A few people have already remarked on some pretty surprising numbers in Arctic sea ice extent this year (the New York Times has also noticed). The minimum extent is usually in early to mid September, but this year, conditions by Aug 9 had already beaten all previous record minima. Given that there is at least a few more weeks of melting to go, it looks like the record set in 2005 will be unequivocally surpassed. It could be interesting to follow especially in light of model predictions discussed previously.
There are a number of places to go to get Arctic sea ice information. Cryosphere Today has good anomaly plots. The Naval Sea ice center has a few different algorithms (different ways of processing the data) that give some sense of the observational uncertainty, and the National Snow and Ice Data Center give monthly updates. All of them show pretty much the same thing.
Just to give a sense of how dramatic the changes have been over the last 28 years, the figures below show the minimum ice extent in September 1979, and the situation today (Aug 9, 2007).
The reduction is around 1.2 million square km of ice, a little bit larger than the size of California and Texas combined.
Update: As noted by Andy Revkin below, some of the discussion is about ice extent and some is about ice area. The Cryosphere Today numbers are for area. The difference is whether you count ‘leads’ (the small amounts of water between ice floes) as being ice or water – for the area calculation they are not included with the ice, for the extent calculation they are.
Update: From the comments: NSIDC will now be tracking this on a weekly basis.
RE: #350
Hank, thanks for the response. In the simulation shown in Figure 1 in the other thread, the mean decrease in September sea ice across the decade was 400,000 square km per year, with a couple of years that seem to approach the ~1 million square km yearly decrease that is likely to result this year. So we could actually be observing an extreme case in the making.
If the trend this year continues for the next few years, resulting in a mostly ice-free Arctic ocean in the summer, will the rate of global warming accelerate, and by roughly how much?
Jamie, I’m just another reader here like you are. You could look for the threads on “albedo” and the notes in the “Start Here” section will be helpful. Your question assumes all other things held the same and only sea ice changes, I think. I doubt that’s realistic.
Meanwhile, sea ice continues to decline. Note the definition of “sea ice” here is “at least 15% ice” — not a solid sheet of ice:
http://www.nsidc.org/news/press/2007_seaiceminimum/images/20070904_timeseries.png
Hank, it is complex (at the core) and yet very simple. Hard to imagine that cold water under the ice Micro-organisms created their own turf protecting scheme, or is it a form of symbiosis between themselves and the ice, in better terms they evolved from the ice and nurtured it in return.
But several consecutive years of consistent warm polar atmosphere took its toll, perhaps the Russian side had several more leads than usual this past spring.
RE: #352 – In my trade, I’ve been trained by wiser people than me, as well as many hard knocks, to be innately suspicious of inflection points. They may actually reveal something that changed, or, may point to an equipment problem.
Re #340
John,
That is an interesting question. I had not considered what would happen to the extra heat now being stored in the Arctic Ocean. But it has been mooted that it could lead to more snow in Canada and Scandinavia causing a new ice age. If you think of the ice covering Greenland, and realize that it all originated from water evaporated from the oceans, then it took a lot of heat to produce that two mile thick ice!
However, IMHO global warming has made the world too warm for snow to lie through the summer, which would be needed for a new ice age, so I will forget about that idea.
There are two main routes for the heat: first as radiation and second as latent heat of evaporation. The radiation will be partly trapped by CO2, but to a greater degree by the main greenhouse gas water vapour. Without the sea ice, it is much easier for the ocean to produce water vapour so increasing the greenhouse effect.
With more water vapour you also get more clouds, and the greatest greenhouse effect is caused by clouds. They block the radiation across the whole OLR spectrum, and can keep night time temperatures very similar to those of the day. The polar night lasts six months, so Arctic temperatures could hover around 0C all winter. The had rain in Svalbard in winter for the first time ever last year.
What I think will happen is that the Arctic will remain warm while Canada and Siberia cool. This will cause winds blowing from the continents to the oceans (land breezes.) Will that have a “lake effect” and produce more snow on the Arctic coast? Will the air blowing from Russia pull in warm air from the Mediterranean, and leave Moscow snow free this winter?
