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Arctic sea ice discussions

Filed under: — group @ 20 July 2011

This is a thread to discuss issues related to the 2011 Arctic sea ice minimum. The following graphs will update every day:

JAXA Sea ice extent:



Cryosphere Today sea ice concentration:




298 Responses to “Arctic sea ice discussions”

  1. 51

    Re shipping through the NWP or NEP (#30, #38 and #42):

    The short answer to Stacey’s question is “zero.” The total tonnage through both Passages together probably doesn’t reach 200,000, and it’s as close to that number as it is mostly due to a 100,000 that traversed the NEP last year, laden (IIRC) with gas condensate or some such. Most of the vessels were built ice-ready, and most had icebreaker support at least available (even if, as in the case of the Desgagnes, it wasn’t actually used.)

    However, that number is going to rise considerably, if this story is any indication:

    http://www.barentsobserver.com/preparing-for-next-years-northern-sea-route-season.4832790-16175.html

  2. 52
    DP says:

    I understand the westerly winds are caused by the temperature differential between the Poles and the Tropics. If the Arctic Sea Ice disappears in Summer will this cause them to weaken or disapear?

  3. 53
    S. Molnar says:

    A couple of random thoughts.

    Re #6 (Hunt Janin): It won’t matter at all if this year’s ice extent is a little above or a little below the minimum of 2007 (there’s a lot of noise), except in the realm of public opinion. I believe that is why so many sane people are rooting for a new minimum – they hope it will spur some real action. I am not so sanguine about the hoped-for effect.

    Re #12 (arcticio): The phenomenon of oil companies trying to exploit the newly accessible areas of the arctic for new oil extraction is what’s known as a positive feedback. To be fair, while the oil companies are certainly evil propagandists, they only supply the stuff; we use it.

  4. 54

    Hi Nick, $49, Good example of more clouds especially in 2011 and also example of ridging from a very Negative Arctic oscillation. There is no such thing has sea ice improving in any way. There are signals,
    as I discuss on my blog, more pertinent signals. Arctic Basin got really cloudy from this time onwards last year. This year there is more ridging against the archipelago. Except for Northern Greenland. The over all image is dying by melting, vanishing old ice. THis extinction itself has huge impacts for ecosystems let alone the climate. The correct way to present sea ice, one word: SOS….

  5. 55
    todd arbetter says:

    @ Stacey:

    Through 2004, there have only been about 100 full transits of the Northwest Passage, starting with Amundson in 1903-1906. These include icebreakers, submarines and warships (known transits, anyway), passenger vessels, sloops, and yachts. There have been two oil tanker transits, both by the SS Manhattan, and these were feasibility studies; the US-flagged tanker was apparently not approved by the Canadian government. In 2008 the Camilla Desgagnés was the first commercial cargo ship in the NWP, and she and another ship returned in 2009. Most of the traffic since 2004 is either icebreakers or yachts (sometimes being chased by icebreakers — the NWP is in Canadian waters, not open seas).

    Commercial traffic is still in an exploratory phase. In order for the NWP to become a shipping lane, it needs to be reliably ice free over a definite period. And Canada can choose to allow or deny ships wanting passage, and regulate it. (The US could similarly put regulations on the Alaskan North Slope.)

    There are fewer known transits of the Northeast Passage, including a huge gap from 1941-1991. The Northeast passage is almost entirely in Russian (formerly Soviet) waters and they may not have been willing to tell the world what they were up to in that era. Also, they may not have let other ships enter their territory. The NEP is generally more navigable (the sea ice is usually thinner than on the Canadian side of the Arctic), and Russian nuclear-powered icebreakers clear the way for their northern Siberian ports to be served.

    As far as the Northeast Passage, shipping lanes could be open sooner, particularly if convoys were escorted by Russian nuclear icebreakers. But were still probably a decade or more away from any regularly scheduled shipping. Commercial industry isn’t going to do this unless they know their ships (and cargo) are safe.

