Ice loss model verification via satellite observations

European satellite confirms UW numbers: Arctic Ocean is on thin ice

By Hannah Hickey (via university of Washington press release)

The September 2012 record low in Arctic sea-ice extent was big news, but a missing piece of the puzzle was lurking below the ocean’s surface. What volume of ice floats on Arctic waters? And how does that compare to previous summers? These are difficult but important questions, because how much ice actually remains suggests how vulnerable the ice pack will be to more warming.

Graph of sea ice volume

Monthly sea ice volume anomalies from 1979 to the present calculated using the UW system. A. Schweiger, UW

New satellite observations confirm a University of Washington analysis that for the past three years has produced widely quoted estimates of Arctic sea-ice volume. Findings based on observations from a European Space Agency satellite, published online in Geophysical Research Letters, show that the Arctic has lost more than a third of summer sea-ice volume since a decade ago, when a U.S. satellite collected similar data.

Combining the UW model and the new satellite observations suggests the summer minimum in Arctic sea ice is one-fifth of what it was in 1980, when the model begins.

“Other people had argued that 75 to 80 percent ice volume loss was too aggressive,” said co-author Axel Schweiger, a polar scientist in the UW Applied Physics Laboratory. “What this new paper shows is that our ice loss estimates may have been too conservative, and that the recent decline is possibly more rapid.”

The system developed at the UW provides a 34-year monthly picture of what’s happening to the total volume of Arctic sea ice. The Pan-Arctic Ice Ocean Modeling and Assimilation System, or PIOMAS, combines weather records, sea-surface temperature and satellite pictures of ice coverage to compute ice volume. It then verifies the results with actual thickness measurements from individual moorings or submarines that cruise below the ice.

“Because the ice is so variable, you don’t get a full picture of it from any of those observations,” Schweiger said. “So this model is the only way to reconstruct a time series that spans multiple decades.”

Chuchki Sea ice

Seasonal ice on the Chuchki Sea, a marginal sea off the Arctic Ocean, in July 2010. Bonnie Light, UW

 

The UW system also checks its results against five years of precise ice thickness measurements collected by a specialized satellite launched by NASA in 2003. The Ice, Cloud, and Land Elevation Satellite, or ICESat, measured ice thickness across the Arctic to within 37 centimeters (15 inches) until spring of 2008.

The U.K.’s CryoSat-2 satellite resumed complete ice thickness measurements in 2010; this is the first scientific paper to share its findings about the recent years of record-low sea ice.

Between 2008 and now, the widely cited UW figures have generated some controversy because of the substantial ice loss they showed.

“The reanalysis relies on a model, so some people have, justifiably, questioned it,” Schweiger said. “These data essentially confirm that in the last few years, for which we haven’t really had data, the observations are very close to what we see in the model. So that increases our confidence for the overall time series from 1979 to the present.”

Arctic sea ice is shrinking and thinning at the same time, Schweiger explained, so it’s normal for the summer ice volume to drop faster than the area covered, which today is about half of what it was in 1980.

Schweiger cautioned that past trends may not necessarily continue at the same rate, and predicting when the Arctic might be largely ice-free in summer is a different question. But creating a reliable record of the past helps to understand changes in the Arctic and ultimately helps to better predict the future.

“One question we now need to ask, and can ask, is what are the processes that are driving these changes in the ice? To what degree is it ocean processes, to what degree is this in the atmosphere?” Schweiger said. “I don’t think we have a good handle on that yet.”

The UW system was created by co-author Jinlun Zhang, an oceanographer at the Applied Physics Laboratory. The UW portion of the research was funded by NASA and the Office of Naval Research.

Other co-authors are first author Seymour Laxon, Katharine Giles, Andy Ridout, Duncan Wingham and Rosemary Willatt at University College London; Robert Cullen and Malcolm Davidson at the European Space Agency; Ron Kwok at NASA’s Jet Propulsion Laboratory; Christian Haas at York University in Canada; Stefan Hendricks at the Alfred Wegener Institute for Polar and Marine Research in Germany; Richard Krishfield at Woods Hole Oceanographic Institution; Sinead Farrell at the University of Maryland; and Nathan Kurtz at Morgan State University in Baltimore.

###

OK, so the question now they say is:

“One question we now need to ask, and can ask, is what are the processes that are driving these changes in the ice? To what degree is it ocean processes, to what degree is this in the atmosphere?” Schweiger said. “I don’t think we have a good handle on that yet.”

Those are good questions. Soot, in addition to cyclical ocean and atmospheric processes should also be investigated, since it has a strong ability to absorb sunlight and be a forcing of its own.

I also wonder if this isn’t some sort of natural cyclic occurance that we are just now becoming aware of due to our space based remote sensing capabilities. We really don’t have any good data beyond the satellite era, but we do have some older interesting anecdotal evidence such as this story:  You ask, I provide. November 2nd, 1922. Arctic Ocean Getting Warm; Seals Vanish and Icebergs Melt.

97 thoughts on “Ice loss model verification via satellite observations

  1. The big question they ask on causes will get lost in the noise generated by the MSM.

    “it’s worse than we thought!”

  2. Bad news: The Arctic sea ice will be here long after all of us are gone.

    Good news: The Arctic sea ice melt will kill all of the polar bears that are causing global warming.

    Do I even need the sarc tag??

  3. Why is everybody getting so concerned by ice? Ice Kills. I much prefer the 80-90+ degrees here in Central America (Honduras). No fear of cold killing anybody, and I have yet to hear of the heat doing likewise. I’ll save my (home-made) ice for my late-afternoon scotch, thanks.

  4. Sigh…. what kind of mental aberration makes people think a downward trend will continue to zero? Looks to me a lot more like the downward leg of a sine wave… And 30ish years of “climate” is half of the KNOWN and WELL DOCUMENTED climate cycle.

    We already know that arctic ice has been low in the past. This obsession is beyond ridiculous.

  5. Legacy warm water from recent el Ninos is still washing into the Arctic which recently has no real recent linear trend in water temperature, as indicated by Bob Tisdale:

    but a big increase since 2007 in winter-summer ice extent oscillation amplitude. Warm water flowing into a cooling Arctic gives this increase in seasonal amplitude.

    However it wont necessarily last. Believe it or not, not all climate trends in the last few billion years have been unidirectional. If the current switch to La Nina ENSO dominance continues, and the AMO enters its down-swing, then the legacy warm water will run out and the Arctic ice will recover.

  6. If this study is 100% right, then the ice decrease must stabilize soon because it can’t go past a complete summer melt. The winter refreeze is going to happen regardless. So it’s easier and more trustworthy simply to let the summer minimum tell us what’s happening. I’m picking increasing summer minima as the sun & Atlantic cool. No fault of the authors of this study, but Mann & Hadley etc have wrecked a lot of trust in science.

