This is NSIDC’s report, and since I’m on a road trip, I’m unable to do an in-depth analysis. However, the WUWT Sea Ice page has more, and you can draw your own conclusions from the data presented there. Here’s one contributing factor, just have a look at 2 meter surface temperature, courtesy Dr. Ryan Maue:
Courtesy Ryan Maue, FSU – click to enlarge
Either global warming acts in blob fashion, or that’s what we call weather. Just remember, when NSIDC says “record low” it is for a 30 year satellite data set, not for the century, or millenium, or longer. Look for pronouncements from Dr. Mark “death spiral” Serreze and from others in the media soon. As a counterpoint to such pronouncements, I suggest reading this post from Willis on sea ice recover mechanisms that seems to be overlooked by the media.- Anthony
From NSIDC: February Arctic ice extent ties 2005 for record low; extensive snow cover persists
Arctic sea ice extent for February 2011 tied with February 2005 as the lowest recorded in the satellite record. Sea ice extent was particularly low in the Labrador Sea and Gulf of St. Lawrence. In contrast, winter snow cover remained extensive in many parts of the Northern Hemisphere.
Figure 1. Arctic sea ice extent for February 2011 was 14.36 million square kilometers (5.54 million square miles). The magenta line shows the 1979 to 2000 median extent for that month. The black cross indicates the geographic North Pole. Sea Ice Index data. About the data.
—Credit: National Snow and Ice Data Center
Overview of conditions
Sea ice extent averaged over the month of February 2011 was 14.36 million square kilometers (5.54 million square miles). This was a tie with the previous record low for the month, set in 2005. February ice extent remained below normal in both the Atlantic and Pacific sectors, particularly in the Labrador Sea and the Gulf of St. Lawrence.
While ice extent has declined less in winter months than in summer, the downward winter trend is clear. The 1979 to 2000 average is 15.64 million square kilometers (6.04 million square miles). From 1979 through 2003, the February extent averaged 15.60 million square kilometers (6.02 million square miles). Every year since 2004 has had a mean February extent below 15 million square kilometers (5.79 million square miles).
Figure 2. The graph above shows daily Arctic sea ice extent as of February 28, 2011, along with daily ice extents for previous low-ice-extent years in the month of February. Light blue indicates 2011, green shows 2007, purple shows 2005 (the record low for the month was in 2005), and dark gray shows the 1979 to 2000 average. The gray area around the average line shows the two standard deviation range of the data. Sea Ice Index data.
—Credit: National Snow and Ice Data Center
Conditions in context
While ice extent grew at average rates for February, the overall extent remained anomalously low. Air temperatures over most of the Arctic Ocean were between 2 and 4 degrees Celsius (4 and 7 degrees Fahrenheit) higher than normal. Over the East Greenland Sea and north towards the Pole, air temperatures were 5 to 7 degrees Celsius (9 to 13 degrees Fahrenheit) higher than normal. Colder conditions, 2 to 6 degrees Celsius (4 to 11 degrees Fahrenheit) below average persisted over western Eurasia, east-central Eurasia and some of the Canadian Arctic.
As air temperatures dropped in the eastern Canadian Arctic in February, parts of the Labrador Sea started to freeze over. However, the Gulf of St. Lawrence remained mostly free of ice. As during winter 2010, when Environment Canada reported that sea ice in the Gulf of St. Lawrence was at the lowest level on record, the lack of ice will make it difficult for harp seals to give birth to their pups on the sea ice, as they normally do in February and March.
Figure 3. Monthly February ice extent for 1979 to 2011 shows a decline of 3.0% per decade.
—Credit: National Snow and Ice Data Center
February 2011 compared to past yearsFebruary 2011 tied February 2005 for the lowest ice extent for the month in the satellite record. Including 2011, the February trend is now at -3.0 percent per decade.
Through most of January, the Arctic Oscillation (AO) was generally in a strongly negative phase, similar to the pattern that dominated the winter of 2009 to 2010. This led to very warm temperatures over the eastern Arctic, helping to account for the low ice extents over the Labrador Sea and Gulf of Saint Lawrence. However, toward the end of January, the AO returned to a positive phase, and ice began to grow in the Labrador Sea and Gulf of St. Lawrence. For more information on current AO conditions, visit the NOAA Climate Prediction Center Web page.
Figure 4. Ice motion charts for December 2009 and December 2010 show mean sea ice drift, with the size and direction of the arrows indicating average speed and direction of ice motion. December 2010 saw stronger anticyclonic (clockwise) motion that transported ice towards the southern Beaufort and Chukchi seas.
