DMI apologizes for their disappeared sea-ice graph debacle

Earlier this week, I published a post titled: DMI disappears an inconvenient sea ice graph . Some of the usual folks who police any sea ice discussion went ballistic over the post, and in some ugly blog posts of their own, suggested I and others were engaging in Lewandowsky inspired “conspiracy ideation”. While others may have been, I wasn’t, and made it very clear, but that doesn’t matter to those types, as that sort of stuff is their m.o. when it comes to criticizing climate skeptics.

The fact is though, that DMI did in fact remove the graph from public view, and offered no explanation to the public when they did it. If you aren’t a daily watching sea-ice fanatic like some of the critics, it was easy to miss that the product had been quality control neglected by DMI.  Worsening the issue, in an email exchange published in that same WUWT story, one DMI employee was quoted as saying (paraphrasing) “I got tired of answering questions about it so I took it offline”. If there were a lesson of how not to instill confidence in the public when decisions are made to remove data products that have been around for years, suddenly disappearing them with no explanation to the public would certainly qualify as a worst-case example. DMI simply bungled the public face of the decommissioning, there’s really no other way to look at it. Had they done this sort of due diligence before removing the graph, and placed a link to an explanation rather than to the new product with greatly differing values, there likely would not have been the questions about why it suddenly disappeared, and what the possible motives might be. The ham-handed response from the DMI employee did nothing but add suspicion to an already poorly handled situation.

They’ve realized this, and offered an explanation and an apology on their website today. I accept both, which I have republished below.

On a personal note, for those elsewhere in the blogosphere who want to try to convince skeptics that the explanation was rooted in technological problems, I suggest this maxim: “you can catch more flies with honey than vinegar”. The ugly labeling of people with legitimate questions while at the same time trying to convince them of details they may not be aware of was just as badly bungled as DMI’s decommissioning. There’s lessons to be learned all around.

From DMI:

Sea Ice extent – explanation on an appearent [sic] divergence between algorithms.

DMI has removed the old sea ice extent graph to focus the attention on the new graph that is based on data from an improved algorithm.

However, the removal of the old sea ice extent graph was done at an unfortunate time, namely, during a period where it seemed that the new and old ice extent plots disagreed (see figure 1). Naturally this has led to discussion among our dedicated followers, about the “true” ice extent. The apparent elevated sea ice extent in the data from the old extent algorithm was an artifact, caused by a new and higher resolution coast mask.

    An off-line update of the old sea ice extent plot (left), where it appears that the sea ice extent is much larger than previous years and

the sea ice extent from the operational algorithm (right), which is DMI’s and the Ocean and Sea Ice, Satellite Application Facility (OSISAF)

official estimate.

Most of our sea ice extent followers know that the old plot includes a coastal mask, inside which sea ice was is accounted for. In summer 2015 this mask was refined and the masked region was subsequently smaller, thus leaving mo re area for classified sea ice and open water. The difference in masked area, before and after summer 2015, is approximately 1.4 million km2. This corresponds to difference of the blue coast lines in figure 2, showing the old and new coastal masks in the left and right panels, respectively. The difference may be difficult to detect on the figure, but the area is quite significant. The increasing sea ice extent that is caused by the new coast mask is not great during summer, because sea ice has a relative short line of contact with land during summer. But the new and finer coast mask will result in increasingly more sea ice, compared to previous years during winter, as the coast line with sea ice contact is increasing. This is the reason for an increasing sea ice extent during current freeze-up period, relative to previous winters. A comparison of the 2015/2016 sea ice extent with previous years does therefore not make sense (see figure 1-left).

    Plots of sea ice types February 22 2015 (left) and February 22 2016 (right) using 2 different coast masks.

The mask used before summer 2015(left) is wider than the new mask (right), corresponding to approximately 1.4 million km2 less area under the new mask.

Because of the deprecated status of the old plot in the past year, DMI has not been monitoring these irregularities. The old plot should, of cause, have been removed when the mask was replaced. DMI apologizes for the confusion and inconvenience this has caused.


h/t to mosher


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Janice Moore

DMI apologizes for the confusion and inconvenience this has caused.

Thank you, DMI.
But, the 30%+ graph is still gone.

Janice Moore

It appears from comments below mine (and I may be mistaken), that many WUWTers need to read this post:
especially the comments,
before concluding that DMI’s removing 30%+ product was simply because the 15%+ product was more accurate.
Several commenters there provide good reasons for the 30%+ product’s being retained, i.e., that the 15%+ (alone) does not provide a complete and “best available science”-accurate picture of Arctic sea ice.


Yes, I don’t think the high cost of hosting one more small graph would be a compelling argument…

Janice Moore

C. Jones, I don’t think the marginal cost per unit of this product was high enough to justify not producing it, however,
Phil (in California), whose opinions I have come to respect highly over the past 3 years, says (here: ) that the 30%+ product was defective, so, I will stop protesting DMI’s action.

Michael Jankowski

It may have been defective…and the time you remove it is when you provide such an explanation, rather than an “I got tired of explaining things” explanation,


“C. Jones, I don’t think the marginal cost per unit of this product was high enough to justify not producing it, however,”
Sorry, I should have put a smiley there, that was my point: I was just making a feeble attempt that I’m sure someone in the bureaucracy would make when challenged on deleting something.
I know from experience when I was in the civil service: we had purged some material that was politically damaging (on the strong no doubt verbal “suggestion” of our political masters), quite contrary to all established law and procedure at the time. Our bosses tried to explain to the auditor-general that we quite simply had to due to space consideration for the physical files. The bosses could not explain, however, why we kept multiple copies of much older, and less important documents…

It seems to me that you are letting DMI off the hook too easily here.
“Most of our sea ice extent followers know that the old plot includes a coastal mask, inside which sea ice was is accounted for.”
That sentence cannot possibly have been reviewed by anyone at DMI before it was published. That makes me wonder about the review routines at DMI.
Besides – and most importantly, it is immensely silly to change the definition of a measurand and still plot it together with a previous and different definition of that measurand. Anyone doing that, without making a note of it in the plot, is totally incompetent within measurement and reporting of time series.
This stands in stark contrast to what DMI tell about themselves at their webpage:
“DMI collects and processes meteorological, climatological and oceanographic measurements/observations, and measures, collects and compiles related geophysical parameters throughout the Realm.
Conducting research and development within its area of ​​expertise, DMI ensures efficient operations and state-of-the-art quality in all productions while monitoring and conducting research on global warming and the stratospheric ozone balance.”
So everything DMI does is supposed to be top notch, except that they can´t write proper sentences, they don´t review what they publish and they don´t understand that you simply cannot change the definition of a measurand and still produce a figure showing data from the new definition of the measurand together with a previous and different definition of that measurand. At least not without making a note of it. That is misleading – is it state of the art?
Something is rotten in the state of Denmark!
I just couldn´t resist saying that 🙂
(Enjoyed your take on SM below by the way. #(:)) )

Just realized that you are not letting DMI of the hook, shame on me.


A comparison of the 2015/2016 sea ice extent with previous years does therefore not make sense
so why do they still have the comparison in the new revised graph?
the old data used a different filter. You cannot simply adjust the new data downwards. this is apples to oranges.
you changed the filter. to try and pretend this did not change the mean and standard deviation is a statistical farce. the history is now invalidated for comparison purposes. So remove it.


The history is…history.

Janice Moore

I think…. that ferd b’s 12:31pm comment was intended to address Eliza somewhere around here:

Pete J.

It’s all relative anyway (based on their mood).