    Institute of the North (www.institutenorth.org) has some materials on the future of Arctic shipping and potential for Arctic commercial activities in general.

    Naval Postgraduate School has an article by Lawson Brigham on the future of Arctic shipping. http://www.nps.edu/Programs/CCS/WebJournal/Article.aspx?ArticleID=67

  6. 56
    ccpo says:

    @Tamino: You science and stats dudes do nice work, but… the methods you use do not account for an speeding up of the process, do they? I didn’t see anything in your post that indicates to a math idiot like myself that this is so. I think you’d be close if you could incorporate increasing rate of decline. If you look at this graph at CryosphereToday http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seasonal.extent.1900-2010.png you will note, eyeballed only, a series of regime changes from 1900 – 1952, 1953 – 1998, 1999 – 2006, and 2007 – present. The slope increases each time.

    @general:

    Some points. In terms of patterns, we should note the ice is not just now at record lows, but was through most of the last calendar year, particularly in the late fall/early winter through to now. This should indicate a generally lower ice volume, and I suspect it does. This echoes the findings of thin, fragmented ice from the observations aboard ship not all that long ago. There was also a finding this spring that the first year ice was some 40 centimeters thinner than previously.

    Let’s add in that most melt happens from the bottom up and the reinforced findings that there is greater infiltration of warmer Atlantic waters than previously known. Add to this the increased runoff from land which is, itself, reinforced by the increasing sizes and extent of thermokarst lakes, which is all affected by… the finding that rapid ice loss is detectable 900 miles inland. Also, i know snow levels were high in the mid-latitudes, but were they also in the areas contiguous to the Arctic Ocean? if so, more snow = more runoff = warmer ocean.

    Add to all this the loss of multi-year ice which is, so far as I can tell, resulting in less static/fast ice which should make the overall ice more mobile and subject to melt as it breaks up, exposing more ice edge, and is more vulnerable to being flushed out of the basin.

    I have also noted, and am seeking info with this point, that much of the ice appearsto be relatively solid, but once a section begins to break up, it looks a lot like cottage cheese. That is, what seems to be relatively solid ice is maybe nothing more than floes glued together with thin ice. This appears to be the case in all areas that begin to break up thus far this year. What I don’t know is, is this normal? I didn’t previously know of the Arctic Terra site, so have no means for comparison:

    As you can see here, each area that begins to melt out ends up looking like the4 areas that already have. http://www.arctic.io/observations/8/2011-07-19/8-N75.876203-W145.631479

    If this is a general condition in the Arctic Ocean, we are, scientifically speaking, in deep doo-doo and should not be surprised at the melting we are seeing given all the other factors listed.

    Another factor might be the length of the melt season as mentioned above. It does seem the minima is trending toward a later time in September. Will we have 49 more days of melt or closer to 56, or even 60-ish?

    Finally, let’s look at those patterns of bifurcation. A recent study reinforced findings from two years ago that tipping points do have patterns that are recognizable.

    1. Wobbles
    2. Increased amplitude of signal
    3. Slowing

    I refer back to the graph I discussed earlier http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seasonal.extent.1900-2010.png and the increasing slopes over various time periods. One can also eyeball this pattern of a stable period, then some increasingly “chaotic” amplitudes, then a tightening, then a new regime.

    I ask you to observe the entire graph as one long approach to a bifurcation. The period 1900 – 1952 = steady state; 1953 – 1998 = increasing amplitude; 1999 – 2006 = slowing and 2007 – present = all hell breaking loose. in some of the lines you can see this pattern on shorter time scales. This is probably a reach, but this has been bothering me for a couple years.

    I realize I am not offering up numbers, but that is what the rest of you do. I am thankful that I can only look at observations, my own and others’, then try to decipher numbers. I don’t run the risk of the modeling/stats impacting my analysis of observable phenomena rather than informing it. (Not that you all do.) I can’t do a model or stat analysis, but my expectations have been pretty good over the years.

