Greenland and Antarctic ice sheet decay update

Image courtesy of Flickr user christine zenino (chrissy575)

[See previous posts here and here. I've been meaning to do a follow up for over a year. Has it been that long?]

First, a question in the comments a little more than a little while ago regarding an alleged contradiction between recent studies on increasing Antarctic ice sheet loss and a paper (Tedesco 2009) on recent reduction in Antarctic snowmelt (i.e. presumably, “if there’s less melting, surely there can’t be more ice loss”). This is a non sequitur- snowmelt extent and ice sheet mass balance being two distinct phenomena- although it’s easy to see why it sounds plausible at first blush. Of course it doesn’t help that the denialosphere confused the issue by falsely claiming a reduction in “ice melt” rather than snowmelt index. (Whether they do this stuff out of  a deliberate desire to mislead people or sheer incompetence, the end result is the same and both are indefensible.)

As I wrote then, the snowmelt index is defined as the number of days multiplied by the extent of surface melt (duration times area) rather than an actual “amount” (either volume or mass) of melting ice (Zwally 1994). In other words, there is no inherent contradiction between greater ice sheet decay and reduced surface snowmelt. Furthermore, rather than exculpate anthropogenic influence on Antarctica as the denialists suggest, the decreased snowmelt might actually be being driven at least in part by human activities. Tedesco and Monaghan finger couplings between positive summertime phases of the SAM with positive ENSOs. And of course anthropogenic ozone depletion and greenhouse gas emissions are suspected to at least partially contribute to the increasingly positive SAM (Arblaster 2006). And of course, we know that that the Antarctic ice sheet loss is accelerating, because we can measure it happening.

But wait! Didn’t a study (Bevis 2009) just show that ice sheet decay as measured by GRACE was exaggerated, contradicting GRACE findings of accelerating ice sheet decay? “Yes!” cried the denialosphere. “Not so fast,” warn the literate. 

The Bevis, et al. study was concerned with long term bias in GRACE measurements (due to underestimates of post-glacial rebound), which aren’t that significant on the timescales discussed in papers like Velicogna 2009.  Bevis et al. note:

any sudden increase in the rate of ice loss will be resolved unambiguously by GRACE since the mass rates associated with PGR [post-glacial rebound] do not change significantly over several years.

In other words, even if the GRACE data were systematically biased, such a bias would be relatively constant on short timescales and not meaningfully contribute to/contaminate measurements of large changes happening over interannual periods, especially changes in the rate of loss. So while the total amount of ice lost may be revised downward, the acceleration in recent/current decay is very much real.

And it’s not as though the GRACE data are the only method of establishing accelerating ice loss. In a recent paper in Science, van den Broeke 2009 calculate GrIS loss using a “mass budget method, which quantifies the individual components of ice sheet mass balance [surface mass balance (SMB) and ice discharge (D)”:

For SMB, we used the monthly output of a 51-year climate simulation (1958–2008) with the Regional Atmospheric Climate Model (RACMO2/GR) at high horizontal resolution (~11 km)… The modeled SMB from RACMO2/GR agrees very well with in situ observations [N = 265, correlation coefficient (r) = 0.95], without need for post-calibration . For D, we used ice flux data from 38 glacier drainage basins, covering 90% of the ice sheet… corrected for SMB between flux gate and grounding line and updated to include 2008

Van den Broeke, et al. compare their modeled/in situ data with GRACE, and found good agreement between the two:

The temporal evolution of the cumulative SMB-D anomaly was evaluated using monthly GRACE mass changes. The spatial distribution of GrIS mass changes was compared to a regionally distributed GRACE solution, updated to include 2008… The high correlation (r = 0.99) between the two fully independent time series and the similarity in trends support the consistency of the mass balance reconstruction. A linear regression on the SMB-D time series yields a 2003– 2008 GrIS mass loss rate of –237 ± 20 Gt year^−1.

