This week we continue to see strong gains in Arctic Sea Ice. JAXA’s extent paused briefly, but has resumed a strong upwards climb, now exceeding 2005 for this date.
JAXA AMSR-E Sea Ice Extent -15% or greater – click to enlarge
In other news, NSIDC released an interesting video using Google Earth.
Here’s the NSIDC animation showing the entire satellite Arctic sea ice record.
According to the Google Earth Blog:
==========================================================
They’ve recently updated their files to show data from 2010, and the results are quite stunning:
According to their site, the 2010 low (reached on September 19) was the third lowest on satellite record:
Average ice extent for September 2010 was 4.90 million square kilometers (1.89 million square miles), 2.14 million square kilometers (830,000 square miles) below the 1979 to 2000 average, but 600,000 square kilometers (230,00 square miles) above the average for September 2007, the lowest monthly extent in the satellite record. Ice extent was below the 1979 to 2000 average everywhere except in the East Greenland Sea near Svalbard.
The U.S. National Ice Center declared both the Northwest Passage and the Northern Sea Route open for a period during September. Stephen Howell of Environment Canada reported a record early melt-out and low extent in the western Parry Channel region of the Northwest Passage, based on analyses of the Canadian Ice Service. Two sailing expeditions, one Norwegian and one Russian, successfully navigated both passages and are nearing their goal of circumnavigating the Arctic.
You can check it out for yourself using this KMZ file
. Or, if you’d prefer, you can simply watch the video below that shows all of the data in the KMZ.
========================================================
In following the link from The Google Earth blog to the NSIDC page link they cite, I noted the September Average extent graph, which is different than the usual annual minimum extent graphs we see.
And of course, it looks like a “death spiral” to paraphrase Dr. Mark Serreze, but it is only 30 years of data, so who’s to say it isn’t part of a longer cycle? One thing that has always bugged me about NSIDC is that they don’t provide data to go with their plots, and of course none was listed with this one, so I decided to use the large size of that plot to hand digitize the values.
Here’s the manually digitized data I got from that NSIDC September average extent graph. Values are year, and average September extent in million square kilometers:
1979 7.20 1980 7.80 1981 7.25 1982 7.45 1983 7.55 1984 7.20 1985 6.90 1986 7.60 1987 7.50 1988 7.50 1989 7.10 1990 6.25 1991 6.60 1992 7.55 1993 6.50 1994 7.20 1995 6.20 1996 7.90 1997 6.75 1998 6.60 1999 6.25 2000 6.35 2001 6.80 2002 5.95 2003 6.20 2004 6.10 2005 5.60 2006 5.90 2007 4.30 2008 4.70 2009 5.40 2010 4.90
I wondered what JAXA would show for September averages. Fortunately since JAXA provides the daily data here, it was easy to bring it into a spreadsheet and calculate the average. Here’s the values I got from my spreadsheet. Values are year, and average September extent in million square kilometers, rounded to nearest hundredths:
2002 6.11 2003 6.28 2004 6.16 2005 5.70 2006 5.98 2007 4.60 2008 5.08 2009 5.53 2010 5.45
Note that 2002 didn’t have a full month of valid daily data, but it appeared to have enough since JAXA plots September extent on their own graph. I plotted them both, using Dplot, and here’s the output:
Feel free to check my work, the output of the spreadsheet I used to calculate the JAXA averages is here: JAXA_2002-2010_SeptAvg
…as a PDF file of values (WordPress.com won’t let me upload XLS files)
It seems that the differences between NSIDC and JAXA average September extent are getting larger since 2007, and that JAXA is always showing more extent than NSIDC. In September 2010 there’s a whole half million square kilometer difference between the two averages. It’s curious.
Speaking of NSIDC, Dr. Walt Meier has asked to do a guest post here, and I’ve approved a slot for him, so I’m going to hold much of my weekly discussion in deference to him. In the meantime, the WUWT Sea Ice Page has a wide collection of images and graphs from both hemispheres to brief you.
Also, if you have not seen it yet, this book review from WUWT contributor Verity Jones on what the Russian Arctic and Antarctic Research Institute thinks about the Arctic Ice loss (they predict a rebound) is well worth a read.
Update: the JAXA average calcs might be in error, an artifact of how the spreadsheet cells return, unfortunately I won’t be able to check again and replot until late tonight, see upcoming announcement. – Anthony
Death spirals are such complicated stuff! I wonder if a falsification could show up by 2014 or 2031 or 2101. I’ll stayed glued to my seat watching for a while longer.
Two sailing expeditions, one Norwegian and one Russian, successfully navigated both passages and are nearing their goal of circumnavigating the Arctic.
One of the 2 was Boerge Ousland. These trips are being used to promote global warming alarm. It is made to appear that global warming has decimated North Pole ice so that there is now open water all around the circumference of the Arctic Ocean. But that isn’t true.
PDF of the 2010 Boerge Ousland trip
http://www.corsair-sweden.com/blog/TheNorthPolePassage.pdf
–page 1 of the PDF, their map shows they did not stay in the Arctic but part of the trip was in the North Atlantic
They say circumnavigated “the Earth on the Arctic Ocean” but to do that they needed to go north of Greenland. They went south of Greenland.
–Page 2 of the PDF, they did not plan to stay in water:
Circumnavigating the Earth on the Arctic Ocean in a single summer is an impossible challenge – if you try to do it the traditional way…..we have chosen a light and lithe trimaran….can easily be pulled onto the shore to avoid pack ice.
They planned to run into ice. So they used a lighter boat that could be carried over where there was no open water.
……………………………………………………………………………………………………………………
P.S. Just to make it clear: I am not saying those involved with these 2 journeys are doing it to promote global warming alarm. Nor am I saying what they did was a small accomplishment. I am simply pointing out that what is perceived about these trips and what is real about them are two different things.
Excuse me Anthony but it is Verity Jones (not Valerie).
Bernie
REPLY: Yep, fixed. Valerie Jones also in my head, former CNN meteorologist – Anthony
“hemispeheres”
First typo correction! How many internets do I win? 🙂
Excellent post.
Great work on the difference between Jaxa and NSIDC extents. It will be interesting to see what Dr Meier has to say about it, though it seems strange that around the same time as his boss starts talking about “death spirals” and no summer ice by 2013, the extents start to diverge (at this rate, there’ll be a 1m sq km difference by 2013), and also about the conclusions of the book that Verity Jones reviewed.
On past form, I expect a whole lot of hand waving.
So to summarize: Another summer has gone by and the Arctic Ocean ice did not all melt – again.
