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Hi Neven,

Great to have you back.

Entirely happy to leave the decision of whether or not its appropriate to make a group prediction to you.

Hope you had a really good hols.

The sea ice has not been terribly well behaved during your absence, but I confidently predict that it will sober up a bit now that you're back to keep several eyes on it.

Stephane Roux


I think that the ice's decline may change regime and that the decline is accelerating.

I bet on 3.9Km2.

By the way, your blog is a great piece of synthetic work.



Good to have you back and hopefully the new blog will generate lots of comments. (Can't do sports on all my coffee breaks.)

So my amateur prediction: 4.1

Methodology: look at the data from a bunch of years, watch the 30 day animations on cryosphere today, compare the values for a bunch of different years and what their animations looked like and then finally watch the last 30 days again holding my breath until a number seems right. (Holding my breath forces a decision.)

To my amateur eyes, and based on random sampling of animations, the ice this year seems more mobile, the shore lines seem less attached and numerically the meltrate is ahead of 2007. Also, even though it is in the last few frames, the North Shore of Prince Patrick Island appears to be melting. I know how useless visual extension is in complex non linear systems, but I think the macrovariables that matter are ice thickness (duh!), ocean heat, circulation and atmosheric conditions (e.g. weather). As an amateur and using current melt rate as a proxy for ocean heat x ice thickness), the mobility suggests a bad ice melt. Of course weather isn't at all in my predictions but that is needed for my vanity later in the year....(I said it depended on weather, remember?).


Alan Clark

With the volume of ice shrinking so rapidly I am surprised that anyone would predict a greater extent than September 2010!


On that basis (and wishful thinking) I expect the actual value to be lower than all the predictions, about 3.8.

Lord Soth

The big factor is the weather. If we get a repeat of 2010 weather conditions, we will still be in the range of 4.3 to 4.5, due to the thinner ice that we are starting with.

If we get get weather conditions like 2007, then, we will be looking at below 4.0 and possibily as low as 3.6

The next month will be critical, as we approach and stradle the solar max. Clear skies will provide the maximun solar loading on the ice surface, melt ponds, leads, and the surrounding ocean. This latent heat will help melt further ice as we head into late summer and early fall.

If we keep getting back to back century breaks (last night still preliminary), things are going to be bad.

With the next Sea Ice Outlook, I expect the mean of predicitons will probably straddle the 2007 ice loss.


NSIDC Icelights also has a short article out on the SEARCH SIO.

Nick Barnes

Interestingly, the NWP and the Nares Strait are both much more icy than at this time last year.
Compare these two shots:


Kevin McKinney

Welcome back, Neven!

A minor SIE flourish to welcome you: as we anticipated in conversation here a couple of days back, 2011 IJIS SIE did cross the 10m mark. It happened last night, six days ahead of 2010.

(I didn't check the value last night, and so am unsure whether the revision is in or not--but the current value of 9,938,125 km2 gives about 60K margin, so it almost certainly won't affect the milestone if the revision is still to come.)

On a more general note, NCDC update is out also; we're back to fairly typical mean temps for the last decade or so. An anomaly giving some pause for thought (meaning I have a strong feeling it's significant, but don't understand its ramifications very well) is that the stratospheric mean was the lowest ever recorded for both UAH and RSS.

Thoughts, anyone?



Actually, 6/16 is only two days ahead of 2010, but it is six days ahead of every year in the record except 2010.

Artful Dodger

Kevin wrote:

the stratospheric mean was the lowest ever recorded for both UAH and RSS

This is a classic fingerprint of increased greenhouse gases. As more outgoing longwave radiation (infrared heat) is trapped near the surface, less reaches the Stratosphere, which then cools to balance it's heat budget.

If you'll recall, this is also why the Arctic lost 40% of it's Ozone layer this Spring.

Lord Soth

Nick, there is a ice plug in the Kane Basin, that is preventing the flushing of the Nares strait. When it clears between now and July 20 (Canadian Ice Center Prediction), Nares strait will flush quickly.

Most of the melting action has been on the Siberia side, and tempertures was cool in the Canadian Archipelego in April and May, so this area will take longer to catch up, but should eventually clear as much as in the past few years. However multiyear ice from the high arctic may fill in the northern north west passage route in late summer as sometimes happen.

Final results are in from IJIS and we have two century breaks in the row. We are now 143,281 sq km, below 2010 and falling.


Look at the most recent MODIS Terra images. Looks like that ice bridge at the south end of the Kane is clearing as we speak.


Since predictions always include the caveat "depending on the weather this summer" it's of interest that Kuglugtuk's forecast for this week feature's weather we'd associate with a warm summer day here in the UK:
Southern route of the North West Passage should free up really soon.
While on the subject of temperatures, also of note is that, after falling away earlier this year under the influence of El Nina, 2011 has clambered back up to nearly equal 2010 on the UAH's AQUA Channel 5 daily global average temperature:
The next few months are going to be really interesting!


Sorry! UAH link should be:


Then choose Channel 5 from the dropdown.

Kevin McKinney

bfraser, you're right, of course--I discovered my error as I went on to read one of the other threads, where the correct information had already been posted. Doubly embarrassing. . .

Lodger, thanks! Those are two facets I thought of, too--but there's more, right? Influence of steepened (negative) stratospheric lapse rate, effect on net warming/cooling, perhaps instability of some sort at those levels, maybe some interactions at the tropopause? Don't really know, but this has to tie to a lot of different things.


