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Arctic sea ice watch

Filed under: — group @ 10 August 2007

A few people have already remarked on some pretty surprising numbers in Arctic sea ice extent this year (the New York Times has also noticed). The minimum extent is usually in early to mid September, but this year, conditions by Aug 9 had already beaten all previous record minima. Given that there is at least a few more weeks of melting to go, it looks like the record set in 2005 will be unequivocally surpassed. It could be interesting to follow especially in light of model predictions discussed previously.

There are a number of places to go to get Arctic sea ice information. Cryosphere Today has good anomaly plots. The Naval Sea ice center has a few different algorithms (different ways of processing the data) that give some sense of the observational uncertainty, and the National Snow and Ice Data Center give monthly updates. All of them show pretty much the same thing.

Just to give a sense of how dramatic the changes have been over the last 28 years, the figures below show the minimum ice extent in September 1979, and the situation today (Aug 9, 2007).

Sep 05 1979Aug 09 2007

The reduction is around 1.2 million square km of ice, a little bit larger than the size of California and Texas combined.

Update: As noted by Andy Revkin below, some of the discussion is about ice extent and some is about ice area. The Cryosphere Today numbers are for area. The difference is whether you count ‘leads’ (the small amounts of water between ice floes) as being ice or water – for the area calculation they are not included with the ice, for the extent calculation they are.

Update: From the comments: NSIDC will now be tracking this on a weekly basis.

504 Responses to “Arctic sea ice watch”

  1. 451
    SteveSadlov says:

    RE: #426 – Here Bloom, let me help you out. It’s called science. We posit a thesis, then seek to disprove or prove it:

    “Thesis: A combination of AGW, ocean / climate oscillatory effects (e.g. AO, PDO, etc), dark particulate deposits, and Russian river dams, in no particular order. The $64,000 question is, what are the relative contributions?”

    This one’s interesting, because, it has room for everyone from Hansen to the CEO of Exxon. This is the sort of thesis which unifies effort, removes politics, and focusses on the science. Maybe the contribution of AGW is 99%, maybe it’s not.

  2. 452
    horrified observer says:

    So far one source of information regarding Greenland melt this flipped summer; Dr. Corell, Heinz Centre, Washington, is cited in the newscoverage of the ecumenic meeting see above posts.
    Whats going on there? Any RC reader with inights on current ‘affairs’ in Greenland – velocites, icequakes, etc. Any open webresources we can follow?

  3. 453
    Timothy says:

    #443 – Alastair, don’t be silly, that’s absurd. Which Hadley model would you be talking about? (And I’ll see if I can check)

  4. 454
    Hank Roberts says:

    Ok, so the Northeast Passage is at the pair of islands straight across the Pole from Hudson’s Bay; to figure out which photo from which satellite pass will image any Arctic location on a given day,
    go here:
    click “Arctic” in the left hand column
    Pick by day and time, then back to the index page for photographs.

    A bit tedious. There’s probably a simpler way to look at a given location over time, that I haven’t found.

  5. 455
    Eli Rabett says:

    As I understand it open to navigation would require that the whole channel be ice free, which open would include regions in which the ice had broken up substantially.

  6. 456
  7. 457
    Larry says:


    Navigation depends on Ice Concentration, type and thickness of ice, floe size, presence of ice bergs, growlers and bergy bits, Wind directions that can close off a channel or create ice presure, etc.

    The following URL shows a trivial example of what is involved. In reality, things get much more complicated.

    ice navigation

  8. 458
    Hank Roberts says:

    Wow. If this goes on, the Russians can put one little icebreaker on station there next summer, and the door’s wide open all the way across.

    I wonder what the toll charge will be for getting through?

  9. 459
    Steve Bloom says:

    Re #s 448/51: Sadlov, if you check the site of your friend “Wrong Way” you’ll find a nice picture showing the NE passage clear for small boats (although as Eli points out not yet for large non-ice-hardened ones). It’s too risky for “Wrong Way” to chance since the ice will close back in with a wind shift, but clear nonetheless. You lose.