Benoit Mandelbrot born 1924 died Thursday, October 14, 2010. As all here know, or should, his “fractal geometry” allied with Edward Lorenz’s Chaos Theory describes complex dynamic systems ranging from atmospheric physics to cell morphology to futures trading on the New Orleans cotton exchange in 1900. Among other things, Mandelbrot’s “self-similar” geometry underlies computer graphics, impacts information theory, bears on quantum probabilities, and so on and on.
From a “climate science” standpoint, Mandelbrot’s iterative/recursive techniques bear on statistical “noise levels,” much as if natural processes were broadcasting information as sets of complex interference patterns. Absent such mathematical context and perspective, anyone restricting inquiries to “bottom-up” research will encounter seeming perplexities which in fact are no such thing.
It would be good to see close by the graph: Average Arctic Sea Ice Extent, September 1979 to 2010
The Average Antarctic Sea Ice Extent, March 1979 to 2010
REPLY: Have a look at the sea ice page
It seems that the differences between NSIDC and JAXA average September extent are getting larger since 2007, and that JAXA is always showing more extent than NSIDC…..Speaking of NSIDC, Dr. Walt Meier has asked to do a guest post here, and I’ve approved a slot for him….
In a perfect world we could expect that no one would be suspicious of the NSIDC having Mark Surreze running it. We are not in a perfect world. It would be unrealistic to expect that people shouldn’t have suspicions. Maybe Walt Meier will allay suspicions in his guest post. But, he may also create more questions. I hope he will be ready to field any challenges from commenters.
John Blake says:
October 17, 2010 at 7:44 pm
My discovery of recursion really opened up the possibilities of programming back in the days of limited memory, both in minis & micros.
As for this post. How many icebreakers were operating prior to 1935?
DaveE.
John Blake says:
October 17, 2010 at 7:44 pm
Oh Hell. I meant my discovery of recursion through the work of Mandelbrot.
DaveE.
“Speaking of NSIDC, Dr. Walt Meier has asked to do a guest post here, and I’ve approved a slot for him…”
Very class act Anthony. Separates you from the wanna bees at RC, desmug blug and others to vile to mention. It must drive them nuts when you allow folks like Dr Meier and others to post here as they would never survive such an act were they to do the same on their blogs.
My admiration for you has no bounds.
Could someone please remind me why is it that comparisons continue to be made with the 1979-2000 average ice extent; and not with an updated period (ie 1979 – 2009)? Ssurely an average over 31 years will provide a much better indication than a 22 year average (over a period when the record my have been anomalous).
I do not agree with Dr. Meier but I do respect his willingness to engage in conversation.
Did this willingness to engage have anything to do with his replacement by Mark Serreze?
DaveE.
John Blake says: (October 17, 2010 at 7:44 pm) Benoit Mandelbrot born 1924 died Thursday, October 14, 2010.
Rest in peace, Benoit Mandelbrot; Earth is a more wonderful place because of you.
All of this prompts me to inquire: Has anyone ever done a ‘rate of change’ evaluation of the matter before us?
You know: The rate of change of loss of sea ice, versus a rate of change of increase of sea ice, and then compared those with the the various rates of change in the oscillations of sea temps?
And what about the velocity of various ocean currents and their rates of change?
Certainly, ocean currents aren’t constant, and so then, neither would their affects be so either.
So much in life depends upon rates of change.
In fact, you might call it the ‘calculus’ of life …
“And of course, it looks like a “death spiral” to paraphrase Dr. Mark Serreze, but it is only 30 years of data, so who’s to say it isn’t part of a longer cycle?”
Thirty years warm, thirty years cold, the sixty-year climate cycle is just a bit too long to fix itself in the public memory.
.
Roger Carr says: October 17, 2010 at 8:42 pm
John Blake says: (October 17, 2010 at 7:44 pm) Benoit Mandelbrot born 1924 died Thursday, October 14, 2010.
Rest in peace, Benoit Mandelbrot; Earth is a more wonderful place because of you.
It is indeed. One of my life’s achievements was getting the Mandelbrot algorithm to reside entirely on an Intel ‘287 math co-processor. RIP
Oh, Cryosat-2, Cryosat-2. . . wherefore art thou, Cryosat-2?
Hi Anthony,
You may already know this, but NSIDC data is on their FTP here:
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135
It’s separated into different files for each month (average monthly values), but the files do include both extent and area. The official Sept numbers are (1979-2010):
7.2
7.85
7.25
7.45
7.52
7.17
6.93
7.54
7.48
7.49
7.04
6.24
6.55
7.55
6.5
7.18
6.13
7.88
6.74
6.56
6.24
6.32
6.75
5.96
6.15
6.05
5.57
5.92
4.3
4.68
5.36
4.9
It looks like your values seem to all be within 0.05 million km^2 (I didn’t check every single value though).
It’s a pain to work with individual files, but once you import them all into one spreadsheet, it’s not so bad. If you’re only working with September, it’s a piece of cake though. 🙂
I just wish they’d give one more sig fig for the monthly averages…don’t know if it’d be significant.
-Scott
REPLY: No I didn’t know of this FTP source, they never seem to offer the data with any of their press releases, and I recently asked Dr. Meier about doing this. The impression I got was they hadn’t planned on making it available. Unfortunately, I’m about to travel, and I won’t be able to replot the graph with these official numbers before I leave. – Anthony
“… I plotted them both, using Dplot… ”
I’ve been meaning to mention that. I found out about Dplot from WUWT, and after looking over the capabilities that it has, I purchased it. I am 100% pleased with it. That thing can wizz through 3D quake plots with ease. I’ve mentioned my satisfaction with it to the program author, but you are the one who first pointed me at it.
Thank You.
Stefan of Perth says:
October 17, 2010 at 8:20 pm
“Could someone please remind me why is it that comparisons continue to be made with the 1979-2000 average ice extent; and not with an updated period (ie 1979 – 2009)? Ssurely an average over 31 years will provide a much better indication than a 22 year average (over a period when the record my have been anomalous).”
Actually, I agree with Mike McMillan in that I would argue that we need 60 years at least. Whilst the influence of PDO cycles on Arctic Ice conditions is not yet FULLY understood, a prudent approach would be to get a set of measurements that encompass at the very least a complete PDO cycle. Even better would be to see several PDO cycles since I would assume some potential for variability between cycles.
We only have 30 or so years of solid measurements. Before that the data is certainly open to debate. Until we have confirmation that the extent is not following a sine curve, of which we’ve only seen half during the satellit era, then I’ll take the measurement against the average with a grain of salt.
Show me extents consistently outside of the min/max for the 60 year period and I’ll start to take notice.
Well done on the two yachts traversing the NW and Northern passages in one year therefore circumnavigating the globe via the Arctic ocean.
A great feat considering some posters on this blog insisted the NW passage wasn’t open 😉
Andy
Great work on the difference between Jaxa and NSIDC extents.”
