Arctic Sea Ice Time Lapse from 1978 to 2009 using NSIDC data

Jeff Id at the Air Vent has been doing some interesting work lately. Before the NSIDC Arctic Sea Ice anomaly plot went kaput due to failure of the satellite sensor channel they have been using, they had created a vast archive of single day gridded data packages for Arctic sea ice extent. Jeff plotted images from the data as viewed from directly over the North Pole. It took him over 15 hours of computational time. An example image is below.

30 Year Arctic Sea Ice - NSIDC NasaTeam Bootstrap

Jeff gathered up all the resultant plotted images and turned them into a movie, but placed them on the website “tinypic” where the movie won’t get much airplay.

I offered Jeff the opportunity to have it hosted on YouTube and posted here, where it would get far greater exposure and I completed the conversion this afternoon.

What I find most interesting is watch the “respiration” of Arctic Sea Ice, plus the buffeting of the sea ice escaping the Arctic and heading down the east coast of Greenland where it melts in warmer waters.

Jeff writes:

I find the Arctic sea ice to be amazingly dynamic. Honestly, I used to think of it as something static and stationary, the same region meltinig and re-freezing for dozens or even hundreds of years – not that I put much thought into it either way. Shows you what I know.

This post is another set of Arctic ice plots and an amazing high speed video. The NSIDC NasaTeam data is presented in gridded binary matrices in downloadable form HERE.

The data is about 1.3Gb in size so it takes hours to download, I put it directly on my harddrive and worked from there. The code for extraction took a while to work out but was pretty simple in the end. This code ignores leap years. Formatting removed courtesy of WordPress.

filenames=list.files(path=”C:/agw/sea ice/north sea ice/nasateam daily/”, pattern = NULL, all.files = TRUE, full.names = FALSE, recursive = TRUE)

trend=array(0,dim=length(filenames)-1)

date=array(0,dim=length(filenames)-1)

masktrend=array(0,dim=length(filenames)-1)

for(i in 1:(length(filenames)-1))

{

fn=paste(”C:/agw/sea ice/north sea ice/nasateam daily/”,filenames[i],sep=””) #folder containing sea ice files

a=file(fn,”rb”)

header= readBin(a,n=102,what=integer(),size=1,endian=”little”,signed=FALSE)

year=readChar(a,n=6)

print(year)

day=readChar(a,n=6)

print(day)

header=readChar(a,n=300-114)

data=readBin(a,n=304*448,what=integer(),size=1,endian=”little”,signed=FALSE)

close(a)

if(as.integer(year)+1900<=2500)

{

date[i]=1900+as.integer(year)+as.integer(day)/365

}else

{

date[i]=as.integer(year)+as.integer(day)/365

}

if(i==1)

{

holemask= !(data==251)

}

datamask=data<251 & data>37 ## 15% of lower values masked out to match NSIDC

trend[i]=sum(data[(datamask*holemask)==1])/250*625

}

###mask out satellite F15

satname=substring(filenames,18,20)

satmask= satname==”f15″

newtrend=trend[!satmask]

newdate=date[!satmask]

After that there is some minor filtering done on 7 day windows to dampen some of the noise in the near real time data.

filtrend=array(0,dim=length(newtrend))

for(i in 1:(length(newtrend)))

{

sumdat=0

for(j in -3:3)

{

k=i+j

if(k<1)k=1

if(k>length(newtrend)-1)k=length(newtrend)-1

sumdat=sumdat+newtrend[k]

}

filtrend[i]=sumdat/7

}

So here is a plot of the filtered data:

North Ice area2

Here is the current anomaly.

North Ice anomaly2

This compares well with the NSIDC and cryosphere plots. This anomaly is slightly different from some of my previous plots because it rejects data less than 15% sea-ice concentration. Cryosphere rejects data less than 10%. In either case the difference is very slight but since we’ve just learned that the satellites have died and are about 500,000km too low, my previous graph may be more correct. I hope the NSIDC get’s something working soon.

All of that is pretty exciting but the reason for this post is to show the COMPLETE history of the NSIDC arctic sea ice in a video. I used tinypic as a service for this 27mb file so don’t worry, you should be able to see it quite well on a high speed connection. It took my dual processor laptop computer more than 15 hours to calculate this movie, I hope it’s worth it. Brown is land, black is shoreline, blue is water except for the large blue dot in the center of the plot. The movie plays double speed at the beginning because the early satellite collected data every other day. You’ll see the large blue circle change in size flashing back and forth between the older and newer sat data just as the video slows down.

