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Nightvid Cole

With no buoy data AT ALL on the Siberian side of the Arctic Ocean, it's hard to know just how thin the ice over there has become. Buoys in other areas are returning first year ice thicknesses in the range of ~140 cm at max.

If the ice in those areas is really only 140 cm thick, then virtually the entire Siberian sector up to 83-85 degrees North is destined to disappear by September. Given that the Alaska side in the last 3 years has pretty consistently melted up to 80 degrees North or so and the Atlantic side up to 82 or 83, I think it will do at least that this year. So I'm going to shoot (tentatively) for just a hair below 2012, near 3.5 M km^2 for NSIDC September monthly extent.

My guess has the potential for revision on the basis of the timing of melt onset in June. If the snow is all gone before June 16 as seen on MODIS, reduce my guess to 3.0 M km^2. If the Siberian sector still has a good snow cover on June 20, increase my guess to 4.0 M km^2 as the area might survive the summer. And if it makes it June 25, I'm going to go for 4.5 but I doubt that will happen.

Nightvid Cole

Just put me in for 3.5, since the data necessary for me to analyse further (as I explained in my previous post) won't be around until after the deadline.


Grateful to you L. Hamilton for permitting intuition, as I have little structured validity for my "prediction". It has been unshakably with me since spring 2007 when, of course, the common opinion was that summer sea ice would survive until the end of the century. The broad spectrum of evidence and events since have consistently, and increasingly, pointed to the possibility of that little monkey being correct. With each adjustment of the "official" forecast - 2080, 2060, 2050, 2030 - my 2007 notion that the ice would for the most part be gone in 2013 does not seem so far fetched. Weird weather here in south Ontario now seems to be the norm. Grateful to all on ASI blog.

Kevin O'Neill

Mean September SIE will be 2.9 Mkm^2

Minimum September SIE will be 2.5 Mkm^2

Based on the assumption that the large increase in ice < 2 meters thick (and the corresponding decrease in ice > 2 meters thick) will result in a 20% decline in September SIE.



I'll guess 3.7, which is nothing more than an eyeball estimate of the long term nonlinear trend. There really is nothing more to my guess than that.

Hans Gunnstaddar

4.35 based in part on the graph provided. Why, because there are no examples of more than 3 years running of lower numbers, and since we just had 3 consecutive years of lower numbers, this year should be greater than 2012. From there I let intuition clarify 4.35

Jeff Poole

2.5 minimum.

Based on little more than watching thin ice melt faster than thick...

And here's another prediction - the mainstream media will all ignore it. Then they'll act all surprised when the blocking weather patterns do a rerun of last year's weather...



Three years going down in a row, seems like it's about as low below climate due to weather as it can go. 5.0 will push it to the high end of climate due to weather. Kinda like what happened with that spike around 1996.


The NAEFS 8 to 14 day forecast shows above normal temperatures over most of Siberia for that period which should melt more snow than normal there. It also shows North America to have below normal temperatures near the Arctic which should preserve snow there. Nevertheless the lack of snow in Siberia should have a greater influence.

Much more of the ice is first year thinner saltier ice which will be more prone to melting earlier and will more likely lead to an earlier warming of the surface waters bringing warmer temperatures to the remaining ice.

A fair portion of the older thicker ice has moved into the Beaufort Sea or near the Beaufort Sea in the Arctic Basin. Since this has mostly melted during the previous several years I expect it to melt this year too...likely even sooner because there is even less of it.

The Bering Sea now has nearly an average ice area so warmer water should develop there sooner than last year and aid in melting out the Chukchi Sea sooner than last year.

There are numerous polyanas.

The wind could affect extent in September if a spreading event or a compaction event occurs near the minimum.


1.98 million Sq. km and a ice free pole, but... a lot mor ice in the NW passage. Possible it's not opening this year.


2.8 Mkm2 +- 0.7 Mkm2

Trying to estimate where the trend is going by eyeball.

Alan Clark

2.6 million

If the volume continues to fall at the present rate then there will be no ice in 2015 or 2016. The extent will have to accelerate downwards to reach zero at that time, so I expect a reduction of about 1 million this year.


2.9 million +/- 0.8

The ice is thin and highly fractured, but behind trends for April. The binned thicknesses suggest 2.5 million or less. However, Cleveland is in active eruption. When the volcanoes in the Aleutians or Kamchatka Peninsula have erupted at this time of year in previous years, it has seriously slowed the melt. Countering that, the ice pulled away from Ellesmere in February removing the grounding limits, and there is a large melt of a band across the central arctic from Alaska to Svalbard in progress which could free all of the ice.


