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Arctic sea ice minimum 2012…

By popular demand, a thread devoted to the continuing decline of Arctic sea ice, and a potential new record minimum this year. As before, the figures are hot-linked and will update day-by-day.

JAXA Sea ice extent:



Cryosphere Today sea ice concentration (interactive chart):



Estimated sea ice volume from UW PIOMAS (updated every month):



Other links: Tamino, the very informative and detailed Neven’s sea ice blog , and some interesting predictions from Gareth Renowden.


195 Responses to “Arctic sea ice minimum 2012…”

  1. 151
    MARodger says:

    Richard D @146
    Ice-free is usually defined as Sea Ice Extent dropping below 1 million square kilometres.
    At the start of the satellite era, the summer Extent was dropping to about 7 million. The record from 2007 is 4.16 million & yesterday’s figure was 4.19 (down from 4.29 the day before). So, although this will be the first year that makes it over half way to an ice-free level, the other half will go with a rush as year-on-year the ice is a whole lot thinner. For instance, you won’t now get very long odds on an ice-free 2013.

  2. 152
    Richard D says:

    many thanks Wili, will check it out

  3. 153

    #151 MARodger, Ice-free is sort of problematic in the near term because of daily tides which continuously ridge first year ice next to Greenland, the last standing obstacle slowing AGW appreciably. In the long term ice free Arctic ocean every year is possible as sst’s become much warmer. In the mean time, the next real attention grabber is an ice free North Pole accessible from the Thames in a few days or so of sailing, which can happen at any upcoming septembers, especially if La-Nina rages strongly in April to July, making the Arctic atmosphere more cloudless. When it comes to weather, the world is one, every region plays a role with one region or another. This year near or present El-Nino saved the NP yet to be seen blue.

  4. 154
    Lawrence Coleman says:

    We have now set two dubious records, a new low for sea ice ‘area’ and also a new record low for ‘extent’. As we are probably going to sea a ice free summer arctic within the next 5-10 year, does anyone know how soon the longer and longer periods of ice free conditions (or another 5mil sq kms of open dark ocean) will really begin to principally affect the northern hemisphere climate? A assume that to a degree the climate is already changing as a percentage of ice albedo forcing. Say that the arctic is totally ice free for about 3-4 months of the year,(very possible in the not too distant future) what changes in ther NH climate are we likely to see and how soon?. I think these are vital and pertinant questions that need answering.

  5. 155
    Lawrence Coleman says:

    Wayne Davidson partially answered my question, “more frequent penetration of cyclones from the south” smashing the arctic even more and accelerating the +ve feedback loop.

  6. 156
    ozajh says:

    NSIDC now shows 2012 as lowest extent in their records . . .

  7. 157

    #156 Ozajh yes time to reminisce enjoy found memories of great predictions, because we have endured them time and time again, got a solid memory of all time greatest moments in contrarian science achieving epic failures worthy of Greek mythology, something our descendants wont believe, they are our modern day legends when some people believed in people failing again and again in being correct:

    wattsupwiththat.com/…/arctic-sea-ice-about-to-hit-normal-what-will-t…31 Mar 2010 – 2010 is looking promising for sea ice recovery again. After all, who wouldn’t want the Arctic Sea ice to recover? WUWT is predicting a recovery …

    The Economist Provides Readers With Erroneous Information About …
    wattsupwiththat.com/…/the-economist-provides-readers-with-erroneo…16 Jun 2012 – By WUWT regular “Just The Facts” A June 16th article in the … In fact, the largest influences on Arctic Sea Ice appear to be wind and Atmospheric Oscillations, i.e.: … for declines in how much sea ice covers the Arctic Ocean, with near ….. The Arctic ice has recovered a little since 2007 which correlates with …

    Sea Ice News: Arctic sea ice “may” have turned the corner | Watts Up …
    wattsupwiththat.com/…/sea-ice-news-arctic-sea-ice-may-have-turned-…13 Sep 2011 – Alerting message from the Arctic: The extent the the Arctic sea ice has … Stay updated with all of the latest plots and maps at the WUWT Sea Ice ….. “too low” in Sept, just wait a couple months — it’ll make a dramatic recovery.