After staring at the graphs above you think you understand what is happening as ice gradually shrinks away. Well the high speed video shows a much more turbulent world with changing weather patterns in 2007 and 2008 summer blasting away at the south west corner of the ice. I’ve watched it 20 times at least, noticing cloud patterns (causing lower ice levels), winds, water currents and all kinds of different things. I’m not so sure anymore that we’re seeing a consistent decline to polarbear doom, with this kind of variance it might just be everyday noise.

Maybe I’m nuts, let me know what you see.

No Jeff you aren’t nuts. Here is the YouTube Video, suitable for sharing:

Here is another video I posted on You Tube last month which shows the flow of sea ice down the east coast of Greenland. Clearly there is more at work here than simple melting, there is a whole flow dynamic going on.

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John

Great video! Two things that stand out when you play the whole thing is that wintertime ice used to get thick off of Newfoundland in the winter, but in the last decade, not so thick. The other thing is that you can visually see that 2008, although there was more ice than in 2007, was still pretty low, historically. But let’s see what this coming year brings in the summer…..

Cathy

Beautifully done. Certainly gives some needed perspective.
(Here’s some irony: there’s an add beneath this post advertising carbon offsets)

Pamela Gray

What would be really instructive is to superimpose jet stream archive data (they have it back to 1996 for the Arctic area) on this video.

Al Gore debunked!, whenever somebody says artic will melt in 5 years just show the video.

Great video! Two things that stand out when you play the whole thing is that wintertime ice used to get thick off of Newfoundland in the winter, but in the last decade, not so thick. The other thing is that you can visually see that 2008, although there was more ice than in 2007, was still pretty low, historically. But let’s see what this coming year brings in the summer…..

Not really historically. Historically would be 1000, 2000, or more years, even than is a snapshot in geological time. 20 or 30 years is pretty meaningless.

Dave Wendt

Congratulations on another terrific piece of work. It’s amazing how this seemingly simple change in presentation greatly enhances the ability to comprehend what’s really occurring in the Arctic ice cycle.

Nathan

I would suggest that the reason the wind and waves can move the ice more in recent years is because it is now thinner.

Austin

The next step is to measure the angular momentum of the ice pack over time. I can see a lot of rotation in the later years.

RexAlan

Well done, that’s fantastic!

Hmm. Not much plot, but still way better than watching “Ishtar.” Definitely two thumbs up.

kuhnkat

Nathan,
it is thinner because the wind and waves were moving it while it was thicker. In the last few hundred years it apparently has never been thick enough for a permanent ice cap to form.
NASA reported that the Arctic was losing ice at about 193,000km2/year up till 2000. From 2000 till 2007 it was about double that. Without the 20 years of thinning the higher loss after 2000 would not have been as large.
Of course, the loss has, at least temporarily reversed. Willing to bet your future on a short, incomplete, data set and study??

John F. Hultquist

Fascinating. On my first view I noticed a prong of ice (in some years) growing eastward from Greenland at about 70 degrees N. or so. At least once either ice or clouds seem to break away from this. Others may have a comment about this. It is just my first look and observation. If you are watching other areas, say Hudson Bay filling with ice, you will miss this. I have some other things to do before dark so I’ll have to look again later.

Paul Coppin

Nathan (18:44:20) :
I would suggest that the reason the wind and waves can move the ice more in recent years is because it is now thinner.

I would suggest that thickness has very little to do with it. The thickness relative to mass and depth of water under it is miniscule. My experience with freshwater lakes and rivers suggest to me that if the forces are there to move it, it will move.

OT – Tomorrow I’m driving to Washington and will be attending the Third Int’l Conference on Climate Change Tuesday. – Cool!
Glenn @ NoFreeWind

I’m no expert but to my addled brain the little film-thingy showed ice reducing in extent in summer and expanding in extent in winter with virtually no difference from year to year.
What was also obvious was that the pattern of ice always depicted the face of Susan Boyle, but it is YouTube so I suppose that’s compulsory.

Jon H
Paul Linsay

Interesting. There’s not a single winter where the ring centered on the North Pole formed by Alaska, Canada, Greenland, Franz Joseph land, and Siberia isn’t packed solid with ice. All the variation is due to ice in the Atlantic and Pacific.

