RealClimate logo

Arctic sea ice watch

Filed under: — group @ 10 August 2007

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

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

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

Sep 05 1979Aug 09 2007

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

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

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

504 Responses to “Arctic sea ice watch”

  1. 1
    Andy Revkin says:

    One thing that’s important is to track what someone is measuring. Chapman/Walsh at UIUC focus on ice AREA while NSIDC estimates ice EXTENT. That’s one reason they have different findings at the moment.

    But everyone I talked to yesterday (Claire Parkinson, Mark Serreze, Walsh/Chapman, etc) agreed we’re in for a remarkable year. Polar bears and Arctic shippers beware.

    More on the implications here:

  2. 2
    Walt Bennett says:

    I went on record last year – as an outside observer, of course – that summer Arctic sea ice will be gone completely within 5 years.

    Granted, that is not a scientific observation. It is more of a gut feeling that all of the conditions which contribute to the melt will continue to strengthen.

    Important to remember is that temperature will rise most rapidly in the polar regions, thus magnifying the overall effect. Also, the Arctic is an albedo-intensive region, and as the albedo rapidly shifts from positive to negative (do I have that right? From reflecting to absorbing), the pace of the melt must quicken.

    Would I be correct to conclude that the re-freeze each winter actually creates less ice than the year before? Perhaps the area is roughly the same, but the depth would be less, correct? Thus, the next summer’s melt can be even more rapid because there is less ice to melt.

    I see this as a self-enhancing feedback process, which is why I say that it will be extremely rapid.

    My question has been: what will the naysayers say when the Arctic, for brief periods, is essentially ice-free?


    “Well, that’s not a bad thing. Look, now we have easier shipping lanes. Anyway, these things are cyclical.”

    In other words, it will be proof of something, just not AGW.

    Question for “group”: Will these observations regarding the rapidity of the melt lend any knowledge to the predictions of how quickly land-based ice might be set loose? We hear talk that the breakup of land-based ice could be much more rapid than previously speculated. Does the Artic sea ice melt inform that understanding in any way?

  3. 3
    Fergus Brown says:

    This shouldn’t really be a surprise; I wrote this on April 12th:

    What about the coming seasons? Last summer’s level was just above the record low. There was some recovery during the Autumn, but then the Winter level was also close to a record low. Normally, a less anomalous Winter would be expected to follow a Autumn ‘recovery’, but this year it didn’t happen that way. It is also worth noting that the period of maximum extent was in late February, rather than the more normal March, implying an earlier than usual shift in the seasonal influence. Given the already low level of Winter ice, the early onset of the thaw season, and the recent trends, it is reasonable to forecast that this year, the sea ice levels in the Arctic will hit a new record low. This is my prediction for the coming seasons. I have not mentioned other factors such as the Arctic Oscillation and Sea Surface Temperature Anomalies, though they have been considered in this forecast. The AO is broadly neutral at the moment, but may be shifting phase; the SSTAs are positive. Both of these influences are consistent with a forecast of low ie levels this year.

    You missed out the PolarView/Damocles site, which is also excellent, and the graphics magnify really well. There’s a link on my blog (sorry!).

    I’d like to ask if the areas of thin ice/open water to the north of N. Greenland and Ellesemere Island are unprecedented? Is there any record of there being open water here?


  4. 4
    VirgilM says:

    I need some perspective on this. What was the Arctic Ice extent in the 1930s? What was the extent during the Medievel Warm Period?

  5. 5
    John L. McCormick says:

    Each year the Arctic sea ice meltback appears more dramatic and prompts the obvious discussions on causes.

    I have tried for a year to persuade scientists to start a discussion on effects.

    For openers, it is obvious the greater expanse of open water eliminates more area of old ice. The new ice will be thinner, melt sooner and more easily break up with storm and wave action. So, it will be no surprise that the 2008 season will be a repeat of or surpass the 2007 meltback.

    But, what impact is that greater expanse of open ocean having on temp and precip in Western North America and more specifically in the world’s grain belt.