Certainly here in the UK I think we will have a mild winter, and suggest it might be a good idea to sell any shares you have in Scottish and Alpine ski resorts :-(
Re 338:
My understanding of the DMS production is that it occurs as the phytoplankton respond to the light and warmth of summer, but I am delighted if someone who knows about this matter would explain if that is incorrect. There is a recent paper on lower productivity in the Bering Sea — that would imply lower DMS production, lower albedo and more warming. I have seen nothing about whether the productivity is falling across the Arctic. If so, there is a simple explanation for the melting ice.
The link at ref mentions skimming the surface layer for various things including surfactants. I have found no further information on the latter, particularly about whether the surfactants were all natural or whether synthetic surfactants and anthropogenic oil sheen have made it so far north. If so, the sequence is clear: more surfactant/oil sheen suppresses bubble formation, reduces CCN and decreases albedo. The ice melts. More fresh water at the surface reduces mixing, lowers nutrient levels and reduces productivity some more.
Essentially, I am proposing an interference at a crucial point in the feedback mechanisms, particularly a disruption of those biological feedbacks which are so much more powerful than mere physics. The physics of higher Weber numbers with falling surface tension is a complication which could go either way — too low and CCN numbers would increase as colliding droplets breakup, but my guess would be for the number to mainly fall in the coalescent range, reducing albedo further.
Robert Essenhigh has suggested that an ice-free Arctic will powerfully feed back cooling from greatly increased snowfall over the northern hemisphere. If the oilsheen/surfactant hypothesis is correct then this feedback is being interrupted and we are sailing uncharted waters.
JF
Does anybody know the last time that the arctic ocean was essentially ice free?
I have seen some press articles stating that it has been over a million years.
However, I can not find anything like a science journal article on the subject.
The Eemian was only 125,000 years ago, but was it warm enough for an mostly ice free arctic?
Would think that ocean deposits would provide needed data, but obtaining them in shifting sea ice would be difficult.
Thanks
re: #355 Alastair
re: sell stock in Scottish & Swiss ski areas
[THIS IS NOT INVESTMENT ADVICE. JUST A COMMENT].
Well, at least the Scots will get those nice wineries to replace the ski areas.
In Switzerland, the banks already aren’t lending to ski resorts under 1500m, and various reports expect pressure on the resorts around Switzerland. Hence, investment in an increasingly-scarce resource (the higher slopes, which will last a fairly long time) may actually be a good investment.
Andrew–Putting a phrase fromyour question into Google
“arctic ocean was ice free”
turns up this link among quite a few others you might look into:
Ocean Drilling Research:
From these four cores we can conclude that from at least 73 million years ago to approximately 45 million years ago, the Arctic Ocean was ice-free …
http://books.nap.edu/openbook.php?record_id=9463&page=1
Who can now prove, OR is ready to bet 1000$, that Arctic will not be ice-free in 2008 – next year?
Overpeck et al “Arctic System on Trajectory to New, Seasonally Ice-Free State” (Eos, Vol. 86, No. 34, 23 August 2005) states: “There is no paleoclimatic evidence for a seasonally ice free Arctic during the last 800 millennia.”
73-45 million years ago was the Cretaceous, there are fossil records of animals like Crocodiles living within the Actic Circle, I referenced a paper about that period in #317 – the abstract is worth reading.
#354 SteveSadlov,
I keep going back and trying to find a reason not to see this as indicative of a fundamental change in the Arctic ice-sheet. I keep failing.
RE: Scottish ski areas. Well, here in California, investment continues apace. The biggest problem is a people problem. Most people here live in very temperate coastal and lowland areas. Once you get past February, the weather in such areas improves to the point where people, for the most part, start to forget about the snow in the more highland / inland areas. So, as a result, ski areas here make or break based on what they can do in astronomical winter. We have wonderful spring skiing. Very uncrowded. If the ski operators ever figure out how to inexpensively remind people that March – May can be as good as or better than Nov – Feb, then they will clean up. As it stands, they are gambling a bit with their expansions, things will definitely get a lot more competitive.