Cumulative SMB-D anomaly (2003–2008) and comparison with GRACE data. Short horizontal lines indicate GRACE uncertainty, dashed lines the linear trends. GRACE values are not absolute numbers, and the curve has been vertically shifted for clarity. The scatter plot in the inset shows a direct linear regression between the monthly GRACE values as a function of the cumulative SMB-D anomaly, together with the linear regression coefficients. (van den Broeke 2009)

Recently, Rignot 2011 combined van den Broeke’s SMB-D method (which they call “mass budget method” or MBM) with GRACE data to reconstruct changes in GrIS and Antarctic mass balance over two decades, from 1992-2009.

Greenland

Initial concerns over accelerating Greenland ice loss arose when dramatic loss was recorded in the early to mid-2000s. However, this regional melting appeared to taper off around 2005, which lead to predictable crowing from climate contrarians who sought to portray this change as a reason to stop worrying about Greenland ice sheet decay.

Pritchard 2009 noted, however, that the extent of dynamic melt was more widespread than has been previously assessed- especially in the northwest- and has penetrated in some areas more than 100km inland and to altitudes as high as 2000m. 81 out of 111 Greenland glaciers surveyed showed melt rates more than twice as fast as nearby flowing ice.

Additional research- using data from GPS in addition to GRACE-  further supported this overall behavior, noting melt had again accelerated in some areas around 2005, especially in the northwest (Kahn 2010).

Rignot, et al. have confirmed that the long term trend for the GrIS is not just one of melt, but one of accelerating mass balance loss:

Total ice sheet mass balance, dM/dt, between 1992 and 2009 for Greenland, in Gt/yr from the Mass Budget Method (MBM) (solid black circle) and GRACE time-variable gravity (solid red triangle), with associated error bars. The acceleration rate in ice sheet mass balance, in gigatons per year squared, is determined from a linear fit of MBM over 18 yr (black line) and GRACE over 8 yr (red line). (Rignot 2011)

Rignot, et al.:

The mass losses estimated from MBM and GRACE are within ± 20 Gt/yr, or within their respective errors of ± 51 Gt/yr and ± 33 Gt/yr. The acceleration in mass loss is 19.3 ± 4 Gt/yr^2 for MBM [ed: 21.9 ± 1 Gt/yr^2 over 1992-2009] and 17.0 ± 8 Gt/yr^2 for GRACE. The GRACE-derived acceleration is independent of the GIA reconstruction, a constant signal during the observational period.

That last part is consistent with the earlier discussion of Bevis 2009- an adjustment to total mass balance loss numbers in GRACE due to glacial isostatic adjustment does not contradict the reality that Greenland is melting, and it’s melting at an accelerating pace.

Antarctica

Once upon a time, discussion of significant melting of Antarctic ice was restricted to the West Antarctic Ice Sheet (WAIS). The East Antarctic Ice Sheet (EAIS) was believed to be much more stable, and in much less danger of melting. A sense of complacency regarding the state of EAIS melt might be furthered in the public’s perception due to conflicting estimates of surface warming in that region. Ice sheet decay in Antarctica is not driven primarily by surface warming, however, and the Southern Ocean is warming significantly. And indeed, recent analysis of GRACE data has shown that the EAIS- long thought to be the more “safe” (e.g. less affected by warming) of the two Antarctic ice sheets- has been shown to be melting as well. (Chen 2009).

Additionally, concerns over Antarctic contribution to sea level rise have increasingly focused on the  Pine Island Glacier- e.g., according to Wiki, “The Pine Island and Thwaites Glaciers are two of Antarctica’s five largest ice streams. Scientists have found that the flow of these ice streams has accelerated in recent years, and suggested that if they were to melt, global sea levels would rise by 0.9–1.9 m (1–2 yards), destabilizing the entire West Antarctic Ice Sheet and perhaps sections of the East Antarctic Ice Sheet.”