    Ignoramus web site looks better than ever now. The oscillations of the Arctic and cloud cover were not so favorable for a great 2012 melt. There was mostly lows over the Arctic ocean.

    Not to forget Joe Bastardi “Trace gas have no effect” guy

    http://www.youtube.com/watch?v=dAjE7NViElA

    http://www.youtube.com/watch?v=AgZU5uvM5Ok&feature=related

    Actually there are myriads of contrarian websites really missing this great melt:

    DenialDepot: Arctic Ice Continues it’s Recovery
    denialdepot.blogspot.com/2010/…/arctic-ice-continues-its-recovery.h…10 Jul 2010 – Arctic sea ice point blank refuses to melt. Continues to Defy alarmists. Maunder minimum ice recovery confirmed. Ice age imminent? I won’t …

    The Climate Scum: Arctic Sea Ice Recovery
    theclimatescum.blogspot.com/2011/08/arctic-sea-ice-recovery.html7 Aug 2011 – The Arctic sea ice extent is now above what it was in the corresponding period in 2007 according to NSIDC. This means 4 years of a steady …

    M.I.T.’s Lindzen:

    “For example, he presents this slide to argue that the Arctic sea ice “death spiral” is nothing to worry about”

    http://www.skepticalscience.com/news.php?p=2&t=71&&n=1319

    We can go on and on, I think this site should show more examples of completely erroneous long range sea ice forecasts because contrarians belief of AGW as a Myth. We must expose those who believe in the wrong things so that their reputations gets enhanced correctly.

  8. 158
    Perk Earl says:

    Part of what Nevin wrote in his blog before leaving on vacation: “I really don’t know what to expect next, but what I do know is that all the records on daily graphs have been broken in the past week. Regardless of how this melting season ends, we know the ice is getting thinner and thinner, and so it’s time for the whole world to look ahead at what an ice-free Arctic could imply. Not for the polar bears or the ice itself, but for modern civilization, for us, humans.”

    It probably means a greed-grab for whatever riches can be excised from the Arctic; precious jewels & metals, oil, gas, and who knows what else. Most likely a lot of militaristic posturing to secure territoriality. A lot of environmental analysis that gets ignored in favor of mo money from extraction, all the while failing to observe the most basic fact, that if we had not spewed so much GHG’s we wouldn’t be chasing our tails in a negative feedback loop that will end up with us with our tail between our legs begging for runaway GW to stop even if it means going with the most absurd geo-engineering idea! “Ah, no need to worry folks. The fix is on the way, and soon we will be back to scouring the Arctic for goodies!”

  9. 159
    Brian Dodge says:

    “Getting back to Derek’s original question, it cannot be answered, as historical extent of the floating sea ice cannot be determined by proxies.” You wish.

    Science disagrees. “These results are consistent with the northern Ellesmere Island record indicating an abrupt termination in driftwood stranding along most of the north coast (>250 km) after 5.5 ka due to the development of exceptionally thick, multi-year landfast ice (ice shelves) with possibly only short intervals of lesser ice since then (England et al., 2008). The growth of these ice shelves indicates very high ice concentrations in the adjacent Arctic Ocean since ca 5.5 ka, which apparently expanded and ice-locked Northeast Greenland coast by ca 3 ka.” And which will cease within a few decades.
    “On suborbital time scales, ice distributions varied in the Holocene, but no evidence exists for large, pan-Arctic fluctuations. Historical records indicate that Arctic sea-ice extent has been declining since the late 19th century. Although this decline was accompanied by multidecadal oscillations, the accelerated ice loss during the last several decades lead to conditions not documented in at least the last few thousand years. Taking together the magnitude, wide geographic distribution, and abruptness of this ice loss, it appears to be anomalous in comparison with climatic and hydrographic variability observed on submillennial time scales and longer-term insolation changes.”
    History of sea ice in the Arctic, Polyak et al. Quaternary Science Reviews 29 (2010) 1757–1778 http://www.cgd.ucar.edu/staff/mholland/papers/Polyak_2010_historyofseaiceArctic.pdf (This also has some discussion of IP25 biomarker to which Kevin Mckinney referred.)