—Credit: NSIDC courtesy James Maslanik and Chuck Fowler, CU Boulder
Ice motion
Typically during a negative AO phase, weather patterns favor the retention of thick ice in the central Arctic and Canada basin, where it can better survive the summer. The negative AO also typically leads to a stronger Beaufort Gyre, which helps move ice from the western to eastern Arctic. There the ice thickens, ridging and rafting against the Siberian coast.
Last winter, the AO was in its most negative phase since at least 1951. However, slight differences from the typical AO pattern in the location of the sea level pressure anomalies had a significant impact on how the ice moved within and out of the Arctic Basin. During winter 2009 to 2010 the peak pressure anomalies were shifted towards the Barents and Kara seas, which helped transport ice from the Canadian Arctic towards the southern Beaufort and Chukchi seas. Since some of the oldest and thickest ice in the Arctic is found north of the Canadian Archipelago, this atmospheric pattern ended up further depleting the Arctic of its store of old, thick ice as that old ice melted during summer in these southerly locations.
This winter also saw a relatively strong negative AO index during December and January. However, as we discussed in our January 5, 2011 post, the positive sea level pressure anomalies were centered near Iceland. This led to a more extensive anticyclonic (clockwise) transport pattern than last winter. This may help keep a more extensive distribution of multiyear ice cover as summer approaches.
Figure 5. The maps of January and February 2011 snow cover data show the extent of snow cover over the Northern Hemisphere (top), and the percent difference from average snow cover extent from 1966 to 2010 (bottom). Strong positive departures can be seen over the midwestern U.S., western China, and Mongolia.
—Credit: NSIDC courtesy Dave Robinson and Thomas Estilow, Rutgers UniversityHigh-resolution image
January and February Northern Hemisphere snow cover
Sea ice extent is only one of a number of data sets scientists use to understand how climate is changing. Rutgers University and NOAA have compiled a 45-year record of Northern Hemisphere snow cover extent from NOAA snow charts. These data show that much of northern North America, Scandinavia and northern Eurasia are snow covered between 90 and 100 percent of the time in January and February. High elevation plains and mountains at lower latitudes, such as the southern Rocky Mountains in the U.S. and Hindu Kush in Asia, also have extensive snow cover.
Over this record, in January, Northern Hemisphere snow cover averages 47 million square kilometers (18.1 million square miles), and in February it averages 46 million square kilometers (17.8 square miles)—approximately 45 to 46 percent of the land area in the region. While sea ice extent was below average for January 2011, this month had the sixth-largest snow cover extent since the record started in 1966, at 49 million square kilometers (18.9 million square miles). Snow was unusually widespread over the mid-western and eastern United States, eastern Europe, and western China. Snow cover in February remained above average at 47.4 million square kilometers (18.3 million square miles), with more snow than usual in the western and central U.S., eastern Europe, Tibet and northeastern China.
Reduced sea ice extent and extensive snow cover are not contradictory, and are both linked to a strong negative phase of the Arctic Oscillation (see our January 5, 2011 post). A strongly negative AO favors outbreaks of cold Arctic air over northern Europe and the U.S., as many people experienced first-hand these last two winters. Whether this is a trend, or in any way linked to ongoing climate warming in the Arctic, remains to be seen.
Further reading
Stroeve, J.C., J. Maslanik, M.C. Serreze, I. Rigor and W. Meier. 2010. Sea ice response to an extreme negative phase of the Arctic Oscillation during winter 2009/2010. Geophysical Research Letters, doi: 2010GL045662.
For previous analyses, please see the drop-down menu under Archives in the right navigation at the top of this page.
What would be truly climate-changy stuff would be if the Arctic DIDN’T warm in response to the warmed left-over El Nino and NAO water circulating into the bowl.
I have projected the linear trend backwards in time to a pre-industrial time of about the mid 1700’s and come up with an sea ice extend for February of about 30 million square kilometers. Since there were no satelites around at that time, is there any way to confirm this extent of sea ice at that time?
Ok, I am confused. I recall reading Sea Ice threads and seeing many comments such as the following:
and more particularly one such as this:
Which between this and numerous other comments on Sea Ice pages seem to suggest that despite the slight recover of area the sea ice had after 2007 what we should really be looking at is sea ice volume.
Accordingly, I was curious, as was others about the Sea Ice volume.