2.9 km^2

Eyecrometer on trend. I don't know enough about the cryosphere to make a truly educated guess.


correction...2.9M km^2. I'm well into wine o'clock here.


3.0 Mkm^2

WAG. there's no model which can predict this with half-decent accuracy, and that's before we get to the influence of random weather effects (tho at least we're guessing monthly extent rather than daily, when we might as well be playing pin the tail on the donkey). if the volume decline continues then it will be reflected in extent, but how that will work out exactly is anyone's guess

Peter Ellis

~4 million. Predicting this far out is a crap-shoot though, I'm just going for somewhere between 2012 and 2007 on the grounds that we have an accelerating downward trend, but two record years in a row seems unlikely.

Zeug Gezeugt

2.5 Mkm^2

Based on 2012 as second exponential tipping point after 2007, increasing Siberian permafrost and sea methane releases and likely complete collapse of arctic summer ice by 2016.

Harold lee

4.1 seems about right. effect of last El Nino 3 years ago wearing off should be cooling for next 3 years with La Nina inputs not to mention all that northern hemisphere snow cover cooling things down.


3,75 +/- 0,25

This is based to my extremely unscientific extrapolation method that currently yields 3,70 or a bit lower. thanks for the reminder of the cleveland eruption. this might up the september number, also there already is Tim's 3,7 so at least two eyeballers have the same answer :-). Also the ~75% confidence for the error bar is eyeballed so draw your own conclusions. The value for 2014 is 2,4 Mkm2 with the same error bar (this isn't science) though it should be higher. Value for 2015 isn't there, though the waning solar cycle that should be on then should be accounted for. 0,5Mkm2??

Climate Changes

2.82 Km2, NP ice free.

Chuck Yokota

2.4 Mkm^2

Based on my feeling that the sea ice volume trend is a better measure of the physical reality of the situation in the Arctic, and that trend is strongly downward.


Fairfax Climate Watch


confidence: low, but higher than any other estimate.

For this year to loose enough volume to bring sea ice volume to zero is consistent with an exponential trend in volume declines from October to September. It would not be consistent however with the extent trend. But the extent trend isn't likely to persist to zero from what I understand.

Also, there seem to be more clouds so far in May compared to last year, judging by a look at the infrared satellite view. According to the new study published in nature by Kapsch (http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1884.html), low-ice-years (i.e. low minimums) are correlated with high cloud cover in springtime through middle May. And 2012 was itself a low-ice-year. So if this year continues to have more cloud cover through May, it would stand to reason that melt this year would at least exceed the trend.

For the ice to reach zero, about 18% additional volume would have to be lost between now and minimum, compared to 2012. That's a few thousand cu. km of extra ice. If there are more open areas of ocean, the increased mixing and wave action will break up and melt the ice more efficiently. Plus, beneath a certain point, the ice will probably melt much faster than ever recorded as it breaks up into many small pieces with a much higher exposed surface area/volume. Based on the volume trend of previous years, it appears we could rapidly be approaching that situation in 2013.


2.4 or more.

I would also refer to the PIOMAS ice volume trend as dropping too fast for extent and area numbers not to see accelerating declines. The vast areas of first year ice and the late season ice that formed in the Beaufort sea fracturing event are not going to last long.

There's too much warm water in the Pacific Ocean and not enough thick ice in the Arctic. The warming is accelerating IMO.



I'm basing my WAG (Wild Ass Guess) on the fact that I believe we've entered a stage where every successive year results in a new record until we reach a fluttering tail as we near zero.

Given the dramatic fracturing in February and March and the general state of the ice, I can't envision any rebound this year.

Regarding this poll, any entries posted at the beginning of the 30 day window are likely to be far less accurate than those submitted just prior to the deadline. Weather will decide the final number but not the general trend of continuing decline.


2.5 Mkm2

Integrating the most simple albedo-feedback rate equation results in the exponential decline, which fitted to PIOMAS results in 2015 for zero volume. Putting zero extent for 2015 in above sea ice extent graph and interpolation gives about 2.5 for 2013.

Frank Pennycook


My fairly uninformed guess. I can see why some have gone high, based on the variability and the chance of a rebound as has happened after previous lows. But I'm swayed by the thought of all the thin and first year ice, and by the volume trend, to think the reduction in extent is likely to accelerate even more from here.