Just Want Truth...

Thank you JeffID!!

Just Want Truth...

I’ll be watching until mid September to see what happens to 2009 melt. Here’s JAXA today :
http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
I’ve got my popcorn ready!

Frederick Michael

Nathan (18:44:20) :
I would suggest that the reason the wind and waves can move the ice more in recent years is because it is now thinner.

This is one of the many reasons why any recovery in the arctic sea ice should be noteworthy. The whole thing is just FULL of positive feedback effects. Low sea ice should lead to lower sea ice without any change in temperature. Furthermore, simply holding at a warmer temperature than was normal say, 30 years ago should lead to steady melting, year after year after year. Temperature should drive the first derivative of sea ice (in a simple minded model anyway).
Any reversal would be completely counter to all AGW theories. If anything the Arctic Sea ice loss should be ACCELERATING. That’s why Gore made his confident prediction about an ice-free north pole. From his point of view, it’s a sure bet.
If it doesn’t come through something HAS TO BE hugely amiss with his point of view.
Golly.

bill

Try these truly amazing timelapses seaice pictures The Big files are realy worth Downloading
http://polynya.gsfc.nasa.gov/animations/amsr
Then for the southern hemisphere try the 480 MB file to watch icebergs on the move:
http://polynya.gsfc.nasa.gov/animations/amsr_south/

jefftfred

Nice work JeffId at Air Vent
For animations on the Arctic and Antarctic ice caps for last 21 days ~1mb AVI
For period Jan 2003 to date (not quite – to date) ~ 20mb AVI
Every day map updates on sea ice cover for the Arctic and Antarctic
http://www.iup.uni-bremen.de:8084/amsr/amsre.html
Also more detailed area maps around both the North and South poles (see the route of the Russian floating weather station NP-36, which you can also Google for real time position and weather data). If there is grey streaks on the area your interested in, come back later, as it updates to fill in those areas.
Don’t forget that there is webcams in eg Antarctica – USAP McMurdo base (night time at present) :http://www.usap.gov/videoClipsAndMaps/mcmwebcam.cfm
And in areas such as Svalbard (Spitzbergen), Greenland, Moscow and northern areas of the US

Fluffy Clouds (Tim L)

me too tx Jeff

Steven Kopits

Just a nice piece of work. Thank you.

rbateman

Nice video. So, even if the ice totally melts up there one summer, it only takes a few extra cold years to bring it back.

AEGeneral

Great work, but audio is noticeably absent.
Recommend Foreigner’s “Cold as Ice” or Rainbow’s “Stone Cold.”

BEvans

Whats with the odd effects on the Great Lakes (between Canada and the US near the bottom right of the map)? Lot of noise in the signal from what I can tell. Doesn’t match up well with http://ice.ec.gc.ca/App/WsvPageDsp.cfm?ID=11890&Lang=eng

Mike McMillan

So how does one go about saving the first animation to disk?

Alan the Brit

Well, I must say I couldn’t see a huge difference over that period between extremes that would suggest significant change that would bother me. How does one know this has not been the case for 000’s of years.
People seem to forget the big increase in sea ice that occurred 100,000 ya that spread to over land. Then the massive global warming that occurred 12,000 ya! without the CO2!

E.M.Smith

Like it.
What I observed was that the winter recovery is always to about the same point where open sea and currents can deliver enough “warmer” water to prevent ice stability. With a heck of a lot of extra cold, you could get a stable larger ice cover, but it would take a lot of cold and some changes to the major currents (like the Gulf Stream). Leaves me wondering just how hard it really is to have an ice age (and leaves me thinking that it is mostly on land and not so much ice cap extension over the ocean.
On the summer side, it just looks like you get a lot of melt, then a rapid recovery. Some years more than others but not a lot of trend. My impression was that even if you melted the whole thing in summer, one month later it’s icing up again and 3 to 4 months later the whole thing is frozen again. Big deal…
In both cases, I don’t see the opportunity for a whole lot of time x albedo change. The minimal ice is not for long, and the maximum ice is not much more maximum. The bounds are fairly similar on a 2 or 3 year average (i.e. an extreme seems to be a “one off” in any given year) and the bulk of the time is spent in the transition phase so you’re talking more like a week or two early / late. So you could model this as “normal” plus a week or two at the low end when “melting a lot” or as “normal” plus a week or two at the high ice end when “frozen a lot”. Somehow a week or so net variance just doesn’t get me exited. 2% of a year? I’d expect it to be lost in the noise, and it looks like it is…
Over all, it looks to me like an oscillator that saturates at each end. It’s going to keep right on oscillating even if you push it a bit one way or the other and dampen back to stability.

