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Notes from The Gathering #5: Arctic sea ice: is it tipped yet?

Filed under: — david @ 13 December 2007

The summer of 2007 was apocalyptic for Arctic sea ice. The coverage and thickness of sea ice in the Arctic has been declining steadily over the past few decades, but this year the ice lost an area about the size of Texas, reaching its minimum on about the 16th of September. Arctic sea ice seems to me the best and more imminent example of a tipping point in the climate system. A series of talks aimed to explain the reason for the meltdown.

Sea surface temperatures were warmer this past summer also; I forget how many standard deviations the temperature was off the trend, but it was definitely anomalous. The region of the meltback is just inside the Bering Strait, where warm water flows in from the Pacific, but in the analysis of Steele et al. this inflow of comparatively warm water was not particularly anomalous in 2007 relative to other years. It could be that the exposure of the sea surface to the atmosphere by the melting ice could have an impact, although the meltback is so late in the solar heating season (September) that this effect seems of limited explanatory value also. Bit of a chicken and egg problem here.

Melting ice can be seen from space, I believe as puddles sensed by the QuickSCAT satellite. The puddles are most abundant in mid-summer when the sunlight is strongest, and by mid-September when the ice meltback was the strongest, the melting season was largely over. Apparently the reason for the disappearance was an anomalous weather system which generated a strong jet of surface winds blowing straight over the pole southward toward the Atlantic ocean, a “Polar Express”. A research ship frozen into the ice in 2006 crossed the Arctic in about a year, about three times faster than the transit time of the Fram in the 1890’s. To summarize, the ice cubes in the freezer tray didn’t melt because the freezer is broken exactly, but because the ice cube tray fell out of the freezer onto the warm floor.

The disappearance of the ice was set up by warming surface waters and loss of the thicker multi-year ice in favor of thinner single-year ice. But the collapse of ice coverage this year was also something of a random event. This change was much more abrupt than the averaged results of the multiple IPCC AR4 models, but if you look at individual model runs, you can find sudden decreases in ice cover such as this. In the particular model run which looks most like 2007, the ice subsequently recovered somewhat, although never regaining the coverage before the meltback event.

So what is the implication of the meltback, the prognosis for the future? Has the tipping point tipped yet? When ice melts, it allows the surface ocean to begin absorbing sunlight, potentially locking in the ice-free condition. Instead of making his own prognosis, Overland allowed the audience to vote on it. The options were

  • A The meltback is permanent
  • B Ice coverage will partially recover but continue to decrease
  • C The ice would recover to 1980’s levels but then continue to decline over the coming century

Options A and B had significant audience support, while only one brave soul voted for the most conservative option C. No one remarked that the “skeptic” possibility, that Arctic sea ice is not melting back at all, was not even offered or asked for. Climate scientists have moved beyond that.


202 Responses to “Notes from The Gathering #5: Arctic sea ice: is it tipped yet?”

  1. 51
    Patrick M. says:

    Re 25

    Check out Gavin’s responses in 8 & 13. Gavin was the one who brought up predictability, not me. Gavin suggested the analogy of rolling a ball down a plane, not me. Gavin gets to draw the graph, not me.

    My opinion is that predicting the climate is NOT a slam dunk. Climatologists are getting better, but they still have a ways to go.

  2. 52
    SP says:

    Bruce at # 38.

    Afraid the BBC’s motor programme, Top Gear, did just your last point,
    http://www.bbc.co.uk/topgear/show/production_notes/polar_special.shtml

    They raced a 4×4 (SUV) versus husky dogs pulling a sled to the magnetic north pole. Though I’m not sure when they held the race, but I think it was shown on TV a couple of months ago.

  3. 53
    Kevin Stanley says:

    re: #40 (barry)
    This has been discussed often on other threads. If I recall correctly, the decreasing arctic trend is considerably larger than the increasing antarctic trend. The antarctic increase is does not offset the arctic decrease.

  4. 54
    John L. McCormick says:

    RE # 16

    Mitchell, re-freeze at a rapid pace is not a headline nor is it a sign for hope. Think thickness; not area.