  7. “…So this model is the only way to reconstruct a time series that spans multiple decades…”

    Why, when I see that word “model,” do I feel so distrustful?

  8. CodeTech says:
    February 13, 2013 at 3:42 pm

    Sigh…. what kind of mental aberration makes people think a downward trend will continue to zero?
    =====
    the same one that makes them think we’re all going to fry…../snark
    (I know you know the snark……but I had to put it in there)

  9. Yeah, yeah, the trend is down, it’s worse than we thought, yadda yadda. What I want to know is, when can we drill for all that yummy oil and gas supposedly under the Arctic Ocean?

  10. “We already know that arctic ice has been low in the past. This obsession is beyond ridiculous.”

    really? is that settled science? do we really KNOW this? tsk tsk skepticism out the door

    hmm, lets see some data on area, extent and volume.

  11. With 70% of the world’s volcanoes under the sea and as volcanoes tend to be clustered around tectonic plate boundaries it is no wonder the ocean temperatures at the north pole vary given the number of tectonic plate boundaries there. Currently there seems to be an unusual increase in the amount of volcanic activity on the Kamchatka peninsular, Iceland and Alaska. So there are probably many more volcanoes erupting under the sea near these places. This should in part account for the warmer waters. Two large underwater volcanoes north of Iceland were known to be erupting a few years ago. The sea floor for hundreds of square kilometers was heated by those volcanic eruptions.
    It seems that volcanic activity increases during periods of low solar activity (from muon activity caused by increased GCRs) and because of the slightly increased tectonic plate momentum produced by the additional extra-terrestrial tidal forces that co-incidentally cause the reduced solar activity. So at present there are a number of conflicting influences. At least by the end of this new grand minimum scientists will know a lot more about these influences and should less rely on models that don’t include such influences.

  12. the model will be confirmed in fifteen years when the summer sea ice extent goes negative. what exactly is negative sea ice?

  13. I remember seeing pictures of one of our nuclear subs surfaced in open water at the North Pole in ~1958. Sounds like with only 32 yrs of satellite data, this is a lot about absolutely nothing.

    Dave Hughes

  14. I cannot understand this wanting to cooll the world. If the world heats up a little to me that is a good thing. Cold kills and kills thousands of people every year. Heat though killing some, kills far less. If the world cools crops fail. If carbon dioxide lowers, crops grow slower. Are we living in a crazy world where the scientists want to change the weather to kill as many as possible? Look at history. The world has always prospered during the warm periods. And waned and the world grew cooler. why was greenland called greenland? Because once it really was green. I rest my case.

  15. Steven Mosher says:

    “really? is that settled science? do we really KNOW this? tsk tsk skepticism out the door”

    Science is never settled [at least, not outside of alarmist circles]. But per your request:

    http://www.ngu.no/en-gb/Aktuelt/2008/Less-ice-in-the-Arctic-Ocean-6000-7000-years-ago

    http://www.sciencemag.org/content/333/6043/747.full

    http://hockeyschtick.blogspot.com/2011/08/new-paper-finds-arctic-sea-ice-strongly.html

    http://hockeyschtick.blogspot.com/2012/08/paper-finds-arctic-sea-ice-extent-8000.html

    It appears to be widely accepted that Arctic ice has been lower during the Holocene than current sea ice levels. And that was when CO2 was much lower.

  16. Steve Mosher,
    Built for the Royal Canadian Mounted Police Force to serve as a supply ship for isolated, far-flung Arctic RCMP detachments, St. Roch was also designed to serve when frozen in for the winter, as a floating detachment, with its constables mounting dog sled patrols from the ship. Between 1929 and 1939 St. Roch made three voyages to the Arctic. Between 1940 and 1942 St. Roch navigated the Northwest Passage, arriving in Halifax harbor on October 11, 1942. St. Roch was the second ship to make the passage, and the first to travel the passage from west to east. In 1944, St. Roch returned to Vancouver via the more northerly route of the Northwest Passage, making her run in 86 days. The epic voyages of St. Roch demonstrated Canadian sovereignty in the Arctic during the difficult wartime years, and extended Canadian control over its vast northern territories.

  17. “Because the ice is so variable, you don’t get a full picture of it from any of those observations,” Schweiger said. “So this model is the only way to reconstruct a time series that spans multiple decades.”

    Of course.

    2009
    The “Polar 5″ in Bremerhaven
    The research aircraft Polar 5 “ended today in Canada’s recent Arctic expedition. During the flight, researchers have measured the current Eisstärke measured at the North Pole, and in areas that have never before been overflown. Result: The sea-ice in the surveyed areas is apparently thicker than the researchers had suspected.

    http://wattsupwiththat.com/2009/04/28/inconvenient-eisdicken/

    Oh no!

    2011
    “Thickening Arctic Ice Is Getting Thinner, Say Alfred Wegener Institute And University of Alberta”

    http://notrickszone.com/2011/05/12/thickening-arctic-ice-is-getting-thinner-says-alfred-wegener-institute/

  18. Its interesting that the reaction to this so far is to say it does not matter or to make more wishful predictions of reversal.

    Some of the projections on a warming world have been stupid, but projections of arctic sea ice melt have proved mostly correct, actually conservative on most models.

    The reason its serious is obvious.

    Currently ice in the high arctic ocean refrigerates the air above it to around freezing point ie melting ice stays at freezing point.

    Remove that ice and the temperatures from the warmer sub arctic where the ice does melt in summer will become more normal across the whole arctic ie 6C – 8C.

    Removing the ice also changes the surface albedo from very high to relatively low – there is more heat absorbtion.

    The combination will give a big jump in surface temperatures, accelerating the melt of the rump of sea ice (likely to hold on north of Greenland) and leading to accelerated melt of land based ice.

    That will be followed by a rise in ocean temperature, especially in the summer.

    We cannot know what the next few decades will bring for certain but the recent trend is clearly significant and an ice free pole in late summer – if not an ice free arctic is entirely possible in years, not decades.

    This study shows that the ice area/extent debate is but one element – volume is even more important – and its collapsing.

    The notion that ice is “recovering” due to rapid growth in late winter seen recently is superficial. A largely ice free arctic late summer will of course lead to rapid refeezing in the winter as vast areas of ocean are in months of polar darkness with temperatures going down to the -20s, -30s and -40s.

