The time has arrived to start taking a close look at the assorted different Arctic sea ice extent metrics, in order to ascertain their respective maxima for 2025. To begin with here’s Zack Labe’s overview of previous years’ maxima:
It now seems highly likely that 2025’s maximum extent will ultimately prove to be the lowest in the satellite era. The remaining question is when this year’s maximum will occur.
My speculation yesterday that AWI’s flavour of Arctic sea ice extent had already achieved its maximum value for 2025 has been negated today:
The NSIDC 5 day average and JAXA extent metrics are also currently at their maximum levels for the year so far, so let’s wait and see which one is the first to take a downward turn.
On March 22, Arctic sea ice likely reached its maximum extent for the year, at 14.33 million square kilometers, the lowest in the 47-year satellite record. This year’s maximum extent is 1.31 million square kilometers below the 1981 to 2010 average maximum of 15.64 million square kilometers and 80,000 square kilometers below the previous lowest maximum that occurred on March 7, 2017.
On several previous occasions “Snow White” and I have documented Ron Clutz’s misuse of MASIE Arctic sea ice extent data on his “Science Matters” blog. We agree with Ron that science matters, so on several occasions we have attempted to direct his attention to my interview with NASA/NSIDC scientist Walt Meier. Walt’s words of wisdom included:
Year-to-year comparisons and trend estimates will be more accurate in the passive microwave data than in MASIE.
It will probably not surprise you to learn that Ron has not learned anything from our repeated efforts. In his article entitled “2024 Arctic Ice Beats 2007 by Half a Wadham” earlier today Ron proudly displays this graph:
You will note that Ron does not provide details of his data source. However I have recently noted a sudden lack of SSMIS passive microwave data emanating from NOAA. The OSI SAF reported it this way on September 12th:
Dear OSI SAF Sea Ice Concentration User,
Due to missing input data, we have not been able to generate L2 products, corresponding to F-16 / F-17 / F-18 since Sep 11 19:36 UTC.
We apologize for any inconvenience.
The NSIDC’s sea ice home page puts it this way today:
Now day 260 of 2024 is September 16th, so it seems safe to assume that Ron is erroneously using his favourite MASIE metric for year to year comparisons yet again. In his article Ron states that:
SII was reporting deficits as high as 0.5M km2 (half a Wadham) compared to MASIE early in September. For some reason, that dataset has not been updated for the last five days.
It appears as though Ron has also not yet learned how to find NSIDC’s sea ice home page on the world wide interweb!
I added this hopefully helpful comment below Ron’s article. For some strange reason it is yet to emerge from his moderation queue:
[Update – September 18th]
Our regular reader(s) will not be surprised to learn that my helpful comment yesterday is no longer in Ron’s moderation queue, but is now languishing underfoot on his cutting room floor.
Ron has written another Arctic article using the graph reproduced above. This one is entitled: “2024 Arctic Ice Abounds at Average Daily Minimum“. In it Ron assures his flock of faithful followers that:
We are close to the annual Arctic ice extent minimum, which typically occurs on or about day 260 (mid September). Some take any year’s slightly lower minimum as proof that Arctic ice is dying, but the image above shows the Arctic heart is beating clear and strong.
Over this decade, the Arctic ice minimum has not declined, but since 2007 looks like fluctuations around a plateau.
Ron has also changed his phraseology regarding the recent SSMIS data outage. This time it reads:
For some reason, apparently data access issues, that dataset has not been updated for the last five days.
“Snow White” felt compelled to leave Ron another helpful comment concerning his new words of Arctic wisdom:
The 2024 Arctic sea ice minimum extent will almost certainly occur at some point over the next month. The exact date and level will vary from one extent metric to the next. Here’s a comparison of the current JAXA extent with previous minima, courtesy of Zack Labe:
Here too is a more detailed look at 2024 extent compared with the 5 lowest annual minima in the JAXA record:
By way of comparison, here is the equivalent graph for the OSI SAF extent metric, which experienced an up tick yesterday but has now reached a new low for the year:
However AWI Arctic sea ice area is currently falling, which may well presage further significant falls in extent:
The NSIDC web site is currently “experiencing technical difficulties”, but hopefully we’ll be able to take a look at their extent graph in the very near future.