    And, the open water of the far Western top of the Bering Strait appears to be adding heat to Barrows AK.

    See the following:

    13 December, 2007 Global Monitoring Division Hot Items

    Exceptionally Warm Winter Temperatures at Barrow, Alaska Baseline
    Observatory

    Global Monitoring Division – ESRL-GMD
    This story entered on 12th Dec, 2007 09:55:45 AM PST

    The NOAA ESRL Barrow, Alaska, Atmospheric Baseline Observatory located on the most northerly habited point of land in the U.S, has been continuously measuring meteorological parameters since 1977. In November of this year, the average temperature at the observatory was +14.3F (+8C) warmer than the monthly norm. From December 1-10, 2007, the average temperature has been
    +22.2 F (+12.3C) warmer than the long term average for December. These exceptionally warm temperatures are likely due to heat from the warmer Arctic Ocean off shore from Barrow that is still not frozen for this winter.

    The Barrow Observatory chief, Dan Endres, who has been at the Barrow observatory for 23 years, notes that in the 1980s the ocean would generally freeze by the middle of October. In recent years, freeze-up has been
    occurring progressively later.

  5. 55
    Bill Glenn says:

    As NASA has reported, the Arctic ice sheet lost half of its volume since 2004. Given the accelerated rate of meltdown, there seems to be little reason to be believe the ice will survive the 2009 summer.

    I’m interested in knowing whether sea level rise will affect the equator more than the higher and lower latitudes. Once Arctic ice melts off, I would guess that sea level will start rising rather fast.

  6. 56
    Matthew Janiga says:

    I’ve also heard that decreased cloud cover played a role in this summer’s melt. Was there any discussion about this at the AGU meeting?

    Also, climate models used to overpredict summer cloudiness I’m not aware if this is still a problem for the more current models.

    Lastly, is there any research on how summer cloudiness in the arctic might change in the future? Or is this something we aren’t able to answer yet, as I suspect?

  7. 57
    weather tis better... says:

    Does anyone have a reaction to the sea ice coverage comparisons shown on these images?

    http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh

  8. 58
    Russell says:

    I am selecting option D. It will return to the mean (if we actually know what that is).
    Gavin your analogy needs a little improvement. How about rolling a non-spherical ball down an incline of variable slope, that has snow and patchy ice, and a gusting wind, on a rocking boat.
    The variability of the ice coverage is an unknown quantity, and the current coverage, although outside the norm to our short record, is most likely to be well within the natural pattern of the system.
    Without a coresponding meltdown in Antarctica, there are many situations that can cause the current coverage, and most of them are not indicators of future calamity.
    I will agree that it is a solvable problem. But at today’s understanding it is not. This is multi-variable choas modeling, that exceeds our current ability. So make your prediction, and I will make mine, and 5 years from now we will compare notes. Maybe by then we will be closer to understanding a system that continues to hold more mysteries, than the fiction section at the local library.

    [Response: Sure. My point was not that climate was as simple as a rolling a ball down an inclined plane but simply that physics allows you to make predictions when extrapolations from short time series do not. - gavin]

  9. 59
    J.C.H. says:

    I’ve not found an estimate of how much of last years ice melted within the Arctic Ocean and how much of it left the Arctic Ocean. It looks to me like very favorable conditions for carrying ice out of the Arctic are in the cards.

  10. 60
    James says:

    Re #54: [How about rolling a non-spherical ball down an incline of variable slope, that has snow and patchy ice, and a gusting wind, on a rocking boat.]

    Which might be a better analogy for the current state of climate prediction. But I’d have you notice that while it’s hard to predict exactly what path that ball will take on its descent, or exactly when it will reach the bottom, it’s still a pretty darned good bet that it WILL reach the bottom.

  11. 61
    L Miller says:

    Patrick, his point was that predictions made from underlying physics differ significantly from predictions coming purely from statistics. It’s still up to you to understand the nature of the predictions made on the basis of physics and form your questions accordingly.