    DanH and other skeptics often have problems distinguishing their beliefs, which are different from mine, and the facts, which are the same for everybody – even though no one knows all the facts. The resistance to learning unpleasant facts, a long recognized part of human nature, is why we have peer review, and multiple expert medical analyses.
    Skeptics only accept peer review if it supports their beliefs; peer review that challenges their beliefs is see as conspiracy. Their most prominent “experts” include the likes of Monckton, Watts, Morano, and “iron sun” Plimer.

  10. 160
  11. 161
    Hank Roberts says:

    Why has the PIOMAS volume been reaching and bouncing back from its annual low point a month or more before the other measures? It’s monthly, so won’t update from its end-of-July chart (seen above at top of post) for a few more days. I’m going by the past few years’ behavior.

    Estimated sea ice volume from UW PIOMAS (updated every month)

  12. 162
    Hank Roberts says:

    P.S. — responses 3, 4, and 5 to this topic are about the PIOMAS anomaly, with some pointers — I think there’s an explanation in there about the reason it shows an uptick while the other measures are still declining, but I haven’t figured out what it is well enough to describe it, nor found it explained clearly anywhere I can point to it.

    Neven says at http://neven1.typepad.com/blog/2012/08/piomas-august-2012.html “That small uptick at the end makes the graph look slightly less alarming.” — as part of a caption to his own ratio graph. Now that looks alarming.

  13. 163
    Hank Roberts says:

    Oh, d’oh. Let me try here.

    In July particularly for 2010, 2011, and 2012, more of the ice melt has been happening faster and earlier — the anomaly is greater, and the graph dives to the low point on the PIOMAS chart for 2010, 2011, and 2012. In July it’s ‘more different’ from the past history — eyeballing, around minus 9, minus 9-1/2, minus 10-1/2 ‘thousand cubic kilometers’ as of the end of July).

    Ten thousand cubic kilometers is, how much, in other units?

    By August and September, the months that always have the most ice gone and the most water exposed, the difference between the amount melted historically and the amount melted the last three years is not as much.

    And that’s important because early melt increases how much open water gets sunlight for how many days — before night falls — so how much added heat gets into the Arctic ocean.

    By September and October, water and ice both lose heat to the night sky very efficiently). Unless it’s cloudy, of course.

    Trying for 7th grade language comprehension here. Corrections anticipated.

  14. 164
    Chris Dudley says:

    Hank (#161),

    Here is the chart you want: http://psc.apl.washington.edu/wordpress/wp-content/uploads/schweiger/ice_volume/BPIOMASIceVolumeAnomalyCurrentV2_CY.png?%3C?php%20echo%20time%28%29?

    That is the ice volume. It is still falling, not bouncing back. The chart that is shown in the article is the ice volume anomaly, a daily departure from the (daily) average since 1979. One of the interesting things about the volume chart is that 2011, not 2007 holds the prior record for minimum ice volume. You might read that off the anomaly chart if the annual minima were marked but this would clutter the story told about the anomaly which is pretty steady decline at all times during the year. The winter ice volume does not recover even if the extent usually does. The summer ice volume falls steadily even if extent can make a bit of a come back after 2007.

  15. 165
    Perk Earl says:

    According to latest NSIDC ice extent, we are now below the old 2007 record and hovering just a tiny bit above 4 million sq. kilometers.

    http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png

    Which means tomorrow it will go sub 4 into the 3′s! Look at the line for 2012 – that’s sharp downward line for this late in the season! Wonder what the final tale of the tape will hit. I’m guessing the new record will be +-3600. 500k sq. k’s less than 07 really ought to turn some heads.

