Yet more sea ice

Continuing from Three views of sea ice. Well, tis now mid-June, so the futurology aspect of the prediction is closing rapidly. Or so you would have thought. I’ve just taken £50 against CR for the ice being below 4.735 (he gets the low side) or above 4.935 (I get the high side). But my principal debt on sea ice is failing to write anything more about it. so, to remedy that!

I was going to suggest that the most interesting way of doing the pool was via Intrade. Unfortunately their Arctic sea ice pool doesn’t look very interesting. The bet is “2010 greater than 2009” and is trading at around 43%, and hasn’t had a trade in a while. Since I’d say ~50% is fair odds, neither buy nor sell is very interesting. Here is a pic:

<img src="" height="225" width="460"

I suspect that I might want to put in some “sell” bids at alower price but I’ve yet to work out exactly how that goes. Maybe later.

It is hard to deny that the current AMSR pic is looking bad for the good guys; but never mind. I’d stick with my old opinions for the moment (I mean, just look at the variability on that chart! One month is hardly a guide to the next) I ought to offer my apologies to those who suggest I look at some sea ice images: I’m afraid I haven’t found the time to do so and this largely reflects a lack of interest on my part; perhaps with a bigger computer and a faster internet connection I might. As it is, I’ll just have to go forward blind.

I thought I’d do a quick “news” search on sea ice and was pleased to find The Economist with a sensible story and, for a bonus, plugging my humble blog. I look forward to hordes of punters turning up with wads of cash ready to throw down. The Economist notes the Arcus sea ice outlook series, which in my mind is pegged as “not doing very well” in the last two years. However, they have learnt one thing from their disastrous May forecast of 2008 – don’t do a forecast in May :-). We’re waiting on the June forecast, which should be interesting.

While I’m here… another link worth reading is RMG’s take on “when will the Arctic first be ice free in summer”. I say worth reading, and I think it is, but I also think it is entirely wrong.

And for those who have forgotten the default bet, and can’t be bothered to read the old post, it is:

That the september mean ice *extent* be below 4.835; but with a “buffer” where we call it a draw: between 4.735 and 4.935, no one wins. I’m taking the “high” side of this; anyone interested in the “low” side let me know.

[Update: ARCUS 2010 is now out; New Boy Nevin gets credit for being the first I saw to blog it -W]

33 thoughts on “Yet more sea ice”

  1. Yes, intrade hasn’t been very interesting. The buy orders have retreated from 30 to 17.5. The volume has only been 48 $10 contracts. I hold 18 no contracts having sold 25 (at 43 to 50) and bought 7 (5 at 30 and 2 at 35) so my trading represents two thirds of the volume of 48.

    The graph only shows daily closing prices because my buys at 30 do not show up.

    My exposure looks like a little more than William’s but the Economist article might send a few punters this way.


  2. If you look carefully, there is a downward turn (dive) ~ end of June esp in the really low years. If you see that this year bet the house.

    [Ah, graphology. It works in the stock market, why not for sea ice ;-? -W]


  3. May forecast of 2008 does look too bad the outcome (4.68m km^2) is near the middle of the range.

    Did you mean the June 2009 or Aug 2009 forecast?
    where the outcome is outside the range of forecasts?

    Also am I right in thinking the first forecast has always been based on data to May only and published in June?

    [Well mostly I was just being a bit snarky, and vaguely remembering that it didn’t come out too well :-). I may have to pay more attention if people are going to be so unsporting as to check up on me -W]


  4. Now to worry. You only disagree 10-20% with me about the ‘when will the ice be gone’ article. My purpose, which I hope was what you meant by the interesting part, was merely to illustrate a means of making the estimate. That particular answer, I have no great confidence in. But I think it may well be a better approach than running the same air-sea-ice model a few thousand times.

    [To be more explicit I don’t think the multiplying-probabilities approach is valid -W]

    Since the linear prediction is 5.37, Wu and Grumbine’s model prediction is 5.13, and Grumbine and Wu’s preferred statistical prediction is 4.78, it looks like we have no basis for a bet this time. I should have soaked you for all the market would bear last year 🙂

    Plus, since we made our prediction (27th of May), the dive in Arctic cover is enough to give even you some pause about the high side bets. ARCUS is just being slow this year, original deadline was end of May, but it got extended to June 12th. I’m hoping they get the summaries out soon.

    [Ah thanks for that. Yes I am being given pause for thought this year. I don’t plan to risk more than I can easily lose (your Prez has already cost me quite enough :-).


