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Colorado Bob

Excellent work Neven.


Thanks, CB!

Colorado Bob

Speaking of Dr. Francis

Climate Change: Greenland Melting Tied to Shrinking Arctic Sea Ice

“Blocking-high” pressure systems spawn most of the warming that melts Greenland surface ice, study says

Vanishing Arctic sea ice. Dogged weather systems over Greenland. Far-flung surface ice melting on the massive island.

These dramatic trends and global sea-level rise are linked, according to a study coauthored by Jennifer Francis, a research professor in Rutgers University’s Department of Marine and Coastal Sciences.



Fish here. I don't know how you have time for your day job, Neven. Outstanding compilation.

Unfortunately, the cracking event this year did not thicken the ice. The Icesat images have clearly shown that the ice thinned on the Pacific side. Thin ice is consistent with Mercator Ocean model data in the Beaufort which shows evidence of mixing of cold relatively fresh water of Pacific origin through the 300 meter Atlantic water layer. The Mercator model also shows the rest of the Atlantic water layer has warmed a bit except for the an area near the Atlantic water inflow where a broader inflow area than last year's has a lower peak temperature.

In short, the NAO and AO are producing the expected results. The ice thickened in spring 2013 when there was a large high pressure area over the *whole* Arctic ocean. This year there is a dipole. The dipole promotes ice export and Atlantic water inflow.

Colorado Bob

North Atlantic freshening from land ice melt, cold blob, stronger storms
Jason Box


I don't know how you have time for your day job, Neven. Outstanding compilation.

Thanks, Fish, it's my night job. ;-)

I wanted to post this a month ago, and do a part 2 at some point, but this works too.

Unfortunately, the cracking event this year did not thicken the ice. The Icesat images have clearly shown that the ice thinned on the Pacific side.

I'm afraid you may be right.


The NSIDC calls the maximum.


The Cryosat map does NOT show thickened ice well above 2m along the coast nor does PIOMAS February animation shown over the Forum. However the Feb average PIOMAS map does. Glitch of PIOMAS gridded data?


Along the coast of ESS I wanted to say.


Qu: Sea ice is frozen ocean water. It forms, grows, and melts in the ocean. In contrast, icebergs, glaciers, and ice shelves float in the ocean but originate on land. For most of the year, sea ice is typically covered with snow.
Quick Facts | Quick Facts on Arctic Sea Ice | National Snow and Ice ...
https://nsidc.org › cryosphere › seaice

- This is a quote from nsidc. I was under the impression snow didn't fall at the poles.

This may be the wrong place to ask but then it may be just the correct one: "Are changes in snowfall occurring, specifically where it's occurring?"

Rob Dekker

Just to get a sense of how insanely warm the past two months were, here is an NCER/NCAR timeseries plot of the 1000 mb (surface) temperatures for Jan/Feb since the 1980's :

As Neven explained, the winter temperatures are not a good predictor for the minimum ice extent in the summer. Historically, the correlation between winter temps and summer melt extent is simply not good at all. Physical explanation may be that small temperature differences in winter do result in substantially thicker or thinner ice, and thus the 'noise' in winter temperatures gets overwhelmed by the variability of summer weather.

Yet, with such a HUGE temperature anomaly over the past winter, it is a really good test of how long this "non-correlation" holds. September will tell...

Rob Dekker

That should say "..that small temperature differences in winter do NOT result in substantially thicker or thinner ice".
And the Y-axis on the plot are in degrees C.


Rob Dekker - your comment highlights how we look at the surface of the changes taking place, and miss the fundamental one - the total heat content available to the system.

There always has been enough energy in the Arctic to keep it ice free; there has never been (at least in human reckoning) a mechanism which delivered that energy to the sea surface.

What is happening, has happened, is the total heat content is rising, and reached a point, where normal fluctuations in the distribution of heat in the Arctic season over season, now have a disproportionate effect on what it looks like.

To illustrate - a melt season like we had in 2012, if it happened in 1980, would have produced a minimum of about 5.5 million KM2. If that happened now, we would be flirting with an ice free arctic - under 2 million KM2; and this doesn't even account for the qualitative difference in the strength of the ice.

