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John Christensen

Thank you for another great PIOMAS update Neven!

Given the weather with some storm activity in the CAB in Sept, I was surprised to see that volume went up as much and suspect that to some degree a new snow layer and snow-filled ponds on the ice have been measured as sea ice increase.

That said, the ecmwf forecast is now showing a high to remain in the CAB for the next week, which will slow down winds and cool down temps, so that more actual sea ice growth will be possible.

This summer IMO seems to have been an exemplary example of how the atmospheric conditions are changing in a warming Arctic:
- Winters are relatively warm and humid at/near the CAB due to later cover of sea ice.
- The Beaufort gyre is reduced, since high pressure areas increasingly tend to be based over land areas - both summer and winter (See e.g.:
http://psc.apl.uw.edu/wordpress/wp-content/uploads/schweiger/ice_volume/piomas_ice_motion_anomaly_JanMarch2017.png )
- Winter-time low pressure areas above the sea ice will increase precipitation, which in addition to higher temps will insulate the ice and reduce sea ice formation, but at the same time should reduce sea ice export via the Fram Strait.
- Reversely, the well-known pattern of summertime low pressure areas in the CAB is further strengthened, lowering temps, increasing cloud cover and thereby reducing sea ice melting.

It seems clear to me that this is where we are heading, and the IPCC prediction models therefore seem to be reasonably accurate, as it could take a few more decades to reach an ice-free Arctic at Sept. minimum.

Consequently, I cannot agree with scientists such as Prof. Peter Wadham, who still in 2016 predicted an ice-free Arctic in 2017 or 2018:

The only really interesting feature that I am considering is the relationship between Greenland and the CAB: For years such as 2007, 2012, 2013, and 2017 we have seen a strong correlation between average air pressure over the CAB and the air pressure over the Greenland ice cap.
Especially in the fall of 2016, where tremendous storms rolled across Greenland with high levels of precipitation in October, the storms kept entering also the CAB.
This year, the air pressure over Greenland has gradually increased and been fairly high and stable over the past couple of months. It will be interesting to see if this helps blocking storms from entering the CAB also..


I predict a third freak winter owing to the stagnating state of multi year sea ice, as outlined at NSIDC, and the return to lagging dmi temps.

John Christensen

Wow - not a huge crowd here these days..

Just wanted to note that the forecast remains for a good start to the Arctic winter: High pressure in the CAB with lows circulating in the northern parts of the continents, providing early extension of NH snow cover, while cooling down the Arctic waters.

And then, for my old discussion with wayne about the relationship between the AO index and Arctic cold or sea ice: The current setup seems near ideal for a cold NH winter and for expanding sea ice, yet the AO index is currently positive, meaning that the overall air pressure above 60N is slightly below average.

I was therefore not correct that a negative AO index (Above normal air pressure) would overall be positive for Arctic sea ice, as the distribution of high and lows seems to be much more important than the average air pressure.


So, John, are you looking forward to a 'third freak winter' and why or why not?

(Do you agree with my amateur assessment?)

John Christensen

As mentioned in my first post, I would say we are generally moving to a regime of less-frigid Arctic winters and cool summers, so yes; in all likehood another freak warm winter.

That said, the current weather is somewhat anomalous for recent years, and I am curious how this will shape temps and wind in the CAB for the coming 1-2 weeks.


All of the trend lines in Wipneus Arctic Sea ice Sept. minimum volume graph show it at, or below, 1 million km3 in 2018. Given average thickness approaching 1 meter, this can be seen as analog of the 1 km2 sea ice extent threshold for an essentially open Arctic Ocean.

Crossing that line would not be the first year of "ice free summer Arctic Ocean" as the value is September minimum, not monthly averages for Aug-Sept-Oct. But the observations show those monthly averages only trailing the minimum by a few years.

With the trend line reaching these threshold levels in the next few years, the Arctic situation may soon a provide an intuitively relatable marker to enhance public perception and attention to global climate change that even deniers will have a hard time distorting, though I am sure they will find a way.

Comparing the color-coded chart of monthly Arctic temperatures to the volume and extent trends suggests that the next warm Arctic summer will take us into new territory. Low volume and extent values in 2007 and 2012 match warm summer months in those years.