[Update – September 4th]
The NSIDC web site is back in action, and their 5 day averaged extent metric is currently still falling quickly:
The ARCUS Sea Ice Prediction Network August report has been published. Note that the predicted numbers are for the September monthly average extent rather than the daily minimum:
For the August Outlook, we received 24 contributions of September pan-Arctic sea-ice extent forecasts…
The August 2024 median forecasted value for pan-Arctic September sea-ice extent is 4.27 million square kilometers with an interquartile range of 4.11 to 4.54 million square kilometers. This is about 200,000 square kilometers lower than the June median and about 250,000 square kilometers lower than the July median, which reflects the faster than average ice loss during July.
The lowest sea-ice extent forecast is 3.71 million square kilometers and the highest sea-ice extent forecast is 5.23 million square kilometers. These extremes are actually higher, particularly on the low end, than the estimates from July.
[Update – September 9th]
There’s been the tiniest of upticks in the NSIDC 5 day extent metric. 1 thousand km² to be precise. However, the others are still slowly declining:
[Update – September 10th]
NSIDC extent has posted a new low for the year, and JAXA extent is still declining. However there has been a slightly more substantial uptick in the OSI SAF metric:
The current minimum is 4.64 million km² on September 8th.
AWI sea ice area has posted a convincing looking minimum on September 4th, which suggests that the central refreeze is already well under way:
[Update – September 17th]
JAXA/ViSHOP/ADS extent has risen significantly over the last two days:
It now looks highly likely that the 2024 minimum will prove to be 4.07 million km² on September 13th. That is 4th lowest for the date, but equal 5th lowest minimum in the JAXA record.
A closer look at some of the other extent metrics will have to wait until this problem is solved:
Not good timing for a data outage!
[Update – September 22nd]
SSMIS data has been flowing again for a couple of days:
This graph may be subject to revision if and when the missing data is recovered, but currently it looks as though the 2024 minimum of the NSIDC 5 day averaged extent metric is 4.28 million km² on September 11th.
[Update – September 24th]
The National Snow and Ice Data Center formally announced today that:
On September 11, Arctic sea ice likely reached its annual minimum extent of 4.28 million square kilometers. The 2024 minimum is the seventh lowest in the nearly 46-year satellite record. The last 18 years, from 2007 to 2024, are the lowest 18 sea ice extents in the satellite record…
Note that this is a preliminary announcement. Changing winds or late-season melt could still reduce the Arctic ice extent, as happened in 2005 and 2010. NSIDC scientists will release a full analysis of the Arctic melt season, and discuss the Antarctic winter sea ice growth, in early October.
The NSIDC also addressed the recent missing SSMIS data issue mentioned above as follows:
Note that a gap exists in the input source data between September 12 and September 18. This gap somewhat lowers our confidence in the minimum extent estimate. However, it appears that September 11 is the mostly likely date of the minimum based on data trends in daily extent values leading up to the 5-day average on September 11 and the extent values after data restarted on September 18. If extent did drop further between September 11 and September 18, it would have been marginal. If the input source data becomes available to fill that gap, our team will update the minimum estimate if necessary.
The JAXA/ViSHOP web site is currently down, so here is the current OSI SAF extent graph for the end of May:
2012’s “June cliff” is almost upon us, and if 2024’s current trajectory continues extent will cross above 2012 for the first time since February in a week or so.
Apart from (presumably accidentally) empirically confirming global warming and Arctic sea ice volume decline, Tony Heller has also been frantically attempting to persuade his flock of faithful followers that the current value of the OSI SAF’s extent metric means that the impending series of “2023 has been the hottest year evah!” stories are all lies.
Here a few examples of his infamous oeuvre, together with “Snow White’s” responses:
Can you rustle up one of those for another date Tony?