More than at any time in the last several million years, the summer ice minimum is now at the whim of variations in our weather - which has become progressively more volatile and energetic.

It might not be 2016. It might not be 2017; but it will be sooner than later that the pendulum swings, and we have a more rather than less active melt season that delivers us under 1 million KM2 at minimum. I think my 2029 estimate is now too conservative.


Rob, this has been a sustained difference of several degrees, for months, as unprecedented as shown in your graphic. Effect on ice thickness in some regions should not be that negligible this time. But I'd agree this plays a lesser role in an early or delayed start of melting.
Jdallen, you miss that, part of that heat content you talk about is overall thinning of ice over the years.


I'll respectfully disagree, navegante. The actually "250 kilo gorilla" is heat at depth in the Arctic basin - mostly below 100 meters or so.

By comparison, the thinning of the ice, now at an average of 2 meters plus chage thick, while significant, I do not think represents as big a change in enthalpy as the increases in temperature at depth.

I think its the heat being retained year over year at depth that's going to be the key player... because it reduces the heat required to raise the temperature of the top 50M or so of ocean, and puts it all that much closer to the threshold required to cause heat to transfer into the ice, rather than ocean.

Since 1980 its estimated that the heat content of the oceans has increased by over 17 Petajoules. 17 x 10^22 joules. That's a pretty astonishingly large amount of heat, even when you consider how small of a fraction of it ends up north of the Arctic circle.

So, the thinning of ice is no doubt significant. I'm not sure its as great in importance as the heat that's flowing in underneath it.


That is a lot of heat Navigante. By my reckoning 17 Petajoules has the capacity to melt about 500 million cu km of ice: is that right? Maximum Artic sea ice is a "mere" 16,000km cubed and even Greenland has "only" 2.5 million cu km cubed of ice. Can you confirm. If so you are absolute right.


I am confused Benje. You may be addressing JD Allen.
If I could understand the mechanism for retaining that heat excess JD Allen, but I don't know about it.
My point is that even if small, the reduction of thickness and ice volume over the years represents heat excess trapped by the Arctic Ocean, in form of latent heat. I dont know what share in total energy increase.

Yvan Dutil

I would like to add some basic physics of phase change to the discussion.

Freezing is a non-linear process. However, in one dimension, it can be described by the Stephan's law.

This imply that the ice thickness would be proportionnal to the square root of the frezzing degree days.

This is probably why we have not seen any correlation between winter temperature and summer ice cover.


Over on the forum Wipneus announces a 125K drop for CT SIA, so it looks highly likely that the max has been reached there also.


Good article on The Guardian by Suzanne Goldenberg: Arctic sea ice extent breaks record low for winter


Yvan Dutil,

Does "Stephan's Law" tell us why sea ice can only get 3 metres thick?

Yvan Dutil

AbbottisGone, if FDD as a maximum ice thickness has also a maximum. Of course compaction can change the picture.

Bill Fothergill

@ Benje & jdallen
(& anybody else interested in Ocean Heat Content)

Much of the early work in establishing a value for the rise in OHC was done by Sydney Levitus of NOAA.

The figure given above by jdallen of 17 x 10^22 joules can by found here...

On the interactive chart, Fig 1 gives the OHC values for 0-700 metres, but Fig 2 gives a value about 40% higher for 0-2000 metres.

Please note that 17 x 10^22 joules is actually the same as 170 Zetta joules, not 17 Peta joules. (A difference of 7 orders of magnitude.)

As regards how much ice that would melt, let's see if I can still remember how to do this stuff...

The latent heat of fusion of water is about 334kj/kg, therefore 17 x 10^22 joules would melt about 5.09 x 10^17 kilograms of ice. (With no temperature change.)

The density of sea ice can obviously vary considerably, but a value somewhere in the vicinity of 910 kg/cubic metre will not be too far off the mark. That means our mass of ice would occupy a volume of about 5.59 x 10^14 cubic metres, or about 559,000 cubic kilometres.