    The National Academy spent more than a year researching and publicizing abrupt climate change. Is it not of equal or, IMO, greater importance, to begin to answer the question: are we building the ethanol industry in a future dust bowl?

    The Arctic meltback has a great deal more to do with how the world will be fed than how polar bears will survive.

  6. 6
    Lawrence Coleman says:

    Re: Walt,
    What you are saying is very logical in most likely going to be correct.
    The re-freeze each winter will result in the ice depth getting thinner
    and thinner and also the edges of the polar region to shrink as well.
    From the 1960-1980 the rate of ice loss each decade was on average 1.4%,
    now in 2007 it is 7.8%. It is safe to assume that in the coming decade the
    loss of ice will escalate to 30-40%. So that probably well within 20 years
    we will have no permanet ice at all in the polar region. It’s a positive
    feedback mechanism.. the less ice and more dark coloured ocean the more
    heat that will absorb, melting even more ice…etc. The great oceanic conveyor
    is in real danger of slowing or stopping completely plunging europe, russia, china
    and canada and north america into a snap ice age.
    If everybody acted in a way as if thier lives depended on it(which it does)
    things would! Trouble is no one still seems to give a shit!

  7. 7
    Badger South says:

    Climate Deniers = Climate Dodos

    “The Dodo (Raphus cucullatus) was a flightless bird that lived on the islands of Mauritius. Related to pigeons and doves, it stood about a meter tall (three feet), lived on fruit and nested on the ground.

    “The dodo has been extinct since the mid-to-late 17th century. It is commonly used as the archetype of an extinct species because its extinction occurred during recorded human history, and was directly attributable to human activity. The phrase “as dead as a dodo” means undoubtedly and unquestionably dead.” — Wikepedia

  8. 8
    Lawrence Coleman says:

    Re: Walt, hmmm? if the great oceanic conveyor was to cease and down to the temperate latitudes were to
    freeze up…logic says that the polar ice cap might well return to normal thickness..or thicker? I’ll pass this to the
    group to discuss, they probably have more insights than me on this thought.
    There is ample evidence that the greenland ice shelves and glaciers are retreating and the pack ice thinning. Again the higher the temps in the region more of the rock beneath the greenland ice is exposed to the sun and the hotter it gets and will no doubt exellerate the rate of land ice melt raising sea levels.

  9. 9
    Walt Bennett says:

    Re: #6

    “If everybody acted in a way as if thier lives depended on it(which it does) things would!”


    Dr. Hansen is one of the most vocal of those who say that there is no way to quickly reverse the effects of AGW. Too much future warming has been built in.

    Things will get much worse before they get better, if we completely stopped adding to atmospheric CO2 today (which we can’t, and which the world won’t be able to do for at least a decade, more likely several decades).

    So, that’s a bit of fantasy on your part.

    However, “visuals” such as this should – SHOULD – get people to start hopping down off the fence, so that perhaps we can keep my estimate at the low end.


  10. 10

    Re #8 where Lawrence wrote ‘… if the great oceanic conveyor was to cease and down to the temperate latitudes were to freeze up…logic says that the polar ice cap might well return to normal thickness..or thicker?’

    That is obviously correct, therefore it could not have been the halting of the oceanic conveyor (THC) that caused the rapid climate changes at the start and end of the Younger Dryas. It was the formation and disappearance of sea ice in the North Atlantic. The sea ice stopped and restarted the THC, not vice versa.

    The Arctic ice will not be able to reform this winter, because the climate in the Arctic will have been changed from pseudo-continental to maritime. Thus next summer, without any ice to reflect the sun away, the Arctic and the whole of the northern hemisphere will warm considerably, and the subsequent rapid climate change will lead to global famine since the farmers will have planted the wrong crops.

    What will the nay-sayers say then – they will blame the scientists!