    Even if the arctic goes ice free in late summers of the future there will still be a big freeze up in the winter and we are seeing big swings in ice area every year now since 2007:

  19. @ Mosher, 1923-1938. EOM

    @ Anthony, “Soot, in addition to cyclical ocean and atmospheric processes should also be investigated, since it has a strong ability to absorb sunlight and be a forcing of its own.”
    If most of the Arctic sea ice is one year old, it is unlikely that tons of soot deposit during one year no? BTW, animations show that remobilization of Arctic sea ice depends on the intenisty of atmospheric circulation. Since extent diminished during the LIA as shown in Kinnard et al, it is very likely this is a transitional phase, just as was seen before the Dust Bowl period, i.e. rapid mode of circulation corresponding with cooling. For how long? Who knows.

  20. Well, see here, the Arctic sea ice minimum Sept’ 2012, nobody told of the ‘great August storm’.

    Then with the ice rebounding at record levels in 2013 ….[Alarmist panic!] “we must counter that”……….ooh it’s so thin and thus the meme remains the…..same.

    Ain’t it time to change the record?

    Arctic Sea ice fluctuates – get over it.

  21. Ice is an insulator, the thicker it is, the less ocean cooling takes place. The questions that should be being asked are how much sea ice is blown by the wind out of the arctic during the year and how much thermal energy is lost vs how much is gained in the Arctic on an annual basis. The Artic volume of ice can be reduce by blowing it out into the Atlantic or Pacific.Thick Sea Ice tends to stick up where it can be caught by the wind like a sail moving it faster. The movement of sea ice into the Atlantic seems to be constant. If the movement of sea ice now is different than it was decades ago it could explain all the changes is area, extent,and volume. The answer my friends is blown by the wind.

  22. I really loathe models now. Why do we always have to wait fifteen years (multiple decades, at any rate) for a model to be proven accurate? When fifteen years (whatever) rolls around and the model crashes, ANOTHER model has to wait fifteen years (or so) to be proven accurate, and then another and so on. They’re just carrying it aloft for future warmists to pass along, meanwhile draining the funds from civilization to put in their own pockets. It’s always “Wait fifteen years (or longer) for this one to be proven true.” By then they can’t give the money back. After the allotted time, they bury their failures as “But that was in the past. We need new funds to test a new model.” And they scream CAGW regardless!

    How about we wait fifteen years for the model to be proven accurate BEFORE WE PAY THEM which, of course, only happens if the accuracy is actually confirmed. Would that encourage true and de-politicized science, do you think? Just maybe??? While we’re all waiting, they can have a modest wage packet, like everyone else. Just a thought.

  23. Those are good questions. Soot, in addition to cyclical ocean and atmospheric processes should also be investigated, since it has a strong ability to absorb sunlight and be a forcing of its own.

    Don’t forget solar insolation/cloud changes, especially decreases in anthropogenic aerosol seeded clouds.

    All of the Arctic sea ice changes (melt and formation) are explained by a small decrease in cloud cover, plus the effect of embedded black carbon.

    My prediction is that as old sea ice with relatively high levels of embedded black carbon melts out we will see a steady increase in summer sea ice extent and volume, starting this summer or the next. In addition winter maximum extent will go back to the anomaly (longer term average) in less than 5 years.

  24. Steve, looking forward to your response. History trumps data hobbying. History actually happened. The two biggest problems that holds back climate science are

    1. historical denial.
    2. overreaching

  25. Athelstan. says: Then with the ice rebounding at record levels in 2013 ….[Alarmist panic!]

    The only reason ice is rebounding “at record levels” is because there was more open water to freeze in winter!

  26. A D Everard;
    How about we wait fifteen years for the model to be proven accurate BEFORE WE PAY THEM which, of course, only happens if the accuracy is actually confirmed.
    >>>>>>>>>>>>>>>>>>>

    I’ve advocated this in the past. Figure out what you want to know (ice thickness, land temps, whatever) and post a prize of $1 billion for the model produces in the next 12 months that is shown to be most accurate in 10 years. $10 billion if accurate to a stringent set of tests. No government involvement except to provide the data. Throw it open to the private sector. You know what you’d get? Really good models for a fraction of the cost that is being p’d away now for crap.

    On the matter of ice, first we had the ice extent panic, now that the ice extent is pretty much normal on a global basis, they want to have the ice thickness panic. I’ve pointed this out as well, ice thickness is a poor proxy. In salt water, ice doesn’t form until the water column has cooled to the freezing temperature top to bottom. So a small change in temp at surface, from just above freezing to freezing, actually represents a massive amount of energy change from ocean surface to ocean bottom. I don’t really give a hoot about extent or thickness. Show me the temperature gradient of the WATER from top to bottom over time, WITH and WITHOUT ice and then I’ll get interested.

  27. your first paper cited was a total FAIL.
    1. No direct measurements
    2. Conclusions limited to the waters north of greenland.

    Next.

  28. Sooooo, James Abbott, without copying all of your comment (above), can we just color you an Arctic-ice kool-aid drinker?

    Don’t suck down any innocent polar bears….

  29. Second paper was also a fail.

    no direct measurements. only covers north of greenland

    where is your skepticism

  30. There is a great deal of evidence that: “… this isn’t some sort of natural cyclic occurance that we are just now becoming aware of due to our space based remote sensing capabilities” is _not_ the case.

    See for example Kinnard et al 2011, Reconstructed changes in Arctic sea ice over the past 1,450 years (http://labs.ceazamet.cl/ceaza/docs/1343273271.pdf); especially Fig. 3.

    “…both the duration and magnitude of the current decline in sea ice seem to be unprecedented for the past 1,450 years. … These results reinforce the assertion that sea ice is an active component of Arctic climate variability and that the recent decrease in summer Arctic sea ice is consistent with anthropogenically forced warming.”
    (Emphasis added)

  31. Third paper is also a fail.
    1. doesnt cover area, extent or volume, it covers storms
    Come on, check before you link

    Im looking for evidence that makes you certain that there has been less ice, area, volume and extent in the past. Not maybe less ice north of greenland..

  32. I’ve read some of the replies but not all.
    Has anyone mentioned that the reason for the sea ice loss is elevated temperatures caused by the green house effect of increased co2 in the atmosphere?

  33. Interesting results, and it will also be interesting to see if they hold up. Before people throw the researchers under the bus, it sounds like at least one of the individuals is taking a pretty reasonable approach:

    “Schweiger cautioned that past trends may not necessarily continue at the same rate, and predicting when the Arctic might be largely ice-free in summer is a different question. . . .
    “One question we now need to ask, and can ask, is what are the processes that are driving these changes in the ice? To what degree is it ocean processes, to what degree is this in the atmosphere?” Schweiger said. “I don’t think we have a good handle on that yet.”