Artful Dodger

3.9 M km^2, +/- 1.0 M


  1. Larry, pls link to the NSIDC September Sea ice data file. This is the official score used for SEARCH results.
  2. Here are SIE values for the last 10 Septembers:
    2003 6.15
    2004 6.05
    2005 5.57
    2006 5.92
    2007 4.30
    2008 4.73
    2009 5.39
    2010 4.93
    2011 4.63
    2012 3.61
  3. NSIDC extent includes the area near the pole not imaged by the sensor. It is assumed to be entirely ice covered with at least 15% concentration. This may be a poor assumption in Sep 2013. A 'North hole' correction may be required based on other data sources.
  4. a +/- 1.0 M km^2 range is +/- 2 SD from the 10-year linear trend.
  5. a Sep 2013 SIE < 2.9 M km^2 or > 4.9 km^2 rejects the linear trend model of SIE decline at the 95% confidence level.


Nick Barnes


Conditions look similar to last year, and I still don't really trust the volume estimates.



This guess is based on extrapolating to 2013 the curve that I have fitted to the graph of historic data posted at the top of this thread. The curve has no formula, and was generated by eyeball, not by any mathematical calculation.


2.2 Mkm^2

Billy JM


Sea Ice Volume will become the most significant Arctic statistic for the remainder of this decade. It's wafer thin now (compared to a decade or two ago) but will still maintain enough integrity to keep Extent and Area somewhere in the range of the last 3 seasons. As Volume continues to decline however, Extent and Area will drop dramatically - but not for another 2 or 3 years.



Crap state of ice means smaller disturbances have the same effect of much larger disturbances in earlier years, therefore we are lookign at more than normal rates of melting, which combined with low volume = 1.8.


~3.2M km^2

This is based on Wipneus' analysis of PIOMAS volume decline by grid cell, which seems to me to be the best way to relate the exponential extrapolations of sea ice volume decline to declines in its extent.


Remko Kampen

+0.5 M, -1.5M is the 'error bar'.
North Pole free.
Argumentation is much like Fred's at 14:42 ('crap state of the ice' now). I am counting on amplifying Arctic amplification and further Rossby resonances for transport of (sub-)tropical to very high latitudes for prolonged periods of time.
I see no relation to EN/SO (the vast meltings of 2007 and 2010 having occurred during two virtually opposite phases).


2.2 M km^2

And smaller next year, close to zero.

It seems that a good number of folks both here and elsewhere have been influenced by the cool weather this spring in North America and Europe. The Arctic temperatures have not been colder than normal, however -- see http://polar.ncep.noaa.gov/sst/ophi/color_anomaly_NPS_ophi0.png

So my guess is that we will set a significant record, given the thinness of the ice and likelihood of an increase in feedback effects. It is going to be a pivotal year.

Hans Gunnstaddar

As of the last prediction made by Donald, there have so far been 31 predictions with an average of 2.81

The highest is 5 and the lowest is 0.

That is presuming the 2nd post is zero, but I couldn't be certain from the way it was written.

Kevin McKinney

Having skipped all previous comments/estimates, I'm going to guess at a 5% decline from last year's 3.41 million km2. That would be about 3.24 million km2.

That's mostly intuition, with factual input being the bad condition of the ice going into melt season. We had a WACC winter, with warm Arctic conditions prevailing; multiyear ice is very low; and of course there are strong indications of weak ice (e.g., the "cracks of Doom.")

That may suffer from timidity, though. I note Dr. Beckwith's (March) expectation that we'll go essentially ice-free this year.


IJIS minimum extent: 1,458 km^2.
CT minimum area: 0,968 km^2.
NSIDC september extent: 1,7 km^2.

The ice in the main pack will need a little bit of time to weaken in the spring and early summer, but once it gets going it will be really dramatic. The amounts of MYI are not impressing and will melt away surprisingly fast in August when everything else is gone.


1.1 million km2 because:

CO2 emissions from fossil fuel combustion will increase this year by 3.2 % to 33.7 GT.
Total global ice loss will thus be 12.000 km3 relative to anno 2000 – of which 10,000 km3 will be Arctic sea ice loss.
In 2000, we had 11,000 km3 of sea ice left in September, this year we will thus only have 1,000 km3 left by the end of Summer.
With an estimated average sea ice thickness of 1.1 meter, there will be 1.1 million km2 left by October 2013.