  11. 11

    If anyone is interested in seeing what is happening at the North Pole NOAA have two web cameras there:
    Unfortunatly this one is sinking:

    For more pictures go to

  12. 12
    Mark C. Serreze says:


    The National Snow and Ice Data Center (NSIDC) will be posting our first of a set of discussions and figures on 2007 sea ice conditions today (Friday, August 10). We’ll be providing updates each week (or as conditions warrant). We did this last year and got a lot of positive feedback.

  13. 13
    Lawrence Coleman says:

    Walt..i didn’t mean the climatic situation would change you said there is still 40+ years of all the pollution we have been emmitting to impact us..what I meant was public attitude would change fast. People would protest governments like never before for doing nothing..did I say George Dubblya? I mean if people realized this is life or death, things on a governmental and private sector level would change in the blink of an eye. Then if it isn’t already too late, the climate in maybe 80-100years time will slowly stabilise back to normal (for the last million years). Then if all the antacids people have been taking for climatically induced stress were dumped into the oceans their ph would resort to normal as well..

  14. 14
    horrified observer says:

    Are we whitnessing albedo flip (Hansen et al) right now? The graph from simulation runs (Hollan/Bitz/Tremblay) shows a dramatic drop once 4 million km2 september mean ice extent is broken. At this pace we will enter september well below threshold lining up for a dangerously low monthly mean.

  15. 15
    interested observer says:

    Any answer to #4?

  16. 16
    Lawrence McLean says:

    Re #4 VirgilM, Check out the website:

    It is much lower now than in the 1930’s.

    The medieval warm period was not as warm as it is now, based on Coral records and other proxies. So, it is unlikely that the ice extent was anywhere near as low as it is now.

    Why did you ask? If your interest is genuine you could find out the information yourself. I found the the above web site in 3 minutes. The second point, there were no satellites in the medieval warm period! I would suggest Lonnie Thompson may have more definitive work regarding that question.

    The people who run this web site are very professional and honest and do not peddle “spin”.

    They seem to be so busy with the like of you they rarely answer my questions.

  17. 17
    rick says:

    I believe the topic of a shut-down of the ocean conveyor belts has been exhaustively discussed in prior posts at this forum and the conclusion was it ain’t gonna happen.
    So, the trend will be more warming in the northern lats.; there ain’t gonna be an ice age for northern europe; and the arctic ice cap is going.

  18. 18
    Eric Swanson says:

    As I’ve tried to point out before, there is a secondary effect to be considered as the reduction of sea-ice extent continues. That is, the outflow of sea-ice and surface water from the Arctic Ocean into the Greenland Sea.

    Each year, as the sea-ice melts, the surface water of the Arctic Ocean becomes freshened. That’s the result of salt rejection during the freezing process. That rejected salty brine tends to sink during the freeze season, adding to the Thermohaline Circulation. However, the fresh surface water that migrates into the Greenland Sea would tend to suppress the THC which has been seen to occur in that area. The net result may be a reduced THC overall and a shift in the path of the in flowing water from the North Atlantic. Should the sea-ice decline in extent continue, it is plausible that the flow or water into the Greenland Sea would increase and include more sea-ice than now passes thru the Fram Strait, as the sea-ice would no longer be the thicker, multi-year ice that is now seen in the area. The flow thru the Fram Strait continues along the eastern coast of Greenland, flowing into the Labrador Sea, which is another area of THC sinking. Thus, it is likely that the THC would be greatly reduced. There is also a flow of surface water and sea-ice thru the Canadian Archipelago into Baffin Bay and that transport would be much enhanced as the sea-ice cover is removed. These processes may already have happened in the late 1960’s, as seen in “The Great Salinity Anomaly”.

    There are those who have claimed that there is no need to worry about a reduction or shutdown of the THC. I suggest that this year’s changes present strong evidence which questions this conclusion.

  19. 19
    Aaron Lewis says:

    I am not an expert on the Arctic, but it is a whole lot more interesting place than these posts suggest.

    First, normal sea water sinks as it cools, and thus normal ocean water freezes from the bottom up. Arctic sea ice includes a lot of freshwater that normally floats on the Arctic Ocean. Under the fresh water on its surface, the Arctic Ocean contains layers of warmer, saltier water, with very cold, very salty water in its depths.