    I’m willing to give him the benefit of the doubt. Sounds like reasonable questions to ask and that he is doing his best to look at the data — and not make assumptions about what we don’t yet have a good handle on.

    We’ll see where this all shakes out.

  34. kent blaker says

    The answer my friends is blown by the wind.

    Most of the multi year ice does not melt as long as it stays in the Arctic.

  35. http://hockeyschtick.blogspot.com/2012/08/paper-finds-arctic-sea-ice-extent-8000.html

    you cite this as evidence?
    Its a modelling study.

    Psst. there MAY HAVE BEEN less ice in the holocene, because it was warmer then than now.
    Imagine that, warmer and less ice? go figure.
    But examine the difference between reconstructing ice extent and actually measuring it.
    Examine the fact that you doubt measurement today when it suits you while at the same time
    believing in reconstructions when it suits you. selective skepticism.

    Why was it warmer in the holocene? many reasons, c02 isnt one of them
    Why is it warm now? many reasons c02 IS one of them.
    Go figure the climate is complex, it can be warm with low c02 and warmer with more
    So, yes, when it gets warmer ice melts with or without soot. go figure

  36. Unfortunately, Seymour Laxon, the lead author of the article is dead, after a tragic accident in January.

  37. @David Hughes

    >>I remember seeing pictures of one of our nuclear subs surfaced in open water at the North Pole in ~1958. Sounds like with only 32 yrs of satellite data, this is a lot about absolutely nothing.

    Precisely. I believe that the ice was thin enough again in the early ’70s for more photographs of the same thing yet again. On both occasions, no one became hysterical, the world did not end, and, as I recall, extraordinarily harsh winters followed for parts of the northern hemisphere within a couple of years. This is a non-issue.

  38. James Abbott,

    If your claim was valid it would also apply to the Antarctic.

    Steve Mosher says:

    “your first paper cited was a total FAIL.”

    I suggest you take it up with the NGU. It’s their peer reviewed paper.

    And:

    “Second paper was also a fail… where is your skepticism”

    I suggest you take it up with the journal Science. It is their published, peer reviewed paper.

    And my scientific skepticism is alive and healthy. It tells me that since the Holocene had much warmer temperatures, it follows that the Arctic would have much less ice then than now. Where is your skepticism?? …oh, right. You have your models.

    Nevermind.☺

    [Also, FYI: CO2 has no measurable effect on global temperature at current concentrations.]

  39. Steven Mosher says:
    February 13, 2013 at 5:14 pm

    Third paper is also a fail.
    1. doesnt cover area, extent or volume, it covers storms
    Come on, check before you link

    Im looking for evidence that makes you certain that there has been less ice, area, volume and extent in the past. Not maybe less ice north of greenland..

    Peak Warming Man says:
    February 13, 2013 at 5:15 pm

    I’ve read some of the replies but not all.
    Has anyone mentioned that the reason for the sea ice loss is elevated temperatures caused by the green house effect of increased co2 in the atmosphere?

    PERFECT!!!!

  40. Some evidence, in context:

    Polyak et al 2010, History of sea ice in the Arctic (http://bprc.osu.edu/geo/publications/polyak_etal_seaice_QSR_10.pdf):

    “The last low-ice event related to orbital forcing (high insolation) was in the early Holocene, after which the northern high latitudes cooled overall, with some superimposed shorter term (multidecadal to millennial-scale) and lower-magnitude variability. The current reduction in Arctic ice cover started in the late 19th century, consistent with the rapidly warming climate, and became very pronounced over the last three decades. This ice loss appears to be unmatched over at least the last few thousand years and unexplainable by any of the known natural variabilities.
    (Emphasis added)

  41. i always thought el nino was when a blob of heated volcano water from indonesia broke off and drifted our way…

  42. I’ve not yet read the article but from the headline it would appear that this organization knows what nobody else knows: How much is the right amount of ice and why. I’m going to be very disappointed if by the time I finish reading it I won’t know exactly how much ice the Arctic should have and why that is the exactly correct value. Because, you see, without knowing that, they’re pulling numbers out of their shorts, and any of us can do that.

  43. From KR’s link:

    This ice loss appears to be unmatched over at least the last few thousand years and unexplainable by any of the known natural variabilities.

    That is the old Argumentum ad Ignorantium fallacy: ‘Since I don’t have the answers, I am guessing that natural variability must be ruled out’.

    There is entirely too much of this sort of pseudo-scientific nonsense in climate ‘science’. The guy just doesn’t know, so he is winging it. Tap dancing, in place of testable, empirical evidence.

    KR’s previous link is even worse:

    …both the duration and magnitude of the current decline in sea ice seem to be unprecedented for the past 1,450 years.

    That means, of course, that the parameters were exceeded 1,450 years ago — when CO2 was very low… which makes a mockery of his assertion that current sea ice levels are “consistent” with AGW. We can’t even measure AGW, yet this rent-seeker is making assertions about it. Zero credibility, there. Try to at least find someone who uses logical consistency.

  44. David Hughes says: February 13, 2013 at 4:13 pm

    I remember seeing pictures of one of our nuclear subs surfaced in open water at the North Pole in ~1958. Sounds like with only 32 yrs of satellite data, this is a lot about absolutely nothing….

    David, while I agree that anecdotal evidence indicates modern arctic ice summer decline is not unprecedented, I’m not sure we can in any way trust cold war era propaganda photographs and their accompanying text in the newspaper. I’d love to see an officer or navigator who was on those subs at the time come forward and confirm the position where those photos were taken. If it was really at or near the pole, that would be convincing.

  45. “One question we now need to ask, and can ask, is what are the processes that are driving these changes in the ice? To what degree is it ocean processes, to what degree is this in the atmosphere?” Schweiger said. “I don’t think we have a good handle on that yet.”

    Jaw drops to table, to floor, and bounces off the wall!!!!

    Schweiger speaks the words of a genuine scientist!!!! WUWT’s influence is spreading. Hope he doesn’t get fired. Schweiger will never be invited to a Hansen sit-in.

  46. Steven Mosher says: February 13, 2013 at 3:58 pm

    “We already know that arctic ice has been low in the past. This obsession is beyond ridiculous.”

    really? is that settled science? do we really KNOW this? tsk tsk skepticism out the door
    hmm, lets see some data on area, extent and volume….

    While I agree (partially, and for once) with Mosh, that ‘anecdotal evidence’ is not settled science, it cannot be denied that such anecdotal evidence does exist, and that perhaps the CAGW crowd are more in the wrong in their continued implications that these events are unprecedented. The historical data he demands is in short supply.

  47. D.B. Stealey says: (to Steve Mosher says:“your first paper cited was a total FAIL.”)

    “I suggest you take it up with the NGU. It’s their peer reviewed paper.”