    More specifically, the study of climate doesn’t involve predicting specific events or conditions. Asking what the underlying physics predicts for a trend is a valid climate question, asking for an exact prediction of next years ice extent is actuly a question about weather. Perhaps you are under the impression that you must be able to predict events specifically to predict an overall trend, but this could not be further from the truth.

    On the topic of Arctic vs Antarctic sea ice, it’s worth point out that the comparison is between summer ice in the Artic and winter Ice in the Antarctic. Winter ice in the Artic is largely bound by the land masses around it, while summer ice in the Antarctica is almost non-existent and therefore also quite stable. Less summer ice in the Artic means lots of sunlight landing on dark water vs reflective ice which can cause further warming. Clearly this isn’t nearly as big an issue for winter ice in the Antarctic.

  12. 62
    Patrick M. says:

    Re 54:

    Well said.

    If it were easily predictable we wouldn’t need smart people like Gavin spending time on the issue.

  13. 63
    One Brave Soul says:

    Well, my reasoning is – if I vote for sea ice it’s gotta come back! ;-)

  14. 64
    Patrick M. says:

    Re 57:

    I understood Gavin’s point. He picked a very misleading analogy; that was my point.

    I understand the distinction between weather and climate. Granted, 5 years is on the very low end of “climate”, but I don’t think you’ll get many meteorologists claiming that predicting arctic sea ice 5 years into the future is in their ballpark.

  15. 65
    Russell says:

    Yes it will reach the bottom, except under the extreme scenerio, boat rocks at the same time wind blows, and UFO passes over head at low level ;-)
    But that only equates to: The ice volume will be greater in January of 2020, than it will be in July of 2020. I am very willing to go out on that limb. It doesn’t take much bravery.
    Currently we have such a small signal-to-noise ratio, that most people have become frustrated and impatient, and want to call anything that meets a very broad category, a signal.
    If you want to maintain that this is science, and not crystal ball readings, then you have to make sure you can determine the distinction, between the signal and the noise.

  16. 66
    Bill says:

    Re: #48. Do you know the difference between the geographic north pole and the magnetic north pole?

  17. 67

    barry (#40) wrote:

    Sea ice coverage in the Antarctic has been larger this summer than last, and shows an opposite trend to the Arctic coverage since the 1970s.

    http://www.gsfc.nasa.gov/topstory/20020820southseaice.html

    If I were a contrarian saying that, I would be answered “you shouldn’t invest your understanding in just one geographical location – you have to see the whole,” but the same criticism can be applied to the post at the top of this thread.

    In the interests of robustness, wouldn’t it be worthwhile acknowledging that qualification and responding to it?

    Of course — but then let’s look at the whole.

    Simply as a matter of the distribution of the continents, we do not expect the Antarctic Ocean to behave in quite the same way as the Artic Ocean, not in the short-run. There is more landmass in the Northern Hemisphere, and ocean has more heat capacity than land, land should warm more quickly, therefore the Northern Hemisphere should warm more quickly.

    The Southern Hemisphere sea-ice area broke its previous maximum by 0.9%, the Northern Hemisphere sea-ice area broke its previous minimum by 27%. These really aren’t comparable. Antarctica’s trends are mixed. While there is cooling which been taking place in the continental interior (which is believed to be largely the result of ozone depletion and possible increased snowfall), depending upon the start and end year, much of Antarctica may show either a warming or cooling trend. However, since the beginning of the satellite era, Southern Hemisphere sea ice extent has declined — with most of the decline occuring in the 1960-70s. (See Tamino’s Sea Ice, North and South, Then and Now.)

    We had expected the ice mass of Antarctica to show a slight rising trend for some time simply as the result of projected increased snowfall, but according to Grace gravity measurements, Greenland and now Antarctica are losing ice mass, and satellite imaging shows that weeks of melt have been occuring in recent far into the continental interior of Antarctica as close as 310 miles of the South Pole. Meanwhile, nearly the entire coastline of Antarctica is showing strong warming, not cooling.