DMI have said that the 30% information is now driven by an entirely different tool. The information for this year is no longer comparable to last year, and so comparisons would be meaningless. It sucks, but sometimes it’s better to drop backwards compatibility.

Peter Miller

An apology!
That must be a first from those controlling climate data.

“decisions are made to remove data products that have been around for years”
Thus indicating that the science producing the data products wasn’t very good, likely isn’t very good now, and probably will be deemed not very good (again) in the not so distant future.

So, simple translation.
We have no reference.
Past estimations of ice extent cannot ,easily, be compared to current estimations.
Even the old estimations were adjusted on a yearly basis.
Feel free to “improve” my understanding.


“Past estimations of ice extent cannot ,easily, be compared to current estimations.”
The 15% extent can be compared.


My feeble recollection is that the notification of the old data going away is over a year old. I usually do not follow sea ice that closely, yet I knew the old method had been superseded and was going away. I was surprised that the old plot lasted as long as it did.
As they say, there is always someone at the end of the line that just does not get the word. But like I said, I do not follow DMI that closely, yet I knew it was coming. So why the fuss?
(I did like the old product better, but maybe I was just used to looking at it.)
Onward with the Latest and Greatest.

Marcus ( unmelted )

..Yes, when you don’t like the results…throw them out and start again….D’oh !

Rainer Bensch

But, but, but didn’t they ‘correct’ the area in the wrong direction? All those predictions of ‘Ice free North Pole’ will look worse than they were anyway.

I have a rather fundamental question:
How do you “improve” a squiggly line graph that goes up and down? Do the “ups” get more uppity? Do the downs resolve more smoothly and pleasing to the eye?

Marcus ( unmelted )

[SNIP – we don’t need that video here, not only is it off-topic, but it ruins the conciliatory mood -Anthony]

Marcus ( unmelted )

Ooops, sorry Anthony..I just like the jingle for some reason ! I’m weird, I know ! LOL


Anthony, you probably won’t put this through, but that’s okay as you could consider it a personal message.
Look, just a little bit of research could have told you that the graph clearly had problems, that it was having these problems for a long time, and that it was discontinued and replaced by a newer SIE graph a long time ago. You could have asked Mosher or people like Walt Meier or, heck, even me (despite our differences wrt AGW I’d give you an honest answer).
Instead you were fooled by Paul Homewood’s post, who was in turn fooled by one of his commenters who clearly thought it was a conspiracy right away without further investigation (perhaps fooled by Steven Goddard who started this nonsense weeks ago). In the comment section I tried to convince them that the old graph was incorrect and that there was no conspiracy to ‘disappear inconvenient data’, but to no avail (probably not even now that the matter has been cleared up).
It was much ado about nothing, but ironically it’s the DMI that ends up apologizing.
In the meantime, Arctic sea ice is extremely low on practically all graphs and may very well break the maximum record set last year. This is the real news.


Pro tip – acting all outraged when people ask for justification does not instill confidence, but rather the reverse.

Lawrence Martinez

It’s a tempest in a teapot, because it has been over a year since announcing the transisition away from the logarithm that supported this old graph. It provided pseudo-science blogger Tony Heller something with which to rile up his readers. It is unfortunate for WUWT that many of its regular bloggers started complaining about a conspiracy, especially after the recent debacle with regards to the Scalia passing.
In addition this silly episode of what I like to call “outrageous outrage” has provided a very convienient distraction from the fact that both Arctic sea ice extent and area are at record lows for this date.
If Anthony Watts was to offer a consilatory gesture to those of us who follow the actual science regarding ice dynamics by posting a thread where a discussion of this winter’s arctic weather and ice dynamics could be discussed, it would greatly be appraciated

Lawrence Martinez

I was not expecting you to be consilatory towards me, I was referring to other individuals who study ice.

george e. smith

Well it used to be just a storm in a teapot.

Lawrence Martinez

Those comments were snark exchanged with an old friend (Jim Hunt) who feels that he has unjustifiably censored by WUWT I never thought you you would have ever read that comment and in retrospect I am sorry it was made.

LM-“If Anthony Watts was to offer a consilatory gesture to those of us”…
LM-“I was not expecting you to be consilatory towards me, I was referring to other individuals who study ice.”
Lawrence, the word “us” indicates that you viewed yourself as part of that group.
LM-“Those comments were snark exchanged with an old friend (Jim Hunt) who feels that he has unjustifiably censored by WUWT I never thought you you would have ever read that comment and in retrospect I am sorry it was made.”
So are you sorry it was made BECAUSE Anthony read it, and shared it here, or are you sorry that you were being petty and “snarky” about total strangers you know nothing about?
LM-“It provided pseudo-science blogger Tony Heller something with which to rile up his readers.”
Are you engaging in “conspiracy ideation” that Tony Heller secretly plans to rile up his readers? tsk tsk

Janice Moore

Nice job, Aphan! (at 2:46 AND 2:35pm) You go, g– …er… fan! 🙂

Marcus ( unmelted )

LOL gi…errr, fan……

Michael Jankowski

“…Those comments were snark exchanged with an old friend (Jim Hunt) who feels that he has unjustifiably censored by WUWT I never thought you you would have ever read that comment and in retrospect I am sorry it was made…”
Pathetic. You want open discourse about arctic weather and ice dynamics and private discourse making fun of people. If you are “old friends” with Jim Hunt, surely you can be a jerk in private to him instead of posting it on the internet and pretending you thought it could never ever make it’s way back to Anthony?
It is unfortunate for those of you who follow the actual science regarding ice dynamics that you chose to reveal yourself to be an immature twat.

And there are two different commenters posting as ‘Michael Jankowski’. Which is the real one?

Robert Austin

In the meantime, Arctic sea ice is extremely low on practically all graphs

Hey, I just looked at “Cryosphere Today” and there is still vast quantities of ice up there. But I guess the consensus is that the ideal Arctic ice extent occurred in 1979 and any deviation in the negative direction constitutes “extremely low”. Alarmist ice wonks just can’t see the big picture for the sea ice minutia.


NevenA I think you and Anthony both have good points.
Did DMI “disappear” the 30% graph? Yes
Was the 30% graph inconvenient? I would call that a mischaracterization. DMI was at fault for mixing data from old method and new method that are not compatible, and when they caught up to their mistake they communicated it poorly. Looks like they acknowledged that, so that’s cool. The only thing inconvenient about the graph is that it was putting out bad data as long as it was. As you say, the mistake was public knowledge for a “long time”, but I think you mistake public knowledge for widely known.
Unfortunately, as you say, there are many partisans who are eager for any opportunity to paint the other side of the argument as frothing-at-the-mouth conspiracy theorists or alternately as evildoers out to communize the world through climate control hijinx. Sometimes people just make simple mistakes. On both sides.