Can somebody please check the calculations? I am having increasing difficulty with my eyes (never mind the brain) and therefore could easily have cocked that up.

cheers btf

Al Rodger

Bill Fothergill,
170 Zj to melt 5.09 x 10^17Kg ice? I find the bottom paragraph on the PIOMAS page is a good memory jogger if I ever forget the ~3,000 Gt(ice)/Zj. (They actually say 16,400 cu km requires "about" 5 Zj.) Working that through, it works out on the nail at 5.1 x 10^17 kg ice. You have to say, it's a mighty fine web page, that PIOMAS one is!!


Sorry Yvan,
I will elaborate.

A little birdy once told me that sea ice can only achieve a thickness of 3 metres naturally i.e. with no compaction.

Does "Stephans Law" explain this as a true fact?

(... maybe I should google 'Stephans Law' ;>)

Yvan Dutil

@AbbottisGone This is likely.

Actually, arctic ice is the third historical problem studied:



To contribute to Neven’s wonderful compilation, I’ve calculated the mean temp anomaly for the period 1 October – 25 March based on this CAD drawing:

 photo Winterpower 2015 - 2016 very small_zpspqnszzr6.jpg

For the Arctic Ocean the calculation added up to a +4.2 dC anomaly.
That might not sound as spectacular compared to the data that have been circling around the Blog and Forum during the last few months.
But I did this FI at the end of ’13-’14, which produced IIRC a mean between +1 and +2 (which was pretty awesome in those days).

My friends, +4.2 over such a large area and during six months is terrifying…
I’ll put a larger version up on the Forum.


Very nice, Werther!

And I agree, 4.2 °C is huge.


Lowest area; close to smallest thickness; lower snow cover on land; low snow depth on ice; and, the hottest NH temps on record.
If anybody has watched LOTR this sounds like Gimli laughing before starting the desperate final battle.

Anyway, for the latest three reasons I doubt this will be a repeat of 2013 but who knows. Gimli and comrades won the battle against all hopes :-)


Damn sorry for the spoiler :-/



Is this a reliable site?



Bill Fothergill

@ AiG

If you are unfamiliar with Berkeley Earth - formerly known as the Berkeley Earth Surface Temperature project (BEST) - you could have a quick dekko at the wiki entry.

Their Global (Land + Ocean) anomaly file is here...

You can easily see for yourself how this stacks up against the HadCRUT, Gistemp and NOAA equivalents. I've been tracking BEST along with these three other surface datasets since it came on-line a few years back.

One of the people working on Berkeley Earth provides comments on this blog from time to time.

Jim Hunt

JAXA extent is back down to the lowest ever level for the date (since their records began). 13,560,921 km² on March 30th:


John Christensen

Thank you for a great Arctic winter analysis Neven!

The only item I was missing was a review of the atmospheric conditions, which certainly seem to have been a factor for the Arctic sea ice this winter:
- November and December were dominated by negative AO index, which brings more cloudiness and low pressures to the Arctic region, causing reduced ocean heat loss, higher temperatures, and moves the jet stream further north with many storms entering the Arctic seas.

(In contrast, Oct, Nov, and Dec 2012 all had negative AO index, which caused predominantly clear skies, more heat loss and increased sea ice build-up).


Um, John: were you trying to confuse me on what a negative AO index means... because you did !

John Christensen


No, I was not trying to confuse you, so please let me know what leads to that state of mind.

The AO index:

John Christensen

Darn, you were right, thanks AIG!

What it should have been:

- November and December were dominated by positive AO index, which brings more cloudiness and low pressures to the Arctic region, causing reduced ocean heat loss, higher temperatures, and moves the jet stream further north with many storms entering the Arctic seas.


...thanx john: because I actually didn't know either way and now I do so cheers!


- nsidc for march 30 looks like it's going to get real bad!


John, I had thought about doing a paragraph about the AO, but as this past season wasn't really all that spectacular AO-wise compared to the previous decade, I decided to just focus on the SLP distribution maps.

But here are small versions of the graphs I had made. The first shows the AO Index numbers from November to February (1-4) preceding the years I also used for the SLP distribution maps:

And here's a graph showing seasonal averages for the 2006-2016 period:

John Christensen

Hi Neven,

Thank you very much for sharing this.