  16. 166

    #153–”As we are probably going to sea a ice free summer arctic within the next 5-10 year, does anyone know how soon the longer and longer periods of ice free conditions (or another 5mil sq kms of open dark ocean) will really begin to principally affect the northern hemisphere climate?”

    Lawrence, here’s what Neven and I came up with in regard to the large question:

    http://neven1.typepad.com/blog/2012/08/wasislac.html

    Some preliminary questions and thoughts, in line with what research we could find. Comments and further suggestions are very much welcomed; as I commented on the thread for the post, it seems to me (as to you, apparently) that we should be looking toward consequences a bit more than it seems we have heretofore.

  17. 167
    dbostrom says:

    Am I overlooking something, or is my bafflement with 2007 as a particularly standout year justified?

    I admit that 2007 was what got my attention, but then I wasn’t exactly focused on the issue. Leaving that aside, what was unique about 2007?

    In retrospect we been banging off records since the very first satellite derived extent measurements. Really, the satellite record doesn’t even appear able to tell us what’s “normal.” It seems fairly obvious we started watching the series quite a few episodes into the plot.

    See this record of anomalies for July, for instance. Looking at that, what’s so special about 2007, or this year for that matter?

    Let alone Watts, many of the rest of us were pretty slow on the uptake.

    Wow are we ever going to be judged harshly, particularly the better the hindsight we have.

  18. 168
    ozajh says:

    dbostrom @ 167,

    2007 broke the record for lowest NSIDC Extent by a HUGE margin, largely due to more-or-less perfect melt and ice transport conditions for the entire summer. This captured a lot of media attention at the time, which continued as several subsequent years got close but failed to reach the 2007 low.

    This low has now been broken, so you may see 2007 treated more as a strong exemplar of an underlying trend, and less as a freak one-off.

  19. 169
    dbostrom says:

    ozajh: …2007 broke the record for lowest NSIDC Extent by a HUGE margin…

    Larger than the mostly unremarked previous record-holder 1995, sure. On the other hand obsessing on the grandiosity of one year’s anomaly is just a slightly less myopic way of failing to see the trend. Two lesser anomalies added together can be more important, more are worse but those go pretty much unremarked in the daily noise.

    “Nothing to see until 2007′s record is broken.”

    Are we going to see a replay of this? I suspect so; there’s nothing in the record suggesting we’re likely to see year-on-year annual anomalies, though monthly records have examples.

    So, we’ll keep on getting used to this, or being used to it in actuality. I’ll be surprised if this year’s anomaly generates the same press notice as 2007, more surprised if in 2-4 years when we see this year’s record broken there’s much attention paid at all.

    We’re just not very good at this sort of thing. Same deal as ignoring 10,000 deaths per year in automobiles that could be reduced by half with some engineering. A steady 10,000/year excess morbidity is boring. Twelve dozen killed by a defective skybridge at a hotel is the sort of thing is guaranteed to get our collective notice.

    We have some very bad problems with our perceptions and cognition not scaling very well.

    Thinking aloud here, sorry.

  20. 170
    Brian Dodge says:

    dbostrom, ozajh -
    If you look at http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/sea.ice.anomaly.timeseries.jpg, they eyecrometer shows that from 2007 on, there is a strong annual cycle. The 2007 melt was he result of enough prior year thinning that the sea ice was no longer an integrator representative of climate (warming causing declining ice), but a responder to weather. Unfavorable weather was able to compact the thinning ice and flush larger quantities out the Fram Straight, where in previous years that bad weather wouldn’t have had such a dramatic effect on the thicker ice. This year, which hasn’t had such bad weather for ice loss, but still has impressive declines, is a second transition, probably a tipping point. The ice thickness last winter finally became so low that even normal weather is causing a crash – and the thickness isn’t going to recover anytime soon to where it will take a bad years weather to cause a 2007 style precipitous drop, let alone to where it can maintain a pre 1950 10 million km^2 extent.
    A potential feedback for thinner winter ice(some ice will always form when the sun sets in the arctic) is that so much open water will be a large new source of atmospheric water vapor over the pole, which will result in rapid early accumulation of thick insulating snow cover. Once the ice reaches a thickness that is mechanically stable to wind and wave action, preventing wetting of the snow(0.5 meter?), the insulation will prevent much further growth in thickness even with -40 degree surface temperatures – and it’s possible that thicker snow will allow much lower winter temperatures than currently seen in the Arctic. When there are outbreaks of Arctic air in coming winters to New York or London, they will be deadly, IMHO.