I assume you are an expert on recent sea ice area variations and I bow to the knowledge I assume you have on that subject. I know nothing about that (because I think it unimportant and uninteresting) and, therefore, I don’t discuss it.
I write to ask you to reconsider your words addressed to our host in this thread.
As Janice Moore has repeatedly tried to tell you, your comments have only discredited yourself and, thus, harmed your credibility with resulting loss of cogency to any future posts you make. Janice is usually overly kind and that may be causing you to miss the fact that she is also usually right: wisdom would cause you to reflect on your behaviour when she condemns it as harshly as she has in this thread.
I itemise your major errors in this thread.
You have promulgated a blatant falsehood; viz. our host was involved in a”conspiracy”.
There was and is no conspiracy. DMI made an error which several people independently notified to DMI.
You have made an untrue accusation against our host; viz. he was “fooled by Paul Homewood’s post”.
There is no evidence that he was “fooled” by anybody about anything. There is only evidence that he pointed out the error of DMI who withdrew the graph without accompanying the withdrawal with an explanation for the withdrawal. DMI has now apologised for that error of omission which was compounded by an error of commission by a DMI representative who made the false claim that the graph had been withdrawn because it was incorrect: this inflamed matters because if the graph were incorrect then that would compound the error of omission, but the graph was not incorrect so the false claim was an error of commission.
You misrepresented the issue in attempt to pretend our host had misrepresented and exaggerated it; viz. you wrote

As to apologies: I think it would be more appropriate for you and Paul Homewood to apologize to DMI for causing such a fuss because you failed to see that the old graph was incorrect, probably because it was discontinued a long time ago and no longer quality controlled, and then imply that something nefarious was going on (‘skullduggery’). And not DMI offering apologies to you which you then magnanimously accept. That’s almost like a rape victim apologizing for wearing a short skirt.

The graph was not “incorrect”: it had stopped being updated and was different from the graph which continued in use. The complaint was that the withdrawn graph had been withdrawn without explanation for the withdrawal, and when that was pointed out a DMI representative made the false claim that the graph was incorrect. That false claim has been withdrawn by DMI and DMI has appropriately apologised for its behaviour. Clearly, any exaggeration of the matter was by the DMI representative and others – including you – who tried to make untrue excuses for DMI having failed to provide a simultaneous explanation for withdrawal of the graph when DMI withdrew it.
You waved a ‘red herring’ by using an offensive and untrue analogy to exaggerate your accusations while deflecting attention from YOUR misbehaviour; viz.

And not DMI offering apologies to you which you then magnanimously accept. That’s almost like a rape victim apologizing for wearing a short skirt.

Nothing our host did was anything like that!
NevenA, I have written this post in sincere hope that reading it will encourage you to reflect on your behaviour it relates and, thus, you may learn from your mistakes (but I doubt you will).


“You have promulgated a blatant falsehood; viz. our host was involved in a”conspiracy”.”
I believe the phrase was “sprinkled with conspiracy ideation”. You want Anthony to get away with saying “whether or not it is skulduggery” and saying the DMI have removed an “inconvenient” graph as not endorsing a conspiracy (which for the sake of argument we shall give you). Equally Neven has not accused Anthony of endorsing a conspiracy theory.
If we are allowing deniabilty without direct accusation, then either both are guilty are neither are.
Neven posted a full, and as it turns out pretty much totally correct, analysis of why the graph could not be accurate. Yet this valuable information was snipped because of a spat about who said what about conspiracies.
[it illustrates how Neven doesn’t get much traction with his blog, his choices in language turn most people off -mod]


I wrote a kind response to NevenA that was intended to be helpful to him.
You have responded saying

“You have promulgated a blatant falsehood; viz. our host was involved in a”conspiracy”.”

I believe the phrase was “sprinkled with conspiracy ideation”. You want {AW} to get away with saying “whether or not it is skulduggery” and saying the DMI have removed an “inconvenient” graph as not endorsing a conspiracy (which for the sake of argument we shall give you). Equally Neven has not accused {AW} of endorsing a conspiracy theory.

Yes, I merely said that NevenA had suggested “our host was involved in a”conspiracy”” but as you correctly say, NevenA had actually said” our host had supported “conspiracy ideation”.
My desire to be kind to NevenA explains why I did not apply the greater charge which you rightly say was the egregious behaviour of NevenA.
I add that I do not consider your contribution helpful to encouraging the self-reflection that I commended to NevenA.


” add that I do not consider your contribution helpful to encouraging the self-reflection that I commended to NevenA.”
That is fine because I do not use your considerations as a guide.
[we don’t use yours either so its a pointless stalemate – move along to something relevant or just move along -mod]

David Cage

It is time that climate science had to use best engineering practice not the low scientific standards of claiming that data is beyond question and then altering it.
Once data has been used and sold as beyond question it should be a criminal offence to alter it in any way for any reason without cancelling any commercial contracts based directly or indirectly on that data. After all even mealy mouthed verbiage cannot alter the fact that it is purely and simply fraud.
We were sold renewable energy on the basis of the 100 months to doomsday if we did not do something hastily and without due care and attention. That time has nearly expired and only the greatest fool cannot see it was at best a wild exaggeration even if not totally without foundation, as a claim.
this is part of the Steven Glass factor that has taken over climate studies.
If you watch the video at the end of shattered Glass which is based on the journalist’s career he sounds just like most of the big names in climate science when interviewed. They all have so many different words to avoid saying they told blatant lies.


No worries.. there will be no sea ice in 2014 anyway.




yes, lol

michael hart

Nice one, skippy 🙂


I wonder what the NOAA version would look like. I guess the special ops team did not get to them in time.

This is good information!
It seems to me, though, that it shouldn’t be difficult for them to compute it both ways: with the old coast masks (so that valid comparisons can be made to previous “30%+” data), and with new, higher-resolution coast masks (for better accuracy). If they did that for a few years, then it would become possible to make reasonable comparisons between between the new and old data.

They should use 100% concentration. Then the number would be really LOW.
Look. you guys ( especially anthony) dont work with satellite data or algorithms.
you cant be bothered to download the data and look
you cant be bothered to ACTUAL READ the algorithm descriptions ( hint UAH has also used an outdated
Since you know nothing, its better to just practice skepticism and SUSPEND JUDGEMENT
instead you conclude that people may have done something wrong
THIS is the biggest reason some people dont want to share data. because laymen screw it up or dont understand it.
Goddard is the worst. Homewood a close second.
Anthony should learn to steer clear of them

Janice Moore

SM’s Mistakes:
1. “…100% concentration…”
— Grossly inaccurate mischaracterization of the request for a 30%+ product.
2. “… you can’t be bothered to download the data…”
— We shouldn’t need to. That is what the data custodian, who has readier access to that data, DMI, is paid to produce.
3. “… ACTUAL READ the algorithm …”
— This only begs the question: DMI knows all about the algorithm and simply refuses to fix it.
4. “Since you know nothing…”
a. The anger jumping off the page out of SM’s comment increased sharply, here and making it obvious that rational thought was no longer operating (if it ever was, and this is a reasonable observation, given the unwarranted snarling, harsh, tone of the entire comment).
b. Given the history of the IPCC-affiliates, to have no suspicions at all would be irrational.
5. “… instead you conclude…”
— Given SM’s alleged writing ability (he sure hasn’t demonstrated it on WUWT — at — all in the past 3 years), such a misuse of “conclude” versus the correct, “suspect” is intentional defamation of character.
Which makes SM a cad (or worse).
6. “… reason some people don’t want to share data … because …”
a. If it has been “processed,” it is no longer “data.”
b. Such a flimsy excuse is laughable — you can’t “screw up” data, you can only use it incorrectly — the real issue is the data twisters’ (of which SM is one as per his defense of his BEST or whatever it’s called data which many scientists on WUWT have said incorporates shoddy or highly questionable methods, e.g., kriging) refusal to share what they did (and why) to create the massaged product they still call “observations;”
c. The data twisters refuse to share their data/algorithms with all comers, not merely the data bumpkins
7. “… Anthony should learn to steer clear of…”
Back in 2007 or 2008, he may have been Anthony’s friend. It is very clear that he is no longer. How do I know? LOL. WUWT’s pages are FULL of evidence out of his own angry mouth. A friend respects and values his friend. That SM is allowed to comment on WUWT is proof of Mr. Watts’ generous nature. It most certainly is not proof of the worthiness of his remarks.
There is a time for everything, a season for every activity under heaven…. a time to give up… .” Eccl. 3:1-8.
Time for Anthony to let go. High time.