    When the Arctic sea ice melts, it opens the surface water to mixing by storms, thus allowing the surface waters to become warmer and saltier. The additional salt in the surface waters means that they are likely to sink (into and through the warmer middle waters) as they cool rather than freezing at the surface.

    Thus, loss of Arctic sea ice not only changes the albedo of the Northern Hemisphere, it opens up a whole Pandora’s box of interesting physics.

    Here, that means that the arctic stops being a desert, and becomes a huge latent heat engine. Think about how much more lake effect snow is now being produced down-wind of Lake Erie, now that Lake Erie has a shorter freeze season, and think about the effects of less ice in the Arctic.

  20. 20
    Spencer says:

    re question from #2 Walt B.: “Will these observations regarding the rapidity of the melt lend any knowledge to the predictions of how quickly land-based ice might be set loose?”

    As I understand it, there is some similarity in the mechanisms. As sea water is darker than ice, so melt pools on the top of Greenland and Antarctic ice darken the surface. Also, warmer ocean water melts ice shelves from below, making them thinner, but the main thing here is a separate matter: they are then more likely to break up and “uncork” the land glaciers behind them. Even more different from the ocean situation, an important possible mechanism on land is that meltwater will sink to the bottom and lubricate glacier flow, speeding it up.

    Overall, I’d say that if Arctic Ocean ice disappears faster than expected, it will not tell us a lot about land ice, but it should reinforce the concern that we do not fully understand nonlinear effects that could make everything, not just land ice, change faster than current models predict.

  21. 21

    The New York Times article missed a little something, which was Siberia had a warm winter/Spring, with especially warm air aloft over that region, as to compared with the Canadian Arctic region. Which I was observing with fascination…

  22. 22
    Dodo says:

    Anybody know where one could find a composite graph of total global sea ice extent? I mean, there seems to be a million sq km positive sea ice anomaly in the SH, but whether this compensates for the big melt in the north is unclear. (Cryosphere today treats the hemispheres like two different planets.)

  23. 23
    Walt Bennett says:

    Re: #21,

    If your implication is “maybe the warm Siberian winter/spring had something to do with warming conditions in the Arctic”, my rejoinder would be “what is the cause of the warm Siberian weather?”

    I would also ask you this: has some anomalous event been the cause of the Arctic warming for the last 30 years?

    In other words, when enough seemingly random events occur in a given period of time, and they add up to a trend, and that trend has not only been predicted but the eventual causes of the trend have been observed and measured for half a century…

    I find it very interesting to see how the denial machine handles this news.

  24. 24
    Andrew says:

    I’m just an amateur, however has any consideration been given to the thickening of the troposphere and accelation of the polar jet stream as to why arctic ice may be disappearing quicker than what climate models have predicted?

    Over the last few years, it seems as though the polar jet stream is being diverted much further south than is customary. The result has been rather cool temperatures in the Northeast US from all that polar air. Understand that this is may also be due to a persistent high pressure system over Greenland.

    There is just so much cold air in the arctic and by emptying it out, that opens up pathways for warm air to enter that arctic from Asia…

    At least that is my pet theory.

    Thanks in advance.

  25. 25
    Andy Revkin says:

    Re comments 4 & 10:
    Perspective is indeed important.
    There are studies showing past instances over last 130,000 years when Arctic was warmer than it is now and sea ice area smaller (particularly early in Holocene ~ 9k to 5k years ago and then the Eemian warm period between ice ages ~ 130k years ago).
    One recent story of mine explores how Arctic flora responded (very resilient):

    As for 1930s and Medieval optimum, Chapman at UIUC and others have some data, but doesn’t seem there was Arctic-wide retreat.

    The main reason this is significant news (to my mind) isn’t how it relates to the global warming trend, but more simply the reality that all that open water is starting to juice up the jockeying over who’s going to control the warming Arctic.

  26. 26
    John Mashey says:

    With the forthcoming Arctic melting, there will clearly be more ships in the Arctic, and I’ve seen general articles expressing general concern about the further acceleration of albedo-lowering from their soot.