Between Jaxa:
http://home.comcast.net/~ewerme/wuwt/cryo_compare.jpg
and
PIPS: (Thanks Dan)
The Arctic Ice seems to be gaining thickness. Assuming the first quotes are correct I assume that means there is still not much to see here?
Then again I have a feeling that now the 2 measurements have flipped positions, I am going to be told (with a very scientific meme) that now the volume doesn’t matter so much as the extent.
At the end of the day, the record of Sea Ice extent and volume are so incredibly short that I still fail to see the point of trying to atribute any changes in Sea Ice with Human Activity when that connection is at times bizzare and apparently changes to suit the whim of the person who is doing the reporting.
Looking at the IARC-JAXA extent data, only 2006 had a lower extent at this time of year. It went on to record a summer minimum of 5.8 million sq km.
First the ocean cools near the equator, then it takes up to 18 years to spread up to the N. Pole. I don’t know what happens in the Atlantic, but something similar is likely at work. At any rate, the ocean has taken a decade plus a bit to cool from the 1998 peak, and the last vestage of the “hot ends” of the 60 year cycle are burning out in the Arctic Ocean.
After this comes 30 years of building ice, just like last time (when it was open at the pole during the 1950’s and ’60s and subs surfaced there… we have photos and personal testimonials…) when the open water froze over during the New Ice Age scare.
tallbloke says:
44.15 year period popping up here
http://cyclesresearchinstitute.files.wordpress.com/2010/06/ssnrec-spectrum.png
Thanks, didn’t know of that one, I usually first look at the Dr. Svalgaard’s spectrum graph.
http://www.vukcevic.talktalk.net/SSA.htm
J. Bastardi forecast a 5.5×10^6km2 summer minima for 2011 I seem to recall, so it will be interesting to see if that is close. I tend to agree with R.Gates though and it will be much lower.
I also expect, given average weather , quick melt in Hudson Bay and that quadrant.
Is it me or is ice on the pacific side already weakening?
Andy
Pamela Gray says:
March 3, 2011 at 7:11 pm
What would be truly climate-changy stuff would be if the Arctic DIDN’T warm in response to the warmed left-over El Nino and NAO water circulating into the bowl.
That would be frightening. It would mean that the oceans are getting exhausted of their heat stores.
The last place you want to pump your warm air from your heater is outside the house, the house being the inhabitable latitudes.
I dare say the public has had enough of the Global Warming causes Global Cooling bilge to last it a lifetime.
Besides, Arctic Sea Ice doesn’t butter our toast, and next thing you know, they’ll be claiming that anthropogenic food comsumption causes global something.
rbateman says:
March 4, 2011 at 4:52 am
“Besides, Arctic Sea Ice doesn’t butter our toast, and next thing you know, they’ll be claiming that anthropogenic food comsumption causes global something.”
___
Actually, we don’t know whether or not the presence of Arctic Sea ice does or doesn’t butter our toast. We don’t have enough data. Ever since humans have been making butter, we’ve had sea ice in the Arctic, so there is no way of knowing how the lack of sea ice in that region might affect the ability of humans to produce butter…or toast for that matter.
R. Gates says:
March 4, 2011 at 6:26 am
rbateman says:
March 4, 2011 at 4:52 am
“Besides, Arctic Sea Ice doesn’t butter our toast, and next thing you know, they’ll be claiming that anthropogenic food comsumption causes global something.”
___
Actually, we don’t know whether or not the presence of Arctic Sea ice does or doesn’t butter our toast. We don’t have enough data. Ever since humans have been making butter, we’ve had sea ice in the Arctic, so there is no way of knowing how the lack of sea ice in that region might affect the ability of humans to produce butter…or toast for that matter.
Now I know you were being facetious here, however rbateman’s claim was that “Arctic Sea Ice doesn’t butter our toast”
now we know that toast has in fact been buttered.
however, there is no documented occurrence of Arctic Sea Ice actively buttering a person’s toast for them.
I think it is therefore a reasonable conclusion to reach that Arctic Sea Ice does not in fact butter our toast. There must therefore be other mechanisms by which our toast becomes buttered.
@Gary Young Mount
Tamino (Grant Foster) from the Open Mind blog, fitted recent sea ice extents in September by a polynomial. Extrapolating this backwards in time, this correctly showed a decrease in September extent before the 1940s.