Perhaps NSIDC homogenizes the bad ice out.
BTW, that was a nice cute Polar Bear in the Boerge Ousland link.
For those who didn’t understand, this is the area in question:
http://img524.imageshack.us/img524/3556/nsidcjaxaseptavgarctice.png
Mandelbrot was, no IS, one of the Greats.
The climate of the Earth is driven predominately by natural forces, not human forces.
Is there any way to retrieve the 1979/80/81/82/83/84 satellite images of the Polar sea ice min/max area and extent?
I am interested because the alarmists do have a habit of manipulating the temperature record to suit their agenda, lowering early temperature records to exaggerate warming.
Is it possible they over estimated the early sea ice maximums and minimums to show a greater decline over the 30yrs than is the actual case? Going by JAXA numbers the decline isnt that great and does not qualify as a death spiral.
From what I’ve learned at WUWT, these data are nice, but kind of meaningless without the commensurate wind data to go with it. Floating ice is driven hard before a prevailing wind, no matter the thickness of whatever is floating.
I think of “death spiral” as intended to convey the idea of accelerating change and not merely a linear decline. But that idea is based on just a few years of data, not 30 years.
SSam says:
October 17, 2010 at 9:44 pm
“… I plotted them both, using Dplot… ”
I’ve been meaning to mention that. I found out about Dplot from WUWT, and after looking over the capabilities that it has, I purchased it. I am 100% pleased with it. That thing can wizz through 3D quake plots with ease. I’ve mentioned my satisfaction with it to the program author, but you are the one who first pointed me at it.
Thank You.
_____________________________________________________________
Well I happen to know who wrote the Dplot software, he works for the USACE ERDC GSL, they blow things up over there, at really high sampling rates, and I do mean really high sampling rates.
” Roger Carr says:
October 17, 2010 at 8:42 pm
Rest in peace, Benoit Mandelbrot; Earth is a more wonderful place because of you.
”
This is certainly true 🙂
http://www.youtube.com/watch?v=E91yxk_pT_A
We all welome and look forward to Dr. Walt Meier.
Can he please bring some of his data with him. We previously asked about Arctic-Antarctic sea ice correlation, when a suitable time shift has been applied to align the patterns (correlation analysis doesn’t naturally handle that sort of manipulation and the mis-aligned data undoubtably gives erroneously low correlation measurements).
Or, at very least, could Dr Meier tell us where we can pick up Antarctic sea ice data in a commonly used and convenient format.
I completely disagree with this evaluation that fact is that since 2007 NH ice has been increasing, Even the 2010 AREA UNDER THE CURVE for the past 3 months IS GREATER than 2009 look at the DMI ice extent. Just wait for 2011 to complete knock NSIDC off their pedestal. Also again we seem to forget about SH ice which is consistently ABOVE!
Is it possible to create an approximation of the sea ice extent by some other means, from as far back as possible, up to and including the present date? The satellite data could then be plotted on this approximation to give some idea of just how the last 30 odd years measured fits in with the bigger picture. This might give some justification for fitting straight line trends to small samples of data. Or then again it might not.
Extrapolation of the straight line plot would indicate (roughly) that in September 1933 the arctic sea ice extent was 12 million square kilometres (I think not, based on historical accounts described on WUWT), illustrating both the risks of extrapolating data trends and the limitations of attributing linear trends to segments of (potentially) cyclically varying data.
AndyW says:
October 17, 2010 at 10:14 pm
Well done on the two yachts traversing the NW and Northern passages in one year therefore circumnavigating the globe via the Arctic ocean.
A great feat considering some posters on this blog insisted the NW passage wasn’t open 😉
Andy
Go read the article again and remember where the NW passage is.
Waiting for Meier to explain Serreze’s Hansening the data.
[This is something I’ve already posted on an Aussie site today. It’s not relevant to sea-ice, but may be relevant to how climate is recorded, and, just possibly, how it’s misrecorded. I certainly feel it’s worth noting, but if you feel it’s too far off-topic, I’ll understand if I’m snipped. Please keep in mind I’m talking about the southern spring, not far from the ocean, at about 31 degrees latitude.]
The discrepancy I’m about to mention may have been due to a simple misread by me or by someone at the other end.
The last two mornings here in the hills south of Kempsey have been freezing. I know that there was frost in some places on Sunday morning.
When I checked the data yesterday, the minimum for Sunday was 3.0. I’m almost certain that’s what I saw on the Elders website. The coldest minimum on record, 2.8, occurred on the first day of October in 1992, so 3.0 on the 17th is freakish. I sat up and noticed, so it’s unlikely I misread.
This morning, yesterday’s minimum had been amended on the Elders website to 3.5.
It’s been in my mind for some time that we should all be making copies of published weather records of our respective localities. I know in my locality there is some very interesting data, particularly the monthly mean temp records, which show all the highest maxima occurring between 1910 and 1920, except for august, which had it’s hottest average maximum in 1946.
I’d hate it if that data were to be mysteriously amended. That’s all I’m saying for now. Like I said, it may have been a simple error. The problem is, twenty years ago it could only have been a simple error. Now we wonder.
Well I think I have the end all-be all comparison of JAXA vs NSIDC;
http://picasaweb.google.com/117077348819630829996/ArcticSeaIce#
Graphs 4-6.
Graph 4: Time series of monthly means for JAXA and NSIDC.
Graph 5: Monthly time series of the ratio of JAXA/NSIDC.
Graph 6: JAXA/NSIDC ratios for the same months combined for all years for overall monthly average (each month shown as it’s numerical order in a year).
If there is any interest, I’ll post the same three graphs for UIUC vs NSIDC monthly sea ice areas (which also has some similar seasonal and longer term trends as the JAXA vs NSIDC monthly extents do).
AndyW says: “Well done on the two yachts traversing the NW and Northern passages in one year therefore circumnavigating the globe via the Arctic ocean.”
Yes I agree it can’t be an easy trip…
But will you agree the top gear team’s expedition to the “North Pole” to prove the ice was still there and it wasn’t open water was equally marvellous?
http://en.wikipedia.org/wiki/Top_Gear:_Polar_Special
Only 60 years? Some cycles are 140,000 years long. There may be longer ones for all we know.
Stefan of Perth says:
October 17, 2010 at 8:20 pm
A very valid point. At which time does the accepted chosen average period of anything, become an irrelevance? 10 years, 20 years, 30 years, 40 years? Is it not all a piece of chartmanship?