    At this time, I think the weather is too great a variable to be certain we will see a new minimum extent or area, but offer these scenarios. Given the current state of the ice, let me state the obvious:

    A. If weather is strongly supportive of ice loss, a 100% chance of new minimum in volume, and 95% chance of new minimum area and 90% chance of new minimum extent.

    B. If weather is relatively neutral in impact, drop each by ten percent.

    C. If weather is supportive of ice retention, perhaps a 60% chance of new minimum in volume, and 50% chance of new minimum area and 40% chance of new minimum extent.

    D. If weather is strongly supportive of ice retention, perhaps a 45% chance of new minimum in volume, and 35% chance of new minimum area and 25% chance of new minimum extent.

    I think the ice, overall, is less healthy than most think it is. I think our instruments are not recognizing differences at a high enough resolution causing us to still overestimate the health of the ice. In other words, as stated earlier, there may be lots of thin ice gluing together older ice. Cottage cheese.

    reCAPTCHA: Gorfanus, Youltai – sounds like Genghis mated with a Roman.

  7. 57
    ccpo says:

    @S. Molnar — 20 Jul 2011 @ 5:40 PM
    To be fair, while the oil companies are certainly evil propagandists, they only supply the stuff; we use it.

    Not quite accurate: they bought up and tore out mass transit, successfully lobbied for roads over rail, successfully avoided higher fuel standards decades after they could have made major improvements (non-US makers have for decades) and have successfully been subsidized all along. Among other things.

    Advertising does have an affect.

    @49 Nick Barnes

    You are using a far too limited set of data. Where and when the ice melts each season is a very noisy data set. I know of only one positive bit of data to suggest optimism: the new ice mass data suggesting greater thickness than I would have guessed. (I addressed that above.) All else suggests a new minimum mass, at least. See my post above.

  8. 58
    Adam R. says:

    It won’t matter at all if this year’s ice extent is a little above or a little below the minimum of 2007 (there’s a lot of noise), except in the realm of public opinion. I believe that is why so many sane people are rooting for a new minimum – they hope it will spur some real action. I am not so sanguine about the hoped-for effect.

    Indeed. If 5-figure death statistics in a European heat wave don’t move the public’s meter, a little missing sea ice will hardly make it quiver. The deniosphere will regurgitate its standard “Satellite records only go back to 1979!!!” response, and the beat will go on.

    Would the sudden slide of the Greenland ice sheet into the sea do it? I’d give that a “maybe”. Would such an event abash A. Watts? Not in the least.

  9. 59
    ccpo says:

    One further observation, based on recent data and trends. Looking at this chart http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.arctic.png we see the current anomaly divergence/anomaly is @1.5 M km. measuring from this chart for the same time the past two years, the difference was closer to @1.1M km. Scary is that the divergence only increases into September. If the ratios hold, we could be looking at a difference of 2M km +/- 200k km.

    We’d possibly see 2.8M km.

  10. 60
    S. Molnar says:

    Re #57 (ccpo): Good point. As a former resident of Los Angeles, where an oil company destroyed the excellent trolley system (I believe it was by buying politicians, not the transit system itself – apparently that was cheaper), I should have been more restrained in my half-hearted defense of the perpetrators.

  11. 61

    #51, Yes ignorant of me, Canadian Arctic shipping companies deliver goods to dozens of Arctic communities every summer fall seasons ( I suppose in millions of tons) , in abnormally shifting schedules, with earlier and later in the year deliveries, they usually do not need icebreaker escorts. But the icebreakers are always strategically located throughout the duration of the shipping season.

  12. 62
    Thomas says:

    @Kevin, @Lennart.
    Extrapolating an exponential forward in time is very uncertain. For any physical system with a linear instability, the amplitude is linear only until nonlinear effects start to become important. Lennart’s comment is an example of one possible limiting factor.

  13. 63

    “Will we have 49 more days of melt or closer to 56, or even 60-ish?”