APE

Jeff and Anthony,
Thanks for sharing this work it really does add some perspective. I think it is pretty clear that the noise is large. Perhaps someone a bit closer to statistical process control (SPC) could do a formal analysis as well. I am thinking that fitting a sinusoid to the average max min locations should suffice for a mean that is if we didnt just use the mean straightway. Then taking delta from that sinusoid would serve as the overall error. Plus minus two sigma or thereabouts should tell us significance of any single point positive or negative (of course we are limited by sample size but at least we would have some idea as to the significance of this whole ice extent thing). I guess if we were picky we could use chauvenets criterion as well. I may take a stab at it after I do some review please forgive me if someone has already done something similar. If anyone knows of similar work please let me know it has been a while since I did SPC. Just like in manufacturing there is no point in solving a problem that doesn’t exist. The burden of proof should be on the AGWers but it seems like all they can come up with are bird migration dates (which also seem to be in the noise band).
APE
PS @AEGeneral 1 vote for foreigner “cold as ice”

APE

sorry just apply SPC on anomaly only as that is what anomaly is… my bad
APE

Gary Crough

Nice work.
I agree with Nathan (18:44:20) the thickness of an ice flow has little to do with what happens to it. A current will move a 16″ deep raft as easily as a 6″ deep raft.
Currents around the N Pole are moving ice SE at about 2.5 miles/per day. The ice is not one big thing but a bunch of flows … some hundreds of acres in size … but the larger they are the more likely stress from conflicting currents will break them up. The sub Skate was able to surface at the N Pole in March 1959 by locating a “lead” (crack in an ice flow which was refrozen but with much thinner ice) … these will always appear within a few days given the ice is in flows (with leads separating them) and on the move.
That video does a great job in showing yearly fluctuations. A similar time lapse on ice flows (showing how they formed, broke up, and moved) would clear up a lot more.

Magnus A

Comparison between 1989 and 2009:
http://farm4.static.flickr.com/3314/3580973564_c2a4d7ba66_o.jpg
(I sent this to the Accuweather blog in a post that compares Arctic ice the last 10 years, but the comment wasn’t published now.)

Shawn Whelan

Interesting story of the Resolute.
Abandoned in the Northern Route of the NW Passage it floated out all by itself.
http://en.wikipedia.org/wiki/HMS_Resolute_(1850)

APE

I also just saw that NSIDC has 2 sigma area bands off thier 79-00 data Ill check a bit further before commenting next time. although it seems like for SPC one should use your current average rather than cherry picking data sets
APE

George E. Smith

So where do I find this video; I just have an empty white space.
George

Great job. Great movie. Interesting factoid: over the duration of the movie the polar bear population increased 300 to 400%.
Note to E.M. Smith: the Laurentide and Cordilleran Ice Sheets both originated in mountains, the former in the highlands of Baffin and Ellesmere Islands (~10,000 ft elevation) and the latter in the Coast Range of British Columbia (also 10,000+ ft). The ice sheets travelled huge distances from points of origin, rather than developing all over Canada simultaneously.

Aron

“People seem to forget the big increase in sea ice that occurred 100,000 ya that spread to over land. Then the massive global warming that occurred 12,000 ya! without the CO2!”
Actually from 20,000 years ago until the European Industrial Revolution there was a steady rise in CO2 from 180ppm to 270ppm. This is often ignored by Alarmists/global Marxists who want the West to take the blame for everything (especially George Bush – blame him for galactic collisions billions of light years away too)
As Asian and African politicians via the UN want the West to pay for the sins of industrialisation that resulted in CO2 levels going from 270ppm to 380ppm, the West should first insist that the East should pay for the initial rise in CO2 (which of course HAS to be manmade!) that was a result of the agricultural and industrial revolutions that began in Asia thousands of years ago. Fair is fair, right?

Clarification: over the 30 year period condensed into the 4 minute time-lapse movie, the polar bear population increased 300 to 400%. That’s more correcter grammatically.