Anthiony
For the sake of our friend Tamino shouldn’t all the text and all the links in this article be in at least 20 point type and highlighted? He has difficulty in seeing things it appears.
tonyb
Thanks for also showing the monthly extent over the years in the blog posts, it does IMO give a better idea of what’s going on. It’s a great idea to show it in the Sea Ice News posts, this should be a recurring graph in your Sea Ice News each month. With the usual sea ice graphs you normally show in the blog posts it can be difficult to get a feel for the overall trend over the years.
Thanks for a great site.
Cryosat2 data should be public in a month or so?
On a seperate note, Richard Black at the Beeb states in an article today:
“Within the last few years, the world has seen the cooling influence of La Nina restrain the rise in global temperatures, before a switch to El Nino conditions put 2010 on course to be one of the warmest few years – perhaps the warmest of all – in recent times.”
Forgive me, but has the predominant ENSO cycle not been El Nino over the past 20 years????
The interesting thing about this data is that the trend from ’79 to ’97 is stable. It’s only following the big ’98 El Nino and subsequent heat input into the oceans that the trend went down rapidly. So AGW’ers are basing their entire polar death spiral theory on 12 years of data following an unusual and largely unexplained El Nino event. Based on this logic I can say that there is a large increasing trend since 2007 !
There are some sea ice graphs going back to 1860 here – http://www.climate4you.com/index.htm got to sea ice and keep scrolling down!
For those interested in the discrepancies between various databases, I suggest listening to EFS_Junior when he comes around. He’s put a lot of work into comparing them and figuring out the intricacies of each (such as their dating method and the running average used by each for smoothing). I’ve done a bit of comparison myself and may also add to the discussion once a get a bit of time to pull up my spreadsheet and summarize some stuff.
-Scott
“899 says:
October 17, 2010 at 9:10 pm
All of this prompts me to inquire: Has anyone ever done a ‘rate of change’ evaluation of the matter before us?”
This is the approach that Tamino has used. He shows an accelerating decline in the minimal Sept sea ice extent, by fitting the data with a polynomial regression. This regression allowed him to make a very accurate forecast of this year’s ice minium, although he attributes the accuracy of his estimate to luck. Anyway, if you look at the whole data set from 1979, you can see that the lose of arctic sea ice has accelerated, especially over the last 10 years.
mosomoso says:
October 18, 2010 at 1:13 am
Yes, you should make archived copies of your local weather data, and keep it safe.
You never know when someone in another country might borrow it, then claim to have misplaced it.
Amino Acids in Meteorites says:
October 17, 2010 at 7:23 pm
As I posted some months ago, multi-year sailing in the Arctic is the norm for traversing passages over 1,000 miles long that are open but very breifly. The people who do this make no pretense of single-season journeys. One does not go up there in a carefree manner and sail the NW passage, let alone circumnavigate the Arctic Ocean.
They go about it in Amundsen style, and in that sense, not much has changed in 100 years.
The Arctic is deadly serious, even in the best of years… like 2007.
I think nearly ALL climate data including ice, run by AGW interests, with few exceptions, is in fact suspect. People are noticing…. especially when real time weather is not changing or becoming cooler and all the scandals with NZ, USA and Russian data, hockey sticks adjustments, etc…. the list is becoming monotonous……. I believe by next year we will start to see a trickle of successful prosecutions.
I wondered what JAXA would show for September averages. Fortunately since JAXA provides the daily data here, it was easy to bring it into a spreadsheet and calculate the average. Here’s the values I got from my spreadsheet. Values are year, and average September extent in million square kilometers, rounded to nearest hundredths:
2002 6.11
2003 6.28
2004 6.16
2005 5.70
2006 5.98
2007 4.60
2008 5.08
2009 5.53
2010 5.45
Maybe I did something wrong, but I get different numbers when computing the September average extent from IJIS daily data (in million square km):
2005 5.53
2006 5.91
2007 4.38
2008 4.83
2009 5.38
2010 5.10
REPLY: I just ran 2010 again independently on another computer in Open Office Calc from scratch and got:
2010 5448828.5
Update: Looking at it again, you may be right, and the AVG function of OpenOffice may have only done the first and last numbers, not the cell range. Unfortunately I won’t be able to test again and correct if needed until late tonight. See the upcoming announcement.
Thanks for double checking the work.
– Anthony
The dire prediction if an Arctic “death spiral” by Dr. Mark Serreze are a joke. Arctic temps are low, sea ice is recovering and the polar bears are doing well – WUWT?
In the mean-time according to the Daily Express here in the Britain ‘SNOW IS ON THE WAY IN -6C FREEZE:-
http://www.express.co.uk/posts/view/205993/Snow-is-on-the-way-in-6C-freeze-
What ever happened to global warming?
Mike Haseler says:
October 18, 2010 at 1:20 am
AndyW says: “Well done on the two yachts traversing the NW and Northern passages in one year therefore circumnavigating the globe via the Arctic ocean.”
Yes I agree it can’t be an easy trip…
But will you agree the top gear team’s expedition to the “North Pole” to prove the ice was still there and it wasn’t open water was equally marvellous?
http://en.wikipedia.org/wiki/Top_Gear:_Polar_Special
Its strange that we get headline news about rotten ice and how its actually so thin that icebreakers don’t slow down….. Yet the ice was strong enough to support a group of Toyota HiLux trucks. You are right it should be highlighted as much as someone with a catamaran circumnavigating the arctic. It won’t be though as it is not on message. But then Top Gear rarely is.
“Is it possible to create an approximation of the sea ice extent by some other means, from as far back as possible, up to and including the present date? ”
Essentially the answer is no. There is a reasonable amount of historical data for the North Atlantic sector of the Arctic here:
http://acsys.npolar.no/ahica/intro.htm
It shows among other things that there was about as much (or little) ice in the 1930’s as it is now. However the situation for other parts of the Arctic is much worse. Where would you find ice data for e. g. the Laptev sea in 1920? Nobody was there. Or for Severnaya Zemlya in 1910? It hadn’t even been discovered!
I think if someone was willing to put enough money and effort into it, it would probably be possible to produce a reasonably complete record of summer ice extent back to about 1950. It would take a big effort though, and require combing through Russian, Norwegian, Danish, Icelandic, Canadian and US Archives, many of which are still classified.
Its strange that we get headline news about rotten ice and how its actually so thin that icebreakers don’t slow down….. Yet the ice was strong enough to support a group of Toyota HiLux trucks. You are right it should be highlighted as much as someone with a catamaran circumnavigating the arctic. It won’t be though as it is not on message. But then Top Gear rarely is.
Please get your information straight.
The term rotten ice (which is very old) was used by David Barber to describe conditions in the Beaufort Sea. Your heroes from Top Gear never left the Canadian Archipelago where ice is thickest and oldest because of the Beaufort Gyre and because it is relatively protected between the islands of the CA.