    Oh yes: Had you forgotten that there aren’t any dams or major water diversions on those Russian rivers? Also, recall that the “dark particulate matter” is a component of AGW, which also influences the AMO, AO etc. So yeah, it’s mostly AGW.

    Y’know, some people have memories. Regarding CT I seem to recall that you developed your liking for them two years ago when the extent matric (NSIDC) showed a record and CT’s area metric didn’t. Fickle, fickle.

    Once again you neither know nor care about the science or the facts. But at least you’re consistent.

  10. 460
    Phil. Felton says:

    “SteveSadlov Says:
    10 September 2007 at 14:59
    Slight change of subject …. Cryosphere Today. I used to be a big fan, but lost my fervor when “adjustments” (in both their depicted record as well as ongoing algorithm) were made earlier this year. Here is but one example. The ice edge has never completely moved north of Svalbard this year. The northeastern portion of that island group has remained ice bound. And yet, CT depicts a several Km swathe of open water in a place that is not open to navigation at present.”

    As does the NSIDC:

  11. 461
    SteveSadlov says:

    Sorry, the post numbering got messed up, my previous post was in response to: # Eli Rabett Says: 10 September 2007 at 5:41 PM

  12. 462
    Timothy Chase says:

    Responding to Alastair regarding…

    Some aspects of the energy balance closure problem
    T. Foken, et al.
    Atmos. Chem. Phys. Discuss., 6, 3381–3402, 2006

    Alastair McDonald (#449) wrote:

    The Energy Balance Closure Problem is that the radiation at the Earth’s surface does not balance. They write in their introduction:

    “During the late 1980s it became obvious that the energy balance at the earth’s surface could not be closed with experimental data….”

    If the problem is regarding the problem that “the radiation at the Earth’s surface does not balance,” why is it it called the “energy balance closure problem”?

    I also notice that the equation that you quote refers to sensible heat flux, latent heat flux and soil heat flux. So it would seem that the problem wasn’t strictly related to radiation but energy.

    Alastair McDonald (#449) continues quoting the paper:

    “In most of the land surface experiments (Bolle et al., 1993; Kanemasu et al., 1992; Tsvang et al., 1991), and also in the carbon dioxide flux networks (Aubinet et al., 2000; Wilson et al., 2002), a closure of the energy balance of approximately 80% was found.”

    Eighty percent? Seems pretty serious.

    Alastair McDonald (#449) wrote:

    In that paper they try to explain that the problem is with the turbulent heat flux but I am sure it is the net radiation (Rn) that is wrong.

    Turbulent heat flux? I thought this had to do with radiation.

    Lets look at what they have to say on the next page, Alastair.

    The most common point of discussion were measurement errors, especially those of the eddy-covariance technique, which cause a systematic underestimation of the 5 turbulent fluxes. Improvements in the sensors, in the correction methods and the application of a more stringent determination of the data quality (Foken et al., 2004) have made this method much more reliable in the past ten years (Moncrieff, 2004).

    pg. 3383


    Things have improved. Sounds good.

    But how well have they improved?

    For an exact determination of the soil heat flux, including storage effects, the energy balance was shown to be closed at night for non-turbulent conditions (Mauder et al., 2006). The storage in the canopy is often negligible.

    pg. 3383

    Closure in the absence of turbulence. Looks like things have improved a great deal then. And it doesn’t look like a problem having to do with radiation afterall – since things balance in the absence of turbulence.

    Alastair McDonald (#449) wrote:

    Even if I am wrong it is not correct to claim that the downwelling radiation has been measured and balanced for decades. It is what everyone assumes but it is untrue.

    Downwelling radiation is measured – and I have given you sources for the spectra before.


    Downwelling radiation isn’t balanced in isolation. Downwelling radiation is balanced against something else. Upwelling radiation perhaps – if it is at the top of the atmosphere. Or upwelling radiation and other heat fluxes (e.g., turbulence) if at the surface.

    Anyway, thank you for pointing out the article: it shows that climatologists aren’t simply engaged in armchair theorizing or making stuff up as they go along.