Janice Moore

Note: “Data twisters” does not (so far as I know) include DMI — this was addressed by me to SM’s generalizations about sharing data, etc…, not to DMI itself.

Marcus ( unmelted )

…Dear Janice, please do not insults ” Cads ” like that ! Us ” Cads ” can think rationally sometimes, unlike Musher !

Janice Moore

Marcus: Oh. (lol) btw: I have never heard of Canadians being called “cads” (except on an individual basis, of course). I’ve heard Cadillacs, jerks, and computer design software called “cads,” but not Canadians. Sorry about that. Well, not really — lololol (since I didn’t do it on purpose).


fine….let’s just ignore what a more up close and personal coastal mask will do
show less ice overall
show faster melt
show lower ice extent in summer
show higher ice extent in winter
…show a more rapid change from one to the other
extreme weather will be next


If you make an assertion, it is up to you to back it up. Until you do, skepticism is the only rational response. It isn’t up to me to prove you wrong, although with the huge differences between models and observations that wouldn’t be hard, it’s up to you to prove your assertion correct.


To borrow Richard Feynman, “science is the belief in the ignorance of experts”. He said that for a good reason since experts tend to develop an arrogance of the kind that Steven Mosher often displays. Look Steven, criticism, skepticisms and questioning of scientific methods are the oxygen of science, while arrogance is the poison the kills it sooner or later. This is evident in when one listens what a certain Richard A Muller had to say about “Mike’s trick”:

The DMI could have avoided all of this by providing the explanation that they did when the discontinued and reinterpreted the graph. They realized the mistake in not doing it and therefore specifically apologized for it, for which they deserve respect.


Steven Mosher:
‘Climategate’ exposed my longstanding concerns at effects of masking; see Appendix A of this.
I have seen no evidence that could possibly justify your having written to our host

Since you know nothing, its better to just practice skepticism and SUSPEND JUDGEMENT

I know enough about this subject to recognise that YOU “know nothing” about it, and your comment is you ‘blowing smoke’ to try to obscure the knowledge of it possessed – in this case – by our host.
I am writing to point out to others that such abusive remarks are your ‘stock in trade’ when confronted by people whom you recognise know more about something than you do.

Gerry Morrow

I have to say I’ve noticed a move to strident and hysterical language when engaging with the sceptosphere from the Great Mosh. Once a man of moderately sceptical views, which he may still hold for all I know, he’s morphed into an spittle flecked (metaphorically of course) demagogue of the alarmist movement.
I am one of those who can take no view about the science in this Brave New World because I’m not a “scientist”. I’ve no particular belief that the scientists are doing anything wrong intentionally, but they sure as hell are doing things wrong scientifically else we wouldn’t have these continuous adjustments and changes, which, unfortunately for the non-scientistific ignoramuses among us, always appear to solidify the debate in the direction the scientific community wants it to go.
Raised eyebrows at this course of events are instantly turned into “conspiracy ideation”. The one that Mosh was involved in known as BEST, aka the Richard Muller Show, homogenised temperatures so that we saw a drop in temperatures in the past. There may be good reason for this, in that the TOB may moved from morning to afternoon, or vice versa, but with all due respect to Mosh, the Best Team, GISS, etc. you couldn’t possibly know the real temperature on the afternoon of 25th February 1932, or whenever, so changing the data to what you think it might have been, no matter how clever the person making the change, is just a guess, a shot in the dark.
I don’t know about others here, but I don’t want my politicians to decide policy on data provided by what appear to be a bunch of amiable bungling amateurs who’ve changed the data to suit their latest thoughts on what they were measuring.

“THIS is the biggest reason some people don’t want to share data. because laymen screw it up or don’t understand it.”
Actually, I think we have a clear case here of the professionals screwing up big time in the presentation of their data and in the very unfortunate timing of the removal of a sea-ice graph with little explanation. ‘Laymen’ naturally became suspicious, given the past very well documented behaviour of the climate science establishment, and hinted/suggested that something fishy might be going on – with appropriate caveats. But this didn’t stop people like Neven A immediately jumping on the ‘conspiracist ideation’ bandwagon in order to affirm the prevailing confirmation bias among alarmists that climate change sceptics are uniquely susceptible to inventing conspiracies on the part of their opposition. I’m sure Lew and his odious little sidekick Cook will be watching this episode very carefully and rubbing their hands together with.barely containable glee. Opportune, no?


Talk of algorithms and downloads sounds like pretending to be helpful in a condescending way but actually being obstructive. Taxpayers pay climate scientists to gather, compile and communicate climate data in a form intelligible to the non technical specialist and non programmer. You might think that such people are incapable of experiencing worthwhile climate thoughts, but you would be wrong. Increasingly in many branches of science, such as biomedical research, a researcher with a biological or clinical background will need routinely to acquire and interpret data from many forms of physical instrumentation – CT, MRI, mass spec, small/wide angle xray scattering crystallography, many forms of electrophoretic gel plots, gene arrays, immunohistochemistry and many more. It makes no sense to assert that if a scientist does not have complete physical and mathematical knowledge of each methodology that they use, down to the level of machine code, then they are forbidden to interact with that methodology. On the contrary, it is the responsibility of makers of advanced scientific instruments, which are made by engineers and programmers, to be user friendly and productive of useful information to people other than engineers and programmers.
Did biologists Watson and Crick fully understand all the theory and maths of X-ray crystallography? No. Did this stop them (with the help of Rosalind Franklin) discovering the DNA helix? No again. If data from X-ray crystallography was forbidden to be viewed by any other than instrument engineers and programmers, would we even today know about dna’s helix? Definitely not.
Professions have a tendency to acquire an inward looking fortress mentality. Why did medieval priests do everything in latin? Obviously to exclude the masses without privileged knowledge of latin. It goes against human nature for organisations tasked with providing a service to avoid the temptation of becoming an inwardly focused self serving club from which all outsiders are seen as a hostile threat. Only by resisting this can a serving profession be a reality and not a pretense.
DMI have a duty like all taxpayers funded scientific organisations to provide intelligable data on what they do. Not just a link to a pile of messy lazy raw data and algorithms.

Jeff Alberts

Actually we should just ignore sea ice, because it really doesn’t matter.

V. Uil

Whenever Steve Mosher pops up with his trade mark arrogance – subtext, you are all fools – it is useful to reflect on “Who is Steve Mosher”.
Don’t know about the other readers, but it makes me feel darn good about my advanced degrees in statistics though admittedly I am a poor marketer.

Frederik Michiels

that explains it all including the adjustments they made

Marcus ( unmelted )

..Ummmm, ” We are sorry, but we don’t like what the graph shows, so we can’t let you see it,…. BUT…… we are sorry that we won’t let you see it any more, so , everything is O.K. right ? ” D’oh !!