#360 Fred T34,
I certainly can’t afford $1000 given my latest pay award (pitiful). But I’ll bet The Arctic Ocean won’t be ice free (no area >15% concentration) at any time in 2008.
My forfeit? I’ll end all of my posts here with the tag-line: “But I’m a complete donkey, so what do I know.” If you’ll do the same in the event that you lose the bet. ;)
FredT34, you can probably find takers on that, if you’re wagering.
http://www.longbets.org
Re: 360
You would probably lose your bet.
The multiyear ice has piled up against greenland and is 5 meters thick.
The is the exact area where the Danish is trying to figure if the Lomonosov ridge joins Greenland, so they can claim (or coshare with Canada) the North Pole, under the Law of the Sea Convention.
Anyways the Danish Vessel ODEN could not proceed as it got within a few hundren KM of Greenland, due to the thick 5 meter ice.
Now the ice in the rest of the arctic is thin and full of holes and melt ponds.
Now if you bet that the North Pole would be ice free in 2008, you might have a small chance of winning in 2008
Re #360 et al.
I agree with Larry that north of Greenland there will still be some ice next year. But if you still want to place a bet try James Annan:
https://www.realclimate.org/index.php?p=161
Make sure you know what you are agreeing because he is not stupid. He has a PhD.
RE: #361 – You seem a bit confused between sea ice and continental glacial ice. What we are talking about in this thread is the former – it freezes out of the sea water. The latter is what is on Greenland, and is sometimes referred to in vernacular as an “ice sheet.” In any case, I think what you may be trying to say is, you believe there has been some fundamental change in sea ice behavior. Perhaps. The question for you is, do you trust passive microwave remote sensing? And a subsidiary question, do you trust the processing of raw data from such sensing especially in light of “adjustments” made earlier this year?
RE: #365 – That is probably the most interesting thing about the current NH sea ice situation. That thickening is a result of three things, wind, the wind’s fetch, and currents. A key set of variables often overlooked in these sorts of discussions.
re: #364 hank
However, the minimum bet length @ LongBets is 2 years… will have to go to 2009 at least.
Re 319 (negative feedback)
Definitions of negative feedback with respect to a metastable state are intuitive but not very general, because there’s no guarantee that such a state exists or can be identified. A more conventional definition of a negative feedback – consistent with both engineering and climate science – would be a response to a disturbance that opposes the initial disturbance.
A first-order negative feedback system does tend toward a stable state, but when the dynamics are more complex, a pure negative feedback system can be unstable, as 306 points out. Consider a shower in an unfamiliar hotel … hmm, a little cold, turn the knob … too hot now … turn the other way … ooh, freezing … other way … ow! Pure negative feedback, turned unstable by dynamics (the delay in the pipe). One quickly learns that it’s better to be less aggressive with the taps, that is, it’s better to be overdamped.
Tom
Hey, he can bet that 2009 will be the _second_ year in a row with a complete Arctic Ocean melt (grin). I just want to see him put up the money there and watch the crowd respond.
Browsing through an ancient volume of Science (March 16, 2007), I encountered this passage regarding what the models have to say:
Now I’m a complete donkey, so what do I know… but from my asinine perspective, it’s astonishing how quickly these models (possibly the ultimate achievement of computer science) are getting shredded by observations.
Re #368
Daniel you are absolutely correct.
Here’s something sort of off topic, sort of not. Anyone here have any thoughts about Wrong Way Flanagan? (Hint – boat …. trapped ….. ice).
A generaliztion:
Is the primary concern limited to hopw much ice will melt?
We are programmed creatures of the visual so meltback is liktly the extent of what we canr elate to.
Asking the larger questions: impact on Western North American precip and temperature ranges during the next winter wheat season; or, where will the massive heat influx to the Arctic atmosphere go when the open ocean freezes—- seems too complex to grapple.
Rather, we awould like to know more before we wager a bet on 2008 meltback.
Where are we really when we face the most compelling evidence of AGW?…looking for a safe wager.