Mind you, they drove to the North Pole, not the geographic North Pole though, but the magnetic North Pole of 1996, which was still within the Canadian Archipelago. And they did it in April, when the melting season has hardly begun and ice only melts at the fringes.
It took me 1 minute to figure this out. Wake me up when the heroes of Top Gear decide to drive to the geographic North Pole in the middle of the melting season. Maybe you can sit in the back.
Has anyone
Ian W and Mike Haseler
You guys realize that the “north pole” they drove the trucks to is the magnetic north pole at about 78 degrees north, right.
Not the north pole at 90 degrees North.
I just ran 2010 again independently on another computer in Open Office Calc from scratch and got:
2010 5448828.5
– Anthony
I did the same thing in Open Office Calc but get 5097088.7. Here’s the calculation I do for the original IJIS csv-file (right-click and ‘save as’ to download the file): =SUM(D3015:D3044)/30.
I don’t see how your September average extent can be that high when only the last three days of the month are higher.
Maybe someone else can check?
REPLY: See my update -A
– Anthony
Hi Anthony,
I got
5097088.7 km^2 using Excel.
-Scott
REPLY:Thanks for double checking! Yes, OpenOffice may work differently from what I’m expecting..unfortunately won’t be able to redo until tonight. – Anthony
NSIDC and IJIS September average extent numbers are quite similar. I’ve uploaded a graph here.
Günther Kirschbaum says:
October 18, 2010 at 7:43 am
I just ran 2010 again independently on another computer in Open Office Calc from scratch and got:
2010 5448828.5
– Anthony
I did the same thing in Open Office Calc but get 5097088.7. Here’s the calculation I do for the original IJIS csv-file (right-click and ‘save as’ to download the file): =SUM(D3015:D3044)/30.
I don’t see how your September average extent can be that high when only the last three days of the month are higher.
Maybe someone else can check?
REPLY: See my update -A
_____________________________________________________________
Günther’s means are correct, as is Scott’s.
In my Excel 2010 spreadsheet, I’ve used linear interpolation to fill in the JAXA data gaps.
Here are direct links to the three graphs I mentioned in a previous post;
http://lh6.ggpht.com/_QiMvdrrujF4/TLv-0LSqSZI/AAAAAAAAAEo/DhmMo5UUNvM/
Graph 4: Time series of monthly means for JAXA and NSIDC.
http://lh6.ggpht.com/_QiMvdrrujF4/TLv_DtCQD-I/AAAAAAAAAEs/8kkCyX0Jbro/
Graph 5: Monthly time series of the ratio of JAXA/NSIDC.
http://lh5.ggpht.com/_QiMvdrrujF4/TLv_MyxW_HI/AAAAAAAAAEw/Ir8Cp-iIkzo/
Graph 6: JAXA/NSIDC ratios for the same months combined for all years for overall monthly average (each month shown as it’s numerical order in a year).
The point of this post appears to be that the Japanese Space Agency’s data on sea ice, which dates from 2002 is a little bit different, and shows slightly larger sea ice extent than the US data from NASA.
There is no exploration of the differences which cause the differences in these results. Can anyone explain why these results would be different? Do they use the same raw satellite data or not? What are the differences between the algorithms to determent sea ice extent.
In fact the differences in data do not seem significant at this time, compared to the reduction in September sea ice extent, which appears to be accelerating.
The idea that a longer time period will show a recovery and that the recent 30 year downtrend is part of a cycle seems wishful thinking to me. Using proxy records, the sea ice extent to a period of about 100 years, shows that the recent trend is a significant departure.
http://www.wunderground.com/climate/SeaIce_Fig04.asp
Günther Kirschbaum says:
October 18, 2010 at 7:35 am
—…—…
You are correct about the Top Gear “drive to the north (magnetic) pole” situation. Thank you for pointing out that misconception.
Now, please explain why the average summer time temperature for 80 north latitude from DMI’s daily measured records have been steadily and consistently DECREASING since 1958?
And in fact, the rate that these summertime Arctic temperatures has decreased even faster just as the levels of CO2 have been increasing. (Note that Hansen somehow claims “his” adjusted and 1200 km projected temperatures” across the Arctic have gone up by 4 degrees when everybody’s actual measured temps are going down.)
eadler says:
October 18, 2010 at 9:13 am
The only truly Global Sea Ice phenomenon is the late September 2007 Arctic minimum and late December 2007 Antarctic Maximum. The former was -2.5M km^2 and the latter was +1.65M km^2 for a whopping -0.85M km^2 Global Sea Ice Anomaly. With an Average Sea Ice Area 0f 20M km^2 this represents a 4.25% departure from normal.
4-1/4% is a great interest rate, but a rather sorry excuse for a Death Spiral.
‘The idea that a longer time period will show a recovery and that the recent 30 year downtrend is part of a cycle seems wishful thinking to me. ‘
The idea that there is a straight linear trend without end in a climactic world almost exclusively dominated by cycles is wishful thinking.
The 1 and only exception is the general cooling of Earth over 4.5 Billion years, which will be rudely interrupted by the eventual expansion of the Sun’s atmosphere a few billion years hence.
Billions and billions.
Now, please explain why the average summer time temperature for 80 north latitude from DMI’s daily measured records have been steadily and consistently DECREASING since 1958?
I don’t have to explain because it isn’t correct. Tamino had a post from last year, but unfortunately it’s not available any longer. In it he showed how summer warmed very slowly (because of the ice), in winter the warming was much faster. Once sea ice gets below a certain threshold during the melting season you can expect temperatures to rise on the top of that DMI bell curve.
MikeA says:
October 18, 2010 at 2:59 am
“There are some sea ice graphs going back to 1860 here – http://www.climate4you.com/index.htm got to sea ice and keep scrolling down!”
Actually, one graph goes back to 1769 for Nordic Seas ice extent. Interestingly, the maximum for April 1769 seems less than what it is now (Ice free north of Svalbard). We also get an impression of the very large inter-decadal and centennial variability.
The greatest difference in maximum extent is between the years 1769 and 1866. These extremes are 97 years apart. If there is a ~60 year cycle of natural variability governing Arctic Ice extent, this fits very well with 1.5 cycle, so it seems to give some creedence to that idea. Also we can see the striking difference in extent between the years 1966 and 1995, particularly in the Barents Sea area, suggesting a ~30 year half cycle. There is a striking similarity in extent between the years 1769 and 1995, a time span of ~230 years, i e 4 cycles of ~60 years.