Marcus, if you read the passage again you will see that they did not remove the graph because they did not like what it showed. The graph of 30% extent was wrong, because the coastal mask had been changed. The graph was incorrect. The sea ice extent never was as big as the graph showed.

george e. smith

Last night, I caught on T&V some ” reporter/interviewer/newsman/whatever conducting a one on one interview with none other than our Penn State WUWT admirer, Professor Michael E. ‘Hockey Stick’ Mann.
Mann spoke at length about the disappearing ice at both ends of the earth. He said, in response to a specific question on ‘Tipping points’, and whether we had reached any, that it is already beyond recovery for the WAIS of the south, and would result in ten feet of sea level rise for folks in Florida.
And the Greenland ice sheet may also be a gonner, and kick in another ten feet for that.
He described how the loss of the Artic sea ice, whether it was DMI disappeared or not, would result in worser heat waves down here where the civilized folks live.
He said in so many words, that the arctic sea ice is necessary for keeping the planet cool, and without it we would all roast.
Well he did describe how the sea ice reflects all the sunlight that reaches the arctic surface, and thus cools the planet, whereas absent the sea ice, the arctic ocean will absorb the solar energy just like the tropical oceans, and we would all roast.
Dunno who the TV man was; some non local channel, I’ve never watched before, but he just lapped up everything Mann said. Well he clearly had no thoughts of his own on any of the climate issues; and that’s not a crime. But it would be nice, to have some contrast for the viewers to weigh up for themselves.
If the chap asked Mann if something was a problem, the good professor jumped right on that and agreed, giving the guy no feeling for severity. It was quite gung ho on any pestilence the chap queried him on.
I’m mentally comparing Mann’s approach to the caution, that Professor Lintzen demonstrates, when he is queried by this or that Congressional committee.
Now I don’t think this TV chap, was deliberately leading Mann on any crusade journey. Out of presumably ignorance he deftly machetteed a lot of underbrush out of Mann’s way, so he just charged in and made the issue bigger than it might have been.
What sent my alarm bells ringing, was Mann’s assertion that the Arctic sea ice is a key cooling mechanism that stops the earth from cooking.
The guy never asked, and Mann never offered a reason why all that ice is there to begin with. Hey Mike, it’s cold up there because there’s very little solar energy comes in there anyhow, so not much sea ice reflection effect.
And it would be even colder up there than it is, if it wasn’t for all the real live heat energy, that is shipped up there by water and air, from the tropics.
So the principal Arctic cooling process, in my view, is the convective transport of heat from the tropics, and not the ice reflection of a small solar radiation input.
With the sea ice intact, the surface Temperature is free to drop substantially below freezing, whereas absent the ice, the Surface Temperature is around zero or at least above the freezing point.
And there’s that little matter of the radiant cooling of the surface by some e.T^4 sort of gray body factor.
The warmer ocean water surface is a better radiator of LWIR than is the much colder ice surface.
Now Mann said that the sea ice could disappear in a hurry if we reached that tipping point, but the WAIS tipping point that we no longer can do anything about may not collapse, for 100, 200, 300 years or so, according to Professor Mike Mann.
So it is nice if DMI us going to keep us appraised of the real Artic picture, because the CAGWMMCC crowd are very busy.
The interviewer specifically asked Mann howcum, the news media aren’t aware of all of this and telling the people about it.


Well he did describe how the sea ice reflects all the sunlight that reaches the arctic surface, and thus cools the planet, whereas absent the sea ice, the arctic ocean will absorb the solar energy just like the tropical oceans, and we would all roast.

Here’s a link to a very good summary of the arctic energy budget. The last three pages are graphics that summarize the budget. At the bottom of each graphic is the warning “NUMBERS DON’T BALANCE!!”. In other words, the balance isn’t fully understood.
One thing is certain. Even with no ice at all, the arctic ocean will not absorb solar energy just like the tropical oceans. Because the sun strikes at an angle, at noon on the summer solstace the ocean will absorb only half what a tropical ocean would absorb. At other times it would be even less. What about 24 hour sunshine, you ask? At midnight, the sun strikes at such a shallow angle that almost no energy is absorbed.
As (almost) always, clouds are a complicating factor. When the ice is present, the sky is CAVU (clear and visibility unlimited). Over water, on the other hand, there are clouds and fog. There are places in the arctic where very little solar energy reaches the ocean surface.
As (absolutely) always, things are complicated. Michael Mann doesn’t deal with that. He deals in simple clear stories that are mostly hogwash.

Sounds like the scientist has resorted to inductivism – and the journalist has left his duty to be a watchdog – a lethal cocktail.

Marcus ( unmelted )

LOL, commiebob, since when did a liberal ever care about ” budgets ” ?

George – wrt shrinking sea ice and MM:
It was all over the news a few days ago about how the melting arctic ice was going to raise sea level and flood all the coastal cities (as part of the report that the last 100 years saw the fastest sea level rise in 2800 years). Not ONE of the networks clued in that the melting of FLOATING sea ice isn’t going to do a whole heck of a lot (and yes, I know about the salinity issue).
Thing is, the media is an unthinking robot that just repeats what AP, Reuters and a few others tell them. The news anchors are nothing more than talking heads that read what’s on the teleprompter. Most of them have long forgotten their high school physics, assuming they didn’t opt out. Often the news has entertainment value, but very little is totally factual. That would be boring. It has to be a sensationalized 10 second clip designed to capture the attention of their audience for their advertisers.
So we can come here and discuss our perceptions of fact. Four witnesses, six stories, the facts hidden somewhere, even video is interpreted with our built in biases.
Mann just can’t help himself. He lives in his own delusional reality. Sadly, he probably believes everything he says. He too has forgotten his basic physics and chemistry.

Gerry Morrow

“He said in so many words, that the arctic sea ice is necessary for keeping the planet cool, and without it we would all roast.”
He’s right to the extent the planet will get warmer at the poles. However won’t this warmer weather cause an increase in water vapour in the atmosphere, and hence more cloud? And won’t this cloud then increase the albedo in the atmosphere, lowering the amount of sunlight hitting the world’s surface?

I was following this for a while before they removed it, and I have to say that it was pretty clear there was something wrong. Kudos to them for straightening it out and apologizing. Mind you it would have been better for giggles at the people who love Arctic ice so much that they desperately want it all to melt away, if the graph had been correct.


It was already for a long time behind a link that said something like ‘you can view the old …..’ They could have added a date to that link and then let it disappear at that exact moment.

My problem is the apparent lack of overlap in time between
A. the end of a depreciated (or even wildly inaccurate) chart or measure being used for years, and
B. the Replacement of A using a “better” calculation model.
I can understand the reluctance to leave A up and running, even with a prominent disclaimer that it is depreciated and B is the far superior tool. A and B are (cough!) DIFFERENT and the explanation is something people would prefer to avoid. Tough! This is supposed to be science, not advertising.

“Because of the deprecated status of the old plot in the past year, DMI has not been monitoring these irregularities. The old plot should, of cause, have been removed when the mask was replaced.”
Yes, it should have, really. When are we to be blessed with the new improved 30% sea-ice plot?
So Arctic sea-ice death spiral fanatics can now breathe a sigh of relief and get back to ‘business as usual’ whilst sceptics are left feeling ever so slightly disgruntled by the sleight of hand which convinced them that the Arctic might be making a recovery. C’est la vie as they say. Alas, for alarmists, the bigger picture still stubbornly refuses to look quite the way they would want it to.

Can someone tell me why, during the Holocene Climate Optimum, when temperatures were higher than they are today for thousands of years (without AGW effects), didn’t polar ice melt away almost completely then, inundating the world — in fact, sea levels were lower, at least in Europe.


Please Google “Milankovitch cycles” re the HCO to find the answer to your question.