  5. An off-topic note: an ArbCom case about climate change has been opened:

    Any comment? You haven’t made a statement at the case page (yet).

    (Putting this under the Bloody Sunday post felt inappropriate, so I’m posting it here.)

    [It is very silly. Alaas arbcomm isn’t very sensible, so the outcome is about as predictable as a typical british libel case; ie not at all -W]


  6. I would definitely bet on the low side. With a record melt of North American Snowcover to its lowest extent in April and May, the latter month being snowcover mostly around the Arctic. This to me is an indicator of the preconditioning phase for rapid ice loss that has been occurring in the last month. A record seems very reasonable at this point, with the snow and ice melt and temperature anomalies all pointing that way. Forecasting is tough, my balance forecast for the North Cascades after issuance has been followed by a cool six weeks in the North Cascades, WA.


  7. I think the acelleration around late June/early July for 2007 was when the melt on the Pacific side passed through the Bering Strait and opened up a wide front in the high Arctic. 2007 was a summer with a very strong Pacific side melt.

    This year seems to have a stronger melt on the Atlantic side which was a pattern is 2006 and the melt in 2006 ended slower. I suspect warm ENSO favours Atlantic side – low winter ice and high summer ice, and cool ENSO favours Pacific side – high winter ice and low summer, and that a change from warm to cool gives a double whammy effect of low winter followed by low summer which may have been one factor in 2007. We look to be getting a similar ENSO switch this year but later.


  8. Re #8: But notice that the main NWP appears primed to open up very early this year, there being no large areas of thick ice in the way. The whole Canadian Archipelago looks much more melt-prone than usual.


  9. But notice that the main NWP appears primed to open up very early this year, there being no large areas of thick ice in the way.

    It’s been changing very rapidly, with very little 100% ice concentration left in the main channel compared to just a couple of days ago. And a big chunk on the west end looking like it will melt out in the next week.


  10. While the sea ice decline this year might set a record low again this year, I suspect what we are seeing is the increasing variability caused by the declining thickness of ice.

    “Therefore, with the ongoing thinning of the ice cover (23, 25), we are likely to experience both large negative and large positive year-to-year changes in Arctic summer sea-ice extent. This variability directly implies a much-reduced predictability of sea-ice extent a season ahead than does thicker ice.”

    A new minimum record this summer (or next) will get calls of “tipping point” raging around the blogosphere as well as mainstream news and politics. However, the next winter and summer likely to be colder, and the summer sea ice is likely to recover for a year or a decade. If there is a tipping point with sea ice, it is not when the summer sea ice all melts, but rather when the winter ice does not recover enough. And that is many decades in the future.

    A summer with weather patterns like 2007, and with today’s sea ice, would have a smaller minimum extent. Most of the thicker multi-year sea ice is gone. It was melted in 2007 and has not come back.


  11. Does this

    look like the extent is lower in 2010 than in 2007?

    [Thanks for that. To me, 2010 looks a lot more solid. There is hope for me yet -W]

    Also while I am commenting, PIOMAS says “Updates will be generated at 3-5 day intervals”. It is now 20 days since last graph update but ‘generated’ may well not mean a publically released update. Are we likely to get timely public updates or should we expect them to hold back such information so they get first use?


  12. >[Thanks for that. To me, 2010 looks a lot more solid. There is hope for me yet -W]

    Trouble is, it seems that it is 3:1 in favour of cryosphere images being wrong:

    Are you deliberately trying to sound desparate with your ‘hope for me yet’?


  13. I prefer the following image from CT:

    just wish comparison images for same day in 2006 – 2009 were available – preferably also with the land snow cover.


  14. Note that the color scale on that second image is logarithmic, while on the first it’s linear. So on the second image it’s a lot easier to differentiate (say) 85% extent than on the first.

    Still, the second shows a lot more open water in Hudson’s Bay compared to the 6/17 image in your first link, which is odd (and I saw the daily image at your second link yesterday, it didn’t all melt last night).

    So, there’s something a bit odd about those images.

    Trouble is, it seems that it is 3:1 in favour of cryosphere images being wrong

    The Bremen image uses a linear scale like the archived Cryosphere Today images (those in your first link) yet looks less solid than the 6/17 archive image.

    Bottom line – it ain’t September until it’s September. Fun to watch, though.


  15. Wired has the scoop on this year’s predictions, with all but one boringly in the 4.2 to 5.7 range, but the one being down to 1(!), close enough to ice-free as to not make much difference.