Recent modeling results have suggested that Pine Island Glacier might already have crossed a threshold of stability (Katz 2010):

[O]ur results suggest that, in contrast to earlier assessments, the scenario of unstable grounding-line recession on retrograde beds in West Antarctica is likely. Indeed, in the case of the Pine Island glacier, it may be presently occurring.

Some had hoped that an increase in precipitation over Antarctica could result in an off-setting increase in surface mass balance. Unfortunately, Rignot, et al. note:

In Antarctica, Pine Island Glacier accelerated exponentially over the last 30 years: 0.8% in the 1980s, 2.4% in the 1990s, 6% in 2006 and 16% in 2007-2008 (Rignot, 2008), and quadrupled its thinning rate in 1992-2008 (Wingham et al., 2009). Simple model projections predict a tripling in glacier speed once the grounding line retreats to a deeper and smoother bed (Thomas et al., 2003). Dynamic losses are therefore likely to persist and spread farther inland in this critical sector. A small positive increase in Antarctic SMB could offset these coastal losses, but this effect has not yet been observed.

For the Antarctic continent as a whole, Rignot, et al. find:

an acceleration in mass loss from the GRACE data of 13.2 ± 10 Gt/yr^2…  [and for] the same time period, the acceleration in mass loss from the MBM data is 15.1 ± 12 Gt/yr^2 [ed: and 14.5 ± 2 Gt/yr^2 over 1992-2009].

Total ice sheet mass balance, dM/dt, between 1992 and 2009 for Antarctica, in Gt/yr from the Mass Budget Method (MBM) (solid black circle) and GRACE time-variable gravity (solid red triangle), with associated error bars. The acceleration rate in ice sheet mass balance, in gigatons per year squared, is determined from a linear fit of MBM over 18 yr (black line) and GRACE over 8 yr (red line). (Rignot 2011)

OVERALL

The take home message from Rignot, et al. is stark.

When we use the extended time period 1992-2009, the significance of the trend improves considerably. The MBM record indicates an acceleration in mass loss of 21.9 ± 1 Gt/yr^2 for Greenland and 14.5 ± 2 Gt/yr^2 for Antarctica…  When the mass changes from both ice sheets are combined together…, the data reveal an increase in ice sheet mass loss of 36.3 ± 2 Gt/yr^2.

Total ice sheet mass balance, dM/dt, between 1992 and 2009 for the sum of Greenland and Antarctica, in Gt/yr from the Mass Budget Method (MBM) (solid black circle), with associated error bars. The acceleration rate in ice sheet mass balance, in gigatons per year squared, is determined from a linear fit of MBM over 18 yr (black line). (Rignot 2011)

Greenland and Antarctica are melting. Moreover, they’re melting at an accelerating rate. This is not an artifact of instrumental bias in GRACE, or due to an insufficiently short time period.

Rignot, et al. conclude:

This study reconciles two totally independent methods for estimating ice sheet mass balance, in Greenland and Antarctica, for the first time: the MBM method comparing influx and outflux of ice, and the GRACE method based on time-variable gravity data. The two records agree in terms of mass, M(t), mass change, dM(t)/dt, and acceleration in mass change, d2M/dt2. The results illustrate the major impact of monthly-to-annual variations in SMB on ice sheet mass balance. Using the two-decade long MBM observation record, we determine that ice sheet loss is accelerating by 36.3 2 Gt/yr2, or 3 times larger than from mountain glaciers and ice caps (GIC). The magnitude of the acceleration suggests that ice sheets will be the dominant contributors to sea level rise in forthcoming decades, and will likely exceed the IPCC projections for the contribution of ice sheets to sea level rise in the 21st century.

This last finding will come as no surprise to those who know that the IPCC AR4 sea level rise estimates didn’t account for nonlinear ice sheet decay, but rather assumed a contribution from Greenland and Antarctica at the observed linear rate from 1993-2003. Using semi-empirical methods (that still don’t explicitly account for catastrophic ice sheet collapse) provides an additional line of evidence for accelerating ice sheet contribution to SLR (e.g. Vermeer 2009).