Switching swiftly to a cherry picked graph of the OSI SAF minimum extent, Tony invokes the spirit of a deceased parrot that went to meet its maker several decades ago. He remains blissfully unaware that I watched the Monty Python dead parrot sketch when it was first broadcast:
When do you suppose Tony will get around to implementing my suggestion of revealing the OSI SAF extent graph for December 8th to his flock of faithful followers?
Or a multi decade graph of NSIDC extent for that matter?
[Update – January 4th]
My prediction has come true in next to no time:
[Update – January 20th]
For some strange reason Tony has been silent about Arctic sea ice extent for a while, and has moved on to the Greenland ice sheet instead:
Presumably that’s in response to an article in The Guardian:
The Greenland ice cap is losing an average of 30m tonnes of ice an hour due to the climate crisis, a study has revealed, which is 20% more than was previously thought…
The study, published in the journal Nature, used artificial intelligence techniques to map more than 235,000 glacier end positions over the 38-year period, at a resolution of 120 metres. This showed the Greenland ice sheet had lost an area of about 5,000 sq km of ice at its margins since 1985, equivalent to a trillion tonnes of ice.
“Snow White” felt compelled to respond to Mr. Heller as follows:
Evidently Tony has still not learned that it’s impossible to compare 1990 apples with 2001 oranges, despite having the difference explained to him on numerous previous occasions.
Stop Press! Tony has suddenly discovered that he’s been comparing apples with oranges all these years!!
Whilst waiting for the all important thickness and volume data to arrive, we’ll start the new year in traditional fashion with a graph of JAXA extent:
The 2023 calendar year finished with this particular extent metric sitting at 15th lowest in the satellite era.
From Niall Dollard on the Arctic Sea Ice Forum comes evidence via the Sentinel 1A satellite that an arch formed in the Nares Strait between Greenland and Ellesmere Island in late December:
Please note the current record low NH snow extent. Matt predicts all that is about to change:
How sure? And in what way "totally different"?
Have you pointed out to Tony yet that the current daily snow cover data you cite utterly negates his recent assertion that "Autumn/Winter snow cover has been increasing for almost 60 years"?
Hot off the Scandinavian virtual printing presses, here is the official December Arctic sea ice extent trend graph from the OSI SAF:
That’s “Steve”/Tony’s current metric du jour. When do you suppose he will bring it to the attention of his horde of regular readers? It’s accompanied by this matching concentration map:
Here too is the CryoSat-2/SMOS thickness map for December 31st, in a different format to the one usually used here:
[Update – January 3rd]
The December PIOMAS modelled gridded thickness data has been released. The calculated volume is 6th lowest in the satellite era:
Here is the equivalent CS2/SMOS volume graph
Here too is the PIOMAS thickness map for December 31st:
This uses the same Greenland down orientation and 2.5 meter maximum scale value as the CS2/SMOS map above.
The end of 2023 had above average sea ice growth, bringing the daily extent within the interdecile range, the range spanning 90 percent of past sea ice extents for the date. Rapid expansion of ice in the Chukchi and Bering Seas and across Hudson Bay was responsible.
Average Arctic sea ice extent for December 2023 was 12.00 million square kilometers, ninth lowest in the 45-year satellite record . Sea ice extent increased by an average of 87,400 square kilometers per day, markedly faster than the 1981 to 2010 average of 64,100 square kilometers per day.
After a delayed start to the freeze-up in Hudson Bay, sea ice formed quickly from west to east across the bay, leaving only a small area of open ocean near the Belcher Islands at month’s end. In the northern Atlantic, sea ice extent remained below average extent, as has been typical for the past decade.
For December overall, 2023 had the third highest monthly gain in the 45-year record at 2.71 million square kilometers, behind 2006 at 2.85 million square kilometers and 2016 at 2.78 million square kilometers.
