Greenland, Antarctic Ice Loss Confirmed in Landmark Study

November 29, 2012

NASA:

PASADENA, Calif. – An international team of experts supported by NASA and the European Space Agency (ESA) has combined data from multiple satellites and aircraft to produce the most comprehensive and accurate assessment to date of ice sheet losses in Greenland and Antarctica and their contributions to sea level rise.

In a landmark study published Thursday in the journal Science, 47 researchers from 26 laboratories report the combined rate of melting for the ice sheets covering Greenland and Antarctica has increased during the last 20 years. Together, these ice sheets are losing more than three times as much ice each year (equivalent to sea level rise of 0.04 inches or 0.95 millimeters) as they were in the 1990s (equivalent to 0.01 inches or 0.27 millimeters). About two-thirds of the loss is coming from Greenland, with the rest from Antarctica.

This rate of ice sheet losses falls within the range reported in 2007 by the Intergovernmental Panel on Climate Change (IPCC). The spread of estimates in the 2007 IPCC report was so broad, however, it was not clear whether Antarctica was growing or shrinking. The new estimates, which are more than twice as accurate because of the inclusion of more satellite data, confirm both Antarctica and Greenland are losing ice. Combined, melting of these ice sheets contributed 0.44 inches (11.1 millimeters) to global sea levels since 1992. This accounts for one-fifth of all sea level rise over the 20-year survey period. The remainder is caused by the thermal expansion of the warming ocean, melting of mountain glaciers and small Arctic ice caps, and groundwater mining.

-

“Both ice sheets appear to be losing more ice now than 20 years ago, but the pace of ice loss from Greenland is extraordinary, with nearly a five-fold increase since the mid-1990s,” Ivins said. “In contrast, the overall loss of ice in Antarctica has remained fairly constant, with the data suggesting a 50-percent increase in Antarctic ice loss during the last decade.” 

Monthly changes in Antarctic ice mass, in gigatones, as measured by NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites from 2003 to 2011. The data illustrate the continuing loss of ice from the continent. The plots here depict results from five different IMBIE team members using different methods. The data have been adjusted to reflect new models of post-glacial rebound.
Image credit: NASA-JPL/Caltech; NASA GSFC; CU-Boulder; Technical University of Munich; Technical University of Denmark; Delft University of Technology, Aerospace Engineering, Netherlands; Durham University, UK; Leeds University, UK

Guardian:

More than 4tn tonnes of ice from Greenland and Antarctica has melted in the past 20 years and flowed into the oceans, pushing up sea levels, according to a study that provides the best measure to date of the effectclimate change is having on the earth’s biggest ice sheets.

The research involved dozens of scientists and 10 satellite missions and presents a disturbing picture of the impact of recent warming at the poles.

The scientists claim the study, published in the journal Science, ends a long-running debate over whether the vast ice sheet covering the Antarctic continent is losing or gaining mass. East Antarctica is gaining some ice, the satellite data shows, but west Antarctica and the Antarctic peninsula is losing twice as much, meaning overall the sheet is melting.

“The estimates are the most reliable to date, and end 20 years of uncertainty of ice mass changes in Antarctica and Greenland,” said study leader, Andrew Shepherd, of Leeds University. “There have been 30 different estimates of the sea level rise contribution of Greenland and Antarctica, ranging from an annual 2mm rise to a 0.4mm fall.

“We can state definitively that both Greenland and Antarctica are losing mass, and as [the] temperature goes up we are going to lose more ice.”

The study shows the melting of the two giant ice sheets has caused the seas to rise by more than 11mm in 20 years. It also found Greenland is losing ice mass at five times the rate of the early 1990s.

The uncertainties over ice cap melting have made it difficult for scientists to predict sea level rise. But Prof Richard Alley, of Penn State University, US, who was not involved in the study, said: “This project is a spectacular achievement. The data will support essential testing of predictive models, and will lead to a better understanding of how sea level change may depend on the human decisions that influence global temperatures.” Rising sea level is one of the greatest long-term threats posed by climate change, threatening low-lying cities and increasing the damage wrought by hurricanes and typhoons.

BBC:

The results show that the largest ice sheet – that of East Antarctica – has gained mass over the study period of 1992-2011 as increased snowfall added to its volume.

However, Greenland, West Antarctica and the Antarctic Peninsula were all found to be losing mass – and on a scale that more than compensates for East Antarctica’s gain.

The study’s headline conclusion is that the polar ice sheets have overall contributed 11.1mm to sea level rise but with a “give or take” uncertainty of 3.8mm – meaning the contribution could be as little as 7.3mm or as much as 14.9mm.

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“We can now say for sure that Antarctica is losing ice and we can see how the rate of loss from Greenland is going up over the same period as well,” he added.

“Prior to now there’d been 30 to 40 different estimates of how the ice sheets are changing, and what we realised was that most people just wanted one number to tell them what the real change was.

“So we’ve brought everybody together to produce a single estimate and it turns out that estimate is two to three times more reliable than the last one.”