Arctic ice extent appears to oscillate with a PDO/AMO like frequency.
kenboldt says:
March 4, 2011 at 7:28 am
R. Gates says:
March 4, 2011 at 6:26 am
rbateman says:
March 4, 2011 at 4:52 am
“Besides, Arctic Sea Ice doesn’t butter our toast, and next thing you know, they’ll be claiming that anthropogenic food comsumption causes global something.”
___
Actually, we don’t know whether or not the presence of Arctic Sea ice does or doesn’t butter our toast. We don’t have enough data. Ever since humans have been making butter, we’ve had sea ice in the Arctic, so there is no way of knowing how the lack of sea ice in that region might affect the ability of humans to produce butter…or toast for that matter.
Now I know you were being facetious here, however rbateman’s claim was that “Arctic Sea Ice doesn’t butter our toast”
now we know that toast has in fact been buttered.
however, there is no documented occurrence of Arctic Sea Ice actively buttering a person’s toast for them.
I think it is therefore a reasonable conclusion to reach that Arctic Sea Ice does not in fact butter our toast. There must therefore be other mechanisms by which our toast becomes buttered.
____
Well, yes, there was a bit of sarcasm, but truly, the shinning sun also butters your toast, for without that wonderful energy source, you’d have no butter, toast, nor energy to butter with at any rate. The interconnectedness of all things was my point, and so, how the presence of lack thereof of sea ice might in fact impact the general existence of both butter, toast, and humans to do the buttering would be the larger point.
phlogiston says:
March 4, 2011 at 9:12 am
@Gary Young Mount
Tamino (Grant Foster) from the Open Mind blog, fitted recent sea ice extents in September by a polynomial. Extrapolating this backwards in time, this correctly showed a decrease in September extent before the 1940s.
Arctic ice extent appears to oscillate with a PDO/AMO like frequency.
I loved the “Survival of the cutest” post. Having lived in Santa Cruz, CA for 50 years now, I can tell you that;
a) The ‘protected’ Sea Lion population explosion of the past few decades has completely decimated local fish populations in close in coastal areas of Monterey Bay, and
b) I’d much rather eat Salmon than Seals, and
c) One of the places I fished as a kid, the Santa Cruz Municipal wharf, yielded thousands of fish of a wide variety of species back then. Endless barred perch, Kingfish, Walleye perch, Rock cod, Flounder, Sand Dabs, Rainbow Perch, Jacksmelt, etc etc.
Now with the exploded Sea Lion population hanging about, the poor folks fishing from the wharf get…nothing. (And I check this personally, several times a month).
Oh yes, for the resident NumNut who believes that the “Pinapple Express” is creating all the rain this year. Balderdash. (That’s an ancient fossil term, for you Gen X,Y,Z crowd).
Our storms and the excessive rain from them have been the classic Gulf of Alaska origin pattern, with very heavy winds and COLDER than normal temps..and have missed the ‘warm spot’ in the Pacific altogether. These cold North Pacific storms have dumped higher than normal rainfall on the CA coast, and much higher than normal snowfall at LOWER ELEVATIONS than normal in The Sierras. 150% of normal in many places.
Oh incidentally, our sea level here hasn’t budged in DECADES either.
It’s so very inconvenient to the ‘story’ when actual data and observations don’t fit the alarmist computer model predictions. One must quickly flee from “AGW will cause snow to cease altogether, children won’t know what it is”…to “AGW will create a lot more snow”, in a hurry eh?
Hmm, how did that prediction about horrible Hurricane seasons coming every year work out again???
But then, what do I know. I’m just a lowly rocket science engineer. Maybe someday I can become a “D” science student like AlGore and create some hockey stick graphs.
Surely we should all go back to cave dwelling, enact massive carbon taxes tomorrow, send all our jobs to emerging market economies who will pollute approx 3X what we do in the West to make the products.
This should solve our ‘warming’ problems immediately. Well, time to break out the firewood for this weekend storm. Brrrr!
What I’m seeing so far is a chance we break thru the 2007 summer low somewhat on the low side, to around 2008 on the high side. I don’t see anything that gives any indication of recovery from 2010 levels back towards 2009 or higher.
r.bates said something about rbatemen and buttered toast.
Actually now r.bateman has been mentioned I wonder if he can now comment on his thoughts over the summer that the combined extent value for both Arctic and Antarctic in December would be 21×10^6km2 ? It never did get to that value and both are low at the moment.
The hoped for winter bounce from the sceptical side of the argument has not happened so far, unless there is a late spring like last year in the Arctic. So that is 2 summers and 1 winter favouring one side of the argument.