  13. 463
    Joseph O'Sullivan says:

    #447 dhogaza

    “USF&W hasn’t made it’s determination, it must (not had to) do so in response to the suit.” True, the final decision has not been made on the status of the polar bear. The final decision is due this January which gives plenty of time to delay until 2009.
    William has an interesting critique of the assessment on stoat:

    Another Endangered Species Act suit has progressed further. The NMFS has started to create a recovery plan for elkhorn and staghorn corals. NMFS had admitted the corals are threatened in part because of higher ocean temperatures. NMFS also admits that that this is due in part to AGW, but accurately states that there is no current regulatory framework to address AGW.

  14. 464

    #446-455, The only thing stopping a competent Cargo ship Captain from using the Northwest Passage is purely psychological. The gates of this passage was ice as tall as masts and many who dare pass it with ships froze to death or got so spooked, after surviving a near death experience told stories which still scare the willies out of any mariner to this day. As NSDIC chap said its been open, the only barrier is charting a deep channel course without remembering the dead frozen. Present day scattered ice floes here and there are so rare, didn’t dissuade our resupply ship (relatively small Cargo ship with two cranes) from arriving this last weekend (gone today).

    Resolute Bay should have been called Winter Harbour (Melville Island) after a 1947 Armada of ships from Boston was forced to stop next to Cornwallis, ice breakers could not go further West due to a huge barrier of multi year ice spanning Barrow Strait entirely, this yearly fall barrier is history along with the frozen sailors, in its wake , just water lots of sea water.

  15. 465
    Phil. Felton says:

    Another interesting graphic on today’s NSIDC update, their graph of area shows a further drop of 180,000 sq km last week slowing though. The really interesting one is fig 3 which shows perennial sea ice, i.e. the area which has been frozen everyday since the satellite monitoring started in 1979, it shows that a substantial portion of that has gone this summer (~400,000 sq km).

  16. 466
    Nigel Williams says:

    Wayne Davidson – man on the spot! Could you give us a google place marker for you so we know where you are looking from?

  17. 467
    Anthony Shafer says:

    Has anyone noticed that North Pole Netcam XL #4 is the only camera still in operation? It had some crazy pictures today-



    does anyone know the long/lat coords of these cameras?

  18. 468
  19. 469
    Timothy says:

    #443 Alastair, I can’t find out what albedo any of the Hadley models use for open ocean, but I did find some documentaion of their latest model, which includes the following (as well as a detailed discussion of their sea ice albedo calculations):

    [sea ice] “is also important in climate change because of the ice-albedo feedback: decreasing ice cover results in more absorption of solar radiation at the surface because open water has a much lower albedo than ice.”

    That looks like an understanding of the feedback to me.

    #445 – Thanks. Yes,Greenland is likely to effect the circulation which could be (locally) more important than energy balance changes.

  20. 470

    Alastair writes:

    [[Even if I am wrong it is not correct to claim that the downwelling radiation has been measured and balanced for decades. It is what everyone assumes but it is untrue.]]

    You’re moving the goalposts. Your contention was that there was no significant back-radiation. In fact there’s about 300 watts per square meter of thermal radiation from the atmosphere. The imbalance in the surface budget is far less than that. The greenhouse effect works just like the books say it does.

  21. 471
    Jeffrey Davis says:

    I looked at the Cryosphere Today pics of the Arctic sea ice that have been complained about. “Several kilometers” would be about a pixel and could be merely an artifact of rendering photographs on a monitor. If there are other pics that show more detail, please provide a link.

  22. 472

    Re #470

    OK, I’ll move the goal posts back again then. (I am acting on a tipoff from Timothy :-)

    The radiation emitted by CO2 and to some extent H2O does not depend on temperature, only on the excitation state of those gases. This is a well known fact amongst spectroscopists, physical chemists, and quantum physicists but not by climatologists.

    Since the the bands are saturated, increasing the concentration of CO2 will not increase the back-radiation. However, it will increase the energy absorbed in the lowest layer of the atmosphere and result in it warming. Unfortunately this insignificant layer, only about 30 m high, is where we and much of the rest of the animal and vegetable kingdoms live.