    The switch from mostly (or all) light to mostly (or all) light is surprisingly quick. I think that may be a fairly strong brake on any tendency for the melt season to stretch much later.

  14. 64
    ccpo says:

    @63 Kevin

    Except that 2/3 of melt is apparently from the bottom up, i.e., water temps. I don’t know the physics involved, but it seems to me the key factor for air temps is cold enough to freeze with limited response for colder temps beyond freezing point. Water temps have no upward bound, however, and so will overwhelm the effects of air temps over time allowing longer and longer melt seasons over time, no?

    Am I far off with this line of thinking?

  15. 65
    dhogaza says:

    ccpo:

    @Tamino: You science and stats dudes do nice work, but… the methods you use do not account for an speeding up of the process, do they?

    Actually, if you could be bothered to visit Tamino’s article I linked to, and his own link to an update (today), you’d see that yes, the quadratic fit does seem to show an acceleration of ice extent minimums.

  16. 66
    Septic Matthew says:

    56, ccpo: @Tamino: You science and stats dudes do nice work, but… the methods you use do not account for an speeding up of the process, do they?

    It’s in the curvature. Follow the links to his work.

  17. 67
    jyyh says:

    “I think that may be a fairly strong brake on any tendency for the melt season to stretch much later” though the thick clouds + warmish currents flowing in the area may/will delay the onset of the refreeze by some days/weeks/(dare I say months).

  18. 68
    Nick Barnes says:

    ccpo: Tamino’s model is explicitly quadratic.

    Yes, my data is noisy.

  19. 69
    Artful Dodger says:

    Nick Barnes #50:

    Your comments indicate a lack of understanding of how NSIDC calculates Sea Ice Extent (SIE). Any gridded cell with over 15% Sea Ice Concentration is counted as “Ice Covered”.

    Here is a chart showing NSIDC average SIE for September 2010:

    ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/Sep/N_201009_extn.png

    100% of the cells in your 2010 MODIS image above counted as “Ice Covered” in the 2010 Sea Ice Extent.

    In your Comment #18, you refer to SIE in 2008. That year, September Extent was also completely covered in the Central Arctic Basin, so no help there for your argument.

    Let’s cut to the chase – Here is the September 2007 Average SIE:

    ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/Sep/N_200709_extn.png

    As anyone can clearly see, loss of SIE in 2007 occurred on the edges of the pack ice, and none at all in the center of the pack, or in the Area covered by your MODIS images.

    Further, you discount the PIOMAS volume data based on how you think melt in the Central Basin should have proceeded. Yet you seem to ignore the actual predictions for Ice Thickness for Summer 2011, from the PIOMAS model itself:

    http://psc.apl.washington.edu/zhang/IDAO/seasonal_outlook.html

    Finally you opine for CryoSat2 data, while completely neglecting NASA’s IceSat Sea Ice volume data. IceSat showed significant thinning from 2003 – 2009. Not surprisingly, the PIOMAS model was validated using IceSat, among other data sources.

    In short, you have selectively chosen Data, then seriously misread and misinterpreted that Data. Since your Methods are suspect, your Conclusions are unreliable.

  20. 70
    Pete best says:

    Arctic summer sea ice projections are for it not to be ice free until 2080 or so. Recent revised estimates say 2030/40. Is this weather or climate?

  21. 71
    Nick Barnes says:

    Artful Dodger: I am well aware of how extent is calculated; I have been patiently explaining it to others here and elsewhere for many years.

    The point I am failing to convey is that the character of the ice, broadly across the arctic, is different this year, in a way which is not conveyed by the measures you espouse. Those two MODIS shots show the difference very clearly, but it can be seen in many other places. Specifically, in 2010 (and in 2006, 7, 8, and 9), the ice was far more broken up, into separate floes clearly distinguishable on MODIS even at the 1km resolution. Separate floes move separately, are prone to breaking up and edge-melting. Separate floes expose the ocean to the air and to wind action, causing increased motion and mixing which in turn accelerate melt. Separate floes are more mobile, and are exported more easily.