Hi Lodger,

I had the impression from somewhere that the fall in Arctic ozone levels this past winter might be due to a deformation of the troposphere;

As a result of extremely warm temperatures in, for example, the Baffin Bay area in January, the Arctic troposphere actually swelled in height, forcing the stratosphere also higher. This made the stratosphere especially cold, which allowed some OH chemicals to deplete the ozone.

This is possibly sort of what you have written above, but not quite?


Hi all,

In several discussions here, I have been at pains to stress that I don't have any particular area of expertise, as relates to sea ice.

I now find that I have discovered an unacknowledged area of expertise, in which I am undoubtably a world expert: my opinion.

Here it is then, for what it's worth, my opinion.

Several people have made the point that it all depends on the weather...

In the best case scenario, 2011 from here on in could resemble 2010. During 2010, the rate of melt between around the summer solistice to the Autumn equinox was very slow. Given that area and extent are now slightly lower, as is volume, this brings it in at slightly below 2010, at around 4.8 million km2.

Given that the starting conditions in 2011 most closely resemble 2010, it is entirely reasonable to predict that ice and sea conditions in 2011 will generate similar weather patterns.

A high level of cloudiness in 2010, for example, may have been caused by a high level of fragmentation in the central ice pack, and the anomalously long opening times of the Passages...


...And on the other hand, 2011 could resemble 2007, in which case the result could be VERY different.

In September 2007, ice volume fell by 4,000 km cubed compared to Sep 2006.

In September 2010, ice volume was around 4,000 km cubed in total. If it falls to a similar extent in 2011 as it did in 2007, this leaves nothing.

Now, 2007 was an anomalous year, strongly influenced a strong El Nino, which does not exist this year; so I don't think it is likely that September 2011 volume will fall as spectacularly for the same reason as in 2007.

Instead, I think it is conceivable that we could see a spectacular volume fall specifically because volume is now so low. September 2010 volume is just 40% of September 2006 volume.

Either, that volume is contained within a much smaller area of normal thickness ice, in which case there are much larger areas of high-albedo open water...

Or, it is spread over the same approximate area, as much thinner ice. The problem being that thinner ice can much more easily be broken by wave or tidal action into broken fragments.

An ice cube has about 5 times as much surface area exposed to seawater as an ice sheet does. The final disappearance of the last of the ice could be very sudden indeed.

Could this happen in 2011? I very much doubt it. But I think it is a possibility. I personally would score it at about a 10% chance - of an essentially ice-free Arctic in three months from now.

(Provided that volume continues to drop, I think there is going to be a higher likelihood of this happening with every passing year.)

All in all, then, combining this post with the one above, my personal SEARCH prediction would look something like:

2.5 million km2 +/- 2.4 million km2.

Robert Grumbine


I was talking with Jim Overland this morning about the SIO. Didn't quite ask your question, but am pretty sure that the answer is more in the vein of 'the more the merrier' than 'professionals only'. I'll try to get him tomorrow about it.

Generally, I think the SIO is more interested in method than in answers. For that reason, a popularity poll is less interesting than a logistic regression (my approach for simple-minded statistics) or Gompertz regression (wasn't that mentioned here?). More interesting would be a method that makes some use of model outputs -- say something that you developed that used the PIOMAS or PIPS outputs to provide your estimates. Or, as done by Wanqiu Wang, the CFS at NCEP (Coupled Forecast System). (Wanqiu, Xingren Wu, and I discussed some hows for that estimate; Xingren is still working on runs for his December 2010 estimate. And we've got a paper or two in mind to come from this and related runs, not least, the reason it's a December 2010 estimate. More, one of these days, over at my blog when I get back to blogging.)

My statistical method, I'm pretty confident now is biased low. So I think it's relatively unlikely that the cover will below the 4.4 +/- 0.5 of that estimate. Wang's model/statistical method (it isn't straight model output; there's a statistical adjustment -- how to do it is what we were discussing) is probably biased high, at 5.0 +/- 0.5. What I think is likely to be the best is the model runs plus different adjustment method that Xingren is currently working on. My intuition tells me that'll come in around 4.7.

One comment of mine that Overland is taking under advisement is to make it more prominent what we're trying to guess -- the September monthly average extent, as computed by NSIDC.


Hi Bob,

Thanks for dropping by.

'the more the merrier' than 'professionals only'

I agree that is important to let the public be involved. It's good that they let the WUWT crowd get involved through a poll. But the crowd here is already plenty involved.

a popularity poll is less interesting

Indeed. If I would have had some sort of methodology or whatever I would definitely have submitted something. But I lack the time, and more importantly, the knowledge to do so.

That's why I'm seeing Larry Hamilton more or less as representing this blog and its community. His submission is based on the Gompertz regression he wrote about extensively in a guest blog a while back.

What I think is likely to be the best is the model runs plus different adjustment method that Xingren is currently working on. My intuition tells me that'll come in around 4.7.

Well, if we combine the poll on this blog, and the one from WUWT (not the way Watts did it -> submitting the category with the most votes, but by taking the average of all votes), you get 4.2 + 5.2 = 4.7.

So, the scientists and the public agree. Policymakers, are you watching? ;-)

One comment of mine that Overland is taking under advisement is to make it more prominent what we're trying to guess -- the September monthly average extent, as computed by NSIDC.

That's a very good comment. I stressed it emphatically on the SIO maling list, and even wrote to Helen Wiggins and Walt Meier that this year it should be stated more prominently what exactly is being projected. Like I wrote in one of those mails: "Because IJIS extent numbers are so popular, many people think the SEARCH predictions are based on IJIS daily minimum extent."

But most people in the know are now aware of this, even Goddard and Watts.

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