Thanks to Neven for keeping the site going. I find the comprehensive monthly analysis more informative than the official sites at NSIDC and PIOMAS, though I certainly appreciate them also.

The Wipneus chart I am referring to is at https://tinyurl.com/wipneus1MKm3Trend
(you will be asked to download the chart)

Full URL for direct link is:


Just catching up on developments, wanted to add my note of appreciation to Neven as well as the commenters.
Any thoughts on providing context for the max-min graph? maybe show alongside min-max for the previous freezing season?


Chances are high that I will be covering next year's melting season, so traffic will probably pick up then.

Any thoughts on providing context for the max-min graph?

I had already renamed 'max-min' to 'total melt' (as it's much clearer), but somehow uploaded the old version to this blog post. Fixed now.

Here's the total freeze bar graph (posted earlier in April):



"Crossing that line would not be the first year of "ice free summer Arctic Ocean" as the value is September minimum, not monthly averages for Aug-Sept-Oct. But the observations show those monthly averages only trailing the minimum by a few years."
I find that a most interesting sentence. That, to me, shows the absolute reality of disintegration of the sea ice in the Arctic.


ooops, embarassing public brain fart...
The Wipneus graph shows all 5 extrapolations near or below THREE million km3 in 2018, not 1 million. Three of the five trend lines do cross 1 million in 2021.

The conclusions, albeit weakened, still stand.

1) Next few years, and next warm Arctic summer, likely to deliver a new record low Arctic Sea Ice volume, and probably Extent also.
Seems too soon to presume Arctic has entered a new state that would prevents next warm summer.

2) Adding my own presumption: The 2007 and 2012 dips were two years after El Nino year. With big El Nino in 2016, 2018 could be another dip year. Robert Scribbler blog mentioned that La Nina phase brings warmer water to Arctic, but I don't know what he based that on. Current ENSO forecast is for weak La Nina for this fall and winter. Even without an ENSO effect, another winter with low freezing units would precondition the ice for a decline in 2018. DMI chart for temps north of 80N following that pattern again so far this fall, but it is still early.

3) Arctic sea ice is one climate change manifestation people can relate to, vs. the more abstract nature of ppm CO2, watts per m2 forcing, etc. So it might increase recognition of our predicament.

4) Anecdotal tidbit. My son lived in Inuit village in Alaska this summer. I asked him what the natives had to say about climate change. He said that even the 20 year olds talked about how much things have changed "since they were kids" (i.e. within last 10 years or so). One example is willow trees now growing on what used to be flat tundra.


DMI temps look very interesting.

FDD, https://drive.google.com/uc?id=0B1HTR0ONiUmEMFZiLWwxUW15QUk&export=download , is therefore worth keeping an eye on!


Using this, http://sites.uci.edu/zlabe/arctic-sea-ice-volumethickness/ , and noting that 1996 is the first time volume goes below the '81-'10 avg. I could suppose with 'some' logic that:

The marketplace would have to acknowledge a 30 year average from '96-'26.

Seeing that would most likely deliver very bad numbers for the planet I would be expecting early movers to be well established in the new paradigm of energy use well before then.

I therefore see major changes to the American economy very soon. They will embrace this extremely well documented technological need for change.

I also expect Trump will change, to win his second term, but I've said that before.

John Christensen

Slightly OT, but wanted to let all know that DMI has launched an Arctic weather overview page with wind, temp, temp. anomaly, and precipitation anomaly:


You already can find the other DMI measures here such as SIE, ice volume estimate, sea ice temp, the DMI 80N temp, satellite images, etc.


Nice expansion of what they already had there. Thanks, John.

Kevin McKinney

Responding to the last few comments in order---

1) The DMI north of 80 temps continue to be 'interesting', to say the least...

2) Trump *should* change to win re-election, but IMO lacks the capacity...

3) Yes, a nice addition to the DMI site!


Dmi temps seem to have just dived but still far above normal.. I basically like to check this a few times a week along with FDDs.