Cheers P


3.1 million km2

history would suggest a rebound after last years significant decrease.
However (unlike previously) the majority of last years decrease was not caused by extreme weather. Arctic cyclones could now be the norm. This suggests a paradigm shift has occurred in the cryosphere. positive feedback of reduced albedo, increased inflow of warmer water, reduced snow cover, less multi-year ice etc. suggests there will only be decreases until zero is reached.



CLIMO / stats for the 'trend' argues strongly for a number higher than last summer, though not by much as the ice thickness in the Bering Strait and Chukchi Sea is markedly lower than at the same time last year. Though a strongly negative AO has dominated the last 6 months, a flip to a modestly positive AO and NAO during the summer will help to spread out the new and multi-year ice during the next few months. The overall motion of the ice pack over the winter was the first time I can recall seeing such a large shifts - and this tends to force cracking/fractures like we've seen.

A big factor that will became apparent within the next 60 days is just how much snow cover built up over the ice. It was an extremely cold winter in much of the western Arctic north of Alaska/N. Central Canada - but this doesn't always mean the ice thickened up in a major way *IF* there was a thicker than normal snowcover which would of 'insulated' the ice and mitigated much thickening.

Otherwise - this is nothing more than a WAG thios early in the melt season because predicting large-scale weather patterns 3-5 months out is not really that easy. ;-|

Jai Mitchell


I believe that extreme variance in atmospheric patterns will produce significant cloud cover in the arctic this year. Plus, the coverage values don't seem as good as the PIOMAS anymore.

Aaron Lewis

Less than 1 million km^2.

The residual ice may not be a continuous ice pack, but I do not know how it will appear the various eyes in the sky. Physically, it will not be zero, but much of the residual may not register as sea ice.

Based on expectation of sea ice forming cold pole(s) that drive large scale transport of latent heat into the Arctic. These weather fronts will also provide storm mixing, raising surface salinity and lowering the melt temperature. These winds will also breakup the ice, increasing its surface area, and reducing its detection.

Water vapor in the atmosphere will prevent the imported heat from being radiated into space.

The surface of all sea ice in July/August will be covered with a film of water, which will decrease its albedo. Also, this summer there will be more low albedo open water.

The main point is that with the changes in large scale atmospheric circulation, the entire northern hemisphere will act as a heat collector and heat store to melt Arctic ice. I think the sea surface height anomalies in the Newfoundland sea and the Barents sea over the last year point to a reorganization of North Atlantic ocean circulation that will facilitate transport of heat farther north.

I may be a year or 2 ahead of myself here, but all of the statistical measures of system stability that I learned from Ed Deming, say that the system is out of control and will rapidly transition to another state.

Climate Changes

Of course I meant 2.82 Million Km2 , not 2.82km2 :|

Bert Van den Berg


1) Within 5 years there has always been an uptick.
2) Over this winter the ice was tracking slightly higher than recently.
3) The overall trend is down, so the uptick will be muted.


I think the decline has decoupled from the annual variance, so I'm saying September mean = 3,000,000 km^2

Minimum should go below 3*10^6km^2

Entropic man

3.8 +/- 0.25

Difficult to say how much of last year's minimum was due to the weather. I predicted 4.0 last year and was shown to be optimistic. Still an optimist, but expecting it to go through the floor after 2015.



Guessing really, a "dead cat bounce" from last year, but not above the former record.

David vun Kannon

3.0M km^2

I would have guessed 4.0 if I thought the system was still describable by a model with a stable mean, or at least trend, and that reversion to the trend made sense. I don't think that is accurate. I think we are in a process driven by albedo change as ice melts and is replaced by dark water, with more energy stored deeper than previously.

If I could delay my prediction until 7 June, I might go lower, say to 2.5. Looking at previous years, the melt really hits its stride after Day 180, so those few days before locking in the prediction could give a clue whether the line was about to fall off the edge of the table or not. But I can't wait, so 3.0 it is.

Tommi Kyntola

1.34Mkm^2, open pole and open nw passage

I base that guess on enhanced feedbacks, poor state of ice, lack of MYI from last year, currents and some further wearher events.

David vun Kannon

Sorry, I should have said Day 150 in my previous comment, not 180.


3.0 +/- .25

Greetings all;

I'm going to put on my systems analyst cap - not being an arctic scientist, that's all I can do - and think qualitatively here for a moment.

When I think about it, what will happen this year will be determined by heat flow, and the question of whether that heat will flow through the ice, or be captured by it.