Toneb, David’s question is a perfectly good question and the Milankovic cycles are irrelevant to the answer. The better answer is to be found by doing a search on “Early Holocene high marine stands” or similar search. In fact, sea level reached a level about 1.5 meters above the present stand. There is very good evidence for this high stand from such disparate regions as Texas, Brazil, Tasmania and Micronesia. There is also excellent evidence in the form of buried (in ice) vegetable matter from the period that was recovered from the Greenland Ice Sheet margins.
Sea levels were “lower” in Europe because isotatic rebound effects on land elevations from lost mass of the melting glaciers had not (and still have not) completed. That is why the sea levels along the US mid-Atlantic coast are “rising” at present The land in Europe during the early Holocene was higher than it is at present. Land was sinking along the coasts of northwest Europe rapidly enough during the Middle Ages to have an impact on folk lore (see the myth of Lyonesse for example), or tales of drowned vllages off Cornwall, Wales or Brittany. Modern sea levels more or less stabilized only within the last 4,000 years and that is definitely still only “more or less.”


Please provide
(a) a reference to whichever alarmist blog provided you with the untrue soundbite about ““Milankovitch cycles” re the HCO”
(b) the answer to the question from David J Strumfels which you claim can be found in that blog.


It depends on which ice disappears. All the floating ocean ice can melt and make almost no difference to the sea level. You can try an experiment with an ice cube in a glass of water.
On the other hand, if all the Greenland or Antarctic ice were to melt, there would be a big change in sea level. We know that didn’t happen because the Greenland ice cores go back 100,000 years and the Antarctic ice cores go back 800,000 years.

The DMI explanation makes sense in that the higher resolution coastal mask made the subsequent results incomparable because the surveyed area changed.. But to data to which the old mask was applied must still exist. Why not just apply the new mask to the old data to get a backward comparable ‘new and improved’ 30 percent chart.
15% ice isn’t a very useful ice extent metric; it includes ice extent fringe pixels that are 85 percent water. The present winter low extent could just mean the sea ice is more compacted by the weather; fewer 85% water pixels does not directly indicate less actual sea ice.
And extent provides no information about thick multiyear ice, which is a major influence on how much sea ice survives the summer. Presumably the same satellite altimetry used for SLR could give some sense of multiyear ice; thicker should float enough higher to be detectable.

Why not just apply the new mask to the old data to get a backward comparable …

I was asking myself the same question.


The question is a good one, but I am not at all confident that the explanation actually does make sense. The 30% isopleth ought to be father off shore than the 15% line. Would the concentration plot actually be troubled by a modified coastal mask unless the isopleth has been moving shoreward? From my GIS days, generating buffers (masks) around complex forms tends to produce simpler forms than the form as a function of buffer width. Greater margins (e.g. 15% vs 30%) should produce inherently simpler geometries as the intricacies of the original form are masked by merged areas in the buffer.

Richard M

When I looked backwards in time at the 30% data I saw a slow progression to higher values. If the current explanation is true, why was there not a step function when the new filter was put online? It still smells a little fishy to me.
I also wondered why they simply didn’t apply to new filter to all the old data in a similar manner to upgrades to UAH version 6 where they applied a new algorithm to all the data. I suspect given the above situation the new filter might show the same increase even when applied back in time.

Fred Harwood

So, will the 30% sea ice chart with new mask be available for those who follow the difference between the 15% and the 30% extent? Or does that difference no longer matter?

Just a common sense prediction: Arctic sea ice extent may still be shrinking, but it is not alarming, and is the result of the Arctic warming in the last decade or two, lagging behind the global warming of about 1980-2000. The planet has since ceased warming the last decade and a half, and I suspect the Arctic will soon follow. El Nino may be having having a temperary effect also. The fact is, mankind is a long way from understanding natural climate change and its variability. Why do people, especially scientists who should know better, jump to the conclusion that the Arctic is going to continue warming? What evidence is there to jump to that conclusion?

Marcus ( unmelted )

…Follow da money !


Not convinced yet, Anthony
This is a fudge
Story has been running for a month now and this is the best they can cobble up?
Thanks to Steven Mosher for providing “explanation
So much wrong with this attempted explanation/excuse/dodge.
“caused by a new and higher resolution coast mask.”
Why were they applying a new mask update to an old offline graph in the first place unless they were still actively using it?
What was the rational or lack thereof in using it?
Why did they not adjust all the past data with the new coastal mask for all 11 years?
That is what one normally does when applying a new technique.
This is a Michael Mann Mickey Mouse excuse that they mistakenly spliced two different data algorithm graphs together.
The DMI is not that dumb, but there excuse is.
“The elevated sea ice extent in the data from the old extent algorithm was an artifact”?
No it was either the sea ice extent one would get if using a new and higher resolution coast mask or it was the real graph if the old algorithm was used and 30% ice was increasing.
“DMI removal of the old sea ice extent graph was done at an unfortunate time, [sure was] namely, during a period where it seemed that the new and old ice extent plots disagreed .”
No the problem was that the old graph 2015 data was higher than the 2014 and had been going up for 3 months.Nothing to do with the 15% graph which never agreed with the 30% graph
“Because of the deprecated status of the old plot in the past year, DMI has not been monitoring these irregularities.”
So why did DMI choose to apply a new screen to a deprecated status old plot in summer in the first place ? If they were interested enough to apply a change in the first place they must have been monitoring it quite closely.
If they were not monitoring it why introduce a new graph in the first place
“The old plot should, of cause, have been removed when the mask was replaced.”
The old plot should have been updated so it was all contiguous and treated equally. Like Mosher’s mates do all the time with their temperature data changes. Adjusting the past records when you introduce a new modifier is Standard Practice for all meteorological procedures. And it is only 11 years data..
Sea Ice extent – explanation on an apparent divergence between algorithms.
DMI apologizes for the confusion and inconvenience this has caused”.
DMI should apologize for this lame excuse of a lame excuse.

Robert B

You just saved me the trouble of writing a long reply. I’ll add that the 30% ice-extent away from the coast would be a better indication of whether the Arctic would disappear like the 15% plot is continually used for.

Marcus ( unmelted )

……..Again, .Follow da money !

Rainer Bensch

If DMI does the updates by hand there would be huge work involved to recreate the whole graph. We don’t program computers that long to do such work, mind you. /s

When is an apology not an apology?
When they don’t replace the bad 30% graph with a new good 30% graph.

Janice Moore


Exactly Myron.

Marcus ( unmelted )

If my car doesn’t run as good as it use to, of course I just throw it away instead of fixing it ! Fixing things was sooooo yesterday ! LOL…./ sarc off..

Myron M,


So many questions
And yes I am one of the 1% ice watchers but do try to stay civil.
By the way WUWT and Neven are the direct causes of the decommissioning.
Not a lot of people know that including WUWT or Neven.
You may remember 3 or 4 years ago when there was a kerfuffle about you using 1 instead of 2 standard deviation graphs in your Sea Ice Graphs.
You got knocked about for it.
DMI 30% may have been one of the graphs in question!
you changed to a 2ST deviation version and then DMI took up data and used a 15% graph running the two together with the 15% linking to the 30% but your version only ever showed the non linked 15% graph here.
Two years ago DMI announced that the graph would be discontinued but they continued to run it.
For years it would show big sudden dips [blips]. which were not corrected.
I believe you had an explanation for this in that the data was taken from satellite which would occasionally drop out a segment of data making the amount of sea ice much smaller until the weather improved enough for the satellites to see the full extent.
Neven knows this but you both misrepresent this by saying the the graph is old and outdated.
It was so outdated that DMI decided to improve it [they say ] in Summer this year.
The excuse might make sense of the rise but why splice it on instead of adjusting all the data as one would normally due

Marcus ( unmelted )

…If you torture the data long enough, it will confess to anything !

They used to change the algorithm twice per year to deal with changing seasons and water on top of the ice. AW provided an excellent explanation of that some years back. So the old graphs used to show an anomaly in the spring and fall when they changed the algorithms.