"Already rapidly disappearing Arctic sea ice is melting up to 25 per cent more quickly than initially believed, according to research conducted partly by University of Calgary scientists. The salt content of snow covering the ice has tricked the European Space Agency satellite CryoSat-2 into concluding that ice is thicker than it actually is ... An ice-free summer once predicted to arrive in 2040 to 2050 could conceivably occur between 2030 and 2040"



Thank you for all the updates Neven. I hope you never stop.


Thanks, Lowenan. I don't know about forever, but I am going to try and step it up again for the 2018 melting season. :-)


Looking at Greenland mass balance on http://nsidc.org/greenland-today/ in late October, it is clear that GrIS is suffering significant melt event in periods where there is limited direct sun light on the ice. Thus, the melt is the result of atmospheric water vapor transport. (1 gr water vapor can melt 7 gr ice resulting in 8 gr runoff). Thus, we can deduce that atmospheric water vapor transport has become a major source of heat for GrIS melt. We can also deduce that atmospheric water vapor transport has become a major source of heat for sea ice melt, regardless of conditions of direct sun light.
I proposed this situation some 15 years ago and had the then-current model Arctic Energy Budget explained to me - repeatedly.
Aaron Lewis
aka "Agres"

John Christensen

Hi Agres,

Sliding somewhat off topic here, but let me comment just once:

The weather events with peak on 9/15 and again 10/29, while including very late season melting at coastal areas were both events of very significant mass balance gain for the GrIS:


I don't see how these events contribute to ice sheet loss - rather it has been the years with blocking pattern type heat domes that have caused extraordinary melting, combined with accelerated melting by warmer sea water.

Susan Anderson

Still OT, but since this comment section is pretty thin and I'm always interested in what Aaron Lewis has to say, and John C's heat dome comment also resonates, I clunk in to say I think trying to identify a single cause is a mistake. A lot of warmth has been shoved north by an exceptionally warm and busy tropical season (still not over). Then there's Dark Snow (soot/particulates) and biological input (algae etc.): "Sea level fears as Greenland darkens" (Shukman) http://www.bbc.com/news/science-environment-40686984

A five-year UK research project known as Black and Bloom is under way to investigate the different species of algae and how they might spread, and then to use this knowledge to improve computer projections of future sea level rise.

The possibility of biologically inspired melting was not included in the estimates for sea level rise published by the UN's climate panel, the IPCC, in its latest report in 2013.


Due to picking up a new job in the "project from hell" arena, I completely missed the entire end of the melting season.

As Neven says, Nothing can be taken for granted with the Arctic.

For me the most concerning thing is we saw exceptionally low summer temperatures, yet we still finished 4th. Which means that the damage was already done in the preceding year and in the preceding winter.

I wonder if we'll eventually see this as a small bounce driven by the end of an exceptionally strong Nino which overwhelmed the early signature. I guess the post mortem of the 2017 melt season will take a few years and throw up a few interesting things.

I'm now in watching mode till the end of the 2018 melt season as I want to see how it all plays out.


Well, dmi temp shows everything going back to normal.

Kevin McKinney

AJbT, I had to look to see what 'normal' meant, as the term has been, er, 'unstable' in recent years!

As of today (the 10th), I'd say it means 'significantly but not drastically above climatology for the season.' So, warm but not crazy warm (for the time of year).

That's following an upspike since your comment, which was probably made roughly when the anomaly was almost down to climatology. That dip is probably actually below current norms--the DMI climatology is normed to 1958-2002. It's now quite rare for the anomaly to get down to the old norm during the winter months. (It basically didn't happen at all in 2016, and only for about half a dozen brief excursions in 2015.) With a Nina probable, we'll see whether there's a few more such in the works for this winter.


I saw the uptick in dmi ....It is most certainly interesting in tandem with the anticipation of further MYI statistics!

What I took serious note of was:... that nsidc's last article (October 5) included MYI... it's as if they know that the whole world knows that it's FUBAR!

In Australia we would call this type of game a "ball-grabber!"


Updated PIOMAS Graph:



I will write a new update this weekend. Sorry for the delay.