    Finally, when dealing with contrarians it might help to remind them every once in a while that heat melts ice. So long as we continue to raise the levels of gases which are opaque to thermal radiation, we can expect the rising trend in temperatures continue. In broad outline at least, the nature of the response from Greenland and the West Antarctic Peninsula will more or less be a given. And with the feedbacks we have been discovering, the response of both is likely to be quite strong.

  18. 68
    B Buckner says:

    For those keeping score, the global sea ice anomaly is now positive, granted with all that thin ice.
    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/global.daily.ice.area.withtrend.jpg

  19. 69
    Eli Rabett says:

    How about coming down the hill at lickety split units of distance per second, and wondering if the driver knows where the cliff is, and if he has a clue where to start stopping to avoid going over the edge. Oh yes, the driver has been known to attempt suicide before. Details about the economics of the situation at the uncertainty principle

  20. 70
    Russell says:

    Re #64
    I am yet to be convinced that the “end is near”. Your analogy pre-supposes the mountain and the cliff. What if we are just cruising along the interstate in Nebraska, doing the speed limit? Is it approriate to slam on the brakes, just in case there might be a cliff ahead (in Colorado)?
    My understanding indicates the CO2 does not have enough ir thermal radiative capacity to warm the planet to a significant degree, and that the fear is that it will trigger positive feed back warming. So far I am not impressed with the real-world evidence that this is actually occuring. My faith in the models, is also not that strong. I looked through Galvin’s model and I was certainly impressed with all the effort that went it to it. But the reality is he has a rich uncle who is willing to put up with it’s lack of real-world performance. If it was a private sector project, and I had to sell it to a paying customer, it would have to match up with the observed data from the real-world. Tweaking the dials on a model that is grossly over-reaching is an exercise in “GIGO”.
    I view this as an important issue, but it has not crossed the threshold of “the end is near”.

  21. 71
    Jim Galasyn says:

    Re the golf-versus-bowling-ball comparison in 8:
    isn’t this the difference between stochastic and dynamical systems? The central point is to understand that climate equations are not stochastic, they’re in the realm of continuum dynamics. So they comprise differential equations that we can integrate into the future. The GCMs are essentially Navier-Stokes equations on steroids.

    At least, that’s how I understand Gavin’s comparison.

  22. 72
    Jim Galasyn says:

    More happy news from the cryosphere:

    Climate change blamed as thousands of walruses die in stampedes
    By DAN JOLING
    The Associated Press

    ANCHORAGE, Alaska — In what some scientists see as another alarming consequence of global warming, thousands of Pacific walruses above the Arctic Circle were killed in stampedes earlier this year after the disappearance of sea ice caused them to crowd onto the shoreline in extraordinary numbers.

    The deaths took place during the late summer and fall on the Russian side of the Bering Strait, which separates Alaska from Russia.

    “It was a pretty sobering year — tough on walruses,” said Joel Garlach-Miller, a walrus expert for the U.S. Fish and Wildlife Service.

    Unlike seals, walruses cannot swim indefinitely. The giant, tusked mammals typically clamber onto the sea ice to rest, or haul themselves onto land for just a few weeks at a time.

    But ice disappeared in the Chukchi Sea this year because of warm summer weather, ocean currents and persistent eastern winds, Garlach-Miller said.

    As a result, walruses came ashore earlier and stayed longer, congregating in extremely high numbers, with herds as big as 40,000 at Point Shmidt, a spot that had not been used by walruses as a “haulout” for a century, scientists said. …

  23. 73
    Jim Galasyn says:

    Re Russel’s skepticism of the greenhouse power of CO2 in 65, what do you think is keeping the Earth warm? You do know that without CO2, the planet would be something like 33C cooler…right?

  24. 74

    barry (#40) wrote:

    Sea ice coverage in the Antarctic has been larger this summer than last, and shows an opposite trend to the Arctic coverage since the 1970s.

    http://www.gsfc.nasa.gov/topstory/20020820southseaice.html

    If I were a contrarian saying that, I would be answered “you shouldn’t invest your understanding in just one geographical location – you have to see the whole,” but the same criticism can be applied to the post at the top of this thread.

    In the interests of robustness, wouldn’t it be worthwhile acknowledging that qualification and responding to it?