  21. 171
    dbostrom says:

    I should add that when I mention 1995, I’m addressing ozajh’s mention of the anomaly magnitude of 2007 as a remarkable feature.

  22. 172
  23. 173
    Jim Larsen says:

    Here’s a chart showing maximum potential solar insolation for 0, 30, 60, and 90 degrees north. Notice that for the arctic, the second half of May, and June and July are the times when the most sunlight is available to penetrate open waters, with about a month of shoulder on each end. September is about residual heat in the water. Even this chart is probably misleading because water reflects better at lower angles.

    http://www.physicalgeography.net/fundamentals/6i.html (scroll to bottom)

    Here’s Arctic Roos’ area graph. Note that for the high solar period in 2012 ice area started out high and ended low as compared to recent years. It looks pretty typical given a visual weighting using the potential insolation chart. Thus, sea ice albedo isn’t significantly involved in the situation yet (beyond what it already was), but in a year where area doesn’t start so high, a lower April 15 through May 15 albedo could prime the system for yet another record smashing year.

    http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic

  24. 174
    Lars Karlsson says:

    Wayne Davidson (157),
    Two of those links you give are actually satire. Let’s see if you can figure out which ones.

  25. 175
    ozajh says:

    dbostrom @ 171,

    I was saying that THE MEDIA saw the 2007 decline as a remarkable feature . . .

  26. 176

    #173–Mmm, that “shoulder” continues to deliver better than 200 W/m2 to the end of August. Clearly, it’s much smaller than the insolation during the height of the season, but I don’t think that even this amount is negligible–after all, the relevant comparison isn’t to the height of the season, it’s to previous comparable periods.

    Compare minima:

    2005: 5.315 million square km
    2006: 5.781 million square km
    2007: 4.255 million square km
    2008: 4.715 million square km
    2009: 5.250 million square km
    2010: 4.814 million square km
    2011: 4.527 million square km
    2012: 4.189 million square km (and running)

    (h/t Neven’s Arctic Sea Ice blog)

    We’re 70,000 km2 and a couple of weeks ahead of 2007, and more than a million km2 ahead (and again, a couple of weeks) of some other recent years. It should be pretty easy to do ‘back of the envelope’ calculations for just how much energy that represents in each case; I haven’t the time or the heart. But though I’m willing to believe that it’s not a huge proportion of the seasonal fluxes, I’m not willing to believe it’s negligible.

    Moreover, if you look at the extent curve for the season, here:

    http://nsidc.org/arcticseaicenews/

    …you see that 2012 has been tracking below 2007 since about the second week of June–IOW, right through the heart of the ‘insolation season.’ More energy than ever before (disregarding the effects of weather, of course–it’s very possible that 2007′s sunny weather more than compensates) has been reaching the sea for that whole time.

    So, Jim, all in all I think you are overstating the case WRT insolation, at best.

  27. 177
    dingibily says:

    Re the PIOMAS anomaly bounce-back after July: This year the late-August melt has been unprecedented, continuing to head steeply downward (area/extent) when all other years had begun to bottom out. This would suggest that the PIOMAS anomaly may be headed for an atypical Aug downturn this year. We’ll see in a few days.

  28. 178
    Jim Larsen says:

    176 Kevin said, “e that 2012 has been tracking below 2007 since about the second week of June–IOW, right through the heart of the ‘insolation season.’”