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38 Responses to “Greenland, Antarctic Ice Loss Confirmed in Landmark Study”

  1. omnologos Says:

    “So we’ve brought everybody together to produce a single estimate and it turns out that estimate is two to three times more reliable than the last one.”

    That must be a first for climate-related science.

    • mrsircharles Says:

      Nonsense. Every measurement at that scale are best estimates of all measuring compounds. Even ice coverage, which is far easier to measure, is a best guess of single quadrants.

      What you’re trying here is to discredit state of the art science because you don’t like the result.

      I have always been pointing out that the Antarctic ice mass is shrinking too. This graph is showing an accelerating trend for both poles => http://www.giss.nasa.gov/research/briefs/hansen_15/fig2.gif

  2. rayduray Says:

    Media Matters tells us who will be distorting the newest sea level rise data contained in this important Science study:

    http://mediamatters.org/blog/2012/11/28/meet-the-climate-denial-machine/191545

    • omnologos Says:

      Media Matters usually strikes me as positively fascist. And once again.

      • greenman3610 Says:

        wow. calling out Fox news is fascist.
        that’s some looking glass world you live in, bro.

        • omnologos Says:

          That’s not what I said.

          This is the second time in a few days. Please stick to what I write. Unless you’ve developed internet-based telepathy in the meanwhile. :)

          I repeat. Media Matters looks to me positively fascist. They have collected a bunch of diverse people, come up with different reasons to list them together, described a “machine” that doesn’t seem to have its parts fit together.

          And I just repeated the same concept three times.

          • greenman3610 Says:

            this is not a “bunch of diverse people”. they are all funded by the same handful of billionaires and fossil fuel corporations. this is a very small but influential group of bad actors – criminals, in fact. That you somehow miss that is extraordinary. Naivety is far too mild a word to describe this. It’s borderline psychotic.

      • rayduray Says:

        Re: “Media Matters usually strikes me as positively fascist.”

        OK, punk. This is deliberate. You know the real story is that Media Matters makes it a point to fight fascism in this country.

        You’re officially a jerk. So off with you.

        • omnologos Says:

          I guess they walked with the fascists one step too often then.

          As for the funding by “the same handful of billionaires and fossil fuel corporations”, I have never seen any evidence whatsoever either of that, or of its efficacy. Just look at Europe.

          (please don’t start with the non-huge funds available to the Heartland Institute…unless you want to demonstrate HI has had the best return on their spending in the history of the world…)

          Anyway, perhaps because of my good looks I have never been approached by anybody offering to fund me for anything on any topic, including climate change. And I have been blogging “skeptically” since 2003.

          • mrsircharles Says:

            Yeah, omnologos. I’m very “skeptically” about yourself at the moment…

          • omnologos Says:

            Am not surprised mrsircharles. OTOH if anybody has any evidence of me being funded by the “machine”, I’m all ears.

            In the meanwhile not one of you has come up with any evidence of a link between the Media Matters “deniers” and especially a financial one. Am not surprised about that either.

            A quick look about who could afford to go to Doha is all I need to understand who’s well funded. With the added luxury that I don’t have to find refuge in paranoid conspiracies about a “machine”.

          • jaryndauss Says:

            “In the meanwhile not one of you has come up with any evidence of a link between the Media Matters “deniers” and especially a financial one. Am not surprised about that either.” – Comment created at November 30, 2012 at 8:39 am by omnologos

            “they are all funded by the same handful of billionaires and fossil fuel corporations. this is a very small but influential group” – Comment created at November 30, 2012 at 1:12 am by greenman3610, 7.5 hours before omnologos’ created its ill-fated complaint.

          • omnologos Says:

            We have a different definition of what constitutesw ‘evidence’.

          • jaryndauss Says:

            “We have a different definition of what constitutesw ‘evidence’.”

            ev·i·dence [ev-i-duh ns] Show IPA noun, verb, ev·i·denced, ev·i·denc·ing.
            noun
            1. that which tends to prove or disprove something; ground for belief; proof.
            2. something that makes plain or clear; an indication or sign: His flushed look was visible evidence of his fever.
            3. Law. data presented to a court or jury in proof of the facts in issue and which may include the testimony of witnesses, records, documents, or objects.

            1 has been met, the article showed that most of those all have a repeating list of at least a few donors/funders. Exxon-Mobil and the Koch Brothers fund and/or donate to virtually every one of those.

            2 has even been met, the links are plain and clear. A matter of public record for most of these, even.

            3 could be met pretty easily as well, assuming this were a court and you were willing to accept facts as evidence.

            It is obvious that you have a different definition of what constitutes evidence. The problem is that your definition is sufficiently divergent from standard usage of the term as to be no longer useful in discussion with anyone not already cemented into your views.

          • omnologos Says:

            I can write a million articles claiming you’re funded by furry little creatures from Alpha Centauri. That would not constitute evidence.