They are simply responding, in my view to pressure by the Danish government/others who have noticed event this due to this site and others, to provide some reply, any reply. You will notice if you look carefully at the new version of the old graph posted above that the original 2015 plot has been put back again. I don’t believe a word of it. sorry.


Fortunately the Scandinavians do not tolerate deception compared to us ect, and in my view they will put the original graph back eventually.

John Peter

At least that used to be the case. In any event, the point made above about volume is equally important. Less extent could be nullified by greater multiyear ice extent within a smaller area.

According to some papers I read some years ago, year-to-year variations in sea ice area are driven primarily by winds and currents rather than temperature. It seems to me to be entirely possible that 30% sea ice area can be growing while 15% sea ice area is declining. A bit of current or wind in the right direction will do the trick. So on what grounds were people saying that the 30% data was obviously wrong?


On the grounds that the people who produce the graph have explained that the introduction of new mask meant the graph was wrong. On top of this the 30% was almost certainly wrong because the conditions that would be needed for the 30% to be growing compared to the 15% were not occuring. It would require an unliklely compaction of the ice that coul dbe seen not to be occuring by other observations.


‘…I suggest this maxim: “you can catch more flies with honey than vinegar”…’
In fact, it is the opposite. Flies are attracted to the acetic acid. If you set out a jar with dilute vinegar, it acts as an excellent fly trap.


I must try this while it’s still legal.

Marcus ( unmelted )


jorge 1:24 pm, + many and LOL and thanks because reading this thread had become quite a chore.


If you really want to attract flies just brush a little phosphoric acid (75% concentration) on a piece of rusty metal. You can get flies even in the winter!


BTW you can compare yearly NH thick ice here (purple)
so if someone bothers to check my guess is that the graph is correct comparing with past months/years ect Thank you CT! LOL

Lawrence Martinez

@ Eliza
Do you understand this graph from your linked page?
Same question regarding a different graph, same linked page.

Lawrence Martinez

One more from your link, this one is for global ice area and anomoly. If you look at area you’ll notice that is is now at an all time low.

Lawrence Martinez,
Thanx for posting the graph of global sea ice. It shows that global ice is not at any record low. Thus, it’s just natural variability.
But if you insist on being frightened, I guess you have that right.

[Comment deleted. ID thief, caught again. -mod]

Richard G

Eliza, I checked your link and your right. The 30% or greater sea ice has a higher extent in 2016 than 2015.

“The old plot should, of cause, have been removed when the mask was replaced. DMI apologizes for the confusion and inconvenience this has caused.”
this makes no sense. why change the mask if it means you must remove the data? what was the purpose in changing the mask?
Were any other masks changed? for example, was the mask on the “15% coverage” plot changed?

Janice Moore

The fact is both graphs are very useful. I don’t understand why they removed the 30% graph

Marcus ( unmelted )

…..They did not like the results..period !

A C Osborn

The really odd things is that the MASIE values aremore in line with the 30% DMI.
So now they will have to either “Adjust” the MASIE values or disappear it too.
Even Mr Neven’s own analysis of Piomas also does not show January Volume as being the lowest ever either, perhaps they should disappear that as well to avoid confusion.

Masie is IMO a better metric. Higher resolution than the microwave pixels since incorporates visual signals also (but I have not investigated the guts of this, just so far what Masie says on the website). For sure summer ice flow meltwater confounds microwave readings, and for sure this can be resolved optically. Essay Northwest Passage. So, Masie in summer must be better. Now, not a big difference in winter. Besides, in winter Masie doesn’t have optical signals for months.
Plus Masie uses 40% ice pixels. Big improvement. Alas, Masie starts in 2006. But, good enough to possibly show arctic ice recovery in the future. As it already seems to be doing, possibly why few refer to Masie.

Marcus ( unmelted )

..Wait a minute…Isn’t Masie done with satellites ? ..Didn’t they just argue that satellites measurements are unreliable ?..I’m sooooooo confused !

“Masie is IMO a better metric.”
Well, that’s an opinion. But the folks who make it have some advice. MASIE is great for its intended purpose of locating the edge of the ice, but not for comparisons over time.
“2. When should I use MASIE and when should I use the Sea Ice Index?
Use the Sea Ice Index when comparing trends in sea ice over time or when consistency is important. Even then, the monthly, not the daily, Sea Ice Index views should be used to look at trends in sea ice. The Sea Ice Index documentation explains how linear regression is used to say something about trends in ice extent, and what the limitations of that method are. Use MASIE when you want the most accurate view possible of Arctic-wide ice on a given day or through the week. “

A C Osborn

MASIE is closer to the 30% than the 15% DMI and now they will have to “Quality Adjust” that or disappear it too.
Even Mr Neven’s own analysis of PIOMAS Volume does not show January as being the lowest ever volume either.

A C Osborn

Sorry for the duplication as the 1st post appeared to have got lost, but was just delayed.

Marcus ( unmelted )

..It will be forever more known as the ” Osborn Hiccup ” ! Your fate is sealed ! LOL

charles nelson

It would appear to me that even with the best will in the world, and all the modern resources available, we have only a vague idea of what current sea ice conditions may be. If you put that alongside the fact that we know little about conditions before the 70s and even less about the decades and centuries before…it’s hard to get too worried about any trends…especially as small as the ones currently being observed.

Marcus ( unmelted )

…We seem to know a lot about what we don’t know and just guess at the rest ! I think Mother Nature has a whole lot of surprises to send our way soon !

Robert B

Just two points
Why does the 15% plot have data going back to 2012 but a 1979-2000 mean? If the 30% plot could be so far off because of a change in masking (which needed to be done prior to better sat. data) then that comparison must be completely meaningless.
Secondly is this plot that has not been updated since (they changed the masking?) 2009.
I think that both show pressure towards biased analysis.

Robert B

The DMI 30% graph was done by the Danes by their own algorithm for 11 years.
The new 15% chart is actually done by someone else with satellite data going back to 1979 hence the different mean and the plot being similar to all other 15% graphs.
The Danes were to embarrassed by their 30% graph differences that they bowed to pressure to use a better, proper Swedish graph.
[OK, maybe not Swedish but it felt good saying that, sorry moderator]

Marcus ( unmelted )

…So it’s actually manipulated garbage ?


I don’t blame anyone for being paranoid about “disappeared” charts and data. That’s the reality of Science today, as a result of warmist machinations, Yamalification, orchard picking of dendro data, stonewalling of FOIA requests, failure to publish data, refusal to provide methodologies, nuisance lawsuits, pal review, biased journals, irreproducible papers, and so on and on.
In its ethics, Science has descended to Lysenkoist levels, where assumption of intent to deceive is a sensible strategy.
I don’t believe that any of the partisans in the commentary above caused this situation, but I think we should all take note that deceptive science by others has eroded trust throughout Science in general. The Ship of Science is sinking, and we’re rearranging the deck chairs, here, arguing about a very small and untimely issue.

Anthony without starting another conspiracy … Why is the mean data shading only showin 1979 – 2000 data surely for statistical accuracy it should show 1979 to previous year ( 2015 ) wouldn’t that be a more accurate comparison representation of the mean data facts vs current data.

Chris Z.