  23. 473
    Nick Barnes says:

    #467: It says here that netcam 4 is on the Polarstern:
    There’s a map here showing the position of the Polarstern:
    which my eyeball suggests is about 87N, 180E.

  24. 474
    Nick Barnes says:

    #466/468: Resolute is at 74.7 N, 94.85 W.,94.85W&z=12&t=h

  25. 475
    SteveSadlov says:

    RE: #459 – That “passage” is a dead end. It does not go all the way through.

  26. 476
    SteveSadlov says:

    RE: #464 – If I understand you correctly, you are in Resolute Bay. What can you tell us about the state of the NWP between your location and the Beaufort Sea? Tell us about its state now, and during the past couple of months. Thanks.

  27. 477
    SteveSadlov says:

    RE: #467 – In the interest of facts, the current location of the so called NP web cams is substantially south of the pole. Every year, cams are placed at ~ the NP in April. Then, they drift with the ice. Typically, they will drift quite far to the south, sometimes into the low 80s latitude.

  28. 478
    Hank Roberts says:

    Anthony, “North Pole” cameras 3 and 4 aren’t at the North Pole:

    “Web Cams #3 and #4 are on the R/V Polarstern (from Alfred-Wegener-Institut) which is working its way north from Norway to solid ice, where these web cams will be deployed. Updates will be posted on this website as they become available.”

    Cameras 1 and 2 were last heard from in early August, when their mounts had tilted and, from the pictures, appeared to be melting.

    Looks like they found solid ice, since those pictures show people in orange suits standing on it; their website doesn’t yet say the location though.

  29. 479
    Nick Barnes says:

    Re #475: on the question of ice in Vilkitsky Strait, I think the words of Wrong Way Flanagan – on site and preparing to sail single-handed through it – should carry rather more weight than those of some random commenter on RC.
    “The Western end of the route is reported to be ice free”.
    The strait is clearly more open now than it was a few days ago – compare that Radarsat image with the one here:
    It is very likely more open than it was in this chart from two/three weeks ago:
    Anyone know where we can get Radarsat images like these?
    Best of luck to Flanagan.

    I find it curious that people put so much emotion and energy into debating these fine details. The big picture is clear: there has been massive loss of Arctic sea ice, especially thick multi-year ice, over the last couple of decades. A number of proximate causes for this have been identified – polar anticyclones, the AO, etc. The existence of feedback mechanisms accelerating this loss – including but not limited to the simple albedo effect – is well-known. The domain experts believe that we are at, or past, a “tipping point”, and that we’re heading rapidly to ice-free arctic summers. If the two passages are not both open now, they will be so in 2008, or 2009, or 2010.
    So: the arctic is changing. What are we going to do about it?

  30. 480
    Steve Bloom says:

    Re #475: Interesting. The accompanying text said it was open all the way (although not safe to use due to the prospect of shifting wind). Also, as noted above, the new NSIDC post finds that the ice lost another 180k km^2 in the last week; slowing certainly, but no minimum yet. But any day now, you’ll be right.

  31. 481
    Nick Barnes says:

    In fact, the later Radarsat image at the Alpha Global Expedition blog shows that the strait is far more clear than in that NatIce chart. The Radarsat shows clear water in an inshore channel around the northeastern coast of the Taymyr peninsula (marked up as the blue path on the AGX page). The NatIce chart (from 27-31 Aug) shows this coast as completely blocked (the southern end of section P).
    I should have realised this earlier, but I wasn’t lining up the charts correctly.

  32. 482

    #477, Steve Around Resolute, yep, wide open, I can’t answer for the Beaufort, but they can:

    Usually done with radarsat shots. Latest product is a bit late, newer one should be on any time soon. Not long ago, it was wide open Ice Free (IF),. A lot of people here have been using ordinary satellite pictures in order to figuire out open water etc. Some of theses pictures have a mix of clouds, fog and ice, poor contrast resolutions (some ice not seen in certain settings) making it difficult to do a correct assessment, the Radar Satellite shots are Sea faring industry standard.
    Ice also migrates as the wind blows, so a “blockage” one day is gone the next. For a non icebreaker ship Captain huge red zones are a dead end.