This old fisherman banged the data from the link from Günther Kirschbaum into a pivot table and got: (Now hold breath to see if this works)
Row Labels 1 2 3 4 5 6 7 8 9 10 11 12 Grand Total
2002 10,544,766 8,961,289 6,255,068 5,917,047 7,933,070 9,881,914 11,890,953 8,788,207
2003 13,532,601 14,362,322 14,705,726 13,656,865 12,182,359 10,905,802 8,848,397 6,770,902 6,126,469 7,543,036 9,918,796 11,894,577 10,912,937
2004 13,201,099 14,069,806 14,122,747 13,104,438 11,744,138 10,717,162 9,011,810 6,704,970 5,958,901 7,685,318 9,836,743 11,820,741 10,663,564
2005 12,819,158 13,528,214 13,830,852 13,187,755 12,049,909 10,438,474 8,321,749 6,195,918 5,530,094 7,203,796 9,696,478 11,528,518 10,352,763
2006 12,650,172 13,438,041 13,512,979 12,981,370 11,659,975 10,303,927 8,086,537 6,376,422 5,913,271 7,383,926 9,236,521 11,316,054 10,229,750
2007 12,903,604 13,698,203 13,717,903 13,035,979 11,941,527 10,498,099 7,665,393 5,301,386 4,380,521 6,002,011 9,252,494 11,460,830 9,962,932
2008 13,062,258 14,117,705 14,352,011 13,492,120 12,123,690 10,599,505 8,394,925 5,956,084 4,837,037 7,210,817 9,861,901 11,659,113 10,460,809
2009 13,122,520 13,998,120 14,217,107 13,587,833 12,327,515 10,668,370 8,263,992 6,149,360 5,382,787 6,830,101 9,390,198 11,492,893 10,431,044
2010 12,877,147 13,769,102 14,278,478 13,835,698 11,995,882 10,030,484 7,904,602 5,968,266 5,097,089 6,341,838 10,317,914
Grand Total 13,021,070 13,876,547 14,092,225 13,360,257 12,003,124 10,520,826 8,378,028 6,184,462 5,442,792 7,163,116 9,621,701 11,634,359 10,325,917
You mean this tiny thing?
double MinRe = -2.0;
double MaxRe = 1.0;
double MinIm = -1.2;
double MaxIm = MinIm+(MaxRe-MinRe)*ImageHeight/ImageWidth;
double Re_factor = (MaxRe-MinRe)/(ImageWidth-1);
double Im_factor = (MaxIm-MinIm)/(ImageHeight-1);
unsigned MaxIterations = 30;
for(unsigned y=0; y<ImageHeight; ++y)
{
double c_im = MaxIm – y*Im_factor;
for(unsigned x=0; x<ImageWidth; ++x)
{
double c_re = MinRe + x*Re_factor;
double Z_re = c_re, Z_im = c_im;
bool isInside = true;
for(unsigned n=0; n 4)
{
isInside = false;
break;
}
Z_im = 2*Z_re*Z_im + c_im;
Z_re = Z_re2 – Z_im2 + c_re;
}
if(isInside) { putpixel(x, y); }
}
}
I understand he’s busy now, but I sincerely hope Anthony Watts will come back to this and explain us how he got the numbers wrong.
Sea ice area, since 1900:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seasonal.extent.1900-2007.jpg
New eye opener- Sea ice extent, 1951 to 2000:
http://www.socc.ca/cms/en/socc/seaIce/pastSeaIce.aspx
rbateman says:
October 18, 2010 at 10:54 am
eadler says:
October 18, 2010 at 9:13 am
“The only truly Global Sea Ice phenomenon is the late September 2007 Arctic minimum and late December 2007 Antarctic Maximum. The former was -2.5M km^2 and the latter was +1.65M km^2 for a whopping -0.85M km^2 Global Sea Ice Anomaly. With an Average Sea Ice Area 0f 20M km^2 this represents a 4.25% departure from normal.
4-1/4% is a great interest rate, but a rather sorry excuse for a Death Spiral.”
It makes no sense to add the sea ice extents forseptember in the Arctic to december in the Antarctic and claim the sum represents some kind of Global Sea ice phenomen.
In the case of both poles, the important ice coverage which determines the climate of the earth occurs in the Summer, when the sun is shining and the absorption of radiation is radically different between ice and water. So the correct extents to add are September in the Arctic and March in the Antarctic.
http://nsidc.org/seaice/characteristics/difference.html
Since the Antarctic ice almost melts entirely in March, the summer ice decline is entirely due to the Arctic sea ice decline.
The winter ice is not a significant factor in the albedo of the earth, because the sun doesn’t shine in the polar regions during the winter.
JAN says:
October 18, 2010 at 11:39 am
MikeA says:
October 18, 2010 at 2:59 am
““There are some sea ice graphs going back to 1860 here – http://www.climate4you.com/index.htm got to sea ice and keep scrolling down!”
Actually, one graph goes back to 1769 for Nordic Seas ice extent. Interestingly, the maximum for April 1769 seems less than what it is now (Ice free north of Svalbard). We also get an impression of the very large inter-decadal and centennial variability.
The greatest difference in maximum extent is between the years 1769 and 1866. These extremes are 97 years apart. If there is a ~60 year cycle of natural variability governing Arctic Ice extent, this fits very well with 1.5 cycle, so it seems to give some creedence to that idea. Also we can see the striking difference in extent between the years 1966 and 1995, particularly in the Barents Sea area, suggesting a ~30 year half cycle. There is a striking similarity in extent between the years 1769 and 1995, a time span of ~230 years, i e 4 cycles of ~60 years.”
Cherry picking 4 isolated years, 1769, 1866, 1966 and 1995 is not a valid way to determine the existence of a 60 year cyclic behavior.
For some reason, the Climate4you website has plotted the April ice extent.
The April maximum in Arctic sea ice extent is not an important climate driver and has varied very little in recent years, compared to the September minimum.
Jan,
I forgot to mention that in addition to the cherry picking of a time frame for the long term data in the neighborhood of Norway, there is also the factor that the variation of the extent line in the figure is shown only in a small region of the Arctic.
The images linked by
Jakers in his post:
http://wattsupwiththat.com/2010/10/17/sea-ice-news-27/#comment-510703
shows the real big picture – a decline in Arctic sea ice which has accelerated in the past years.
This may not be the thread to post this but I just adored Mandlebrot. I used to type in one of his algorithms before leaving the lab Friday and then let it run all weekend. The results just mesmerized me Monday morning. They reminded me of quaint paisley print fabric. One of my current favorite middle school math teachers has Mandlebrots covering her classroom walls. One would have to be stone cold to not appreciate the beauty of maths.
I adored Carl Roger as well, who died the same day Liberace did (my grandfather was the voice coach for a local boy who become one of Liberace’s musicians). I did a graduate thesis that attempted to meld together Roger’s theory of development within a group, with Soren Keirkegaard’s individualistic existentialism. Vygotsky, who coined the phrase “zone of proximal development” was another one of my heros who died before he could eclipse Piaget. These men just leave me twitterpated!