Projection of sea-level rise from 1990 to 2100, based on IPCC temperature projections for three different emission. The sea-level range projected in the IPCC AR4 for these scenarios is shown for comparison in the bars on the bottom right. Also shown is the observations-based annual global sea-level data (red) including artificial reservoir correction. (Vermeer 2009)

References:

  • Arblaster, J.M. and G.A. Meehl (2006): Contributions of External Forcings to Southern Annular Mode Trends. Journal of Climate, 19, 12, 2896-2905, doi:10.1175/JCLI3774.1
  • Bevis, M., et al. (2009): Geodetic measurements of vertical crustal velocity in West Antarctica and the implications for ice mass balance. Geochemistry, Geophysics, Geosystems, 10, Q10005, doi:10.1029/2009GC002642.
  • Chen, J.L., et al. (2009): Accelerated Antarctic ice loss from satellite gravity measurements. Nature Geoscience, 2, 859 – 862, doi:10.1038/ngeo694.
  • Katz, F.A. and M.G. Worster (2010): Stability of ice-sheet grounding lines. Proceedings of the Royal Society: A, 466, 1597–1620, doi:10.1098/rspa.2009.0434.
  • Khan, S. A., et al. (2010): Spread of ice mass loss into northwest Greenland observed by GRACE and GPS. Geophysical Research Letters, 37, L06501, doi:10.1029/2010GL042460.
  • Rignot, E., et al. (2011): Acceleration of the contribution of the Greenland and Antarctic Ice Sheets to sea level rise. Geophysical Research Letters, in press, doi:10.1029/2011GL046583.
  • Tedesco, M., and A. J. Monaghan (2009): An updated Antarctic melt record through 2009 and its linkages to high-latitude and tropical climate variability. Geophysical Research Letters, 36, L18502, doi:10.1029/2009GL039186.
  • van den Broeke, M., et al. (2009): Partitioning Recent Greenland Mass Loss. Science, 326, 5955, 984-986, doi:10.1126/science.1178176.
  • Velicogna, I. (2009): Increasing rates of ice mass loss from the Greenland and Antarctic ice sheets revealed by GRACE. Geophysical Research Letters, 36, L19503, doi:10.1029/2009GL040222.
  • Vermeer, M., and S. Rahmstorf (2009): Global sea level linked to global temperature. Proceedings of the National Academies of Science (USA), 106, 51, 21527-21532, doi:10.1073/pnas.0907765106.
  • Zwally, H.J., and S. Fiegles (1994): Extent and duration of Antarctic surface melting. Journal of Glaciology, 40, 136, 463-476.
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37 responses to “Greenland and Antarctic ice sheet decay update

  1. PS. I really ‘like’ your Blog title.

  2. So deniers took good science (Bevis 2009) and turned it into the usual Bevis and Butthead science that they are comfortable with.

  3. Off Topic observation from North of Greenland, I’d assume katabatic winds have opened a lead in the sea ice:

    http://www.ijis.iarc.uaf.edu/cgi-bin/seaice-monitor.cgi?lang=e&mode=img&size=L&date=set&y=2011&m=02&d=16

  4. Excellent overview.

    You didn’t mention Wu et al (2010), who argued that Velicogna’s results overestimate the downward trend to to their IGA correction. Does the good agreement between GRACE and SMB methods suggest that the GRACE results are correct (and by implication, Wu et al’s results are not)?

    • I haven’t looked at Wu 2010 yet. Is this a different claim from the Bevis 2009 issue? On its face, it doesn’t sound that plausible [edited to add: that it would invalidate the finding of accelerating loss], as the bias (to materially affect Velicogna 2009’s finding of *accelerating* mass loss) would have to be both significant and increasing over time. I would like to think I’d have heard of such a problem!

      Might be good for a follow up post. Thanks for the reference.

  5. This is just more of the same old crap.

    [Oh, the irony.]

    The glaciers are melting Ooooh! And they are melting at an accelerated pace!! Ooohhhh be scared!