    And: (to Steve Mosher says:“Second paper was also a fail… where is your skepticism”)

    “I suggest you take it up with the journal Science. It is their published, peer reviewed paper.”

    Umm, Mosher is not saying the papers are bad; he is saying they are irrelevant for your point that there was less ice then. Same for the third paper.

    And as for nuc subs in the open water in the 50s or 60s (of course there was some open water in the summer, even then), I remember the sub people saying they have to look for places to surface because the ice was too thick/old to break through in many places…and the same people commenting that they dont need to do that nowadays, even in the winter.

  48. Theo Goodwin says: February 13, 2013 at 6:31 pm

    “One question we now need to ask, and can ask, is what are the processes that are driving these changes in the ice? To what degree is it ocean processes, to what degree is this in the atmosphere?” Schweiger said. “I don’t think we have a good handle on that yet.”

    Schweiger speaks the words of a genuine scientist!!!! WUWT’s influence is spreading…”

    Well said Theo. Once, every scientific article on climate and weather seemed to have a paragraph saying something along the lines of; ” … but [….] will get a lot worse in the future due to the effects of CAGW…”
    I’d formed the opinion that this had become a standard insertion demanded by reviewers, but maybe the above indicates a return to the normal approach to science.

  49. trafamadore,

    Recall that I was helpfully providing information that Steve Mosher requested.

    Now, why don’t you try to answer dp’s question: tell us how much Arctic ice is the right amount? Don’t worry about the Antarctic, just tell us how much sea ice the Arctic is supposed to have. A sport like you should have the answer right at your fingertips.

  50. phlogiston says:
    February 13, 2013 at 3:43 pm

    “If the current switch to La Nina ENSO dominance continues, and the AMO enters its down-swing, then the legacy warm water will run out and the Arctic ice will recover.”

    Recover? Why does everyone assume conditions are abnormal? I can as easily proclaim the last 30 years of ice extent, area and volume decline IS the recovery to arctic-normal conditions.

  51. The topic has lost some appeal, because

    the main driver is AMO and natural

    the second main driver is black carbon

    http://judithcurry.com/2013/02/08/open-thread-weekend-8/#comment-293710

    there are significant negative feedbacks, such as open sea heat loss and increased northern hemisphere snow cover

    and everything else is not really important, except perhaps the sun.

    Currently, not much to worry about, just clean up black carbon and keep an eye on the sun.

  52. Steven Mosher says:
    February 13, 2013 at 3:58 pm

    “We already know that arctic ice has been low in the past. This obsession is beyond ridiculous.”

    really? is that settled science? do we really KNOW this? tsk tsk skepticism out the door
    hmm, lets see some data on area, extent and volume.

    Reading this and your subsequent responses, it comes across that your request for “proof” of what happened in the past (i.e., before the satellite record began) cannot be ever be satisfied, because the only evidence that exists is anecdotal. Kindly clarify if you are suggesting the null hypothesis is that arctic ice has never been as low as it currently is in the past and if you’re implying there is no acceptable data that could be used to falsify your hypothesis.

  53. Regarding Mosher:

    For those of you who are trying to convince Mosher that there was less Arctic ice in the past, I think you are overlooking something. The topic in this forum is sea ice volume, not sea ice extent. The only data about Arctic sea ice volume is from satellites and dates only to 2003. Mosher has you on a technicality, so to speak. No matter what anecdotal evidence you cite, it is not evidence of volume.

    On the other side of the coin, ten years of satellite records is not something to get excited about. Read about the satellites, click in the article above, and learn about their techniques. They estimate volume from surface features of the ice.

    As scientist Schweiger said, this data gives scientists some wonderful questions to answer. It does not answer even one question about causality.

  54. From the dastardly (but easy to reference) wikipedia:

    http://en.wikipedia.org/wiki/Properties_of_water

    As the surface of salt water begins to freeze (at −1.9 °C for normal salinity seawater, 3.5%) the ice that forms is essentially salt free with a density approximately equal to that of freshwater ice. This ice floats on the surface and the salt that is “frozen out” adds to the salinity and density of the seawater just below it, in a process known as brine rejection. This denser saltwater sinks by convection and the replacing seawater is subject to the same process. This provides essentially freshwater ice at −1.9 °C on the surface. The increased density of the seawater beneath the forming ice causes it to sink towards the bottom.

    On average the arctic ocean is about 1000 meters deep. Under water currents mess with all this of course, but stop and think about the process. Going from half a degree above freezing to 1/2 degree below freezing at the surface means 1,000 meters of water are giving up a stupendous amount of heat. But we’re all wound up about the ice being 10 cm thick or 20 cm thick? It could be 10 meters thick. The amount of energy change compared to the water column itself is minuscule.

  55. The meme that a submarine surfaced in open water at the North Pole in 1958 has a thousand lives. It’s a zombie lie. http://reallysciency.blogspot.com/2012/01/zombie-lies.html

    The USS Skate did surface at the North Pole in 1959 – but it had to break through ice in a frozen lead to do so. In 1960 the Commander of the Skate, James Calvert, wrote Surface At The Pole, Commander James Calvert USN, The Extraordinary Voyages of the USS Skate. In it he details how the Skate didn’t find any open water on their 1959 cruise until several days *after* they surfaced at the North Pole – and when they did it was hundreds of miles from the pole and the ‘open water’ was a hole in the ice about two-feet in diameter!

    This stuff is so easy to verify you have to *want* to believe the lies and actively turn a blind eye to the truth. There’s really no other plausible explanation.

  56. Re:davidmhoffer says: Going from half a degree above freezing to 1/2 degree below freezing at the surface means 1,000 meters of water are giving up a stupendous amount of heat.

    No, that’s not the way it works. The Arctic Ocean is composed of layers of water with different properties, and at the base of the surface layer there is a big jump in density (known as a pycnocline), so convection only involves the surface layer down to that level (about 100-150 metres).

    A complete explanation of how sea ice forms can be found at http://www.arctic.noaa.gov/essay_wadhams.html

  57. Theo Goodwin says:
    February 13, 2013 at 7:59 pm

    The only data about Arctic sea ice volume is from satellites and dates only to 2003. Mosher has you on a technicality, so to speak. No matter what anecdotal evidence you cite, it is not evidence of volume.

    ———————–

    Wrong.
    From 1957:
    “Northpole ice has decreased by something as 40% in volume…this has been going on for 30-40 years”

  58. In addition (my prediction is) winter maximum extent will go back to the anomaly (longer term average) in less than 5 years.