Considering the massive amounts of energy involved, while insolation does apply a lot of energy to the ice, I will suggest that that energy source is dwarfed by the net energy present in the arctic ocean beneath the ice. While the near surface watertemperatures may be as low as ~-1.5, the reservior of energy available to melting is at least 2 orders of magnitude higher than that in the atmosphere. So, when surface temperatures are lower, this supports higher flow of heat through the ice, permiting more freezing. You increase the temperature, and the heat flow stops, and instead is picked up by the phase transition of the ice melting. The illusion is that the heat in the atmosphere and sunlight is doing the job, but I think we'd find the energy flowing into the ice from underneath exceeds that by a factor of 10. The key effect of warmer atmosphere is to halt the heat flow, and force into the ice directly. For this reason, unless the weather changes caused by more clouds due to more open water drops temperatures over a wide region below freezing consistently, the effect will only reduce the potential melt back by 10% (QED, no "bounce" from that.)

I will also hypothesize that in the past, the higher physical integrity of the ice limited exposure to both sub-surface and top surface temperatures. With the physical strength of the ice as seriously compromized as we've seen this year, I think by nature, that will affect the melt exponentially. Namely, as the "granularity" of the ice pack increases, we will see more energy applied to the pack relative to its volume, as ice surface accessible to water contact increases.

So, while I'm not thinking there will be a "melt out" this year, I do think that we'll see a break in the "traditional" pattern visible over the last couple of decades, with continued, serious decline both in end of summer extent and volume. I'm also predicting open water at 90N.

Rob Dekker

Larry, if I put in a number now, can I still change it later (before June 7) ?

I'd really like to FIRST see what snow melt is doing this May.

Spring snow cover reduction is a good early indicator of how much heat the Arctic is going to absorb in summer, and thus how much ice will melt.


2.9 +/- 0.2

Part intuitive extrapolation from the long-term and medium-term trends; part based on present weather patterns. We see persistent high pressures parked over the north pole since the 2007 event, which is helping to drive these warm temperature anomalies. Evidently, spring has arrived in many parts of northern Europe and Russia, with air temperatures now well above average since mid-April, according to NCEP/NCAR data. This pattern is expected to linger for weeks. This is already weakening the Laptev, Kara, and East Siberian Seas, evidenced by festering polynyas. SSTs have remained well above average in areas like Barents Sea, much to the detriment of the Arctic ice from the vantage point of currents. The possibility of bottom melt aided by the Arctic Ocean's exposure to sunlight resulting from the massive 2012 ice loss adds to the uncertainty, but in my opinion, not for the better.

Martin Gisser

2.0 +/-0.7

Based on eyeballing fuzzy curves plus remembering the crack scare. More math won't help, methinks.

Eyballing the NSIDC graph I would expect 2.7. But 1) there's the nosedive of >2m thick ice (cf. Dosbat). 2) The fracturing earlier this year with cracks extending into MYI suggests that ice dynamics is now dominated by FYI, so I guess MYI will crumble like never before, ripped apart by cracks entering from thinner ice. 3) Wipneus' exponential trend of PIOMAS thickness gives 0 for 2015. Quadratic trend gives 2017, which methinks is a more plausible curve than exp. Looks like my 2.1 guesstimate is around the way down to there.

(I'm oscillation between sensing 2.0 as too radical and too conservative. So I hit the Post button now.)

Bob Bingham

With the ice mass being low and already cracked it will break up quickly.
When predicting an ice free Polar sea I wonder what exactly is ice free? As far as affecting the weather I think that anything around 1 million square kilometres could be considered 'ice free'.http://www.climateoutcome.kiwi.nz/ice-melt.html

Espen Olsen

3,014.699 M km2 is my "qualified" estimate, I will not tire you with the calculations behind this figure.
And I expect less than 499,000 km 2 in 2016!
But I still believe the volume figure is far more important at this point in the remaining life of the Arctic Sea Ice.


2.5 +/- 0.5 Just based on a continuation of last years trend. I don't think it will go up, it's just a question of how far down.


When I look at this graph I see the red line as the new mean and as such the last two years can be seen as recovery years, so this year could see a radical drop, the balance of probabilities suggest that lots of snow cover led to a late freeze at depth and consequently poor ice quality of FYI. Without a shred of hard evidence I believe lots of fresh water left through Fram with the ice replaced by warmer Pacific /Atlantic waters. Once the FYI begins to melt I expect it to be rapid leaving vast areas for the breaking up MYI to get blown into and isolated in, leading to it too rapidly melting. If this process isn't largely underway by July 25th then I may change my view.