Andy
Andy W writes,
“The hoped for winter bounce from the sceptical side of the argument has not happened so far, unless there is a late spring like last year in the Arctic. So that is 2 summers and 1 winter favouring one side of the argument. ”
This spring as the Arctic melt season begins, I suspect we won’t see as many ignore-the-science predictions of “recovery” as were common last spring. Judging from comments above, this year’s predictions will more often concede that yes, Arctic ice is declining, but that’s just because of PDO/AMO/sine waves/sunspots/Atlantic water/or anything else except ACC. Recovery can still be imagined, it’s just far enough away that no evidence shows it.
As of early March, my guess for September mean NSIDC extent is 4.6. What’s yours?
geo says:
March 5, 2011 at 7:58 am
What I’m seeing so far is a chance we break thru the 2007 summer low somewhat on the low side, to around 2008 on the high side. I don’t see anything that gives any indication of recovery from 2010 levels back towards 2009 or higher.
____
There are essentially only 2 camps on the issue of arctic sea ice:
Camp 1: The GCM’s are generally correct and the 40% increase in CO2 since the 1700’s is now overwhelming any other natural variations and Arctic sea ice will slowly spiral down over the next few decades until we have a seasonally ice free arctic. Furthermore some models seem to show that this seasonally ice free Arctic will have profound effects on atmospheric circulation patterns (i.e. affect the N. Hemisphere weather).
Camp 2: Nope, CO2 levels, despite being at their highest levels in at least 800,000 years have little or no affect on Arctic Sea ice, and the last few decades of decline in the Sea ice is all the result of ocean cycles such as the PDO, AMO, etc., solar cycles, or some combination thereof, and we are just at the point when arctic sea ice will begin a slow recovery as these natural cycles shift back. Folks like Joe Bastardi would be in this camp.
Of course, the Camp 2 people were quite giddy with delight when the Arctic Sea ice appeared to make what they called a “recovery” of sorts in 2008 & 2009, and of course were quite disappointed last year when this supposed recovery did not continue on. But not to be discouraged, they quickly point out the fact that it took several decades for the sea ice to fall this far so one can’t expect it to go straight back up. Additionally, some in Camp 2 point out that the big losses for the Arctic Sea ice have all been because of the winds in the Arctic, and have nothing to do with heating, etc.
The Camp 1 people people know that there is indeed years of ups and downs of natural variability, but it is the long term trend that really matters, and that the likelihood of there being a seasonally ice free Arctic between 2030 and 2100 is very high, and that furthermore, the likelihood that this condition is being caused by the 40% increase anthropogenic GH gases (and related positive feedbacks) is also quite high. Finally, the odds that the GCM’s would have just “happened” to have modeled the effects of increasing CO2 that just “happened” to have matched natural variability is very very low.
Of course, I am in Camp 1, (at least 75% so, meaning I am not sitting on the fence between the two), though I stand on my tippy toes to peek over the fence and at least explore and weigh the arguments that the more educated in Camp 2 throw out. Many here in Camp 1 are “true believers” and have long since sat down by the 95-100% warmist campfire, certain in their convictions. I have no problem with that, and perhaps one day I will join them, but for now, I’ll stand near the fence and peek over occasionally. Certainly though, in the next few years, if the Arctic Sea ice continues its anticipated decline, skeptical voices such as Joe Bastardi will slowly fade away and it will be very hard for anyone to believe the AGW skeptics position, just as no one today (at least not rational people) believe that cigarette smoking does not cause cancer.
As far as where I stand on this year’s summer sea ice minimum…it looks to be heading back close to 2007’s lows this year. The dipole anomaly and related negative AO (early in the season) has made for a generally warmer than average winter in the Arctic and the sea ice extent has been below average for the whole winter. A first projection this year puts the minimum extent somewhere around 4.2 million sq. km, but a warmer than average spring and summer in the Arctic, with a lot of early summer season melting (i.e. more early season open water) could certainly push the minimum extent down even below 4.0 million sq. km..
And thus R. Gates disregards the null hypothesis, a cornerstone of the scientific method.
During the holocene it has been up to several degrees warmer quite a few times. Did CO2 cause the ice caps to melt then, too? Gates is just making his usual argumentum ad ignorantium: “Since I can’t think of any other cause, then it must be due to CO2.”
Scientology.
Smokey says:
March 5, 2011 at 2:12 pm
And thus R. Gates disregards the null hypothesis, a cornerstone of the scientific method.