Rob Dekker

Excellent post by Tamino :

for anyone who thought that Arctic sea ice decline slowed down after 2007 :

I’d like to congratulate all the readers who have read the last two posts. You now know a helluva lot more about Arctic sea ice and how it has changed, than most people. You know:

- It has declined dramatically
- The decline has not recently stopped or even slowed.
- The decline isn’t just a summer/fall annual minimum thing; it has declined throughout the entire year.
- The annual minimum decline dropped steeply in 2007.
- The geometry of the continents (of land areas in general) affects the relationship between the sea ice edge latitude and its extent.

I’d guess that you are now prepared to discuss the issue intelligently. I’ll opine that you are far better prepared to discuss it intelligently than any of those who have recently been claiming it isn’t still declining.



This article is saying winter is shorter by a month in New Zealand: so that can't be good for Argentina!


Rob Dekker:

This article by the same author showed an acceleration in the decline of Arctic sea ice extent followed by a deceleration of the decline of Arctic sea ice extent.


Rob Dekker

D_C_S, you did not read that article all the way to the end.


I maintain that this, https://drive.google.com/file/d/0B1HTR0ONiUmEMFZiLWwxUW15QUk/view , is the most interesting thing on the planet at the moment!


According to the seasonal anomaly graph above it's only the orange line that straightens up!

Therefore I predict another wild swing to global sea ice! (Yay, put the house on it!)


Rob Dekker,

Contrary to your claim, I read both articles before you posted a link to one of them, and I read both articles again after you posted a link to one of them.

The article at the link that you posted deals with annual average Arctic sea ice extent. The article at the link that I posted deals with annual average Arctic sea ice extent, then annual Arctic sea ice extent minima, and then the annual Arctic sea ice extent maxima.

I was referencing the section of the latter-mentioned article that deals with annual average Arctic sea ice extent, which is the topic of the former-mentioned article.

In the article at the link that I posted it states "We can be confident that it’s not declining as fast as it was during the 2003-2007 time span, when it really took a nosedive.", referring to annual average Arctic sea ice extent.

Elisee Reclus



A linear decline in Arctic sea ice area, A, along with a declining average Arctic sea ice thickness, T, implies a decelerating decline in Arctic sea ice volume, V, unless the decline in T is accelerating. I’ll make this more rigorous below.

If A is positive and declining and its decline is either linear (neither speeding up nor slowing) or decelerating (slowing), with A as a function of time, t, being continuous and twice differentiable, and T is positive and declining, with T as a function of t being continuous and twice differentiable, then the decline in Arctic sea ice volume, V, must be decelerating (slowing) unless the decline in T is accelerating (speeding up).

Proof: Assume that A(t) and T(t) are each continuous and twice differentiable. Note that V = A T. Then V'(t) = A(t) T'(t) + A'(t) T(t), and V''(t) = A(t) T''(t) + 2 A'(t) T'(t) + A''(t) T(t). Assume that A(t) > 0, A'(t) < 0, A''(t) ≥ 0, T(t) > 0, T'(t) < 0, and T''(t) ≥ 0. Then A(t) T''(t) ≥ 0, 2 A'(t) T'(t) > 0, and A''(t) T(t) ≥ 0. It follows that V''(t) > 0 and that the decline in V is decelerating.

Even if the decline in T is accelerating and/or the decline in A is accelerating, the decline in V could still be decelerating. Similarly, even if there is an accelerating trend in the decline of Arctic sea ice extent, E, a decline in V could still be decelerating.

Since I think that V is a better measure of remaining Arctic sea ice than each of A, E and T, I wouldn’t assume that the loss of Arctic sea ice is not slowing based only on a linear trend in the decline of A or E or T.


I stated in my previous comment that I believe that volume is a better measure of remaining Arctic sea ice than each of area, extent, and thickness.

On the other hand, probably the best measure for projecting to when the Arctic might be virtually free of sea ice would be the measure with the trend that is closest to being linear, in my opinion.

If Arctic sea ice volume were to decelerate significantly (which I'm expecting, maybe that is wishful thinking) while the trend in Arctic sea ice extent were to remain close to being linear (which seems to be the case currently, according to the article that was posted above by Rob Dekker) then probably the trend in Arctic sea ice extent would be better for projecting to when the Arctic might be virtually free of sea ice, in my opinion.


I found this article via the guardian:


It seems to imply that real panic is only on the horizon by the year 2500, hence the slow nature of the global politics on this subject at the moment.