    Not much of a prediction you might say when Arctic sea ice area was above the anomaly at maximum for both 2010 and 2012. But I posted that before I checked the data, so it sorta counts.

  59. Newspapers were full of stories reporting record Arctic warmth and northerly sea ice extent in the early 1920s, and again in 1939 (http://trove.nla.gov.au/ndp/del/article/94847838):

    THE WORLD WARMS UP
    Scientists’ Explorations in the Arctic

    Extraordinary phenomena have been observed in the Arctic during the last 20 years. The southern boundaries of the icefields have retreated considerably northward, the temperature of the atmosphere has risen, and warmth-loving fish and other creatures have begun to make their way north.

    The summer of 1936 was very warm in Eastern Greenland, and from the beginning of July onward the ice-crust along the coast retreated as far north as 72 deg. latitude; farther north than anyone could remember its having shrunk before. June of the same year was exceptionally warm in Leningrad – warmer than any other June of the 20th century.

    And in 1932 the small research vessel Knipovich succeeded in sailing all the way round Franz-Josef Land for the first time in the history of Polar navigation. During the same season the steamer Sibiryakov rounded the north of North-East Land, and in 1935 the Sadko achieved a feat which any Polar explorer of the past would have declared impossible – she sailed through open sea from the northern extremity of Novaya Zemblya to the northern extremity of North-East Land, and then reached latitude 82 deg. 84 min. north. Never before in the history of Arctic exploration had a vessel sailed freely on open seas in such northerly latitudes.

    Arctic Warmth Increasing
    Soviet scientists were the first to draw attention to the increasing warmth of the Arctic. In 1921 Professor N. M. Knipovich pointed out that the waters of the Barents Sea had grown perceptibly warmer since the investigations he had made in that area at the beginning of the present century. Indeed, of recent years, this rise in the atmospheric temperature of the Arctic regions had been considerable. In March 1920 the thermometer rose 10 degrees above normal in Novaya Zemblya and in Leningrad the same March achieved a record temperature for middle of the last century.

    Even the average winter during the last 20 years has been much milder. Icebound rivers on the northern areas of Soviet Russia, for instance, are opening earlier on the average, and freezing over later.

    Birds are arriving and vegetation blossoming earlier in the spring. In the Leningrad district in 1934 the bird-cherry was in flower by May 7 – half a month earlier than the normal time. And the cuckoo’s call is to be heard some 10 days earlier than it was in the middle of the last century. It seems, too, that the bounds of everlasting frost are retreating northward.

    About a century ago the famous traveller Shrenk discovered that in the town of Mezen wells had to be dug through ground frozen all the year round. But an expedition sent out by the Soviet Academy of Sciences in 1933 found no frozen ground at all in Mezen; the limit of everlasting frost had retreated some 25 miles north of the town. Obviously the climate must have grown very much milder to thaw out the frosts of Mezen.

    Of recent years, also, quite a number of warmth-loving fish and other organisms have made their way far to the north, along the coasts of Greenland, and eastwards into the Kara Sea. Formerly the salmon was not known at all east of the Barents Sea, but recently salmon, and also cod and herring, have been found in the Kara Sea. The mackerel, too, used never to be met with north of North Cape, but in 1937 I was sent a specimen caught off Novaya Zemblya, close to the entrance to the Strait of Matochkin Shar; while in 1933 the porpoise, which is not normally seen further east than the Kanm peninsula, was actually observed east of Taimir.

    Earth’s Temperature Rises
    This rise in temperature has also been going on all over the world. The average atmospheric temperature has risen not only in Europe and North America, but, most remarkable of all, in the Southern Hemisphere also – in Santiago de Chile, in Cape Town, and even in the tropics at Bombay and Batavia.

    Nor has it grown warmer only in the plains; the rise has extended even to areas of high mountains. What, then, are the causes of this rise in the earth’s temperature? Not long ago it was thought that the growing warmth of the Arctic must be due in some ways to an increase in the influence of the Gulf Stream, But, apart from the fact that the Gulf Stream is only one of the factors influencing climate and weather in the north, the rise in temperature, as we have seen, is also noticeable in the tropics and in the Southern Hemisphere.

    Obviously, that cannot be blamed on the Gulf Stream. We are witnessing, in fact, a change in climate which has affected almost the whole world – and naturally the Gulf Stream itself is being warmed by this general rise in temperature. The rise is being accompanied by a general intensification in the rate of circulation of our atmosphere, which in turn can only be caused by changes in physical conditions elsewhere than on the earth itself, such as an increase in the quantity of the solar heat received by the earth’s surface.

    The quantity of solar energy received by the earth can be increased by two causes – a greater irradiation of heat on the part of the sun – or because cosmic space or the terrestrial atmosphere is becoming more absorptive of solar energy.

    In the present state of scientific knowledge it is impossible to say which of these two alternatives more closely corresponds to the facts. It is equally impossible to say anything definite on the question of how long this rise in temperature will continue, whether it will continue at all, or whether the climate will soon return again to its normal condition.

    In the post-Ice Age, 3000 to 5000 years ago, there was a period when the summer temperature was even hotter than it is today. But whether we are witnessing the reproach of another such period – or whether it is merely a question of a climatic variation which will only last a few decades – is a question which at present can not be answered.

  60. Kevin O’Neill;
    No, that’s not the way it works. The Arctic Ocean is composed of layers of water with different properties, and at the base of the surface layer there is a big jump in density (known as a pycnocline), so convection only involves the surface layer down to that level (about 100-150 metres).
    >>>>>>>>>>>>>>>>>>.

    I’ll take your word for it.
    Which leaves a water column of 100 to 150 meters that still has to change temperature to support a few cm of ice. That water volume and the temperature change of it dwarfs the energy represented by phase change of water to ice in the ice layer.

  61. Does anyone know the ice extent prior to the massive storm that destroyed so much of it 4th Aug-9th Aug last summer? If so it would be an intereesting projection to see where the ice would be now if it was not for that storm.
    See Antartica is in good shape….also notice it is never discussed.

  62. “Kevin O’Neill;
    No, that’s not the way it works. The Arctic Ocean is composed of layers of water with different properties, and at the base of the surface layer there is a big jump in density (known as a pycnocline), so convection only involves the surface layer down to that level (about 100-150 metres).”

    Instead of speaking from a position of authority you should provide a link to the essay from which you have quoted verbatim!

    http://www.arctic.noaa.gov/essay_wadhams.html

  63. Manfred says:
    February 13, 2013 at 10:08 pm

    From 1957:
    “Northpole ice has decreased by something as 40% in volume…this has been going on for 30-40 years”

    http://i680.photobucket.com/albums/vv161/Radiant_2009/popularmechanics1957-2.jpg

    You claim that Theo Goodwin was wrong when he wrote “The only data about Arctic sea ice volume is from satellites and dates only to 2003. Mosher has you on a technicality, so to speak. No matter what anecdotal evidence you cite, it is not evidence of volume.