    I wasn’t paying any attention to 2007. It’s all 2012 VS average. Before the solstice the ice was high (but only in context of this decade), and afterwards it was low by a similar magnitude. It crossed median a bit before the solstice, according to the area chart I found.

    I agree with your definition of “shoulder” and I don’t know what the energy loss is, so I don’t know when solar input is matched by outbound IR, so I couldn’t tell you if 200W is significant or not.

  29. 179
    MARodger says:

    dingibily @177
    Examined up close, the PIOMAS ‘bounce back’ seen since 2010 is well into it’s stride by the end of July as graphed here (usually 2 clicks to ‘download your attachment’)
    It is probably fair to anticipate 2012 will become a ‘double dip’ year with the impact of the cyclone. All will be revealed in the next PIOMAS update.

  30. 180
    Jim Larsen says:

    And the kicker is that anomalies for the early season occur at *much* lower latitudes than anomalies for the late season.

  31. 181

    [edit: off topic]

  32. 182
    dingibily says:

    So, is the extraordinary late-Aug melt primarily a result of the unusual early-Aug storm or an inevitable consequence of thinning ice and more exposed water in recent years?

  33. 183

    #182 dingibily (nice nickname). No. A cyclone consolidates ice towards its center, a strong Anticyclone would have been more devastating. The ice was melting quite fast despite a generally cloudy arctic summer.

  34. 184
    Andy Lee Robinson says:

    Updated PIOMAS video for sharing, longer and slower for easier digestion:
    http://youtu.be/_8bMoAybGno

    Original divx version: http://haveland.com/share/piomas-arctic-1979-2012-07-pov-anim.avi

  35. 185
    Paul Beckwith says:

    Since December, 2011 I have been giving presentations linking Arctic sea ice destruction with extreme weather, etc. Since August 10th, 2012 I have been predicting that the sea ice will be completely gone from the Arctic by the end of this years melt season. Here are presentations that lead me to conclude this…I post all this stuff in real-time on facebook (Paul Beckwith) and twitter (PaulHBeckwith); please friend and follow me. Note that the last link is a presentation I gave on Jan 17th this year discussing all the sea ice links to extreme weather, etc. and the imminent sea ice failure…rather than publishing papers on this for my thesis I have been focused on getting this information out to the public, and contributing to AMEG (Arctic Methane Emergency Group) work.

    August 27th update
    http://arctic-news.blogspot.ca/2012/08/paul-beckwith-on-ice-speed-and-drift.html

    Article in Canadian Parliament paper August 27th
    http://www.sierraclub.ca/sites/sierraclub.ca/files/ht-oped.pdf

    August 18th update
    https://docs.google.com/file/d/0ByLujhsHsxP7cnB0bXhNNFFSQjQ/edit

    August 17th update
    https://docs.google.com/file/d/0ByLujhsHsxP7MGQ4RUI1ZmMzUTg/edit

    August 16th update
    https://docs.google.com/file/d/0ByLujhsHsxP7b1A3T3RLMnlZYVE/edit

    August 14th update
    https://docs.google.com/file/d/0ByLujhsHsxP7dUQwYXJ6bXRSd00/edit

    August 10th update
    https://docs.google.com/file/d/0ByLujhsHsxP7NUE4SzZ5NmFsdzA/edit

    Canadian parliament All party climate change caucus June 7th
    https://docs.google.com/file/d/0ByLujhsHsxP7NG42RjVQLXBrV1k/edit

    Detailed presentation on sea ice to extreme weather links Jan 19,2012
    https://docs.google.com/file/d/0ByLujhsHsxP7NThkM05iN1BXZ2s/edit

  36. 186
    dhogaza says:

    Since August 10th, 2012 I have been predicting that the sea ice will be completely gone from the Arctic by the end of this years melt season.

    Ain’t going to happen, and IMO, such wild-eyed predictions don’t help, they provide the denialsphere with an easy target.

  37. 187

    re: 186

    “Ain’t going to happen”

    We went to Alaska this summer. And even as far south as Anchorage it was easy to see that the Arctic is going to be cold for a long time. A complete melt-out will never be seen by me or thee. By the time it warms enough to have produced a melt-out, we’ll be dead.