Would that be an entirely wrong way to read this article because I think it's worth looking at?


This directly compares 2016 and 2017 dmi temps!

Rob Dekker

DCS said

Proof: Assume that A(t) and T(t) are each continuous and twice differentiable. Note that V = A T. Then V'(t) = A(t) T'(t) + A'(t) T(t), and V''(t) = A(t) T''(t) + 2 A'(t) T'(t) + A''(t) T(t). Assume that A(t) > 0, A'(t) < 0, A''(t) ≥ 0, T(t) > 0, T'(t) < 0, and T''(t) ≥ 0. Then A(t) T''(t) ≥ 0, 2 A'(t) T'(t) > 0, and A''(t) T(t) ≥ 0. It follows that V''(t) > 0 and that the decline in V is decelerating.

You don't know if A''(t) ≥ 0 nor do you know if T''(t) ≥ 0.
You are just assuming that.

So what remains is your statement : "If Arctic sea ice volume were to decelerate significantly (which I'm expecting, maybe that is wishful thinking) "


Rob Dekker:

Of course they are assumptions. I proved that IF Arctic sea ice area is declining and its decline is not accelerating and the average thickness of Arctic sea ice is declining and its decline is not accelerating then the decline in Arctic sea ice volume must be decelerating.

Do you know the meaning and the significance of A''(t) and of T''(t)?


Rob Dekker: PS

The assumptions are in the context of the proof and are confined to the proof and the if-then statement. The proof is directed to people who are familiar with mathematical proofs and who understand the relevant math. Mathematical if-then proofs virtually always include an assumption, which may or not be explicitly stated as being an assumption.


I stated, with a proof, that if area and average thickness are each declining linearly then the decline in volume must be decelerating. I stated, without a proof, that if the decline in area is accelerating and the decline in average thickness is accelerating then the decline in volume could still be decelerating.

Here is a hypothetical scenario to demonstrate that the decline in volume can decelerate as the decline in area accelerates and the decline in average thickness accelerates.


(1 Mm^2 = 1 million km^2)

Area in Year 0: 12 Mm^2
Area in Year 10: 8 Mm^2
Area in Year 20: 3 Mm^2

Decline in Area From Year 0 to Year 10: 4 Mm^2
Decline in Area From Year 10 to Year 20: 5 Mm^2

The decline in area accelerated.


Average Thickness in Year 0: 3.5 m
Average Thickness in Year 10: 2.5 m
Average Thickness in Year 20: 1 m

Decline in Average Thickness From Year 0 to Year 10: 1 m
Decline in Average Thickness From Year 10 to Year 20: 1.5 m

The decline in average thickness accelerated.


Volume = Area X Average Thickness

Volume in Year 0 = 12 Mm^2 X 3.5 m = 42 thousand km^3
Volume in Year 10 = 8 Mm^2 X 2.5 m = 20 thousand km^3
Volume in Year 20 = 3 Mm^2 X 1 m = 3 thousand km^3

Decline in Volume From Year 0 to Year 10: 22 thousand km^3
Decline in Volume From Year 10 to Year 20: 17 thousand km^3

The decline in volume decelerated.

Rob Dekker

That's good work DCS. Thank you !
You even made both A''(t) and T''(t) negative.

It's still a mathematical exercise though.
If this scenario will pan out in real time or not will depend on the bigger question : Will summer heat melt 'volume' or will it melt 'area'.

If it melts area than you will be right and volume will decelerate.
But if it melt volume then volume will just go down (linearly) and at some point, as Wadhams stated before : "In the end, it will just melt away quite suddenly". Area that is.

Seke Rob

Was thinking of this Lars B iceberg that broke loose few months ago. Picture this floating in the Arctic Sea, then translate that volume into say 1 meter thick ice and the impact on weather and heat exchange with the atmosphere. Think I much prefer the area over volume. The more area, the more 'seeding ground' there is for new ice as well as putting the breaks and intake in late autumn, winter and spring. Sure, the heat loss from the arctic ocean would be less, but then at least below that ice the cold water layer can build up, instead of having that heavy mixing with deep water.

rant end

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