    Then you proceed to produce your quote. I’m sure popular mechanics was, in 1957 (a good year btw – I was born then!), a fine publication, but I question whether the seeking out of a Professor of Meteorology and getting a staff reporter to ask him loaded questions actually counts as evidence at all, especially since he went on to state “If this continues till (sic) the end of the century there will be very little summer ice in the Arctic, or only small patches of it.” That didn’t work out so well, did it.

    Fwiw, I think that it’s way too early to be making any definitive pronunciations on Arctic sea ice volumes since (a) satelite measurements have only recently begun to be taken and (b) I have yet to see any definitive verification of the data. Because of that, anyone who makes any kind of claim about long term trends must, of necessity, be reliant on models and anecdotal evidence. That is as true for sceptics as it is for Mosher. ;-)

  64. The only problem with all this concentration on Min and Max is that woefully fails when analysing cyclic phenonema.

    Normally, in most (all?) other areas of science when looking at cycles of any form then there are four points, not two, that are of primary interest.

    The two other relevant points are the ‘zero or central crossing’ ones. These are the ‘central’ values about which Arctic Sea Ice oscillates. http://i46.tinypic.com/2ezgzk5.png

    The precise timing of these ‘zero crossing’ points (as well as the timing of the Min & Max) along with the Min and Max range shows a more complex picture than just simply ‘all year larger’ or ‘all year smaller’ would suggest.

    The best way to determine these ‘zero crossing’ points is to find parts of the signal which have the least varience year on year.

    Those, for Arctic Sea Ice, appear to be ~21st May and 14th to 21st Dec.

  65. ” We really don’t have any good data beyond the satellite era,…”

    We don’t know yet if we even have good data from the satellite era. Scientists and explorers of the days past were equally sure that they knew what they knew with their methodology back then. Modern instrumentation can lie every bit as well as ancient instrumentation. Apparently modern scientists can lie even better. So yes, there has been progress in scientific endeavour in the modern age, jut not the right kind.

  66. @davidmhoffer says:
    February 13, 2013 at 4:58 pm, February 13, 2013 at 8:34 pm & February 13, 2013 at 10:53 pm
    @Kevin O’Neill says:
    February 13, 2013 at 9:36 pm
    @edcaryl says:
    February 13, 2013 at 5:24 pm

    So if the run-off from these Russian rivers in the past created a layer of fresh water on top of the Arctic. Wouldn’t that greatly improve ice forming?
    And now that this run-off is greatly diminished, wouldn’t you expect thinner ice?

  67. After going through some of Cryosat2’s raw data last spring, it became clear to me that Cryosat2 is not going to be able measure sea ice thickness in the way its primary mission intended. The tiny swaths of data from each orbit changes so much from orbit to orbit (waves, tides etc) that it makes no sense.

    I speculated that it would only be able to provide seasonal averages or maybe it needed to be re-purposed for other missions.

    Looking at some of the data presented around the Net from this new paper, it looks to me like this is indeed the case. A few snapshots, a video showing 12 datapoints from October2010-March2011 and October11-March2012. Does it take one full year before they can reprocess the data to give us a March 2012 estimate? What’s going on during the melt season? Why is there so much missing?

    Video of the numbers here.

    http://spaceinvideos.esa.int/Videos/2013/02/Monthly_sea_ice_volume

    Wake me up when they can provide something better than this. It does not verify the PIOMAS model which is just based on someone’s imagination.

  68. Ockham says:
    February 13, 2013 at 7:31 pm
    phlogiston says:
    February 13, 2013 at 3:43 pm

    “If the current switch to La Nina ENSO dominance continues, and the AMO enters its down-swing, then the legacy warm water will run out and the Arctic ice will recover.”

    Recover? Why does everyone assume conditions are abnormal? I can as easily proclaim the last 30 years of ice extent, area and volume decline IS the recovery to arctic-normal conditions.

    You’re right – I was unwittingly using catastrophist language. As Richard Lindzen put it “to imagine that the end of the 19th century represented climate perfection is not a sign of intelligence”.

  69. Hi Mosher,
    You say and quote the following:

    Steven Mosher says:
    February 13, 2013 at 3:58 pm

    “We already know that arctic ice has been low in the past. This obsession is beyond ridiculous.”

    really? is that settled science? do we really KNOW this? tsk tsk skepticism out the door

    hmm, lets see some data on area, extent and volume.

    Here are papers flat out saying “ice-free” so no area, extent or volume because it’s “ice-free”

    Abstract
    ……….A large set of samples of molluscs from beach ridges and marine sediments were collected in the summer of 2007, and are presently being dated to give a precise dating of the ice free interval. Preliminary results indicate that it fell within the interval from c. 8.5 to c. 6 ka – being progressively shorter from south to north. We therefore conclude that for a priod in the Early Holocene, probably for a millenium or more, the Arctic Ocean was free of sea ice at least for shorter periods in the summer. This may serve as an analogue to the predicted “greenhouse situation” expected to appear within our century.

    http://adsabs.harvard.edu/abs/2007AGUFMPP11A0203F

    Abstract
    …………….The combined sea ice data suggest that the seasonal Arctic sea ice cover was strongly reduced during most of the early Holocene and there appear to have been periods of ice free summers in the central Arctic Ocean. This has important consequences for our understanding of the recent trend of declining sea ice, and calls for further research on causal links between Arctic climate and sea ice.

    http://www.sciencedirect.com/science/article/pii/S0277379110003185

    Abstract
    Calcareous nannofossils from approximately the past 7000 yr of the Holocene and from oxygen isotope stage 5 are present at 39 analyzed sites in the central Arctic Ocean. This indicates partly ice-free conditions during at least some summers. The depth of Holocene sediments in the Nansen basin is about 20 cm, or more where influenced by turbidites.

    http://geology.geoscienceworld.org/content/21/3/227.abstract

    Abstract
    …Today’s ice cover (2 to 4 meters thick) over the Arctic Ocean provides a shadow that prevents coccolithophorids (photosynthetic, planktonic algae) from living there. Sparse, low-diversity, but indigenous coccolith assemblages in late Pliocene to mid-Pleistocene (but not Holocene) sediments imply deep penetrating warm currents or an ice-free Arctic Ocean, or both, as those layers were being deposited.

    http://www.ncbi.nlm.nih.gov/pubmed/17796050

    http://www.tos.org/oceanography/archive/24-3_polyak.html

  70. I don’t find this surprising at all, 2007 had a very low minimum, and 2012 had the storm that broke up a ridiculous amount of ice and flushed it south where it melted. It takes a few years for ice volume to recover after such events, and I fully expect that it will recover, barring another freak storm that parks itself over the arctic in mid-Summer.