Günther Kirschbaum says:
October 18, 2010 at 3:30 pm
I’m guessing if it was averaging the first and last dates of the month then he was doing the equivalent to adding a comma in Excel instead of a colon.
-Scott
eadler says:
October 18, 2010 at 6:53 pm
But aren’t we discussing the effect of warming here and not cause? I couldn’t care less if the decreasing Sept minimum is a positive feedback to warming if the warming isn’t AGW. And if the reduction in the minimum is caused by AGW, why isn’t it affecting April too?
-Scott
eadler says:
October 18, 2010 at 6:31 pm
The important thing to remember is that nobody told the Antarctic and Arctic they had to both come to work at the same time.
i.e. – there is no global warming CO2 forcing.
Just for those who can’t see the forest for the trees, I put both graphs together… like this:
http://www.robertb.darkhorizons.org/seaice.anomaly.Ant_arctic.jpg
This latest incarnation is a bit more ‘unadjusted’, because CT ‘adjusted’ Arctic Sea Ice Anomaly down 1M km^2 in 2007, going back to 2000. So, being the maverick that I am, I just slid that puppy back up there. Ye-Haw!!
Whoa, lookee there: Those Polar Cowboys are flying up & down like a bull ride at the rodeo.
“It makes no sense to add the sea ice extents forseptember in the Arctic to december in the Antarctic and claim the sum represents some kind of Global Sea ice phenomen.”
Why sure it does: If you bothered to look at the Global Sea Ice Anomaly graphs, you’d see that there is an average point in that graph right smack on 20M km^2…. mid way between the 2 times. It’s a moving target all the time. Ya got to lead the target if you want to hit it. Take 1979, around Sept/Oct. See that? 20M km^2. Great. Now we look at Sep/Oct 2010. Once again ……
20M km^2.
The point isn’t about analysis paralysis.
Point is that there ain’t a whole lot of difference between 1979 and 2010 as far as Global Sea Ice is concerned.
Slice & Dice any which way, and still the answer is the same because there’s no warming boogey man in this image:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/global.daily.ice.area.withtrend.jpg
See The Sea Ice record of Newfoundland from 1810.
http://www.socc.ca/CMS%20FTP%20Data/seaIce/images/nfld_ice2.jpg
rbateman says:
October 18, 2010 at 11:03 pm
Why sure it does: If you bothered to look at the Global Sea Ice Anomaly graphs, you’d see that there is an average point in that graph right smack on 20M km^2…. mid way between the 2 times. It’s a moving target all the time. Ya got to lead the target if you want to hit it. Take 1979, around Sept/Oct. See that? 20M km^2. Great. Now we look at Sep/Oct 2010. Once again …… 20M km^2.
That is so funny! What a nice cherry pick! What I see is that, generally, the blue line (daily area) is at or above the gray line (mean area) in 1979, and on until about 1997 or 98 after which it is at or below the gray line.
eadler says:
October 18, 2010 at 7:02 pm
eadler says:
October 18, 2010 at 6:53 pm
“Cherry picking 4 isolated years, 1769, 1866, 1966 and 1995 is not a valid way to determine the existence of a 60 year cyclic behavior.
For some reason, the Climate4you website has plotted the April ice extent.
The April maximum in Arctic sea ice extent is not an important climate driver and has varied very little in recent years, compared to the September minimum.”
If you read my post again, you will see that I comment on the graph in the linked site, and do not “cherry pick” any years other than what the graph shows. And I do not “determine” the existence of a 60 year cycle. Some people have argued that such a cycle may exist, and I say “IF there is a 60 year cycle…” then the referenced graph seem to support that idea.
If you cared to looked closer, you would also see the other graphs containing the other areas of the Arctic Seas as well:
“Figure 2 in Vinje (2001), showing the reduction in April sea ice extent in the Nordic Seas since 1864. Nordic Seas (NS), eastern area (E), and western area (W) time series given by 2-yr running mean and regression lines. Linear year-to-year interpolations of the ice extent have been made for the western area for 1940 and 1944–46, and for the eastern area for 1868–70, 1874–78, 1880, 1892, 1894, 1940–41, 1943–48, and 1961. The blue area to the right shows the time extent of the satellite-era shown in the figure higher up in this paragraph. Apparently, much of the sea ice reduction in this region occurs in concert with the termination of the Little Ice Age and the following warming during the 20th century.”
“Time series showing the August ice-extent anomalies (x 1000 km2) in the Arctic Ocean along the coast of Russia, Siberia and Alaska: The Kara Sea, the Laptev Sea, the East Siberian Sea, and Chuckchi Sea (Polyakov et al. 2003). The composite record show large sea ice variations around a small negative trend since 1900, although the trend from a statistical point of view is not significant (Polyakov et al. 2003).”
What’s interesting is that all these graphs show that the annual and decadal variability is very large for all areas of the Arctic for all times back to the 1860’s at least. This is also confirmed by Jakers latest record from Newfoundland area:
http://www.socc.ca/CMS%20FTP%20Data/seaIce/images/nfld_ice2.jpg
There certainly doesn’t seem to be any stasis anywhere before 1950, and certainly not “accelerated” reduction of ice during the past decades. Quite the contrary.
As to your statement: “The April maximum in Arctic sea ice extent is not an important climate driver and has varied very little in recent years, compared to the September minimum.” – Do you have any evidence supporting that the September sea ice minimum is an important climate driver?
….Meanwhile..The arctic has turned Less cold & from what I can tell will stay that way for a few. I was surprised to see the gain we had yesterday & I hope i’m surprised again tomorrow & the next but i’m thinking not. Any thoughts??
rbateman:
If only it was as simple as looking at the global ice extent average for the answer to whether climate change is occurring due to increases in greenhouse gases in the atmosphere.
Why are you suggesting that we could get any insight into climate by adding arctic ice to antarctic ice when they are so fundamentally different and are affected by different forces? (see: http://nsidc.org/seaice/characteristics/difference.html ).
The antarctic sea ice consists primarily of first year ice that melts back every year to approximately the same point. Antarctic ice surrounds the edge of a deeply frozen continent and is influenced by a circumpolar ocean current. http://en.wikipedia.org/wiki/Antarctic_Circumpolar_Current
The conditions resulting in the current minimal expansion of Antarctic sea ice (minimal as a percentage of total antarctic ice extent, which is considerably larger than arctic ice extent) are different from the forces acting upon the arctic. The reliance upon antarctic ice may prove unwise as the recent expansion in the antarctic may not continue for much longer and may be explained by other factors. (See: Resolving the Paradox of the Antarctic Sea Ice at: http://www.sciencedaily.com/releases/2010/08/100816154958.htm which discusses the paper: “Accelerated warming of the Southern Ocean and its impacts on the hydrological cycle and sea ice” by Jiping Liu and Judith A. Curry and http://www.skepticalscience.com/Why-is-Antarctic-sea-ice-increasing.html
By contrast to Antarctic sea ice, Arctic sea ice consists of perennial ice (or at least half or more of it used to consist of ice that is more than 2 years old see: http://nsidc.org/images/arcticseaicenews/20101004_Figure6.jpg for a chart showing the decline in perennial arctic ice) and first year ice that floats at the pole and is generally surrounded by continents.