Re #367
2040 is presumably from Holland, Bitz and Tremblay, discussed here:
https://www.realclimate.org/index.php/archives/2007/01/arctic-sea-ice-decline-in-the-21st-century/#more-391
Mentioned several times above.
I tried to post updates of Bitz’s RC plots showing the current extent, but mods rejected (copyright I guess). Yes, it does begin to look like even the most pessimistic model projections will be wrong, but early days yet. That tends towards confirming a long-standing suspicion. Climate modellers used to being beaten about the head by sundry nit-picking contrarians might lean ever so slightly towards conservatism – in both model design and parameter choices. Compounding tiny conservatisms could lead to significant under-prediction in a complex modelling exercise. There’s already other tenuous evidence in that direction (vis sea level predictions).
RC should invite Cecilia Bitz back to comment, once the September mean ice extent is in.
Yes, ice models got it wrong, but have they been programmed to integrate “hot” Polar Anticyclones? I have seen 2 such phenomenas in the past 25 years (North American side only), in 2007 and 2005, it is stuff that is not even in the text books, let alone programming. I think we must go beyond the computer code competence debate and focus on the reasons why its +30 C in Northern Quebec when there is still snow and ice on the lakes while further South it was +15 C! My best guess, and for lack of a complete rack of data to plunder, its the upper Polar atmosphere which was warmer, given a stable anticyclone which warms up abnormally warmer descending upper air. Looking at Cryosphere Today animation and at NSDIC cloud cover report:
ttp://nsidc.org/news/press/2007_seaiceminimum/images/20070822_cloudanomaly.png
It is highly likely that there was a similar stagnant High Pressure North of Alaska in June. Anticyclones usually give colder weather in the Arctic, so this is perhaps something definitely to study, when the surface (white snow covered ice) is not the primary source of heat and melting occurs.
A sunset today towards the Arctic Ocean Open water was quite early, by 5 to 10 minutes, this strongly suggests an extreme lower troposphere which is unusually warm to the West of 74 43 N 94 57 West , the Upper air sun oblateness is a little more normal above the horizon, slightly warmer than last yea at this time.
Thanks much, Glen Fergus (#375), for providing the attribution and the link (as I should have done). Regarding plots of the current extent, I am also grateful to someone a couple of hundred posts ago who shared the Cryosphere Today link.
http://arctic.atmos.uiuc.edu/cryosphere/
The materials there are exceptional in terms of graphically conveying what’s going on at the ends of the earth.
But Glen, in any other profession (even computer science, where practitioners are accustomed to compounding innaccuracies) “ever so slightly” would connote a near miss. It should be clear by now that the models are missing quite badly. 2040 minus 2007 (the date of AR4’s publication) is 33 – when the correct answer is probably closer to 3. That’s off by an order of magnitude.
The public consequence of this degree of inaccuracy, whatever social causes may have factored into it, is that leading climate scientists have contributed to the perception that AGW is something we don’t need to worry about for another few decades. Granted, this is an absurd conclusion from the IPCC report as written. But it’s a conclusion many people have arrived at, nevertheless. If this has happened because scientists have been “beaten about the head” as you suggest, then one has to conclude that such forms of persuasion have proven quite effective in this instance.
It turns out the passage I quoted in post 371 above is not from Holland, Bitz and Tremblay, but from a review (a pretty good one) in the “Polar Science” issue written by Serreze, Holland, and Stroeve.
http://www.sciencemag.org/cgi/content/abstract/315/5818/1533
Sorry for the inconvenience (which is God’s final message for mankind, according to saint Douglas Adams).
#375: Are the models wrong?
Current sea ice extent is 4.42 km^2. Add this data point to the red curve on figure 2 of the page you linked to (the red curve correspond to actual observations while the other 7 are simulations), and the red curve still looks like an 8th run of the same set. Curve number 8 is low but doesn’t stand out. And, even when the model is perfect, there is still a 12.5% chance that the observed run is the lowest one of the ensemble.
12.5%… To me, this means that, most likely, the model is missing something significant.
Well, for the last few years reality has been at the low end of or below simulated runs. So now we have the actual data of those last few years, and it’s just a matter of understanding it…
I would be interested in hearing climatologists’ conjectured explanations and how they plan to check those conjectures. So. Some conjectures I’ve seen on this thread.