    Of course — but then let’s look at the whole.

    Simply as a matter of the distribution of the continents, we do not expect the Antarctic Ocean to behave in quite the same way as the Artic Ocean, not in the short-run. There is more landmass in the Northern Hemisphere, and ocean has more heat capacity than land, land should warm more quickly, therefore the Northern Hemisphere should warm more quickly.

    The Southern Hemisphere sea-ice area broke its previous maximum by 0.9%, the Northern Hemisphere sea-ice area broke its previous minimum by 27%. These really aren’t comparable. Antarctica’s trends are mixed. While there is cooling which been taking place in the continental interior (which is believed to be largely the result of ozone depletion and possible increased snowfall), depending upon the start and end year, much of Antarctica may show either a warming or cooling trend. However, since the beginning of the satellite era, Southern Hemisphere sea ice extent has declined — with most of the decline occuring in the 1960-70s. (See Tamino’s Sea Ice, North and South, Then and Now.)

    We had expected the ice mass of Antarctica to show a slight rising trend for some time simply as the result of projected increased snowfall, but according to Grace gravity measurements, Greenland and now Antarctica are losing ice mass, and satellite imaging shows that weeks of melt have been occuring in recent far into the continental interior of Antarctica as close as 310 miles of the South Pole. Meanwhile, nearly the entire coastline of Antarctica is showing strong warming, not cooling.

    Finally, when dealing with contrarians it might help to remind them every once in a while that heat melts ice. So long as we continue to raise the levels of gases which are opaque to thermal radiation, we can expect the rising trend in temperatures continue. In broad outline at least, the nature of the response from Greenland and the West Antarctic Peninsula will more or less be a given. And with the feedbacks we have been discovering, the response of both is likely to be quite strong.

  25. 75
    Russell says:

    Re: #67 The mother of all GHGs is H20. The rest of GHGs are like planets orbiting the sun. They exist, but are a tiny fraction of the whole. If we don’t have a positive feedback, we don’t have an emergency. We have a very managable situation.

  26. 76
    Jim Galasyn says:

    Re the old water vapor claim in 68:

    Water vapor is responsible for about 50% of the greenhouse effect, clouds contribute about 25%, and CO2 and other GHGs contribute the rest. Not “a tiny fraction”. You also need to account for the large difference in residence time between H2O and CO2, which is important for dynamics over long time scales.

  27. 77
    Ray Ladbury says:

    Russell, where on earth are you getting your “understanding”? First we have the empirical fact that Earth is warming rapidly–something must be providing the energy driving this warming. If it is not CO2, then what is is. Second, why do you think GCMs have all these adjustable parameters that can be freely tweaked. Most of the forcings are determined independently of the current warming trend, and greenhouse forcing in particular is nailed down to a narrow range by several independent lines of evidence.

  28. 78
    Hank Roberts says:

    > I assumed the issue is whether the summer minimum in
    > 2008 will match that of 2007, or whether it would
    > recover somewhat. David]

    Thanks, David, that makes sense.

    Heck, we can simplify it — will they have to again add new white space to the anomaly chart, to have room for the line to fit on it, as they did (twice, I think) in the past year.

  29. 79
    dhogaza says:

    So far I am not impressed with the real-world evidence that this is actually occuring.

    Here’s a chance for you to educate us, then.

    Please give us an itemized list of the real evidence that warming is occurring, and for each tell us why you find that evidence unimpressive.

    My guess is that your list is going to quite short and is going to reveal just how little you know about the overwhelming evidence that’s accumulating, but this is your chance to prove me wrong.

  30. 80
    Thomas says:

    68,69:

    In absolute terms H2O GH forcing is greater than CO2. Unfortunately H2O levels respond very well to temperature increases. If I add a little CO2 (or other forcing) the directly induced warming evapoartes more water, and the H2O forcing increases. This is refered to as a positive feedback -and in this case it operates on a pretty fast time scale ( a couple of weeks ). Some of the other potential positive feedbacks involving methane-hydrate release, or albedo changes due to loss of glacier ice operate on much longer time scales tens to hundreds to thousands of years.