    If it happens quickly, there won’t be hominid witnesses at all.

  38. 188
    Ric Merritt says:

    Paul B, 185: Arctic ocean will contain nary an ice cube some time in 2012.
    dhogaza, 186: Eschew wild-eyed predictions.
    Jeffrey D, 187: No complete melt-out (c’mon, Jeff, definition, please) in the next several decades.

    I sense some wagering opportunities.

    [Response:
    :)
    ]

  39. 189

    re: 188

    What do I mean by “complete melt-out”? I didn’t think that was hard. No ice in the Arctic. As in “complete”.

    I’ve been wrong before, but there’s still a lot of ice up there. Think about all the ice in Greenland. It will really need to warm up A LOT to melt that. Do you think you’re going to live long enough to see that? I don’t think I’ll see it, but I’m in my 60s.

    For me to see it would require real fast warming. The political/agricultural instability that kind of rise would entail would preempt witnesses, don’t you think? I think it would require ~1C more of warming to accomplish a melt-out. If you’re in your 20s now, you’ll be in your 70s by the time we get another 1C of warming. D you think you’ll see it?

    I’m a genuinely bleak catastrophist by the way. The political inertia/reluctance to tackle this issue just confirms my misanthropy.

  40. 190
    MARodger says:

    PIOMAS has updated a couple of days early (to day 238). Last volume = 3,599 cu km, well below last year’s minimum. Graph of recent year-on-year anomalies here (usually two clicks to ‘download your attachment’).

  41. 191
    Lauri says:

    re: “complete meltdown”

    Not likely soon as there is so thick ice against northern Greenland and the islands. However, a significant reduction is possible. A couple of days ago, the boundary of fast ice was less than 300 miles from the North Pole, see http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?mosaic=Arctic.2012242.terra.1km (to the right of the North Pole in this picture).

  42. 192
    DavidR says:

    The PIOMAS data along with estimates from the Greenland an Antarctic Ice Sheets indicate we are permanently melting around 800-1000 Gigatonnes of Ice per year. A back of envelope calculation suggests this requires more than 1% of the total solar input to earth each year.

    Has anyone calculated the impact this is having on the rate of warming?

    [Response: You have made a mistake somewhere: 1000 GT ice melting a year is roughly 3x10^20 J/year. Solar input is 240 W/m2 so over a year is 240*5.1*10^14*365*24*3600 ~ 4x10^24 J/year. So more like 0.01% of solar input. Alternatively, the energy in W/m2 required to melt the ice is about 0.02 W/m2 compared to a current radiative imbalance of ~0.5-1 W/m2. - gavin]

  43. 193

    #192 Gavin, therefore ice can melt despite clouds… Which incidentally will delay the onset of freezing.

  44. 194
    Susan Anderson says:

    NSIDC seems to have a new report out:
    http://nsidc.org/arcticseaicenews/2012/09/arctic-sea-ice-falls-below-4-million-square-kilometers/

    To my eye, nice graphic on sea surface temps, with two steep drops. Will there be another one? Time will tell.

    On ice-free, I seem to remember official definition is for a short period (day?) and with a small proportion of ice remaining (thin, lose, broken?). Sloppy layperson that I am …

    Meanwhile, with Leslie and Son of Isaac (see Wunderground, S of I off topic a bit for my point, and your detailed weather reports) there appear to be some issues about weather perturbation in process. In particular, those northward heading low pressure whirligigs are getting a bit closer to the Arctic etc. given the current state of agitation and meltdown. Time will tell.

  45. 195
    Susan Anderson says:

    It has occurred to a number of observers that models are now lagging real-time. I know modeling has been the norm, but at this point I’m wondering if a better incorporation of real-time observations needs to occur. I know, it’s easy to shoot from outside, but since there is so much criticism of models it bears repeating that so far they are understating the case in multiple ways.


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