  33. 483
    SteveSadlov says:

    With that, I will concur with (Nick Barnes Says:11 September 2007 at 12:46 PM) regarding the need for a big picture view. For 2007, what has been the most obvious oddity has been the degree of melt back in two specific basins – the East Siberian Sea, and the Chukchi Sea. While Svalbard has incurred a poor melt back, these two basins have been completely cleared. I noticed that Polarstern has given up on reaching the pole and instead, seems to be doing some sort of study in the area of the NW Chukchi and NE East Siberian. Good for them. That is definitely where I would want to be, to look at the issue.

  34. 484
    Ark says:

    There’s a status update on the NSIDC site (
    New alltime low sea ice extent (4.24 million km2), and large areas that have no ice for the first time.

  35. 485
    John Wegner says:

    Here’s the MODIS/Terra satellite image from a few hours ago of the NorthWest Passage.

    The middle passage is closed off by the sea ice in the Beaufort Sea while I think a ship could slip through in the Southern passage if they were steaming full speed ahead (and were willing to take significant risks.)

    Last week, the inner passages of all routes were closed off by ice but it has melted this week.

  36. 486
    CobblyWorlds says:

    Nick #479,

    I totally agree: whether or not the North West Passage (or indeed the North East) is open is a complete irrelevancy to me. As far as I can see we’re heading for a seasonally ice free Arctic, an end state that we will reach faster than previously thought.

    What will be the impact on the trajectory of Northern Hemisphere warming (hence global warming)?

    What will be the impact on Northern Hemisphere(NH) precipitation patterns?

    What will be the impact on Greenland’s northern flanks and Arctic river discharge, hence sea level rise (this rapid loss of Arctic ice seems to Bolster Hansens cries of alarm)?

    What will be the impact on resource availability and costs (particularly fossil fuels)?

    What will be the impact on Northern Hemisphere trade/economy/politics?

    It really looks like we’re in a rapid (decadal+) transition to a seasonally ice-free Arctic. This is an event that draws an impenetrable veil over the future.

  37. 487
    George says:

    John Wegner, why have you made over a dozen repetitive posts to cast doubt on NSIDC data and to fight back the mainstream news item that the NW passage is open? Are you being paid to play that role?

  38. 488
    Nick Barnes says:

    CobblyWorlds #486. Yes, these are the key questions now. Also, what will be the impacts on the arctic ecosystems? As far as I know, we have no evidence of ice-free (or largely ice-free) arctic ocean summers, going back into prehistory. The organisms and systems of the arctic are highly adapted to the sea ice, from the aquatic micro-organisms mentioned in earlier comments all the way up to polar bears and whales. This sudden disappearance of the ice is undoubtedly catastrophic.
    As an amateur, I expect the most significant long-term climate impact to be accelerated melt of Greenland and of the smaller ice sheets, due to albedo-driven regional warming. There are positive feedback effects specific to melting of glaciers and ice sheets (for instance, the lubrication of ice movement by melt water under the ice). Just as for the sea ice, we don’t really know the magnitude of these effects and the domain experts seem to be becoming gravely concerned that they have been underestimated.
    But as I say, I’m only an amateur. Any Greenland experts nearby? Are there any useful sources of relevant data on the web, like CT and the NSIDC sea ice page?

  39. 489
    John L. McCormick says:

    RE # 486

    Cobbly: allow me to edit your comment:

    This is an event that draws an impenetrable veil over the future [of ethanol in Western North America}. This might be a good time to consider dumping ethanol shares, if you own them.

  40. 490
    Hank Roberts says:

    John Wegner wrote earlier that he believes the optical satellite images are more accurate than the radar imagery. Cite please? If you are the John Wegner who has published research on the Arctic, from Emory, you may be speaking from personal experience; that’d help. Of course we can’t tell who’s behind a name, as ordinary readers.)

    Wayne Davidson in this thread just above (11 September 2007 at 2:02 PM) says the shipping industry relies on the radar satellite images.