K Stabenow

2.0 M km2 if it is indeed a tipping point.

michael sweet

I guess 2.75 Mkm2. I think the volume will go down about 25% this year and the extent will follow the volume down. Last year had normal weather and is likely to be repeated starting with thinner ice. With 2007 weather it could go lower.

Michael Sweet


Newbie here. I have been casually watching the arctic melt since 2007. I have been lurking and learning here for about a year. It has been nice to see such smart well informed people discuss climate without having to put up with ignorant deniers. I have a background in pure math, but not much science.

I predict 2.7 because the minimum volume is dropping so fast and there is plenty of FYI. Plus, 2.7 is charmingly close to e.

Thanks to Nevin and all the other folks (A-team, etc.) for this important and informative blog. I can't imagine a more important service to humanity than warning about the climate cliff we find ourselves careening off of.


2.8m KM2

There's not much upside except statistical theory and a really cloudy melt season but certainly downside. If the ice is as rotten and thin as I fear as it could nudge 2m but next year will be the ice free pole and remnant ice only.

Based mainly on the wisdom of others at this blog and a lot of associated reading and fossicking your contributors have led me towards.


3.8 +/- .4. Upside is snow North American snowpack delayed melting and downside is major storm tossing ice out the Fram. Think snow will win this year but 2014-2015 ice maximum drops below 11M and melt out becomes an expectation.

r w Langford

sq km 3.14159 seems appropriate under the mathematical constraints of atmospheric and oceanographic conditions at this time.


2.5 km2
1) Number of open leads promoting melting
2) Significant amount of thin single year ice
3) Shore albedo change
4) Impact of arctic methane emissions
5) White bear whisper number


2.9 million sqkm. loss rate appears to be around 5% of the original 7million sq km, each year, since 2005. It could be higher with increased solar absorbtion as more ice is lost. This assumes a normal weather pattern like recent years, no outliers like 2007.


3.2 sq km


2.5 +/- 0.5 mkm2

My reasoning is based on a slightly different observation. I've noticed that the areas with heavy red/yellow on the AMSR-E charts in early/mid May tend to be the final resting place of the pack melting in September.

Going on what we are seeing this year, there will be a small area of pack left over Greenland and the CAA with the north pole still slightly covered. but not by much. Although it looks like the ice over by the CAA will also break down too.

In the end it will depend largely on the weather patterns and that has become more and more unpredictable over the last decade.

It will be interesting no matter what and I don't believe that there will be any recovery at all. If we look back to 2006, which experienced massive radical melt early on, which we now see as "normal", there was no real "regrowth" after the weather turned against melt. There was, in fact, only a near miss of the 2005 low and a continuation of the decline.

Only the massive solar low at the end of cycle 23 brought a small and very limited respite from the 2007 crash, but certainly no "gains" on the trend.

L. Hamilton

@Rob Dekker (and anyone else) ... if you haven't voted yet, no hurry, the SEARCH deadline is June 7. I'd prefer not to revise estimates you've already sent in, just because that will confuse me, but in an extreme case let me know.


the average of 59 estimates is 2,834513 Mkm2 +/- 0,5458

but the reason to make a second post is that i eyeballed the later numbers wrong. it's 2016 2,4 Mkm2 and 0,0 Mkm2 latest on 2019, 2018 being the best guess. I hope the previous estimate was not earth-shattering to anyone.

The current ASIB crowd source estimate would require a daily melt of about 83000 km2 to be true. To get this in perspective this is a circle with a diameter of 325km or 202 miles (for our imperial friends). One would have to bicycle pretty well to keep with the melt.

L. Hamilton

The SEARCH SIO folks are interested in hearing our results, if we choose to send something in.

I count 60 responses so far, this experiment is generating real data.


This is a great initiative, Larry! Thanks for taking it on.

My guess would be 3.25 million km2, give or take half a million.

I will have the poll on the ASIF finished later today.

Hans Gunnstaddar

LH: "I count 60 responses so far, this experiment is generating real data."

Apparently due to the flexible parameters of how one could go about making a prediction, more people than usual are chiming in. The variations in thought process is amazing.

But on a different note since I've already made my prediction earlier, http://nsidc.org/arcticseaicenews/

Most posters on here probably tune into that site in the evening to get the latest Arctic ice extent reading. Something I’ve noticed about 2013 vs. 2012, is how much more consistent the ice freeze/melt flow pattern is this year vs. last year. Does that suggest the weather is less turbulent, and if the pattern holds will it translate into less melt?