    [Whether or not someone finds the accelerated decay of the Greenland and Antarctic ice sheets, with attendant sea level rise, alarming or "scary" is up to them.]

    Quick, put up some wind turbines, that’ll stop the melting!! It’s ridiculous.

    [Yes, that would be a ridiculous response. I am not proposing wind turbines as a silver bullet solution to ice sheet decay, however. Maybe you should go argue with whoever is actually making those claims?]

    So what if the glaciers are still melting, and so what if they are melting at an accelerated pace.

    [It has profound implications for future SLR, which has implications for increased storm surge risk, and so on.]

    By your own graph you can see an accelerated GROWTH between 1995-1996, but again who cares?

    [Indeed. A one-year "trend" is not particularly meaningful. A 17+ year trend is more difficult to dismiss.]

    All of this is just more evidence of climate change only, none of it is evidence that CO2 is the cause.

    [Are you seriously going to argue that GHGs aren’t driving the present warming on multidecadal timescales?

  6. Well, that is the effect of the global warming that we are experiencing. I hope we can do something to prevent this one.

  7. Sorry, you lost me at “denialists”

    • Come now, Mike, be honest! Mainstream science “lost” you a good while back. It’s flattering that you’d like to give the credit to me, but we both know that statistically speaking your rejection of the evidence almost assuredly has to do with your ideological predisposition and how you perceive potential solutions conflicting with it.

  8. Sorry, your argument folds at “denialosphere”. If you can’t present an argument with civility and without ad hominem, there is no argument.

    Thanks for playing.

    • Hi Mike!

      Two questions:

      1. What “argument” am I supposed to making here, that you feel “folds” because I used a word that hurt your fee-fees?
      2. What is the politically-correct term the people who reject mainstream climate science prefer? I’ve never been that great at remembering PC labels.

    • Ah, an ad hominem about a non-ad hominem.

    • Mike Jowsey,

      Do you deny that the ice sheets are losing mass at an accelerating rate?
      Do you deny the importance of this?

      Thanks for answering.

      • Hi MapleLeaf
        They may be losing mass. It is interesting to watch. Over the next 18 years the trend may change again. Who knows? 18 years is a blip. It’s interesting, though. Here are some more interesting viewpoints for you (just to balance things a bit):

        Wal et al (2008) found that inbuilt adjustment of englacial hydraulic systems “may have only a limited effect on the response of the ice sheet to climate warming over the next decades”.

        Nick et al (2009) concluded that “tidewater outlet glaciers adjust extremely rapidly to changing boundary conditions at the calving terminus,” stating that their results implied that “the recent rates of mass loss in Greenland’s outlet glaciers are transient and should not be extrapolated into the future.”

        Zwally et al. (2005), found that “the Greenland ice sheet is thinning at the margins (-42 ± 2 Gt/year below the equilibrium-line altitude) and growing inland (+53 ± 2 Gt/year above the equilibrium-line altitude) with a small overall mass gain (+11 ± 3 Gt/year; -0.03 mm/year sea-level equivalent).”

        Wake et al (2009) “it could as well be stated that the recent changes that have been monitored extensively (Krabill et al., 2004; Luthcke et al., 2006; Thomas et al., 2006) are representative of natural sub-decadal fluctuations in the mass balance of the ice sheet and are not necessarily the result of anthropogenic-related warming.”

        Etterna et al (2009) revealed the “total annual precipitation in the Greenland ice sheet for 1958-2007 to be up to 24% and surface mass balance up to 63% higher than previously thought,” with the largest differences occurring in coastal southeast Greenland, where the seven scientists said that the much higher-resolution facilitates captured snow accumulation peaks that previous five-fold coarser resolution regional climate models missed.

        As to the importance, not sure. Gore doesn’t think it’s too important, going by his US$14m seaside mansion purchased recently. Nor do Shepherd and Wingham (2007): the two researchers concluded that the current “best estimate” of the contribution of polar ice wastage to global sea level change was a rise of 0.35 millimeters per year, which over a century amounts to only 35 millimeters or a little less than an inch and a half.