            And I really cannot see how can anybody show that the whole “machine” exists at all. I know personally a great number of skeptics who don’t care what oil companies think, and besides in Europe the same oil companies are on the warmist side.

          • otter17 Says:

            Nobody claims a well-oiled machine or a well-orchestrated conspiracy, and from first glance the Media Matters article doesn’t claim that either. From what can be discerned, self interest is involved, though. There are companies and individuals that look out for their own interests and put their money towards interests that support them. Sometimes, they support think tank organizations that are in conflict with actual scientific organizations. It happens in America, just like lobbying and political donations occur.

            There are publicly available documents, such as Exxon’s past tax forms such as Form 990 that show donations. Donations to Heartland, Competitive Enterprise Institute, George Marshall Institute, Heritage Foundation, and I think another that I can’t find at the moment. These organizations and their general statements are in contradiction with climate science organizations. Sometimes, the reason listed for the donation is “climate change”.

            Also, the Media Matters article includes a lot of links and references. Might have to take a look into a few of them sometime.

      • skeptictmac57 Says:

        According to Merriam Webster:
        Definition of FASCISM

        1
        often capitalized : a political philosophy, movement, or regime (as that of the Fascisti) that exalts nation and often race above the individual and that stands for a centralized autocratic government headed by a dictatorial leader, severe economic and social regimentation, and forcible suppression of opposition
        2
        : a tendency toward or actual exercise of strong autocratic or dictatorial control <early instances of army fascism and brutality

        Now explain to us again,in detail, how Media Matters is fascist.Or was that just some bit of demagoguery ?


  3. [...] Greenland, Antarctic Ice Loss Confirmed in Landmark Study (climatecrocks.com) [...]


  4. [...] like Greenland with amazing accuracy – 1000X better than previously. We now can know how much ice is being lost on Greenland and Antarctica. We are now able to date when glaciers melted in the distant past; by analyzing the minerals in [...]

  5. atoieno Says:

    Omnologos says:

    “Look over there…a fascist”

    Meanwhile the ice melts.


  6. Antarctic.
    In paper: Recent Antarctic Peninsula warming relative to Holocene climate and ice-shelf history (http://www.nature.com/nature/journal/v489/n7414/full/nature11391.html, Mulvaney 2012),
    it is the sentence:

    “The connection shown here between past temperature and ice-shelf stability suggests that warming for several centuries rendered ice shelves on the northeastern Antarctic Peninsula vulnerable to collapse. Continued warming to temperatures that now exceed the stable conditions of most of the Holocene epoch is likely to cause ice-shelf instability to encroach farther southward along the Antarctic Peninsula.”

    Earlier, however, is the sentence:

    “Although warming of the northeastern Antarctic Peninsula began around 600 years ago, the high rate of warming over the past century is UNUSUAL (BUT NOT UNPRECEDENTED) in the context of NATURAL CLIMATE VARIABILITY.”

    Over the last 100 years, this ice core record shows warming at a rate of 1.56±0.42°C per century, over the last 50 years, the rate of warming has increased to 2.6±1.2°C, but not outside the limits of natural variation over the past 2,000 years.

    • greenman3610 Says:

      thanks for that – Always worth acknowledging that conditions have changed
      regionally over time –
      I think the caution here is that the current global context for Antarctic warming does appear to be unprecedented over quite a long period, i.e. northern polar melt, global temp rise, sea level rise – and the strength of the forcing currently being applied is far stronger than natural forcings – going back to say, the last big asteroid strike.

  7. danolner Says:

    Just in case anyone needs reminding, Omnologos is the kind of commenter who isn’t even capable of clarifying whether *one of his own webpages* is a joke or not. The man’s a troll, though I’m not sure he quite has the wit to know it himself.

    • omnologos Says:

      Dan – your comment is OT so you are the troll. That page is a joke, only it’s a joke too subtle for you to comprehend. In fact, you haven’t understood it yet, despite me repeating this same answer several times.

  8. danolner Says:

    “A joke too subtle for you to comprehend”. Tee hee! that made my day. Yes, you’re right, it is too subtle for me to comprehend. It must be lonely being such a unique genius.

  9. Wes Says:

    Ignore him or block him. Do not feed the trolls. He has yet to add anything to the discussion here besides distraction, and if you read the comment stream you’ll see how he got us off topic. The ice sheet melt is a critical problem – in a large list of critical problems – and wasting time on trolls doesn’t help.

    • omnologos Says:

      Peter is that rare non-skeptic blogger, who doesn’t go into overdrive when a non-compliant voice pops up in his blogs. I guess and hope he doesn’t consider me a troll, in the sense of a timewasting commenter looking for trouble and a fight.

      In this thread as in all others, I hope I have not introduced OT stuff myself.

    • rayduray Says:

      Dear Wes,

      Re:”Ignore him or block him.”

      I second that emotion!


  10. [...] Greenland, Antarctic Ice Loss Confirmed in Landmark Study (climatecrocks.com) [...]


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