During the holocene it has been up to several degrees warmer quite a few times. Did CO2 cause the ice caps to melt then, too? Gates is just making his usual argumentum ad ignorantium: “Since I can’t think of any other cause, then it must be due to CO2.”
Scientology.
____
You sit comfortably on the other side of the fence, in Camp #2, by the skeptics campfire. When the direction of sea ice is no longer a random walk, but is heading in the direction that your models indicate it would with the 40% increase in CO2 since the 1700’s, the null-hypothesis is no longer valid when applied here. Something is indeed happening outside of natural variability and the models tell us what and why.
Gates says:
“”…your models indicate it would with the 40% increase in CO2 since the 1700′s, the null-hypothesis is no longer valid when applied here. Something is indeed happening outside of natural variability and the models tell us what and why.””
Sheesh, this guy Gates just doesn’t get it.
What models? Models are the curse of the Warmists. They’re almost never right. Well maybe twice a day.
Mr. Gates doesn’t remember that the 1700s were called the Little Ice Age. So its gotten warmer since then . No kidding.
Rocky H writes,
“What models? Models are the curse of the Warmists. ”
No, most scientific interest in the Arctic centers around data, which show melting faster than predicted by the models. So researchers have been scrambling to figure out why, and where it’s all going.
“Mr. Gates doesn’t remember that the 1700s were called the Little Ice Age. So its gotten warmer since then . No kidding.”
Was 1980 still the Little Ice Age? It’s gotten warmer since then, no kidding.
Gneiss says:
March 5, 2011 at 3:23 pm
Was 1980 still the Little Ice Age? It’s gotten warmer since then, no kidding.
Tough to explain the sea ice trend when the measured change in temperature (between 1980 and now is negative …. (Granted, not very negative, but it is still still negative with UAH data being below zero.)
Also, let’s assume somehow that a “global average air temperature” (for regions of the earth below 80 north in previous decades) did somehow affect current sea ice extents in the Arctic in winter. (When actual observation shows that sea ice melts in the summer – when measured 80 north temperatures for each summer have been declining since 1958.) So, exactly what IS the calculated change in sea ice extents for a approximated global change in temperature of only 1/4 of one degree?
Does not this measured change in sea ice extents require a change in temperature of some 12 degrees? And does not this difference between actual real-world results and unreal-world models indicate that the models (modelers!) are dead wrong in their assumptions (er, models)?
Gneiss says:
“Was 1980 still the Little Ice Age?”
Reading comprehension -1. The depth of the LIA was mid-1600’s – ≈1800. Estimates vary. But that was approximately the low temperature point.
Since then the planet has been gradually emerging from the LIA. The current warming is exactly what would be expected. Therefore, the null hypothesis remains un-falsified; there is no measurable difference between natural variability and observations.
According to the scientific method, of which the null hypothesis is an important part, you need to convincingly show that the CO2=CAGW conjecture has caused the climate to exceed its previous Holocene parameters.
“Therefore, the null hypothesis remains un-falsified;”
Smokey, it would appear that you don’t know what a null hypothesis is or how the concept is used in science. Perhaps you should describe the concept you are referring to and we can help you identify the correct terminology.
Thank you R. Gates for reminding the readers of the big deal made last year on WUWT about the winter ice cover (for some reading see: http://wattsupwiththat.com/2010/03/31/arctic-sea-ice-about-to-hit-normal-what-will-the-news-say/). Back then the fact that the winter ice cover approached the 1979-2000 mean and was the latest freeze-up on during the satellite record, many readers and originators of these articles said the extensive winter ice cover meant the summer ice would recover. And as we all know, that didn’t happen.
Now I see a lot of back peddling saying how winter ice has nothing to do with what will happen in to the summer ice in the Arctic Basin. And it is true, we cannot predict what the summer ice extent will be based on the winter ice extent. The southerly reaches of the winter ice cover are thin first-year ice that melt easily in summer. But we can say that ice growth may have been limited by warmer than normal winter temperatures (and perhaps ocean temperatures too—though I haven’t looked at the ocean buoy data). What is important is how thin the ice in the Arctic basin is and what the summer weather patterns will shape up to be. 2007-2010 were dominated by the Arctic Dipole Anomaly pattern, which in 2007 was persistent and strong the entire summer and helped lead to the large ice loss that occurred that year. But it has been present every summer since then, contributing to continued anomalously low ice years.