  71. Mosher,
    You might also be interested in the following:

    Abstract
    A 10,000-Year Record of Arctic Ocean Sea-Ice Variability—View from the Beach
    We present a sea-ice record from northern Greenland covering the past 10,000 years. Multiyear sea ice reached a minimum between ~8500 and 6000 years ago, when the limit of year-round sea ice at the coast of Greenland was located ~1000 kilometers to the north of its present position. The subsequent increase in multiyear sea ice culminated during the past 2500 years and is linked to an increase in ice export from the western Arctic and higher variability of ice-drift routes

    http://www.sciencemag.org/content/333/6043/747.abstract

  72. Jim south London says:
    February 14, 2013 at 4:43 am
    ———————————

    I think you forgot /sarc

  73. Climate stability when it was warmer???? WUWT I ask you???

    Abstract
    Low-frequency and high-frequency changes in temperature and effective humidity during the Holocene in south-central Sweden: implications for atmospheric and oceanic forcings of climate

    …………The maritime climate mode was disrupted by the abrupt cold event at 8,200 cal year BP, followed at 8,000 cal year BP by a stable Holocene Thermal Maximum. The latter was characterized by T ann values about 2.5°C higher than at present and markedly dry conditions, indicative of stable summer-time anti-cyclonic circulation, possibly corresponding with modern blocking anticyclonic conditions. The last 4,300 year period is characterized by an increasingly cold, moist, and unstable climate.

    http://link.springer.com/article/10.1007%2Fs00382-005-0024-5?LI=true

  74. Sean says:
    February 13, 2013 at 3:43 pm
    What will happen to their model when the AMO turns negative in a few years?

    The sea ice will increase. It may do so even before then as the AMO is already on its downward swing. However, it will likely be too late to make much difference in the debate. By that time a decline in global temps will be obvious and the scam will be over.

    There will likely be one more El Niño warm year (2014?) keeping the warmist hopes alive. When we go over 20 years without any warming how can they possibly keep claiming disaster is looming?

  75. Bill Illis says:
    February 14, 2013 at 4:28 am
    After going through some of Cryosat2′s raw data last spring, it became clear to me that Cryosat2 is not going to be able measure sea ice thickness in the way its primary mission intended. The tiny swaths of data from each orbit changes so much from orbit to orbit (waves, tides etc) that it makes no sense.

    I’ve been wondering why no data has been forthcoming. Thanks for clearing that up. It’s clear you are right on the money or we would already have been inundated with alarmist rantings about the ice.

  76. Manfred says:
    February 13, 2013 at 10:08 pm

    Thanks. It seems that there are historical reports of volume. I stand corrected.

  77. Richard M says:
    February 14, 2013 at 6:45 am
    Bill Illis says:
    February 14, 2013 at 4:28 am

    Thanks, Richard and Bill. The best that can be said about these satellites is that they are getting started. They might be valuable some day.

  78. Atmospheric temperature has flatlined at a fairly high level. It is clear that it is not the delta t melting the ice (wink). But why is Antarctica not melting?

    I’d be a lot more worried if it were. 90% of the continental ice (the kind that raises sea level when it melts) is down there. Greenland has only 10%.

  79. Richard M says:
    February 14, 2013 at 6:42 am
    Sean says:
    February 13, 2013 at 3:43 pm
    What will happen to their model when the AMO turns negative in a few years?

    The sea ice will increase. It may do so even before then as the AMO is already on its downward swing. However, it will likely be too late to make much difference in the debate. By that time a decline in global temps will be obvious and the scam will be over.

    By that time there won’t be much Arctic sea ice left so they’ll need to retask the satellite.

  80. I note that trafamadore has never responded to this:

    “…why don’t you try to answer dp’s question: tell us how much Arctic ice is the right amount?”

    trafamadore is such an insufferable know-it-all that he should have no trouble answering a simple question like that.

  81. @ CodeTech / February 13, 2013 at 3:42 pm

    parafrasing:

    Sigh…. what kind of mental aberration makes people think a downward trend cannot
    continue to zero?

    the snow before my house door is just disappearing into “zero” since the atmospheric temperature is now above zero degrees Celsius (+), in one or two days it will be gone (completely)

  82. I am distrustful of “reconstructions” of what the ice was like in the past, especially because it often fails to match up with conditions suggested by Viking sagas. The seas during the MWP were more open during the summers than is stated in any paper I can find, in my humble opinion.

    There are somewhat mysterious structures in the high arctic consisting of two parallel stone walls, with no sign of any sort of roof. They are of a size and shape where a roof could have been made by hauling a boat from the water and turning it upside down to use it as a roof during the winter. It has been suggested that Vikings sailed north during the summer, and then “wintered over,” hunting to get things which were of value back in Europe, especially Walrus ivory (African ivory from elephants was unavailable for a time due to problems trading with Muslims) but also polar bear fur and sealskins.

    Such activities are not possible without much less sea ice.

    Concerning the “volume of ice,” any model must take into account considerable differences in how windy the winters are, due to differences between a negative and positive AO. The winds determine how many pressure ridges are formed. The “keel” of a pressure ridge can stick down as far as 150 feet. You can’t just state the ice is six feet thick “on average,” and ignore the places where it is 150 feet thick, nor the fact some years there are many more pressure ridges created than other years.

  83. Clearly the climate is changing and changing fast. Just because the changes are not predictable does not mean they are not occuring and are not critical to millions of people. Stay in some shaded area of thinking and ignore the obvious – the daily weather in your face for example. Not one part of the planet is excluded from this change. I am astounded at the claim that half a degree does not make a difference, well consider how you as a person feels when your body temp is running just half a degree hot. The planet is the same. Yes the stat’s are not perfect, yes the models are not perfect but the direction is clear and the end result is easy to calculate. Earths population in 1900 approx 1.3 billion, in 1950 approx 3 billion in 2010 approx 7 billion. If you want to claim that humans are not the cause of this climate change, then please explain how this population explosion has not impacted the planet.

  84. bern says:
    February 17, 2013 at 8:12 pm

    Clearly the climate is changing and changing fast.

    Why are you still using a computer if you think there is a problem? And if you think population is a problem, how about volunteering yourself our of the gene pool?

    Just relax and take a breath. The temperature of the surface of a planet is NOT the same as the internal core temperature of a living organism. Or do you have a fever every time the sun shines on your skin?

    Sheesh!

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