        Of course, the relationship between CO2 and ice mass loss is at best a tenuous and unproven hypothesis. But we’ll leave that for another day.

        Thanks for your questions.

      • It appears Jowsey tries a “but, but, but, AL GORE!”. Mike Jowsey would be wise to look up where Al Gore’s new “seaside” mansion is actually located. If he did, he would likely found out that this “seaside” mansion would not even become a “seaside” mansion if ALL ice on earth would melt, including associated rise due to expansion.

        And nice to see yet another denier (there, I said it) cherry-pick. As Shepherd and Wingham note in their abstract, right after the 0.35 mm/year:
        “However, much of the loss from Antarctica and Greenland is the result of the flow of ice to the ocean from ice streams and glaciers, which has accelerated over the past decade. In both continents, there are suspected triggers for the accelerated ice discharge—surface and ocean warming, respectively—and, over the course of the 21st century, these processes could rapidly counteract the snowfall gains predicted by present coupled climate models.”

      • Marco:
        Just going by what has been reported:

        Apparently not as worried about dangerous sea level rises as he touts in his speeches, Former Vice President Al Gore and his wife Tipper have purchased a seaside villa in Montecito, California.

        http://www.examiner.com/climate-change-in-national/it-s-good-to-be-green-al-gore-buys-9-million-seaside-home

        I wasn’t cherry picking. Space limitations precluded the publishing of huge excerpts. Was simply citing a few papers with interesting conclusions. As for the acceleration of glacial flows, I refer you to Nick et al, cited above.

        Thank you.

      • You’re seriously referring to the Examiner. It shows you’re not very much of a “critical” thinker if that is your source of information.. Nor are there space limitations here such that you HAD to leave the last part out.

      • Marco – thanks for the gratuitous ad homs. Meanwhile, I still refer to the science of Nick et al cited above wrt increased glacial flows. Thanks.

      • Pointing out that someone who uses “the Examiner” as a source of information is not using his critical thinking, is not an ad hominem. It’s a logical conclusion drawn from the provided evidence.

  9. Wu et al (2010) approach the Glacial Isostatic rebound (GIA) issue differently. They use sea surface altimetry and tide gage data to constrain oceanic mass changes, GPS data to constrain rebound of the crust and GRACE for total mass changes. Previous research corrected for GIA first and then calculated the mass changes. Wu et al (2010) complete this process simultaneously. This approach sounds like it has merit but the devil is in the detail and that is the GPS data used is very limited, because there are just not enough station in Greenland to accurately portray the crustal movements and the GIA is tuned based on just one location. That is where the final results could break down. A robust methods such as Velicogna use is going to be more reliable than a potentially better approach with limited reliability measurement.

  10. Mike Jowsey,

    Thanks for your “answers” and display of cherry-picking– I’m probably not the firs to point this out to you, but you are in denial about AGW and its consequences. You blew your cover when you made reference to Gore.

    I also find it intriguing how some of your citations claim that there is a net mass gain over GIS (Zwally et al. (2005)), while others say there is a decrease but it is likely natural fluctuation (Wake et al (2009), and another which says that the contribution of ice loss is GSL small (Shepherd and Wingham (2007)). You are not presenting a coherent or consistent picture.

    The facts, GIS is losing ice at an accelerated rate, so is WAIS. Globally glaciers and ice sheets are losing ice. Arctic ice volume is decreasing at an accelerated rate. And it seems to me that you would have us believe that this is not related to the observed warming or that it is all just a blip? I think you also need to read Polyak et al. (2010).

    Estimates of increase in GSL are being revised upwards, not downwards. See skepticalscience.com for more. Also see the findings of Song and Colberg (2011) regarding the latest estimates of contribution of ice sheet loss to GSL.
    Also recommend that you read Rholing et al. (2009). Bart Verheggen has a recent post on Rholing et al.