The ocean currents influencing the Arctic ocean (see map at: http://www.vukcevic.talktalk.net/Arc1.gif and http://maps.grida.no/go/graphic/ocean_currents_and_sea_ice_extent ) come primarily from relatively warm ocean waters from the Atlantic flowing through the Nordic Seas into the Arctic Ocean via the Barents Sea while to a lesser extent, the warm Pacific waters flow across the Bering Sea and enter the arctic through the Bering Strait. These currents, particularly the Pacific current, flow under the arctic ice cap and becomes part of the transpolar current that exits the arctic at several points, including the Fram Strait . http://www.eoearth.org/article/General_features_of_Arctic_marine_systems and http://psc.apl.washington.edu/HLD/
Given the geographic differences and the different manner in which ocean currents influence the ice at the two poles, it does not make sense to attempt to hide changes at one pole with changes at the other. Instead, the two should be examined separately to determine what is influencing them.
Additionally, expecting the signature of warming to show up in all places at the same time and to the same extent is not part of the AGW theory, thus showing that a clear signature of warming does not show up in a specific instance such as antarctic maximum ice extent does not accomplish much, (particularly when there are other indicators that warming is occurring in the antarctic). Applying a skeptical approach to the more extreme AGW predictions and the politically motivated voices supporting AGW is clearly necessary, however, this does not excuse denying that there has been any physical change to arctic ice or using unsupportable positions to imply that the change is meaningless. Claims that a change is meaningless need to be backed with the same scientific rigor as claims made that AGW is responsible for the change.
While various prognosticators that have predicted a recovery of arctic ice
http://wattsupwiththat.com/2010/02/09/prediction-arctic-ice-will-continue-to-recover-this-summer/ , or its near complete disappearence at the summer minimum by 2016 (or 2019 at the outside), the arctic ice has so far not responded in a convincing fashion to either of these projections. What changes have been observed appear to support a diminished ice cover by 2050 compared to pre-2000 levels, but even this is not guaranteed.
The recent focus on the speed of the formation of first year ice in October of 2010 would appear to be irrelevant to any long term projection. Based on the experience in projecting trends in 2010, it may not have much influence on the maximum arctic ice extent which will occur in 2011, as this appears to be constrained by geography. Additionally, it will be of little consequence to the state of arctic ice if it melts away by next September. (Generally, the arctic maximum has shown a smaller rate of decrease in extent than the summer months. A recent paper finds, unsurprisingly, that the geographic patterns in the arctic act as a constraint on the maximum arctic ice extent. The paper proposes that instead of looking to maximum ice extent for determining the impact of warming in the Arctic, that the latitude of the arctic ice edge, averaged zonally over locations where it is free to migrate, should be used to describe sea ice cover. Based on this method, the paper concludes that the location of the sea edge has been receding just as rapidly during wintertime as other seasons. http://wattsupwiththat.com/2010/09/13/study-landmass-shape-affects-extent-of-arctic-sea-ice/ http://www.gps.caltech.edu/~ian/reprints/Eisenman-2010.pdf )
Based on observations, the current state of arctic ice is significantly below recent historical averages from the period of satellite records. The annual average arctic ice extent for 2009, a so called “recovery” year by some, was 11.18 million square kilometers (4.32 million square miles), 970,000 square kilometers (375,000 square miles) or 8.0% below 1979 to 2000 average and 740,000 square kilometers (286,000 square miles) or 6.2% below the 1979 to 2008 average. http://nsidc.org/arcticseaicenews/2010/010510.html
At the end of the summer 2010 the ice levels declined from 2009, with under 15% of the ice remaining the Arctic being more than two years old, compared to 50 to 60% during the 1980s. There is virtually none of the oldest (at least five years old) ice remaining in the Arctic (less than 60,000 square kilometers [23,000 square miles] compared to 2 million square kilometers [722,000 square miles] during the 1980s).
http://nsidc.org/arcticseaicenews for October 4, 2010
The year 2010 appears headed for an annual average ice extent that is well below the 1979 to 2000 average and the 1979 to 2009 average in spite of the melt season having the latest start date in the satellite record and having a start that almost touched the average line http://wattsupwiththat.com/2010/04/02/artic-sea-ice-extent-update-still-growing/
Even with the fortutitious looking late start to the 2010 melt season, the average arctic ice extent for the month of June 2010 was the lowest for the period of satellite records. Even though June was a minimum, September was “only” the third lowest extent in the satellite record.
Based on the 2010 example, which defied all prognosticators, the only “recovery” that can be relied upon is that the arctic ice extent expands after September until March of the following year, after which it will decline. One winter season of “recovery” of arctic sea ice extent will not constitute a recovery. Maybe the state of arctic ice will change, but any recovery of arctic ice conditions to a pattern similar to the conditions that existed in the 1990’s will take several years (after all it took several years of melt and ice transport to get into the current situation). Until there is a significant recovery of perennial arctic ice at the summer minimum, any recovery of ice extent at the winter maximum will be meaningless.
Instead of trying to hide the change that has occurred in the arctic by adding in the unrelated antarctic ice extent or treating first-year ice as the equivalent of perennial ice or sweeping the change away as a matter of “natural variability” we should try to understand the various forces that are creating the current situation. There is more than melting of ice due to surface air temperature change driving the state of arctic ice. The flow of warmer water from the Atlantic and Pacific may be causing the ice to melt from the bottom up. Additionally, there appears to be a change in air circulation patterns and the amount of ice being transported out of the arctic through primarily the Fram Strait and to a lesser extent the Nares Strait that is affecting the amount of perennial ice. There could also be changes in cloud cover or water vapor content in the arctic air. These may be part of a longer term cycle or they may contain the fingerprint of human induced causes, but we need to understand the physics that drives these cycles before we can say what impact human activities are having or not having. While there are strong indications that the changes to arctic ice may be the result of human induced influences, additional research is clearly needed to prove or disprove the impact of this influence. Attempting to hide the change in artic ice with antarctic ice is not the answer to discovering why there has been a significant decline in arctic ice or determining if there is a possibility that arctic ice will return to pre-2000 conditions.