I was trying to consolidate your numbers with the monthly values from my data from NOAA, which seem to be slightly different:

Winter Nov Dec Jan Feb
2006/07 0,521 2,282 2,034 -1,307
2007/08 -0,519 0,821 0,819 0,938
2008/09 0,092 0,648 0,8 -0,672
2009/10 0,459 -3,413 -2,587 -4,266
2010/11 -0,376 -2,631 -1,683 1,575
2011/12 1,459 2,221 -0,22 -0,036
2012/13 -0,111 -1,749 -0,61 -1,007
2013/14 2,029 1,475 -0,969 0,044
2014/15 -0,53 0,413 1,092 1,043
2015/16 1,95 1,444 -1,445 -0,023

What is noticeable from these numbers:
1) The winter of 2006/07 saw positive AO in Nov, Dec, and Jan, which seems to work a bit like melt ponds in the early spring: If the ocean does not loose heat in early winter months, ice extent tends to stay very low. And this winter had exceptionally low ice extent.
3) The 2009/10 winter had great (AO) conditions for ice growth after a slow start
4) The winter of 2011/12 also saw positive AO in early winter months, setting the stage for the summer of 2012.
5) The winter of 2012/13 on the contrary saw lots of clear skies and significant ice growth causing lots of 'recovery' discussion at the time.
6) The three latest winter seasons were not great from a weather perspective with positive AO in early months for two of them and just slightly negative AO for the start of the 2014/15 winter.

It is clear - and Wikipedia IMO has the best guide to the AO - that this is not the sole factor, but one of the components influencing the environment in which sea ice is created during the Arctic winter.

John Christensen


Your first AO graph is actually great, as it shows the winters of 2006/07 and 2011/12 starting with very positive AO, and this past winter being as bad as those two for the first months of winter.

- Which certainly does not bode well for the coming melt season (If you like the ice to stay that is)

It seems to be less important how the AO is behaving in Jan and Feb compared to Nov and Dec.

If you had included the cold winter of 2012/13, it would have provided a nice contrast to those other years.


John, especially for you, here's the first graph including all years from the 2006-2016 period:


The biggest player shuffling the Arctic climate deck is ENSO.

At this time there is a full blown trend towards a La-Nina:


Truly at the wrong time of the year. The result is less clouds in the Arctic mostly covered by more snow. As expected, clear skies even in March favors sea ice accretion, but soon this will change, the biggest factor of this season is the greater snow cover in some large parts of the Arctic Ocean area. This slowed accretion a great deal during darkness, but also increases it in the spring when the higher sun would have done otherwise. I expect a sharp decline of sea ice extent when sun elevations are high enough to rip open the snow insulation. That is a coming crucial moment for this year. The steeper the trend decline in extent the greater the melt.


April might get nasty!!

John Christensen

A true work of art, thank you Neven!

Comparing to the longterm AO index for winter months (See below), it is clear that the four seasons with very positive AO (2006/07, 2011/12, 2013/14, and 2015/16) are outliers and that we have seen reduced sea ice area and extent increases during those winters.

Hi wayne,

It will be interesting, if we will indeed have a La Nina event this year, but I have not seen any papers linking La Nina to negative AO/clear Arctic skies, so please share if you have references or your own data to support that.

Looking at the longer-term AO trends for winter months, it seems like we have a multi-decadal trend, as seen from the averages of NOAA AO data:

Period Winter (Nov-Feb)

Average (1950-2015) -0,28

Average (1950-1959) -0,50
Average (1956-1965) -0,75
Average (1966-1975) -0,40
Average (1976-1985) -0,54
Average (1986-1995) 0,42
Average (1996-2005) -0,24
Average (2006-2015) -0,05

From the numbers above:
1) Long-term average AO (1950-2015) is negative for the winter season (Nov-Feb), indicating overall tendency for clear skies.
2) Negative AO was most pronounced in the period of 1950-85.
3) 1986-95 indicated a decadal-long shift to positive AO during the main winter months, which generally must have reduced ocean heat loss and therefore limited sea ice growth
4) 1996-2005 saw overall negative AO again, but since 2006 we have seen a jigsaw/non-decided trend for AO during winter months.

