue. As long as the glacier doesn’t break up, the resistance for the downflowing part from the inland icecap is higher than when the glacier is fragmented and floating in the rest of the icefjord. This increases the flow and the breakup point retreats faster than with a non-fragmented glacier. But there still is resistance as an underwater morene hinders the free outflow of the icebergs at the end of the fjord.

  38. mwhite says:

    “Chile: Man arrested over glacier ice theft”

    “Police in the south of Chile have arrested a man on suspicion of stealing ice from the Jorge Montt Glacier.”

    So that’s where the ice is going

  39. Olen says:

    As some have commented a lot stuff is covered by ice and who knows what is crushed under the ice in Greenland. Is it not better to understand how the planet works over time than to attempt to freeze understanding to the present and call the natural flow of events abnormal.

    The attempt to equate the results of climate over tens of thousands and even millions of years to a few decades seems a bit unusual.

    In the horse and buggy and lumber wagon days blinders were put on horses and mules so the horse or mule would not be distracted by the surroundings panic and stampede. Now we have the climate change crowd that want blinders on people to limit the view on climate but they want us to panic and stampede to their cause.

  40. Steve Garcia says:

    I dunno – I look at that glacier with the dates, and if the dates are correct, then that glacier argues totally against global warming (or at least Greenland warming).

    Notice how close the two lines are “1964″ and “2001″? Think about all those reconstructions from Mann et al and Everyone et al. Wasn’t the 1980s and 1990s the warmest period in the temperature record?

    I dare anyone to look at that glacier and point out the Hockey Stick for me.

    Right when the warming is warmest, the glacier stopped melting. That is what that photo tells me.

    Perhaps we have a Glacier Divergence Problem here.

  41. rossbrisbane says:

    Anyhow? Some have suggested scientists do not know.

    Some say too remote?

    What is this with ice anyway?

    We have Winter for sure! Things recover – don’t they?

    This whole climate change thingy is bull-dust – plain and simple!

    Gore-guff – that’s what they all say.

    Well let’s put all that a side for just a few moments. On ice so to speak and you all quiet down and hush up – you hear me. Anyone and everybody – you should get yourselves a notebook or lap top or iPad or tablet or PC or whatever – put those “feets” with good coffee brew and have a good read of this. I promise you this – this isn’t your boring dull crap-out about science. It tells us the truth in a narrative that all will LIKE – you okay with that – good.

    Why even a good sounding Texan girl (University of Texas) comes into the picture looking at all this stuff.

    Right here – have a read……………………………

    Lesson: Make it real to you. Feel your own humanity. And by all means show a little compassion for our world because we just maybe messing around with it too much lately.

    For the Christian Only…….

    If you go to Church ask God to show you and direct you as to what is the right thing to do. Don’t just go putting your offering in the bag neglecting that which God may want you to do.

    Have a nice day.

  42. rossbrisbane says:

    In the winter of 2010, Jakobshavn’s ice front did not re-advance as it usually does, so it began the 2010 melt season in the same location as the 2009 summer melt season. As a result, the glacier had the potential to experience significant retreat during the summer of 2010. The breakup in early July 2010 occurred on the northern tributary to Jakobshavn Glacier. The southern tributary actually drains a larger portion of Greenland’s central ice sheet, so a retreat there could lead to a more substantial ice discharge.

    Jakobshavn is a large and important glacier, draining over 6% of the Greenland ice cap and more potential sea level rise than any single source in the Northern Hemisphere. It is also one of the most rapidly changing glaciers in the world with thinning rates estimated at up to 15 meters per year. Jakobshavn over the last decade has followed a pattern of calving and retreating, and as recently as July 2010 suffered a significant retreat of ~1.5 km. This very active glacier is the subject of intense amounts of study, so flying the same survey lines several times allows us to determine the pattern of thinning over the entire glacier. This is essential for understanding the processes at work. A surprise result from first two years of IceBridge flights is that the thinning extends much further inland than had been suspected; in fact it extends beyond the limits of our survey. As a result, a second mission to Jakobshavn is planned for this year to extend the survey inland an additional 75 km. When those lines are reflown next year, we will have a more complete picture of the evolution of the glacier. It is findings such as this that have made IceBridge so key to helping us understand the changes in the polar regions.

  43. tty says:

    Actually the retreat of the Jakobshavn Isbrae reversed much more recently, in the 1940’s as a matter of fact. There is one data point missing in that illustration at the top. It looks as if the ice retreated, though slowly, between 1931 and 1953. However there is a USAF trimetrogon photograph from 1946 that shows that the ice-front was then in about the same position as in 2001 and that it actually advanced about 5 kilometers between 1946 and 1953.
    The photograph is on p. 141 of this paper:

  44. Brian H says:

    Eric Huxter says:
    February 1, 2012 at 9:53 am

    NASA quotes a total retreat of over 45 kilometers in 159 years, 10 in the past deacde. With a ruler and the satellite image, plus a little calculation using EXCEL, this is distributed as follows per decade:

    Decade Retreat (km)

    The rapid retreat over the past decade merely makes up for the pause from 1964 – 2001.

    I get 146 km from 1851-1960 which is 146/40 = 3.65 km/decade, and 13 km from 1961-2010 which is 13/5 = 2.6 km/decade. So it’s about 5 km short of “making up” the shortfall. So the next decade needs to melt about 8.6 km. to properly catch up.
    :) .

  45. woodNfish says:

    From the article (emphasis mine): “Greenland glaciers’ current retreat is not necessarily irreversible, their extent is tightly bound to the variability of our warming world.”

    This article is BS and needs no further review.

  46. Mickey Reno says:

    [Quote]Molon Labe says: I don’t understand how the glacier has retreated when the photo clearly shows a glacier reaching well past the oldest indicated line of advance?[/quote]

    I wondered the same thing. The NASA web page hosting the photo says that the photo was taken in 2001, so 2001 line is where the actual glacier extent was at the time. Note that the glacial ice is a bit gray or blue compared to the whiter ice ‘downstream.’ That ice, they say, is seasonally formed sea ice in the glacial fjord, and so not part of the glacier.

  47. Mickey Reno says:
    February 2, 2012 at 10:00 pm

    The lower part of the glacier is not sea ice but icebergs broken off of the glacier. The year lines show where the break off occurs, but the whole fjord is filled by the floating broken parts of the glacier, because at the end near the sea an underwater morene hinders the icebergs to reach the open water, As the ice (in summer) advances 7 meter per day (!), the gigantic blocks of ice are pushed over the morene wall, but also by wind and tides.

    Anyway incredible view (was there in the year 2000)!

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