Moving on to the “Conditions in context” section:
Warm conditions prevailed over the central Arctic Ocean and Beaufort Sea regions, as well as over Hudson Bay and much of northern Canada, with air temperatures at the 925 millibar level (around 2,500 feet above sea level) 8 to 9 degrees Celsius above the 1991 to 2020 average. Elsewhere, relatively cool conditions prevailed, with air temperatures 2 to 4 degrees Celsius below average in southwestern Alaska, easternmost Russia, Scandinavia, and southeast Greenland. Cool conditions in the Bering and southern Chukchi Seas explain the rapid ice growth there. By contrast, the warm conditions over Hudson Bay, continuing since November, explain its delayed start of ice formation there.
The atmospheric circulation pattern for December was marked by low sea level pressure over the Gulf of Alaska and northern Europe and high sea level pressure over central Russia. This pattern led to cold Arctic air flowing across the Chukchi Sea and into the Bering Sea as well as advection of relatively warm air across Canada into the Beaufort Sea:
Here’s a taste, but there’s much more at the dedicated article linked to above:
[Update – January 12th]
A change is as good as a rest, so here’s the AWI “high resolution” AMSR2 Arctic wide sea ice extent graph
It’s currently highest for the date in the AMSR2 era by a significant margin.
Here too is the ice age map for the end of 2023:
[Update – January 19th]
Something seems to have gone wrong with the processing of the mid-month PIOMAS gridded thickness data. For the moment we’ll have to make do with just the CryoSat-2/SMOS thickness map:
and volume graph:
With the perennial caveat of a probable upward revision when the reanalysed data is released, Arctic sea ice volume is still close to the bottom of the range during the CryoSat-2 era.
In addition especially for Matt, “Steve”/Tony and numerous others of a “skeptical” persuasion, here are the latest Environment & Climate Change Canada snow extent and snow water equivalent graphs for the northern hemisphere:
Last but certainly not least is the Rutgers Global Snow Lab northern hemisphere snow cover anomaly chart for December:
[Update – January 29th]
A winter cyclone is stirring up the far North Atlantic. It’s currently forecast to bottom out later today with a minimum MSLP of 937 hPa:
The storm has been creating a long period swell directed at the ice edge in the Barents Sea. By midnight that swell will be battering the ice in the Fram Strait too:
[Update – January 30th]
According to Environment Canada the cyclone bottomed out with an MSLP of 939 hPa at 12 PM UTC yesterday:
Associated with the storm is a pulse of abnormally warm air reaching to the North Pole and beyond:
Here’s how JAXA extent looks as the big swell arrives:
And here’s the lead enhanced AWI AMSR2 concentration map of the Atlantic periphery:
Let’s see how things change over the next few days.
[Update – January 31st]
Here’s a preliminary look at the effect of the recent Arctic cyclone and other “weather” on the sea ice in the Fram Strait and Barents & Kara Seas:
There is also another cyclone heading for the Barents Sea. This one is forecast to bottom out at 936 hPa at around midnight tonight near the Norwegian coast:
P.S. The cyclone mentioned just above has been named Storm Ingunn by the Norwegian Meteorological Institute:
👀 This swirl of cloud is #StormIngunn – an intense area of low pressure that's still rapidly deepening
😮 Wind gusts of over 120 mph have been reported in the Faroe Islands with the storm now moving towards Norway pic.twitter.com/TNuo52L7MW
It’s that time of year again! Tony Heller has been asserting that “summer is over at the North Pole” for several weeks now, and the 2023 Arctic sea ice minimum extent will occur at some point over the next four or five weeks. The exact date and level will almost certainly vary from one extent metric to the next.
To get the minimum extent ball rolling, here’s Signe Aaboe’s graph of previous summer minima based on OSI SAF data:
Here too is Zack Labe’s equivalent, based on JAXA data:
My Arctic alter ego was checking out the new “X” rated edition of Twitter when “she” couldn’t help but notice that Elon Musk had allowed Tony Heller back into the climate “debate” thereon, albeit with a new handle.
“Snow White” also noticed that for some strange reason Tony was telling lots of porky pies about Arctic sea ice again! Hence:
Here's @TonyClimate demonstrating yet again that either:
1) He has no understanding of all things #Arctic, or
2) He understands well enough, but he pulls the wool over the eyes of his faithful flock of followers.https://t.co/yYNhpSncLE
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