    Does anybody have pointers to any more specific numerical studies about the relative effects of existing soot sources on the Arctic ice versus likely effects from shipping? Put another way, will controls (assuming any set of governments can agree on them) on Arctic shipping emissions help, or will they be essentially irrelevant by the time shipping there is substantial?

    Google: soot sources arctic ships
    didn’t find exactly what I wanted, but the following was interesting:

  27. 27
    catman306 says:

    Here, that means that the arctic stops being a desert, and becomes a huge latent heat engine. Think about how much more lake effect snow is now being produced down-wind of Lake Erie, now that Lake Erie has a shorter freeze season, and think about the effects of less ice in the Arctic.

    Comment by Aaron Lewis

    Aaron, what happens if huge amounts of snow fall in the area around the Arctic Circle during the Arctic winter but stay on the ground until late in the Arctic summer when it all melts from the warmer temperatures? Wouldn’t that whole area be a cold wet desert in that case?

  28. 28
    Miikka Raninen says:

    ESA has much more interesting pictures of the density of the polar ice cover at:

    Should have the 2007 comparison picture out in a few weeks…

  29. 29
    Ezequiel Marti­n Camara says:

    Re: 10

    > What will the nay-sayers say then – they will blame the scientists!

    Idi Amin: Yes, you are my advisor. You are the only one I can trust in here. You should have told me not to throw the Asians out, in the first place.
    Nicholas Garrigan: I DID!
    Idi Amin: But you did not persuade me, Nicholas. You did not persuade me!
    — The Last King Of Scotland

  30. 30

    #23 Walt

    With regards to Siberia being warm there is a simple explanation, once the Northern Hemisphere reaches a certain state of heat (energy), it does not lose it overnight. Heat radiation escapes to space at a constant rate, if the system cools from a higher state of heat at fall, during winter, eventually spring will be warmer, not necessarily at always the same geographic location since the Earth rotates.

    There is no anomalous event similar to this one, not in my about 25 winter seasons of observing from within the Arctic. There are years when synergystic combinations (as mentionned in the article) cause open water with relatively very small polynias, but nothing like a new ocean appearing before our eyes.

  31. 31
    Walt Meier says:

    Following up on Mark Serreze’s comment early. The NSIDC update is on the web at:

    This will be updated once or twice a week through the rest of the melt season (end Sept or early Oct). It includes a daily image of extent and a timeseries of the seasonal behavior compared to climatology and previous low years. Looking at this, one can see that this year is quite stunning.

    A couple of notes:

    On area vs. extent – NSIDC uses total extent, which the total area covered by at least 15% sea ice. Area just counts up the area covered by sea ice. Thus, area values are lower since extent includes regions not completely covered by ice. Extent is a more robust value to use to compare to other years. Area estimates from the satellites can be biased by surface melt and atmosphere. This much less of an issue for extent, so it is more reliable to use extent.

    On earlier sea ice: It was quite warm in the 1930s, but the best data available indicates that we’re well below the extents in the 1930s. This could be due to a thicker overall ice cover back then that was more resistant to melt.

    Walt Meier
    Research Scientist
    National Snow and Ice Data Center

  32. 32
    interested observer says:

    Re: #31

    What is the best data available? When I looked at the UIUC material, it seemed like their view was that one should be cautious when using their pre-1953 data.

  33. 33
    Aaron Lewis says:

    re 27
    Did you ever see a lot of melting snow without a lot of mud? Did you ever see a lot of mud in a desert?

    That snow machine is driven by heat. Think of snow as a way to transfer heat from the warmer water to the air over the colder land. Just because it snows, that does not mean(all)the heat has gone away. The latent heat of the moisture from the water remains in the air.(Some of)that heat will come back as a warm wind or rain to melt the snow. Some of the heat will be radiated away. The point of Gavin’s 6 Aug. 2007 post was to help us understand how much heat will remain. (Excel is so much fun!)