Pamela Gray
I was thinking of your interest in jet streams last night as I watched an excellent BBC programme called ‘The Jet stream and Us.’
I didnt know that it was only first known about in 1945 when American bombers were sent to bomb Japan. They failed, due to what they described as a very strong wind which made their bombs deviate miles from the target when trying to carry out bombing at very high altitudes. Their superiors denied this and called them idiots, and all scientific opinion said it was impossible (sound familiar yet?)
Of course they eventually started to realise what the high wind was and began to trace it.
Ironically the Japanese themselves knew of it twenty years earlier and a non English speaking researcher published a paper about it in Esperanto which no one was aware of (perhaps another lesson that research in a language other than English may be throwing up interesting things on AGW)
The point is that the only civilians killed in mainland US by enemy action were as a result of the Japanese military attaching bombs to high level balloons and sent into the Jet stream, thousands of which reached the US. One of them exploded in Oregon killing five children.
Catch the programme if you can, which unfortunately degenerated into a global warming scenario at the end claiming the position of the Jet stream could alter which would make us here in the UK much warmer. Or altenatively if it shifted elsewhere much colder….
I totally agree with you about superimposing jet streams over the arctic to see if there is any correlation.
The UK has had two coolish wet summers over the last two years because the jet stream was in the wrong place. Lamb believed it fundamentally affected our past climate. I suspect its full impact is still unrecognised even though the science is so settled.
Tonyb

UK Sceptic

I had no idea the Arctic sea ice was so dynamic. Thanks to Jeff Id for all that hard work slaving over a hot keyboard. They say you learn something new every day. One of the reasons I love reading this blog. 😀

Jeff
Good work, great video and I agree with your comments.
I started to look at the Arctic only around two years ago having believed -like you-that it was this great mass of permanently frozen ice. Then I started to examine the historic records, of which many survive, which demonstrate that the Vikings are only one example of life in the Arctic region.
This is a rewrite of an earklier item I posted here, so my apologies, but it is important to get over to those who claim this melt period is ‘unprecedented’ that this is by no means so if we look at history;
1 The following link describes the ancient cultures of the warmer arctic 5000 to 1000 years ago
http://en.wikipedia.org/wiki/User:Lithoderm/Inuit_culture
2 This relates to an Arctic culture thriving in warmer times 2000 years ago
From the Eskimo Times Monday, Mar. 17, 1941
The corner of Alaska nearest Siberia was probably man’s first threshold to the Western Hemisphere. So for years archeologists have dug there for a clue to America’s prehistoric past. Until last year, all the finds were obviously Eskimo. Then Anthropologists Froelich G. Rainey of the University of Alaska and two collaborators struck the remains of a town, of inciedible size and mysterious culture. Last week in Natural History Professor Rainey, still somewhat amazed, described this lost Arctic city.
“It lies at Ipiutak on Point Hope, a bleak sandspit in the Arctic Ocean, where no trees and little grass survive endless gales at 30° below zero. But where houses lay more than 2,000 years ago, underlying refuse makes grass and moss grow greener. The scientists could easily discern traces of long avenues and hundreds of dwelling sites. A mile long, a quarter-mile wide, this ruined city was perhaps as big as any in Alaska today (biggest: Juneau, pop. 5,700).
On the Arctic coast today an Eskimo village of even 250 folk can catch scarcely enough seals, whales, caribou to live on. What these ancient Alaskans ate is all the more puzzling because they seem to have lacked such Arctic weapons as the Eskimo harpoon.
Yet they had enough leisure to make many purely artistic objects, some of no recognizable use. Their carvings are vaguely akin to Eskimo work but so sophisticated and elaborate as to indicate a relation with some centre of advanced culture — perhaps Japan or southern Siberia —certainly older than the Aztec or Mayan.”
3 This link leads to the Academy of science report of the same year regarding the Ipiutak culture described above
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1078291
4 This refers to the Vikings living in a warmer arctic culture 1000 years ago
People might be interested in reading a very interesting book about the Vikings called ‘The Viking world’. It is a very scholarly and highly referenced book running to some 700 pages and deals with all aspects of the Vikings. It is good because it does not have an axe to grind, but deals matter of factly with all aspects of Viking culture and exploration.
There is a large section on their initial exploration of Greenland, the subsequent establishment of their farms there, everyday life, how they gradually lost access to the outside world as the sea lanes closed through ice, a record of the last wedding held In Greenland and how trade dried up. It also deals with Vinland/Newfoundland and it seems that it was wild grapes that helped give the area its name, it being somewhat warmer than today.
This is one of a number of similar books that record our warmer and cooler past throughout the Northern Hermisphere. Al Gore wrote a good book in 1992 called ‘Earth in the Balance’ in which he explored the changing climate.
The book ‘The Viking World’ is Edited by Stefan Brink with Neil Price Published by Routledge ISBN 978 0 415 33315-3
5 This refers to a warmer arctic 75 years ago recorded on Pathe newsreel by Bob Bartlett on the Morrisey during his journeys there in the 1920’s and 1930’s and reported in all the media.
http://boothbayharborshipyard.blogspot.com/2008/08/arctic-explorer-on-ways.html
Wednesday, 10th August 1932
The ship rolled heavily all night and continues to do so….
The glacier continues its disturbances. No real bergs break off but great sheets of ice slide down into the water and cause heavy seas. About noon, the entire face of the glacier, almost a mile in length and six or eight feet deep slid off with a roar and a rumble that must have been heard at some distance. We were on deck at the time for a preliminary report like a pistol shot had warned us what was coming. The Morrissey rolled until her boats at the davits almost scooped up the water and everything on board that was not firmly anchored in place crashed loose. But this was nothing to the pandemonium on shore. I watched it all through the glasses. The water receded leaving yards of beach bare and then returned with a terrific rush, bringing great chunks of ice with it. Up the beach it raced further and further, with the Eskimos fleeing before it. It covered all the carefully cherished piles of walrus meat, flowed across two of the tents with their contents, put out the fire over which the noonday meal for the sled drivers was being prepared, and stopped a matter of inches before it reached the pile of cement waiting to be taken up the mountain. Fortunately, in spite of heavy sea, which was running, the Captain had managed to be set shore this morning so he was there with them to help straighten out things and calm them down.”
As well as the events detailed under we have reports from the 1790’s onwards of massive ice melt which eventually prompted an expedition by the Royal Society, by which time it had frozen sold again. We also have the records of the Hudson Bay co which clearly show the fragile nature of the Arctic.
It appears the region has periodically warmed to amounts as much as, or greater than today. Whether it is as cyclical as is being claimed-60/70 years-is difficult to determine as there are large gaps in our knowledge from the end of the Viking period as the LIA made the area even more inhospitable.
A reduction in ice extent since 1979 is of little consequence if you look at the historical record of this region.
It would be really interesting to see a properly researched article on the Arctic through the ages so we can put current events into a better perspective.
Tonyb