  41. 491
    Mike T says:

    CobblyWorld #486 and Nick #479,

    I also find it interesting that so much is written and debated while the big picture remains veiled. The veil may remain however because we choose to not pull it aside and see what we’ll have to do to avoid a rather short nasty future. Today, we are admitting most of the polar bears, walruses, and seals dependent on ice floes for birthing will not survive the warming already built into the system. Today we are beginning to admit quite a bit of the ice of Greenland will melt in this century (probably sooner) and much of the planet’s coasts will be flooded by the resultant rise in sea level. Millions will be displaced. However, we, as an organized planetary civilization, are very reluctant to make the next step and move away from the easy fixes of Al Gore and towards the stark reality mandated in George Monbiot’s “Heat” and Mark Lynas’ “Six Degrees”.

    Today, the average American produces about 25 tons of fossilized carbon dioxide or its equivalent in other greenhouse gases a year, the average European about half that. (IPCC 4th Assessment Report, WGIII, Summary for Policymakers) Yet Monbiot makes the clear argument that to lower CO2 additions to the atmosphere to manageable levels while being fair to everyone on the planet we will have to reduce the European amount by about 90%, the American level by 95%. And we have to make the change to this lower level in the next few years or, basically, it will be too late.

    As we see now in the Arctic, the positive warming feedbacks from the natural systems involved will overwhelm our ability to check that warming. The planet will go from the positive feedback of an albedo change through the positive feedbacks of methane release from the melting permafrost and carbon release from burning forests to the terminal stage of massive positive feedback from methane releases from melting methyl hydrates on the ocean floor. And it may do this in a geologic blink. Can anyone say the warming will stop before we reach Venus-like temperatures on Earth’s surface? Water vapor is also a greenhouse gas so we cannot depend on the oceans to stop the warming; they will also become a major positive feedback at a certain point.

    IMO, the planetary civilization has only two realistic choices that do not involve weapons of mass destruction, replace or restrict fossil fuels very soon or face runaway global warming. I’d like someone in this group to add more choices to my rather limited list. I hope this rather simple man has missed a lot.

  42. 492
    SteveSadlov says:

    RE: #487 – NSIDC’s approach relies on lots of post processing of passive microwave data. It is highly appropriate to look deeply into it. It’s all about counting pixels, removing “suspect” ice from the data, and, the ever difficult challenges of discerning between clouds, bare ice, and the snow that covers portions of the ice. It is a non trivial thing to get both the areal extent plots and to derive the graphical images shown at NSIDC, Cryosphere Today, etc. This is not to say that, in the big picture, extent has not declined since at least the late 70s. What it is to say is, in order to be maximally scientific, accuracy is important. It lends credibility to threat assessments. It eliminates hype.

  43. 493
    Alex says:

    Don’t worry about oil from the artic for now. It will take many, many years to get any from there. That fruit is very unripe.

    I do bother about weather patterns this winter, next summer melting, and what happends from there on.

  44. 494
    Ryan McCourt says:


    I’ve been following the situation in the arctic for awhile now, and very closely this year. I also discovered RC earlier this year and have been absorbing all the content. This is my first post on RC. Some of my thoughts (forgive me if I ramble):

    It seems that this story (about the severity of the sea ice loss) is getting buried by the media. And when it is referenced, they still try to paint a picture of ice-free summers as far off as 2030 -2050. Now, for those following the situation, I think almost all of us would agree that we will see an end within a couple years. The most likely range is probably 2009-2012. Even if somehow it defied all odds and lasted until 2015, that is still a long ways from 2050. So why is it that this study came out on the 7th of September, amidst the most catastrophic loss of sea ice on record?

    Articles like this seem to be designed to intentionally mislead the public. I’d call it sloppy journalism if it didn’t seem so purposely constructed. And then there was another article today (also CNN) which depicted the scene a little more realistically. It featured numbers and comments from NSDIC senior research scientist Mark Serreze. I figured the truth would finally be told… but instead he pulled the rug out from under our feet and laid this egg : ‘Most researchers had anticipated that the complete disappearance of the Arctic ice pack during summer months would happen after the year 2070, he said, but now, “losing summer sea ice cover by 2030 is not unreasonable.”’
    Back about a month ago, as sea ice dipped below the old 5.32 record, I predicted that if conditions persisted, sea ice could hit 4.25. Now that we are slightly below that figure, (and still slowly plodding along) I don’t feel good about being right. Denialists can continue to call us alarmists if they wish. At some point, people are going to wish they had heeded those bells sooner.