    The real difficulties come with some of the feedbacks that are harder to characterize. Potential changes in cloudiness or cloud albedo. Changes of vegeatation, changes in oceanic and/or atmospheric circulation. My nonprofessional opinion is we haven’t encountered all of the surprises in these areas yet. Didn’t the rapidity of the arctic/subarctic vegetation feedback largely catch the climate community by surprise?

    To what extent might the black carbon become more important if a significant area of the greenland ice sheet becomes an ablation zone (net melting)? Could the BC become concentrated at the surface as older and older ice melts? This is a big effect on mountain glaciers, but these are many times dirtier than polar ice caps.

  31. 81
    Lawrence Coleman says:

    Re: Gavin 65 I have been very impressed as to the accuracy of the computer models the IPCC researchers have been using..they overall forcast current trends very accurately given a narrow standard deviation for unforseens. The rise in ocean temp is bang on the money, the concentrations of CO2 in the atmosphere has been predicted 10 years ago again by computer modelling and it’s also very accurate. What I have noticed however is that most models are slightly too conservative coz they dont factor in the effects of methane and nitrous oxide, ozone and other lesser but contributing greenhouse gasses. So I happen to have a lot of faith in computer modelling, not just because it’s all we have at this point in time but because their history vindicates their effectiveness in the real world. That’s right russell..GIGO….scientists have always been very fastidious and fanatical NOT to feed garbage into their algorithms.

  32. 82
    Peter Williams says:

    Re Russell #65:

    As someone who has developed models for complex hydrodynamic systems in academia in astrophysics, in national labs on weapons programs, and in the private sector to boot, my $.02 is that you don’t know jack. It is a complete free-market fantasy notion that gov’t funded scientists have models that wouldn’t survive the “real world” of the private-sector, and that somehow having Uncle Sam pay the tab means the quality goes down. Quite the opposite. In my private-sector job, I depend daily on research funded by NASA, NSF, and the NIH, and on models developed by gov’t-funded researchers. That stuff is the best there is. Boeing wouldn’t last a minute without the decades of fundamental aerodynamics research and modeling done by NASA and NACA for the last 60 years. Similar statements could be made about any high-tech industry; take your pick.

    As for your opinions on the models, uhm, what is your background? Got radiative transfer and geophysical hydro nailed down? If not, why should anybody other than you place any value whatsoever on your opinion of the models? If you disagree, hey, follow your free-market muse and start a climate model company. Let me know when the IPO is so I can sell short.

  33. 83
    Peter Williams says:

    If you really want to know how well the private sector makes models, take a look at how companies model their exposure to risk. Now see, free market forces have made these models very reliable and robust, and this keeps the credit system running smoothly, and…. oh, wait.

  34. 84
    Russell says:

    First of all, I didn’t mean to sound shrill in my last posts. I had a bad afternoon, and I didn’t have a proper outlet, so I vented a bit of frustration on the blog, that I should have re-directed to thermal radiation of the troposphere.
    I don’t have time to go into a line-by-line discussion of this issue, right now, but I will give you a chance to get your jabs in, soon.

  35. 85

    Russell writes:

    [[My understanding indicates the CO2 does not have enough ir thermal radiative capacity to warm the planet to a significant degree,]]

    That’s kind of a meaningless statement. What is “thermal radiative capacity?”

    [[...So far I am not impressed with the real-world evidence that this is actually occuring.]]

    That one quote says it all, I think.

  36. 86

    Russell writes:

    [[Re: #67 The mother of all GHGs is H20. The rest of GHGs are like planets orbiting the sun. They exist, but are a tiny fraction of the whole. If we don’t have a positive feedback, we don’t have an emergency. We have a very managable situation.]]

    According to Kiehl and Trenberth’s 1997 energy budget for the Earth-atmosphere system, water vapor causes 60% of the clear-sky greenhouse warming and carbon dioxide causes 26%. Also, the water-vapor feedback is indeed a “positive feedback,” so by your own definition, we have an emergency.