    Yes, IceSat was good. The PIOMAS data which I specifically question post-dates IceSat.

    Of course I have “selectively chosen Data”. I have a point to make: that the ice is less broken-up than in previous years. I have selectively chosen data which shows that. Choosing data is the only way to extract information from it. I have not “seriously misread and misinterpreted that Data”, or at least you have not shown that I have done so.

    Certainly my “Conclusions are unreliable”. However, I have at least reached conclusions: I have made my forecast for this September’s minimum. What is yours? State it here, and then let us revisit the question in September, and we will see what we shall see.

    Finally, please be less obnoxious. We are on the same side; I am simply opining that 2011 is going to turn out more like 2008 than like 2007, and giving my reasons for that opinion. If I were going to nitpick as you are nitpicking, I would start by pointing out that I don’t anywhere mention NSIDC (so “how NSIDC calculates Sea Ice Extent” is irrelevant), and that “you opine for CryoSat2 data” is ungrammatical and meaningless. Also, capitalizing Random words makes you Look Silly. So let’s not nitpick, eh?

  22. 72
    Neven says:

    Northern Sea Route almost open

    I agree with Nick Barnes that the central Arctic looks markedly different from last year, but of course this year we have mainly seen compaction due to a pretty strong Beaufort Gyre, which was totally absent last year around this time.

    We’ve got some lows stirring things up at the moment. Maybe next week we’ll start seeing holes in the central ice pack.

  23. 73

    #64, 67–

    Well, in the long term, yes, warmer water will overwhelm cold air. Presumably that’s why that one study (the citation for which I’ve lost, darn it) found a summer-free Arctic to be unstable. In their runs, a summer ice-free Arctic led to a perenially ice-free Arctic.

    However, in the present regime the water isn’t all *that* warm yet, and the radiative forcing is pretty strong. jyyh is right about the clouds; they have a very strong effect, according to this study of the end of the 2008 melt season:

    http://epic.awi.de/Publications/Sed2010a.pdf

    (h/t to the Artful Dodger, who first posted this link to Neven’s Sea Ice Blog, IIRC)

    “Freeze-up progression was enhanced by a combination of increasing solar zenith angles and surface albedo, while inhibited by a large, positive surface cloud forcing until a new air-mass with considerably less cloudiness advected over the experiment area.”

    But that said, it seems unlikely that we’re going to see “months” of unrelieved cloud in the Arctic any time soon.

  24. 74
    Neven says:

    @ Nick Barnes #50

    I had a look at that part of the Arctic around this date in 2007.As you can see, the ice pack was pretty compact too back then. Last year was pretty spectacular in that sense, but if you zoom in on that part of the central ice pack North of the Canadian Archipelago for this year, you’ll see there is a lot of latent hole-potential. All it needs is some diverging winds, and it’ll look like 2010 in no time.

    It is something to keep an eye on, but IMO not necessarily an impediment to a new record low.

  25. 75

    2011/07/20 Realclimate.org
    @lawrence coleman

    Yes, in September we can expect a situation like in 2007. The chances are fifty-fifty. You can follow our latest prediction on http://icdc.zmaw.de/cryosphere.html?&L=1

    Regarding the longer time scale it is illustrative to see the recent decrease in the context of the variability of the September sea ice extent over the last Millennium as simulated by a comprehensive Earth system model:

    http://www.wissenslogs.de/wblogs/gallery/16/millennium_eis.jpg

    http://www.wissenslogs.de/wblogs/blog/klimalounge/mechanismen/2011-02-11/kipp-punkte-in-der-arktis” (reference)

    However, we have to be very careful with the interpretation of the model results since the simulated decrease happens 30 years

  26. 76
    Mark Serreze says:

    The strong anticyclone over the Beaufort Sea that had been dominating
    the weather over the Arctic Ocean has definitely broken down, take a look at the analysis charts from the Canadian Meteorological Center http://www.weatheroffice.gc.ca/analysis/index_e.html. In response, the ice loss
    rate seems to be slowing down. While this change towards a more cyclonic pattern in mid summer is quite typical, recent years have seen greater dominance of the
    high-pressure pattern that promotes rapid summer ice loss. We’ll just have to wait and see what happens, weather-wise, over the remainder of the summer. On the other hand, old relationships between weather patterns and ice conditions don’t seem to be holding up that well anymore. Case in point, last winter we had a strongly negative Arctic Oscillation pattern which by conventional wisdom should have favored retention of ice the following summer. Instead we ended up third lowest on record.

  27. 77
    jimvj says:

    One could expect the curves of successive years shifting en masse – with noise added of course – downwards. But instead there seems to be a bunching in May-June and in Nov-Dec. Is this an artifact?

  28. 78
    ccpo says:

    @dhogaza, Septic, Nick:

    Thanks for the replies, but “quadratic fit” doesn’t mean anything to me. I’ve been quite clear on not having math skills.

    If you mean to say that a quadratic fit somehow mathematically creates an accelerating function, OK.

    Oh, images indicate the Northeast passage is open as of 7/21.

    http://www.arctic.io/observations/8/2011-07-21/8-N71.52674-E152.298268

    http://www.arctic.io/observations/8/2011-07-21/8-N72.280536-E145.302858

    You heard it here first!

    ;)

  29. 79
    Nick Barnes says:

    ccpo@78:

    If you mean to say that a quadratic fit somehow mathematically creates an accelerating function, OK.

    Yes, exactly, it does. A quadratic function has constant ‘acceleration’ (second derivative).

  30. 80

    #77–

    Well, in my humble (but probably insufficiently so, or I’d keep my mouth shut) opinion, it’s not likely an artifact.

    Rates of change in various Arctic parameters are not uniform across the seasons–temperature change, for instance, is greatest in winter, while I believe the decline in ice extent is greatest for summer. So it doesn’t seem a stretch to think that variability can vary, too–which would show up as the ‘bunching’ in the graphs that you remark upon.

    Additionally, there may be negative feedbacks that are especially effective during the transitional seasons. For instance, open expanses of water in the high Arctic in October are apt to freeze rapidly, so the more open water, the more opportunity for rapid gains in sea ice area/extent. By this logic, especially low minima may tend to be followed by especially rapid ice growth–though of course, that ice will be of the most fragile sort.

    The same logic could apply in spring to the case where there is widespread thin ice–it represents an opportunity for rapid declines.

    Come to think of it, this last is rather reminiscent of what we’ve actually been seeing over the last couple of seasons, isn’t it? Rapid gains (like the ‘double hump’ in extent accompanying the very late maximum of ’10) and rapid losses (like the record melt rates we’ve seen the last couple of months)?

  31. 81
    SecularAnimist says:

    Adam R. wrote: “If 5-figure death statistics in a European heat wave don’t move the public’s meter …”

    The European heat wave arguably did have an important impact on public opinion about global warming — in Europe.

    If the USA experiences 5-figure death statistics from a heat wave, perhaps it will wake some people up.

    On the other hand, more than 30,000 people die every year in car accidents in the USA, and this is accepted as a cost of “enjoying” our auto-centric “lifestyle”, so who knows.

  32. 82

    Sorry — that graph is not at all impressive. I would certainly not use it to argue climate change with anybody.

    [Response: Not sure what you are referring to, but if you want cleaner graphs showing the trends, try NSIDC or Cryosphere Today. - gavin]

  33. 83
    ccpo says:

    @kevin: indeed, there is typically a pulse of heat from the oceans and land as freezing takes place in the fall. As you noted, the later this happens, the later energy is being added to the atmosphere from the ocean and land… thus pushing freeze back even more, just as we saw with areas of Canada not freezing up till December? No?

  34. 84
    Hank Roberts says:

    > low minima may tend to be followed by especially rapid ice growth ….
    > widespread thin ice–it represents an opportunity for rapid declines.