King of Cool

A fascinating presentation which opens up many observations.
Would love to see a similar one on the Antarctic.
I still cannot fully understand why there is a SH/NH difference if there is true global warming whether it be solar or CO2 induced. Gut feeling is that there has to be some other factor such as more aerosol pollutants in the NH creating some albedo effect.
Without looking at it another dozen times and I know it is only a snapshot, but to my layman’s mind I would have thought that the winter outer extremities should have been also reducing. This does not appear to be the case.

bill

King of Cool (01:17:45) : From my post above
Southern Hemisphere: Browse the AVIs etc in this directory but it is worth trying the 480 MB file to watch icebergs on the move:
http://polynya.gsfc.nasa.gov/animations/amsr_south/

Hugo M

Mike McMillan (22:36:02) : So how does one go about saving the first animation to disk?

Whoever also has difficulties with shock wave format videos,
just paste the following urls into h ttp://keepvid.com

h ttp://www.youtube.com/v/6j8SGs_gnFk&#038
h ttp://www.youtube.com/v/RnqNXxewpdw&#038

and save them as .flv or .mp4 onto your hard drive

Ken S

Fantastic work. The things that stands out for me watching the maximum and the minimums pulsate back and forth is not so much that it wont won’t entirely melt one northern summer – but that when it does it won’t look strange at all in the context of such a strong and variable cycle. If I was presented with such a visual representation for any other phenomenon I would feel reasonably confident that every now and then (say, over hundreds of cycles) there would be bound to be some near or even actual nils in the summer. It just comes across as that variable. That’s the layman’s high level interpretation anyway.

Another Ian
Dave Middleton

Mike D. (00:19:15) :
Clarification: over the 30 year period condensed into the 4 minute time-lapse movie, the polar bear population increased 300 to 400%. That’s more correcter grammatically.

But a 300% to 400% decline in polar bear populations sounds so much more IPCC’ish. ..:)