    PS: I am curious to know where you gabbed the text in your post…I have a pretty good suspicion ;)

  11. The evidence supporting accuracy of GRACE measurement of polar ice loss is compelling and, as pointed out by Mapleleaf, our concerns should be directed at the effects of GRACE findings on sea level.

    I would suggest that accelerated ice loss should also be very much directed at the effects on ice sheet stability, particularly of WAIS, a marine ice sheet and therefore all the more vulnerable to attack from a warming Southern Ocean and warm currents flowing from the Pacific and Atlantic.

    While not under-estimating the significance of increased ice flows from the Pine Island and Thwaits glaciers, which drain 20% of WAIS, perhaps attention should be paid to effects on the massive Ross and Ronne-Fitchner ice shelves.

    Were these to contract, they would permit significant glaciers flows from the Trans-Anatartic Mountains and expose vast areas of WAIS to warm water seriously undermining stability of the entire ice sheet. Could that produce significant and rapid sea level rise by 2100?

  12. Hi Thingsbreak,
    I appreciate your website. I am trying to understand this whole climate thing, but alas, I am not the scientific type.

    My 6th grade son had to do a science fair project and chose an experiment suggested by his teacher. He floated some ice in a water filled container. As the ice melted, the container did not overflow- which means the water level did not rise.

    If the Antarctic is floating ice and it were to melt, how could it cause the oceans to rise ?

    Just trying to understand.

  13. Pingback: Ice sheet overview [A Few Things Ill Considered] | Death By Cucumber News

  14. Jerry Mitrovica’s been doing some interesting research on gravity and sea level rise which is counterintuitive, (which I often seem to find means that it’s probably right ;)

    The Gravity of Glacial Melt

    http://harvardmagazine.com/2010/05/gravity-of-glacial-melt?page=0,0

    Sea levels would rise unevenly as ice sheet melts, study says

    http://www.theglobeandmail.com/news/technology/science/article9752.ece

    The Secret of Sea Level Rise: It Will Vary Greatly by Region

    http://www.goodplanet.info/eng/Contenu/Points-de-vues/The-Secret-of-Sea-Level-Rise-It-Will-Vary-Greatly-by-Region

    As an aside:
    Greenland ice sheet saw record melt, study finds
    “‘Area of the size of France melted in 2010 which was not melting in 1979,’ expert says “

    http://www.msnbc.msn.com/id/41197838/ns/us_news-environment/

  15. Well I think that a close watch on sea level rise is the only way to understand what is happening. If it rises and accelerates then we know.

  16. Pingback: Climate News and Blog Recap – 2011 03 05 « The Whiteboard

  17. thingsbreak: Thanks for this post – it was a great resource for a lecture I had to give recently on Greenland and Antarctica.

    Chances are you’ve already seen it, but a new paper by Schrama and Wouters (JGR, 2011) looks at regional mass changes on the GIS, along with mass changes on other Arctic glaciers (Ellesmere Is., Baffin Is., Iceland, and Svalbard, or EBIS). From GRACE they estimate an acceleration of mass loss of -22 Gt/yr^2 for GIS + EBIS, and show that accelerated mass loss has progressed to northwest Greenland.

  18. Great post! By the way, you occasionally write Rignot’s name as “Ringot”. I like the Beatles too, but…

  19. The impact of human’s activity is visible exactly by this example. It has to have some effect on the environment when we burn fossil fuels. I am quite curious what recent occurrences from Japanese islands can bring now and in the future. That kind of disasters can have a significant influence on entire world.

  20. Sorensen et al 2011 find ice loss from Greenland using ICESat alone from 2003 to 2008 in the same range, 191 ± 23 Gt yr−1 to 240 ± 28 Gt yr−1. This fits in with the pattern seen on individual glaciers even the small non-calving glaciers such as Mittivakkat.

  21. Pingback: Arctic ice thins dramatically - Page 31 - US Message Board - Political Discussion Forum

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