I think 2.8 for PIOMAS minimum. Extent and area are much less certain, since there will be likely a lot of thin ice at minimum which could also melt. But I'll make a blind guess at 2.8 mio km^2 extent.


Some maths: assuming average thickness of 2m for the 83000km2 daily melt. The heat of fusion for water is ~333550J/kg. The energy required to melt this much of 0 degree ice is 55,37 PJ which translates to 15,38 GWh that would be about the same as the yearly production of electricity in a country like Slovenia (20,273 km2), but only 0,026% of the daily production of electricity in the world (data from wikipedia). People stating humans can't make an impact on environment are loonies.

Michael Hjorth

3.5 mill km2

Primarely based on your courve, Larry.

Sea ice in Nares Stait between Greenland and Ellesmere is already breaking up now, much earlier than last year. So even if spring is a little late in Greenland now, and sea ice did create more problems for shipping this winter than the previous, it's likely that the ice will recede further this summer.

Michael Hjorth


3.9 mill km2
I expect some recovery after last year's plunge. On the other hand, the ice is also thinning rapidly, so I expect the recovery to be modest.

/Lars Karlsson


3.85 m km2 for NSIDC Sept avg

Taking into account the trend, an approximate combination of upward and downward fators, and a big shoulder shrug in terms of whether statistics, models and physics are diverging or converging in the Arctic.

It would be interesting to develop our own probably distribution type estimates, applying some common labels (eg very unlikely, unlikely, likely) to some common numeric ranges (e.g. <1m, 1-2m, 2-3m,3-4m etc). Next year maybe.


PIOMAS for september 2,200 km^3
15% extent at minimum 2,75 mill km^2
Navigable, but not completely ice free North Pole.

To my amateur mind, PIOMAS is the most important data to follow, since Artic melting basically just physics and mainly a question about energy balance, with the ice 'sucking up' excess energy by melting. Extrapolating the exponential trend, should give the September average for PIOMAS around 2.2 +/- 0,2 kkm^3.

I find the 15% extent somewhat less interesting - except that it is measured data, updated daily and the maps gives vital cues for interpreting the ice conditions. Extent must be more interesting for navigability than for assessing the ice-melt, and during the winter months it is almost completely irrelevant for the Artic sea, as it mostly measures ice extent outside the Artic sea itself, with the Arctic sea always frozen.

With that in mind, I hesitate to extrapolate the 15% extent-data. Over the last decades, volume have gone consistently down, while the extent have less so, and even shown some appearance of normalcy in parts of the season for those who look superficially on the numbers. The reality is of course a thinning of the ice. However, when the volume approaches zero, extent will too, no matter how one extrapolate the data. Therefore, extent data will brutally meet a paradigm shift, which we might have seen the start of last summer.

Thus, extent might be as high as 4.0 Mkm^2 with lots of thin and badly broken up ice, or we might have a melting carnage and stop at an extent of 1.5 Mkm^2, with a small but stable sea ice north of Canada and Greenland. My gut feeling if I have to give a number? 2,75 Mkm^2. The NW passage will be open, and the pole will be somewhat navigable, but not completely free of ice.

Espen Olsen


Very nice worded analysis. The words are Volume, Volume & Volume!

Kevin O'Neill

Larry, it's probably worth restating that the guesstimate should be for the September monthly average - not the September minimum.

In similar polls like this I've noticed a bit of confusion. We tend to headline the minimum SIE and I think a sizeable number of readers mistakenly submit minimums instead of monthly mean.


2.2 m km2 sept avg

Larry, great initiative;
The whole arctic seems to me to be unstable, transitioning to a new state, so and such it seems possible that we get a new minimum this year.
I find it difficult to estimate the rate of re-freeze; it tends to be high in recent years.
@Erimaassa - could you check the math? My calculations show 26% - not 0.026%


you're correct. *blushes* 26% it is. forgot to add one kilo- (m3 of water -> 1000kg). so the peta-J should be exa-J , pretty massive amount.


Since the deadline is a bit off, I will continue to contemplate. I will predict a continued rapid retreat of Puisortoq North Glacier in Greenland and merging with an adjacent glacier terminus.

Kevin McKinney



Blushing in my turn: Kevin O'Neill is right. My previous estimate was based upon the lowest daily minimum, not the September mean, as the directions clearly state.