The only explanation for the erroneous high 30% values during 2015/16 (if that’s what they turn out to be) is that they used the NEW mask (giving a larger basic area) with the OLD method of calculation. There must logically be some sort of fixed correction factor involved, for the discrepancy of the measured area (minus the masked pixels) and the actual area (including the masked pixels). That difference became smaller with the finer-grained mask, so the correction should have been lowered at the same time.
What is profoundly unlogical (and therefore unconvincing to me) is that they forgot to use the correct way of calculating from the newly-masked data for the 30% plot, but made a smooth transition on the 15% plot at the same time, and yet weren’t able to simply switch the 30% plot to the new calculation as well. Both plots are derived from the same data AFAIK, only with a different between “no ice” and “ice”, which naturally is not a black-and-white binary distinction because of the finite (and considerable) area of every pixel on the satellite images, so you have to “posterize” the raw data to measure areas at or above a particular percentage of ice present. It should be no great thing to even make the percentage value a variable that either the viewer, or certainly the compiler of the published graphs, can input ad-libitum to generate graphs related to any relative ice/water percentage they might desire. A proper method workable for 15% minimum ice cannot be failing for 30% minimum ice, as the difference is merely a different threshold applied to the very same source data. No matter how that has been masked (or not).


Could be wrong but the new mask should only apply to the 30% data. This was different from the 15% graphs because they assessed coastlines in a totally different way. The new mask should not be being applied to any 15% graph.
They use totally different algorithms .
DMI 30% is original Danish math mastery.
30% is the Danish original Algorithm from 11 years ago.
15% is the Swedish/IPCC/World Algorithm from 1979.
No coastal masking included.
Much better than the Danish, obviously.
As the Danes have admitted.

Janice Moore

angech the amazing Swede (smile),
Just wanted to tell you how much I am enjoying reading your insightful (and sometimes humorous) comments. Thanks for all the great info.!

Chris Z.

…only with a different RELATION between…. – sorry!

William Grubel

Now how about the RSS Northern Polar Temperature Lower Troposphere (TLT) – 1979 to Present graph. I notice it has quit updating too. Seems like every time something starts to show a trend the warmistas don’t like it simply stops updating.

if the topic here is agw then it does not matter what the sea ice is doing. the only thing that matters is whether whatever the sea ice is doing can be related to the rate of fossil fuel emissions by way of warming, but there is no empirical evidence to support that relationship.

J. Munshi,
Exactamundo, Jamal. We need evidence! But they have no evidence.
Next! …


I still don’t understand why we compare everything to the start date of 1979, at the end of a cold period, when ice levels were known to be high. Maybe they were unusually high and not the norm. Maybe now is not death spiral; just NORMAL.
Oh well, what do I know?

1979 marks the start of the satellite record and accurate sea ice measurements. Earlier data has much greater uncertainties. The timing is a bit unfortunate.


This is a symptom of a cancer that afflicts climate “science”. The prevailing opinion is that “improvements” to the data can and should be made in real-time, with no concern that by doing so they may invalidate or muddle 100+ years of previous work done by so many people.
Hard copies of the data are not retained, the digital data is tampered with daily, the changes go unexplained, and requests for any sort of records or explanations re met with obstruction or angry denunciations.
No other science that I know of operates like this. The original records and data are sacrosanct. Post-hoc meddling is misconduct. But climate “science” has a culture problem where this sort of thing is encouraged.


When data blasphemes … via telling the truth … and it got a bit too interesting, too fast.
@Jamal Munshi All true Jamal, except perception/emotion/BS is how team AGW rolls. Nevertheless hard data will win this, it always wins anti science religious argumentation over time.
Hopefully before we drop-off the twig.


The real question is, seeing that they had one of the longest term CONSISTENT measurements of sea ice…
…. why would they change the masking and the algorithm?
The only way you can tell REAL changes over time is keeping the same methodology.

Excellent question Andy. Even if we know the mask is wrong, why would it matter? After all, we are looking at anomalies. Right?

Taylor Pohlman

I think folks are missing the point of having these two graphs. They obviously aren’t directly comparable, because of different algorithms, but relative to each other, I look for situations where it the gap is widening, I assume the ice is spreading out, and therefore average volume is decreasing vs. if the gap is narrowing the ice is compressing. Otherwise, if you just look at the 15%, it’s impossible to know if expanding extent is due to more ice vs. existing ice spreading out. Frustrating to not have that insight any more.


“Frustrating to not have that insight any more.”
It is that comparison with even the slightly longer sea ice record that they will DESPERATELY be trying to hide over the never few years !!


You can use sea ice area vs sea ice extent to get an indication.


I took awhile but finally the DMI did what I and many others were asking for and even apologized for the confusion they had created with their communication. The apology certainly was a surprise considering the usual behavior in climate science, but very welcome.
What is interesting in their explanation is the fact that they updated their costal mask, does that mean that they will keep their traditional 30% ice coverage metric for their other sea-ice products?


“I got tired of answering questions about it so I took it offline”.
That person is no scientist.
A real scientist LOVES to talk about their work, to anybody anytime. They will talk the ears off a total stranger who shows the tiniest hint of interest.

I read that all this would happen over these graphs a year and a half ago…


Interesting, where did you read (a year and a half ago) that the DMI would update their coastal mask, forget to adjust the 30 % algorithm, and later be forced to reinterpreted the graph? Yeah sure, they said that the old graph was substituted with a new, and hinted of the discontinuation, but this?

There was a discussion about them removing it when it was pointed out that sea ice was increasing, I think it may have been on Tony Hellars site…


You should read the entire question before trying to answer it.


I think what this highlights for many of us laymen and women is that empirically, we have no idea of ice volume. Just area is imaged and “modeled”.
Is that correct, the ice volume is modeled. As in best guess? As in we generally have no idea on thickness of sea ice?
Given that the “guess” changes as alterations are made, do we have any real idea of the accuracy?
I seem to be getting tired of models having an appearance of fact, this issue with the 30% error shows that clearly. We are to accept that it or the 15% was ever right in the first place

Clovis Marcus

While I accept the explanation that underlying land mapping will change the output. I think there are still some legitimate unanswered questions
I wonder when the new coastal mapping was applied because I;d have expected a step change which I don’t see. Is there something in the algorithm to smooth that out? If so why? It would have rung alarm bells immediately.
I’d also ;like it backed up with a comparison graph for,say, 6 months before and 6 months after the change in input data, to show how the plots were affected. It’s the sort of forensics I’d have to give if one of my projects went wrong. I’d be expected to show external forces had caused the failure.


I wonder when the new coastal mapping was applied because I;d have expected a step change which I don’t see.

According to the DMI it was applied in Summer, a time when there isn’t much sea ice near most of the Arctic Ocean’s coasts. As things filled up again with ice reaching the shores, the disparity became larger. Makes sense really, but it hadn’t crossed my mind. Thanks for the suggestion.


NIce of you Neven to admit that the DMI explanation was something new, even to you. Too many alarmists are acting as if they knew this all along. Kudos to DMI for explaining and apologizing for confusion that resulted from the lack of communication.


“Too many alarmists are acting as if they knew this all along.”
I see many “alarmists” saying they knew there was something wrong with the plot, not that they knew these kind of details. Many, including myself, said that accusations of nefarious intent were premature. So many commenters here jumped straight to the blame game without having any kind of an answer, and many are still doing so. It would seem that inflammatory rhetoric is preferred to finding answers. Now, there are plenty of commenters here who are indeed seeking answers, but there’s an awful lot of nonsense diluting them.


Brian, I do agree that discussions concerning climate science have become quite unproductive. And I do agree that suspecting malice is premature when simple incompetence is sufficient, as long as no documentation is available. Do you agree that that crying “conspiracy ideation” every time some criticizes climate scientists is even worse as it is purely anti-scientific.


Good point Clovis. The excuse is they introduced it in summer when the coastline was not so involved. Sounds a trifle dodgy as they showed new and old areas with masking that were quite different .
Where is the step. Is it less in Summer.
I presume they showed winter comparisons?