  45. 495
    Charlie says:

    Hi! I have been following the sea ice melt. I am a botanist, so weather and climate patterns are very important to me, but I am not an expert on climate. If the jet stream shifts north, it will either cause massive drought here in southern California, or floods as the subtropical jetstream comes north. Perhaps both, varying from year to year.

    Anyway, I have a question that maybe someone here can help me with. I don’t understand why melting Arctic ice would make the jet stream shift north. Once the ice melts, the coldest areas would be over Canada and Siberia in the winter, not the Arctic, right? Wouldn’t this actually shift the jet stream south as high pressure associated with the arctic circulation would set up over the continents rather than the Arctic? Also, wouldnt air actually flow from Canada and Siberia TO the arctic?

    Wouldn’t this cause big dips of the jet stream over Asia and North America? This wouldnt necessarily bring more rain to California though, as the winds would be coming off of the mainland. This might actually result in colder, drier conditions in California.


  46. 496
    Nick Barnes says:

    CT update: 2.92 million square kilometres.
    Also the southern hemisphere ice area is at a record high: 16.26 million square km.
    Re #491: Consider both these facts together, and add the fact that the dramatic arctic sea ice loss is a complex phenomenon not entirely attributable to AGW. If the world were heating up that quickly, the antarctic would be melting too.
    Please, stop speculating about methane hydrates. There’s more than enough noise on this channel already. It takes centuries for heat signals to propagate down to the sea floor: the clearer consequences of AGW are far more urgent, and give us plenty to worry about and work on in the meantime.

  47. 497
    Nick Barnes says:

    #494: The thinner ice in the central arctic basin, the laptev sea, the northern beaufort sea, north of Svalbard, etc, might go in the next few years, as the melt seasons start earlier, run faster, and end later because of the warmer sea temperatures (although this year has seen remarkable weather conditions which might not be often repeated; 2008/2009 might well have more ice than this year). And much of that ice might also be swept (by the gyres and the trans-polar drift) into the multi-year pack, not to be replaced. But the thick multi-year ice, packed up against Greenland and the Canadian Archipelago, might survive long after 2015. It’s a very cold part of the world, and likely to remain that way for a while because of the cold landmass. As I understand it, that’s why Serreze and colleagues are looking at 2030 or beyond.

  48. 498
    Larry says:

    Well the new cryosphere results are in for Sept 12, and we are at a new all time low for ice area. Ironically the south pole is at an all time maximum for ice area.

    Im sure the denialists will jump all over the SH numbers, however statistically the SH numbers mean very little, and is just the typical variance, you would see in a small sample.

    On the other hand, the NH numbers are extremely significant statistically.

  49. 499
    Jeffrey Davis says:

    Don’t worry about oil from the artic for now. It will take many, many years to get any from there. That fruit is very unripe.

    movie scenario. very unripe.

    15 years from now, you’re a crew member on one of the mobile rigs pumping oil in the summer and early fall from the arctic basin. You’ve got a good job. Seasonal work, but the monthly is so high you don’t have to work the rest of the year. You’ve had a hard day. It’s Miller Time! You and your bearded buddies kick back, open some brews, light some cigars, and (after some Bruce Willis wise cracks and male bonding jokes), the lit stogies light fumes and blows everyone to hellandgone. The gusher burns furiously and incandescently (think “Wages of Fear”) for months until aged, creakiest Bruce Willis(!) arrives to put out the fire. Triumph! The crew kicks back, drinks beer, smokes stogies. Meanwhile, all the ice on Greenland melts and the resulting tsunami swamps the vessel assigned to put out the well head fire.


  50. 500
    Sue says:

    Hello everyone – I too have been watching the sea ice and am confused about the new historic maximum in the antarctic ahile we have a new historic minimum in the arctic. Can someone explain why global warming would cause this? Is it that the variations are going to be increasing?