    Eli remarked on this at his blog — seeing the annual cycle emerge in recent years.

  35. 85
    Pete Dunkelberg says:

    Here is a graph of arctic sea ice extent today compared to (what it used to be plus or minus two standard deviations). We are well outside of 2 SD range.

  36. 86
    350limit says:

    #35 Check out the atmosphereic methane concentration reported by NOAA each year in September. If number 4 in your scenario happens, it will surely show up in this time series.

    It rose steadily until the mid 90s but was flat 1995-2005. It appears to have begun to increase slightly again in the last two years. See Figure 2 at http://www.esrl.noaa.gov/gmd/aggi/

    You can also get underlying data methane concentration at specific sites such as Barrow AL.

  37. 87
    dhogaza says:

    john burgeson:

    Sorry — that graph is not at all impressive. I would certainly not use it to argue climate change with anybody.

    Well, it only covers a small number of years.

    This one is more impressive if you want to argue climate change.

    The grey band is +/- 2 std deviations, as you can see we’re between 4 and 5 standard deviations from the 1979-2000 norm.

    I’m sure you know what that implies …

  38. 88
    Titus says:

    jimvj @77 asks a question that has puzzled me.

    Why do the ice extent anomalies lessen as the ice forms and then again as it melts? If the measurements were taken at these points it would show very little variation and a much better projection year on year as other factors like wind and currents change.

    I’d be interested to hear resonses.
    Thank you

  39. 89
    Peter Ellis says:

    @77/@88 Look at the shape of the Arctic Ocean. You have a wide central expanse, but at lower latitudes it’s mostly land – the only open areas of water are the Bering Sea par the strait and the Greenland Sea past Fram strait. As ice spreads outwards from the Pole during freeze-up (and retreats towards it during melt), you hit a point where the central basin is full, and further north/south expansion or contraction of the frozen zone doesn’t actually change the extent much at all. This is what leads to the “bunching” of the melt trajectories in May / November.

  40. 90

    All eyes on Laptev Sea. which traditionally had a barrier of ice preventing a mass exodus in Fram strait.
    If this vanishes, as I wrote before, September 2007 will look like a lot of ice. Already Fram strait is overwhelmed with pack ice:

    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.5.html

    above normal anomaly as if its winter.

  41. 91

    #76 , As Mark wrote, a break is in place for ice flows, the low forecasted over the Laptev area should give a short reprieve, whether long enough to slow down current ice momentum remains to be seen and also a possible secondary revealing look over Northern Greenland…

  42. 92
    Rob Honeycutt says:

    Lou Grinzo made a comment very early on in this thread regarding this chart at Neven’s site. Lou said that he thought the curves would flatten out as we neared zero due to there being more multi year ice.

    That made me think, what about the actual quality of the ice as it melts year to year? I remember watching one of Dr Barber’s lectures online and he was talking about how the quality of the ice was very poor as they sailed past where they thought they should be encountering solid ice. So, my question is, as we move closer to summer ice free conditions is the quality of the ice going to play a role in how quickly it disappears?

    The implication being, potentially is the trend going to continue that quadratic curve where we have more of a crash landing at zero rather than a soft landing like Lou suggests might happen?

  43. 93
    Scruff says:

    Question: I saw this mentioned here in comments maybe a year ago but I don’t remember the answer. As the artic ice and antartic ice slowly go away (through melting and evaporation) would that not at first temporarily cool the planet, kind of like the way that a swamp cooler works, by putting cool moist air into the atmosphere and into the oceans? But then when the temps begin to equalize and the balancing cool of the pole ice is gone would that not also serve to drive and keep up temperatures?

    [Response: Yes, but it is a very small fraction of the extra heat coming into the system - the vast majority of which is going to heat the oceans. -gavin]

  44. 94
    Neven says:

    I have started an animation that should capture the coming increase in ice transport through Fram Strait.