    The ice seems to be up to lots of melting in the last week if the Bremen map is anything to go by. I’ve been paying pretty close attention to it over that time, and the changes really do seem large. In particular, the northern Canadian Archipelago has gone from near-complete coverage to a state I don’t recall seeing before, and ditto for huge areas of the main pack on the Bering Strait side.

    As I say, this is all based on memory, and I can’t figure out how to get that site to show comparative maps of more than the previous day. Anyone?

    Anyway, if it keeps up at this rate maybe someone will have to do a “we are own all your sea ice” video for Maslowski. 🙂

    [Thanks for the Wired link. I say, ha ha ha:

    “In hindsight, probably too much was read into 2007, and I would take some blame for that,” Serreze said. “There were so many of us that were astounded by what happened, and maybe we read too much into it.”

    Well actually some of us said so at the time. And the headline “Tricky Sea Ice Predictions Call for Scientists to Open Their Data” seems to indicate some confusion on Wired’s part -W]


  16. The ice seems to be up to lots of melting in the last week if the Bremen map is anything to go by. I’ve been paying pretty close attention to it over that time, and the changes really do seem large. In particular, the northern Canadian Archipelago has gone from near-complete coverage to a state I don’t recall seeing before, and ditto for huge areas of the main pack on the Bering Strait side.

    Cryosphere today shows the same, though it’s exaggerated in visual impact due to their logarithmic color scale. Shows more detail in structure than the linear scale used by Bremen, but if you’re not wary will make you overestimate melting. But that structure shown in more detail is interesting considering we have roughly three months more of melting coming ahead.

    My own prediction?

    It will all come down to when the melting season ends.

    It’s going to be the most interesting summer since 2007, though, regardless. Those thinking that it will “recover to 2006” are pipe-dreaming.


  17. In particular, the northern Canadian Archipelago has gone from near-complete coverage to a state I don’t recall seeing before

    I’ll repeat what I said three days ago:

    “It’s been changing very rapidly, with very little 100% ice concentration left in the main channel compared to just a couple of days ago. And a big chunk on the west end looking like it will melt out in the next week.”

    And as you point out, it’s continuing. Very interesting. At this point I think it’s inconceivable that the NW Passage won’t open this year. Last year, apparently a bunch of older ice jammed down there, and it’s going.

    Anyway, I haven’t bet on any particular number, and believe it will end up between 2008-2009. But I might be surprised. I’ve been surprised at how the high rate of melting has continued despite the excess April thin-ice “nearly reached normal!” extent having melted quickly away.

    Of course, Goddard assures us that there’s more ice this year than every before. Snort.


  18. Sorry for the redundant comment on the CA, but I have to say it looks more melty every day.

    Looking again at the Bremen sea ice page, I see that scrolling down all the way finds a 21-day animation, albeit of the gray-scale version only. It seems to confirm my impressions.


  19. Given the following sequence of numbers

    4969, 4570, 4709, 4872, 4270, 5964, 5611, 5110

    1. What odds would you give of the next number being lower than 4037?

    and 2. higher than 8737?
    Err, that seems a bit extreme, so how about 3. higher than 5537?

    I don’t think I need offer prizes as to what these numbers are.

    If you want to know the average of those numbers is 5009
    Std deviation 552
    Linear trend for 2010 is 5511

    My answers to 1, 2 and 3 would be such that the numbers reported by Wired look at bit too high if you exclude the extreme outlier. But what do I know?

    Perhaps the more relevant odds questions are
    4. probability of next number being lower than 4802?
    and 5 chances of next number being higher than 5002?


  20. I hope it’s OK to mention this: A few weeks ago I have started a little blog concerning the Arctic sea ice only.

    [Brief mentions of relevant blogs are fine -W]

    I have recently written a blog post on that Cryopshere Today sea ice concentration map in the comparison section, called Inner Conflict.

    I have also written a post on the Northwest Passage with some animations, such as this one that shows the difference with last year.

    I have mentioned the betting over here in this post.

    I’m writing Sea ice extent updates every 2-3 days, and some silly posts in between.

    It’s not my intention to be plugging my blog (which will close at the end of the melting season), but I’m trying to create a central place for the smart people to discuss the state of the sea ice.

    On topic: Mr Connolley, I’d be very interested in taking the low side of your bet for EUR 20.