  34. 34
    Timothy Chase says:

    Andy Revkin (#25) wrote:

    As for 1930s and Medieval optimum, Chapman at UIUC and others have some data, but doesn’t seem there was Arctic-wide retreat.

    The main reason this is significant news (to my mind) isn’t how it relates to the global warming trend, but more simply the reality that all that open water is starting to juice up the jockeying over who’s going to control the warming Arctic.

    Likewise, in earlier periods, at least over the human history of the past 10,000 years, a warming of the northern hemisphere meant a cooling of the southern. It sea-sawed back and forth. But this time the warming is pretty much a global phenomena. The West Antarctic Peninsula is going, melts are occuring deep within the Antarctic interior, and the ice-mass balance of Antarctica is falling. There is cooling in some areas, but the net trend is the same.

    In human terms this is unprecedented.

  35. 35
    Karl Sanchez says:

    Is there any connection between the very persistent low over the Gulf of Alaska and the rapid erosion of sea ice seen north of the Bering Sea?

  36. 36
    Travis O'Brien says:

    Re: #5

    I agree completely that we desperately need to talk about the effects of a rapidly warming Arctic on agriculture in the American Midwest.

    I think that not only are we building the roots of an ethanol industry in a very drought-prone region (and a region that may see less water as the Arctic warms), we are covering the Midwest in the same crops that covered the region in 1930 before major drought triggered the Dust Bowl. It seems to me that we’re asking for dust and trouble, albeit we haven’t ravaged the topsoil as badly as we had in the 1920’s.

    Can we quantify the danger of Arctic warming and reduced sea-ice in terms of North American precipitation? Are there any estimates of precipitation in the northern hemisphere is affected by Arctic warming?

  37. 37
    Timothy Chase says:

    Karl Sanchez (#34) wrote:

    Is there any connection between the very persistent low over the Gulf of Alaska and the rapid erosion of sea ice seen north of the Bering Sea?

    I believe there is.

    A high pressure over the Arctic Sea is “pushing” sea ice out of the Arctic and into the subarctic where it tends to melt more quickly. If you look at the 30-day “movie” of ice distribution for the Northern Hemisphere at…

    Cryosphere Today

    … you will notice that it is near the Bering Sea that the large swath of low-density sea-ice is concentrated and that it appears to be moving most quickly towards the Bering Sea.

  38. 38
    F Mackenzie says:

    re: #25, and the jockeying for sovereignty in the Arctic: what’s scary about it is that they are after the huge reserves of fossil fuels that have been inaccessible till now under the ice. Just imagine what happens if all of that CO2 gets churned out into the system!

  39. 39
    Gareth says:

    Jeff Masters at Weather Underground has an interestingnew post on sea ice. Consider what he has to say about the impact of Arctic sea ice melt on global weather patterns:

    Loss of Arctic sea ice will also dramatically change the global weather and precipitation patterns. For example, the jet stream should move further north, bringing more precipitation to the Arctic, and more frequent droughts over the U.S. In any case, the reduced Artic sea ice should give us another delayed start to winter in the Northern Hemisphere this year.

    For me, this is the really big question. What does a rapidly melting Arctic do to NH weather patterns? The potential for dramatic shifts is obvious, but as far as I know only one group is trying to model this (Colorado?). Should be a rather urgent subject for research, I’d have thought…

  40. 40
    Jack Roesler says:

    Very interesting Gareth. Here in Northwest Ohio, 5 of the last ten days have been over 90 F., with dewpoints up to 77 F. The meteorologists attribute it to high pressure keeping the jet stream north of the Northern US. This is what Jeff Masters has said was to be expected. I suspect this will become a new, unwelcome feature of our weather here.

    Oh. We’ve had many more days over 90 F here than normal, so far this summer.

  41. 41
    J.S. McIntyre says:

    re #36

    Regarding ethanol, you might be interested in the article by Jeff Goodell in the current issue of Rolling Stone.

    According to his report it’s a huge scam that has no real benefit for anyone … except certain special interests. Bad for the environment, bad for corn prices, just plain bad.