  37. 87
    Jim Cripwell says:

    Ref 71 dhogaza writes “Please give us an itemized list of the real evidence that warming is occurring, and for each tell us why you find that evidence unimpressive.” Surely you have got this wrong. What we should be discussing is all the things that show that while the earth’s temperature did increase at the end of the 20th century, temperatures have now stabilized, and the earth is now starting to cool. Such things as the fabulous ski season there was in the southern hemisphere in 2007, followed by an equally impressive one now occurring in the northern hemisphere. The killing frost there was in Argentina on November 14th 2007, which destroyed millions of dollars worth of crops. The enormous freeze of arctic sea ice that occurred in November 2007. The RSU MSS satellite data that shows the earth’s temperature had a negative anomaly in November 2007; the first negative this century. Do you want me to go on?

  38. 88
    Nick Barnes says:

    Hank Roberts@71: yes, they grew the chart twice in 2007, once from -2 to -2.5, once from -2.5 to -3. I think that the second time they grew the topside as well, for symmetry; at the start of the year it ran from -2 to +2.

  39. 89
    AEBanner says:

    The total world primary energy production in 2003 was 4.4 × 10^20 Joules, which was sufficient to melt 1.3 × 10^3 Gigatons of ice, where 1 Gt = 10^9 metric tons. This figure is about twice the estimated amount of ice actually melted.

  40. 90
    Hank Roberts says:

    > Do you want me to go on?
    Jim Cripwell, Gavin already told you he didn’t want you to go on.
    So stop.

  41. 91
    James says:

    Re #80: [Such things as the fabulous ski season there was in the southern hemisphere in 2007, followed by an equally impressive one now occurring in the northern hemisphere.]

    Did you forget the sarcasm button? Fabulous ski season in the northern hemisphere? Not in these parts (the SIerra Nevada). The downhill areas that have opened are running mostly on manmade snow. Didn’t get any significant natural snow until the beginning of this month, and only about a foot so far – conditions more typical of late October/early November.

  42. 92
    Jim Galasyn says:

    Re Jim’s “good news” in 80:

    Then there was all that great rainfall in Australia this year that stopped the worst drought in a century… oh wait.

  43. 93
    Peter Williams says:

    Jim, (#80)

    I also note that the Dow has risen 10 out of the last 21 trading days, and US GDP is at an all-time high. So clearly we can extrapolate that it would be alarmist to speak of a looming risk of a recession, right? Do you want me to go on? Ever hear of cherry-picking? It’s what people do when they’re trying to sell you something, or what they do on talk radio when they want you to feel the delight of righteous indignation. Hardly scientific. Besides, you didn’t even explain why your laundry list was evidence of cooling. Without a framework of understanding, it’s not clear what those isolated events indicate. Why is a very fast refreeze of Arctic ice evidence of cooling? I’m not remotely an expert on that, but gee, seems kind of what you might expect, given the radiative efficiency of open water. If I really wanted to know, I’d ask an expert, not someone with a list of talking points.

    Besides, the ski season in the Sierras is lousy so far, so you’re doing cherry-picking upon cherry-picking. Don’t quit the day job.

  44. 94

    #65 Russell:

    If it was a private sector project, and I had to sell it to a paying customer, it would have to match up with the observed data from the real-world.

    If it was a private-sector project, it would likely come without source code, and of course it would match up beautifully with past observations ;-)

  45. 95
    Tilo Reber says:

    “No-one has mentioned the fate of polar bears yet, do we just wash our hands of this species or do we try to relocate as many as possible to sactuaries and zoos?. Canada is a poor option since it will also be largely swamped as sea levels inevitably rise as the greenland melt intensifies. What do you guys think?”

    At this point, the sea ice in contact with the northern part of Ellesmere Island and the northern part of Greenland is still there year round. The polar bears in the western Hudson bay seem to do fine with the abscense of sea ice for 3 to 4 month a year. It would take quite a bit more warming to achive an abscense of sea ice at the northern part of Ellesmere and Greenland for 3 to 4 month a year. And until that occures there is probably no danger of polar bear extinction.