Minimum: .9 (just below the 'essentially ice free' level)

September mean: 1.5

As others have pointed out, much of the ice is even more rotten and cracked than in previous years. There is more CO2 and CH4 in the atmosphere than ever before. And I think we are at the point where sudden catastrophic collapse is imminent. Where I live, very large lakes go from virtually completely ice covered to virtually ice free in one day--it is called the "ice out day." Given the increasingly thin, weak ice, I think this is our "ice out" year.

Question: There has recently been some news about how rapidly the Arctic Ocean is acidifying. Do pH levels have any effects on ice formation, one way or the other?


2.8 M Km^2. Normally I would expect a rebound from last year's record but I doubt the resiliency of the Arctic now. With early cracks, high temps, and an ever-increasing advection of heat into the Arctic and a relentless increase in GHG forcing, I think the melt will continue.
Thanks for doing this, Larry. I submitted the same estimate last night but I think it got eaten by the spam filter feeder.


Syddbridges, I haven't seen your comment in the spam locker. Sorry it got lost.


Okay, everyone, the NSIDC 2013 Arctic SIE September minimum: May poll is now ready on the Forum, as is the Cryosphere Today 2013 Arctic SIA daily minimum: May poll. There were a couple of problems that needed solving, but it's looking okay now, so cast your votes. I start a new poll at the start of every month.

Keep in mind the differences between:

Area vs extent

Daily vs monthly/September average

And these aren't PIOMAS sea ice volume polls.

Ac A

3.8 mil. km^2

- I noticed some folks confused extent minimum in september with average september value, these are DIFFERENT numbers.

Explanation of estimate - we never had 2 minima in the two consecutive years, so some rebound is expected. Polynomial trend gives 4 mil. km^2, so half way to 2012 minimum gives 3.8.

Lets see! Thanks Larry for this,


Ron Mignery

3.1 M Km^2

= Wipneus's 3.2 projection of exponential trends shaded down to account for increased Fram transport as the polar high tends towards Greenland as Siberian side ice disappears.



Extent is the least important metric IMHO. Area is far more important & Volume tells the story.
PII2012 may delay Nares Strait advection but I believe that the CAA will again swallow up any MYI that approaches.
I'd be more surprised by 4 than 0 but 2015 is still my best guess for hitting bottom.(for 1 day)
Larry - I'll be interested in seeing what can be extrapolated from the poll. Can geographic data be extracted so that we could compare say Canadian guesses as opposed to American or European?



I'm curious at the difference that some people have between their "Mean" and "Min" September values:

Name Mean Min Diff
Kevin O'Neill 2.9 2.5 14%
DoomComesSoon 1.7 1.478 13%
NLPatents 3.0 < 3.0 At least 0%
Kevin McKinney 3.24 3.43 -6%
wili 1.5 0.9 40%

Noting that the historical difference is between 1.0% and 7.5% (with an average of 3.4%) -- although admittedly it has been trending upwards, though not by that much.

I am most concerned by Kevin McKinney, who raised his estimate. I'd guess that he applied his correction in the wrong direction, since 6% seems not unreasonable.

Note that NLPatents makes sense, I am including it only for completeness.


3.2 million km2 (mean September 2013 extent of Arctic sea ice).

Not a rigorous prediction - just based on shape of the curve, intuition and a guess that, given the range of other influences on sea ice, the accelerating rate of decline won't show up in the results every single year.


3.0 M km^2

Intuition - The snow in Siberia seems to melt rapidly exposing a lot of dark tundra. The ice is thin and if I remember the method correctly, Tschudis ice age maps should overestimate the amount of old ice. We should see the effects of thin ice letting more sunshine through the ice.

Sourabh Jain

2 million km2 or below.

Its my intuition based on ice volume trend provided by PIOMAS. However, March cracks/Beafort gyration have redistributed the ice. So, ice is thicker at places where it melts anyways. Therefore, there is a higher chance that it will melt this year at places which had thick ice until last year.


Again, I also read in a blog posted on this site that there is no longer a barrier to prevent warm pacific ocean from getting into arctic ocean.

So, based on above factors, my intuition is that the ice will melt extensively this summer.


The average has risen a bit, it's currently at 2,865896 Mkm2 with 74 entries. Kevin McKinney's revision is included.

Michael Atkinson

3.3 M km^2



Kevin McKenney was completely correct. Everyone else labeled theirs mean versus min, and I somehow read his backwards.

Sorry for any confusion.

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