  42. 42
    Jack Roesler says:

    This is off topic, but the study out today on high cirrus clouds in the tropics is very interesting. I read it at Their finding was fewer, not more clouds, thus more global cooling. However, I think this just makes the CO2 contribution to warming even stronger, as it would be warmer were it not for this negative feedback.

  43. 43
    llewelly says:

    Walt Bennett (#2) said:

    My question has been: what will the naysayers say when the Arctic, for brief periods, is essentially ice-free?

    They’ll say the Arctic must have been ice-free in 1421, when the Chinese Navy circumnavigated Greenland.

    hey,, what is it with wordpress blogs and disappearing preview?

  44. 44
    John Mashey says:

    re: 36, 41 Ethanol is OT in this thread…
    but as much as I enjoyed Goodell’s “Big Coal”, I think he hasn’t looked deeply enough into this, especially with regard to plausible trends, multiple studies with different numbers, use of switchgrass/miscanthus instead of corn, etc. Put another way, I think I give more credence to Argonne National Labs, UofI, Vinod Khosla, etc. Finally, recall that the petroleum industry has no reason whatsoever to like ethanol.

  45. 45
    John L. McCormick says:

    RE # 44 John Mashey

    Discussing ethanol is very much related to this thread if you have an interest in understanding the impact on North American temp and precip as the Arctic sea ice rapidly disappears during our mid-summer.

    Its simple: when you read ethanol, think grain. When you think grain, think global surplus. Then, you can factor that euphamism called ethanol into the thread.

  46. 46
    FredT34 says:

    Please note that on July 15, the English swimmer Lewis Gordon Pugh was able to *swim* 1 km in the North Pole exact location (google on this) – proving for WWF that there was enough free water to achieve this. This was impossible ten years ago (this crazy guy was just wearing a speedo in a -1.8°c water…)

  47. 47
    Bill says:

    There is, of course, more to sea ice than just its extent. Thickness, amounts of multi-year ice, etc, etc. What’s most interesting in these two images is the asymmetry of the areal reduction. Significant changes is the Laptev, Siberian, and Chukchi Seas; in the outflow areas of the Khatanga, Lena, and Kolyma rivers but not the same dramatic changes out from the McKenzie. What is going on here? Meanwhile, in the Greenland, Barents, and Kara seas more modest changes in area. Yet, again, in the Canadian lower Arctic archipelago significant changes. A perplexing pattern.

  48. 48
    Technetium says:

    Hey guys, probably a silly question from a “still learning” guy. How are photo’s showing melting icecaps any different that the plots showing rising temperatures? I would expect that since the global temperature has risen between 79 and 07, that ice would melt. I would think, in order to add any new useful info, you would need to compare ice volumes with those of earlier hot years, like in the 30’s to help determine whether the ice is similar to what was going on then, or whether it has melted way more. Thanks for the informative blog. I find this place and ClimateAudit very interesting, I only wish there was less bickering and veiled shots taken at each other in the posts =D

  49. 49
    Rod B says:

    re “Climate Deniers = Climate Dodos…”


  50. 50
    John Mashey says:

    re: #45 & OT

    I’d be delighted to see a Friday Roundup or specific topic called “Expected temperature and precipitation trends in the US & Canadian mid-west”….

    but turning *this* thread into an ethanol discussion is the kind of OT-amplification that eventually ruins a bulletin board.

    I’d expect there would be *many* other climate factors relevant to mid-West climate discussion than Arctic Sea Ice. From a quick look at the Index, I’d guess one could argue for an ethanol discussion in half of the topics (not even counting the Sheep Albedo Feedback), but that really doesn’t make sense.

    sci,energy has 4000+ hits for ethanol, might be a better place, or maybe there’s an RC-quality on fuels.

    Grain: I’ve heard of this stuff, having grown up on a farm with corn & wheat & oats. However, when I think about ethanol, I think ahead to switchgrass, miscanthus, or genetic-engineered versions thereof, as opposed to crops tuned for food for thousands of years.