These longterm shifts are also visible from the NOAA graphic, although it is looking at Jan, Feb, March:


Hi John,

These are observations like your AO data (care to show papers on how AO going all the way to the Great Lakes can be taken seriously for the Arctic?), far better than papers, the data is in the sky. In March just past there was 3 weeks of solid clear skies, along with very few apparent tropopause cloud condensation nuclei. The last time trend toward La-Nina in spring was 2008 (and certainly 2012) with similar Arctic clear skies periods . THese can be also observed daily on HRPT satellite products.

And its simple to understand, EL-Nino peaks coincide with greater # of thunderstorms world wide. But in particular the Anvil CCN overshoots past the tropopause in the equatorial Pacific spread all over the world including the Arctic, hence fallout from El-Nino Cumulonimbus creations create more clouds. The opposite holds just as well, when La-Nina is trending, there is usually a remarkable more prominent absence of clouds in the Arctic.


Now that we can see the whole winter in review. Does anyone think the storm at the very end of Dec 2015, that seemed to telliconnect the near peak of El Nino with the cold blob in the North Atlantic, and bring above freezing temps close to the North Pole was a Dragon King Event?



John, one of the first blog posts I wrote involved Wayne's theory on the link between ENSO and Arctic cloudiness: Arctic sea ice melt: a correlation with ENSO?


A hell of a theory, Wayne. Allow me to ask, do you expect Big Blue this time?



Yes, big blue , you remember it well, it was 2008, nothing exactly repeated that spring yet, but this season is very close. April will confirm so.

Every Arctic spring has its own style. This years signature is with greater snow cover (along with record warm temperatures and extensive cyclonic penetrations). Warmer temperatures and more open water is what to expect during a very strong winter El-Nino. 2016 Arctic spring skies turned blue very quickly. In part by the North Pacific and Atlantic sst's cooled by greater multi cyclonic cloud coverage lasting months, and the sudden further warming from the sun of an already warmer Arctic atmosphere.

2016 much thicker snow cover is also very interesting, it slowed ice accretion but delays direct exposure of sun rays to sea ice. Sublimation will eventually, open up the snow like stretched open cloth fibers, this will start happening in about 3 weeks. I would expect a very accelerated melt because the sea water under the ice was spared a greater loss of energy. Especially if 2016 big blue continues, and by all imagery available there is no expansion of cloud cover in any Arctic quadrant as usually should be in April. That was 2008's main feature, 4 weeks cloud free following a March likewise, the relentless sunshine gave very early melt ponds.

John Christensen

Thank you for the link Neven!


I will certainly check out your theory and also it's very enlightening to see more about your background.

The NOAA AO index is still positive, but is clearly trending towards moderate negative, so will be very interesting to follow the development.


Thanks Wayne. Only one comment. Last time I checked over the forum, the kind of consensus there was that the snow depth over most of the Arctic ice was relatively small after this Winter. Is there a source of information that indicates otherwise?



This may be a matter of graphs which cover the entire Cryosphere, there has been a great amount of snowfall early this past winter between October and November.


Background is the right term, my background is literally the Arctic right outside, which more than 30 years of meteorological observations in the Arctic, nice experience for a meteorological observer.

There is no solid well versed science without myriad observations, there is no scientific theories that I know of which don't require a confirmation of sorts. My biggest discoveries or theories came about by extensive data collection first, the opposite process of most scholars, the experience eventually percolates to a realization . Instead of theorizing from well accepted physical models (which are artificial constructs, especially like the AO) , I transcend ideas from living through the real model in situ.

Papers are nice though, for instance Toxophene fallout from Southeast Asia is common here (from science papers). Therefore cloud seeds from overshooting tropical CB's is the next logical step to conclude that there is a Tropic to Arctic fallout process.

I prefer my peer being the future , because there is no tougher reviewer or peer than the observations yet to be written from a reliable source, writing papers is good but time consuming, is a gig for others to do, and sometimes I join them. But I much prefer writing discoveries directly (my web pages) to anyone who has an interest in Atmospheric science or really deep cutting edge optical physics.

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