    [OK, you’re on -W]


  21. Thanks for accepting the bet. If I win it, I will donate the EUR 20 to a project in Pakistan where they teach people to build efficiently burning wood stoves. Even though Pakistan has been a bit of an oven lately, I believe.


  22. Latest PIOMAS data seems to show a reduction in volume anomaly of over 2,000 km^3 in the last month (my memory says the current steep drop had barely started in the mid May update). If we lose another 3,000 km^3 in the next 3 months we reach 0 ice volume.

    Surely not?


  23. Michael, where does your 3000 km^3 come from? I calculated 14,400km^3 average for September – current anomaly if sustained of 10,700 km^3 leaves 3700 km^3.

    3700 may be too high because:

    Daily minimum should be a little less than September average.

    The trend in volume anomaly during July & August seems to be down in recent years (just eyeballing graph).

    If both of these are accounted for then probably less than 3000 km^3 but that leaves little if any room for “If we lose another 3,000 km^3”

    Being low now, there is time for it to bounce back more towards trend.

    Extrapolating volume anomaly change seems like counting things before they have happened. How much bounce back towards trend to expect does not seem easy to answer so I shall ignore it but expect the answer to be too low.

    3700 km^3 is significantly less than 5800 km^3 in Sept 09. How would we expect that to change things? Perhaps 20% less thickness and 20% less extent? 5.36m km^2 from 2009 less 20% = approx 2007 extent record of 4.3m Km^2.

    This takes advantage of the lower volume of ice which seems undoubtedly a factor to be aware of. However there are other factors as brought out in the SEARCH outlook report like: lower SST near ice margins for previous summer as used by Tivy…

    The other thing is how trustworthy is the PIOMAS data? Still early days? Will it project large ice free areas that when inspected are not ice free? So do we need to see what happens in September before trusting May anomaly information?


  24. Crandles, I’m only using my eyeballs on the average volume chart posted at PIOMAS, but I’m pretty sure the September average is between 13k and 14k, and lower than 14k. Current anomaly is around 10k, so if anomaly goes down another 3k, we reach 0 ice volume.

    I wouldn’t say that a continuation of the recent trend in anomaly is likely, but is there any reason why it would be impossible? In winter as the anomaly gets lower there will be more open sea, more escape of heat, and so the lower the anomaly gets, the harder it gets to push it down further.

    But in summer the more open ocean, the more heat absorbed from the sun, and I can think of a reason why melt can’t continue at the same fast rate as long as the same favourable conditions for melt persist. Other than running low on ice, and the fact that later towards the end of the melt season there will be less solar energy to sustain a faster melt.

    Is a continuation of the current anomaly trend like continuing a trend of 6,6,6 on a dice roll, or is it more like continuing a trend of 4,5,6 on a dice roll?


  25. I haven’t seen any response to my wager of June 17th for 100 pounds, which I made in the comments section under “Three views of sea ice”, and I think I may understand why. I was accepting your default bet, but I didn’t state that clearly enough in my post, i.e. I wagered that the extent of Arctic sea ice will be less than 4.735 M sq km, or 1 SD below the 4.865 average. Now I do believe that the likeliest outcome will be a “push” with neither of us having to fork out or try to collect, but looking over the latest data it seems that I am more likely to be right in my pessimistic forecast, which is unfortunate for the long term prospects of polar bears and our children’s children.

    [Oh sorry I should have replied. Yes, I’ll take the bet. Please don’t wager more than you can afford to lose -W]


  26. Michael, I was using the text to the right of the thumbnail “The model mean seasonal cycle of sea ice volume ranges from 28,600 km^3 in April to 14,400 km^3 in September.”. But I agree that the monthly volume chart does look more like 13,400 than 14,400 km^3 for September while agreeing with the April figure. I wonder which is wrong?

    If you rolled 4 5 6 on a dice you wouldn’t see that as a trend. A 7 would break the model and any other number wouldn’t follow the trend so there is too little room for that trend model to survive. Consequently 666 is the better model of the two offered. At some point the fair dice model will be broken and you will change to a weighted dice model.

    But maybe something better than those two:
    With extent there has been a tendancy to bounce back to trend – when a large area melts it cannot melt again that season. So perhaps observing a pendulum’s positions is more like the model and it won’t take as many more high obsevations to break the model than with a dice – we are already at 5sd for volume so the fixed pivot point pendulum model is looking broken but when do we replace it and with what? A constant speed movement in the pivot point or an accelerating movement of the pivot point?


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