  45. 95
    ccpo says:

    I’ve updated my Northwest and Northeast passages post. I had called a 50/50 chance of them being open by 7/19 and was close to being half right – by my definition of “open.”

    http://aperfectstormcometh.blogspot.com/2011/07/current-state-of-arctic-sea-ice-laymans_21.html

    Also updated tracking of ice through the Fram Straight. I’m tracking specific bits of ice to get a sense of how quickly ice moves through. Surprisingly, some ice has moved northward! Check out #18.

    http://aperfectstormcometh.blogspot.com/2011/07/tracking-arctic-sea-ice-loss-via-fram.html

    FYI, per Neven’s animation, there’s the previous 42 days of animation year-round at Cryosphere Today, but it’s the whole Arctic:

    Black and white: http://arctic.atmos.uiuc.edu/CT/animate.arctic.bandw.0.html

    High color: http://arctic.atmos.uiuc.edu/CT/animate.arctic.color.0.html

    @Neven: You previously mentioned an ice bridge related to the Laptev and ice transport via the Fram. I cannot track this down. Can you elucidate?

  46. 96

    ccpo , ya, for all intentional purposes you are right, when the ice coverage is 40% , that gives 60% open…

    Neven, Key to watch is also Fram Strait, which has enormous winds, at times moving things in any direction fast.

  47. 97

    Seeing this graph makes me more skeptical than ever. Still “on your side” but confidence level has dropped over the past year.

    [Response: Still not following you... What graph is troubling you? The data is what the data is. - gavin]

  48. 98
    Jathanon says:

    re: #97 john burgeson says: 22 Jul 2011 at 11:13 AM
    There is some info here going back to 1953, which gives a good perspective.
    http://nsidc.org/sotc/sea_ice.html

  49. 99
    Geoff Beacon says:

    The dissociation of sub-sea methane hydrates in the Arctic is not one of my biggest worries. I know it may kick-in if releases are great enough to overwhelm the bacteria that consume the methane before it reaches the surface (See. Elliott et al. [2011],Marine methane cycle simulations for the period of early global warming http://esdtools.lbl.gov/info/hydrate-publications/climate/Elliott_JGRB_2011.pdf)

    But there is a report on http://www.foxnews.com “Mass Extinction Caused by Deadly ‘Earth Burp’” reporting research by Micha Ruhl and others (http://www.foxnews.com/scitech/2011/07/21/mass-extinction-caused-by-earths-burp/).

    This is interesting for two reasons. The first is that it could be scary.

    “A small release of carbon dioxide from volcanism initiated global warming of the atmosphere, increasing temperatures in the oceans,” Ruhl told FoxNews.com. “Methane is stored in the sea floor — it’s a molecule which is caught in some kind of ice structure. As soon as the temperatures got above a certain threshold, the ice melted and that methane was released.” (earlier they mention “over 12,000 gigatons of methane”)

    The second is the tone of the report:

    Ruhl noted that events far back in history when the planet was dramatically different are hardly comparable to the modern world.

    “What we don’t know is what the thresholds are today,” he explained, saying simply that the findings dictate further study, not panic.

    I’m past panicking but should I try to be scared?

    Is it too tenuous to present to policy makers?

  50. 100
    dhogaza says:

    John Burgeson:

    Seeing this graph makes me more skeptical than ever. Still “on your side” but confidence level has dropped over the past year.

    Hmmm, on that graph the minimum sea ice extent for the years 2007-2010 are each lower than any of the years 2002-2006. And currently 2011 is ahead of 2007 (reached 7M km^2 earlier than any other year).

    How does this make you “more skeptical”?

    So arctic sea ice extent somewhere between 4 and 5 std deviations from the 1979-2000 mean (as shown on the NSIDC graph Gavin and I linked) makes you more skeptical?

    What’s it going to take? 10 std devs?

    Does this graph make you more skeptical, too?

    What is there here to increase your skepiticism? Please explain your rationale.


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