    Speaking of Ellesmere Island, there are fossilized forrests on the island. This would tend to indicate much warmer weather there in the past. Probably warm enough to produce ice free summers at the pole. How did the polar bear survive such a time.

    [Response: They didn't. The Ellesmere forests are from the Eocene (50 million years ago). - gavin]

    Concerning the discussion of the tipping point and the heating effect due to loss of albedo, the question I have is, how did we then get back to ice ages in the past, when all of the polar ice was melted and there was no ice caused albedo. Shouldn’t the earth have continued to stay too hot to allow ice ages to return under that scenario?

  46. 96
    Philippe Chantreau says:

    Jim Cripwell, you’re saying that one negative temp anomaly in 7 years is proof that the Earth is cooling. That’s grotesque. It seems that you have a serious double standard on burden of evidence. Imagine all the things I could say on GW and AGW if I allowed myself to make such a jump to conclusion. Gee, the possibilities…

  47. 97
    Nick Barnes says:

    Tilo Reber@87: “It would take quite a bit more warming to achive an abscense of sea ice at the northern part of Ellesmere and Greenland for 3 to 4 month a year. And until that occures there is probably no danger of polar bear extinction.”

    This is exactly what the arctic sea ice specialists are talking about. What else do you suppose they mean when they say “an ice-free arctic summer”? Which they predict for, variously, 2040, 2035, 2030, 2025, 2017, ….

    And the models say that once the summer ice is gone, it’s not easy to bring it back. The heat that could melt a single metre of sea ice (e.g. first-year ice) can heat (say) the top 40 metres of open ocean by 2 degrees C.

    The polar bears are in serious jeopardy. There are presumably some areas of fast ice, e.g. on the coastal areas which you mention, especially the northern coast of Greenland – cooled by the ice sheet – which might work as natural refuges.

    While I’m here, can I encourage anyone wittering about the rapid November regain in sea ice firstly to notice that this was predicted by the experts and secondly to take a look at the chart.

  48. 98
    Pekka K. says:

    Re 34: STOP PRESS:
    A most recent and reliable information, although not yet corroborated by independent sources, is that Mr. Santa will be mothballing his multiple North-European industrial operations due to the dismal near term forecasts of snow availability. This will, of course, be a great loss to the regional economies.

    He is reported to be negotiating a transfer of the Swiss/French treaty covering the CERN facilities. These extensive cave labyrinths will be on the market in the near future as the elusive Higgs boson will soon be trapped. Their proposed major project of actually demonstrating the Big Bang has now definitely been rejected for EU Framework Program funding.

    The CERN facilities are ideal for political reasons. Santa’s famed Earth Rotation Switch (ERS) has to be guarded at all costs against any and all prospects of weaponizing. As has been known for some time, the ERS allows its possessor to perform quite impossible feats of global delivery – although with some undesirable side-effects. For instance, it actually has been observed to turn minutes into hours during some evenings, after the sunset.

    The new facility will be powered by a New Sahara Solar Corporation plant to be located nearby.

    The plan is reportedly backed by serious money from the usual suspects in Shanghai. We are formally assured by our confidential sources that the trademark photo opportunity “Me, on the knee of Santa” will continue to be available to the millions, but without the current airport congestion problem.

    Season’s Greetings!

    Pekka

  49. 99
    Chuck Booth says:

    Re # 87 Tilo Reber’s question about polar bears on once-forested Ellesmere Island and Gavin’s response:

    Had polar bears existed when Ellesmere Island was forested, they probably would have been eaten by the carnivorous dinosaurs that lived in that region:

    http://www.athropolis.com/arctic-facts/fact-dinosaur.htm

  50. 100
    Tilo Reber says:

    “They didn’t. The Ellesmere forests are from the Eocene (50 million years ago).”

    Good point Gavin. So let’s bring the time in some. How did the polar bears cope during the Holcene optimum? If the temperatures were higher than today, then can we also assume that the Arctic sea ice melted in the summer? I seem to remember hearing that there was a period of time when the Atlantic and Pacific bowhead whales could visit each other in the Arctic.


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