– phytoplankton
– virus-like”particles, biological feedback
– “hot” Polar Anticyclones
-” it all started when we lost the overall ice thickness and mass between 1989 and 2000. This loss occurred without the benefit of the albedo feedback. The mechanism for this loss has not been explained or understood to my knowledge. “— is this true? It at least points to a direction on which to focus
Did I miss other proposed explanations?
Are there any other guesses as to why simulations and observation are probably in disagreement?
Calculate this carbon footprint and tell me if I have a problem. My neighbor owns these vehicles and I am truly disgusted.
1972 Chevy Blazer K-5 454
1996 Chevy Suburban 2500 454
2006 Ford F-450 Powerstroke 6.4 Liter Diesel
2006 Audi RS4
2000 Porsche Targa
1996 Buick Roadmaster 5.7 Liter(he says)
2005 Hummer H2
What is the damage here?
Steve #367,
I’m only confused by why you think me confused.
Overpeck clearly refers to the ocean ice sheet as you would not get an Arctic seasonally free of glacial ice – glaciers take >1 year to come and go. My reference to the Cretaceous was to add to a poster who had referred to it above.
I did see the animated gif referred to earlier with regards changes to datasets. But I’m not a professional, so I have to rely on the professionals, if people like NSIDC retract this years data then I will (with relief) change my opinion appropriately. I am not qualified to second guess. However Peter Wadhams earlier this year was talking about the possibility of an ice free Arctic by 2020 due to findings on ice-sheet thickness, with NSIDC staff saying it was unlikely. All that was before this melt season. I await their opinions on that with interest.
But if Serreze was saying in March that we might be near a change in behaviour:
“When the ice thins to a vulnerable state, the bottom will drop out and we may quickly move into a new, seasonally ice-free state of the Arctic… …I think there is some evidence that we may have reached that tipping point, and the impacts will not be confined to the Arctic region.”
Then where does this melt place us, further away from any such transition point?
The impact of weather on the ice can generally be viewed as a random factor, any trend in weather may be down to AGW and local changes, so it’s hard to say what trends will continue. In any case as we have seem this year, a particular “weather event” can still have an impact that creates such changes they are likely to affect following years, and indeed the overall trend.
Perhaps the next few years will see an unexpected cooling – but I wouldn’t place and climb a ladder on the assumption that if I fall I’ll have a soft landing.
Hi Brendan. Some just can’t seem to ever get satisfied. At this point he should diversify and get a large boat or an airplane (both nice ways to burn fuel and spend money).
However, purely from the emissions POV, it’s better to have all of these vehicles owned by the same guy, who can use only one at a time, than have each one of them owned separately (and therefore all used concurrently). Think about it, each one of these cars spends probably over 95% (likely over 97% in fact) of its time parked, which is a good thing.
#380: well, your neighbor can have as many cars as he likes, but he can only drive one at a time, so it doesn’t relly matter how many cars he has: at any time at most one of them will be on the road polluting, and the others are just pieces of metal sitting there like tree stumps.
Re #380, 382:
Each vehicle takes energy to make. As a rule of thumb, 10% of the total energy used by a car goes into making it and 90% into driving it. A person with 6 lawn ornaments and 1 useful vehicle is still making 60% more CO2 emissions than someone with just 1 useful vehicle, assuming those lawn ornaments get scrapped at about the same rate as regular vehicles.
The vehicles also need to be stored somewhere. In the best case they’re just left sitting on the lawn, costing no resources. What is more likely is that they are on some sort of pavement (concrete being a major source of CO2), perhaps even in a garage.
Beyond the CO2 aspect, those cars represent a lot of wasted resources in a world with a lot of needy people.
Brendan, the “carbon footprint” is calculated from _fuel_use_.
If he sold them, would they be used more than if he keeps them?
A lot of us right now are in this transition, with internal combustion engines on vehicles we have long owned, use intermittently, and can’t replace yet. Come back and post your total gasoline, electric, and natural gas use per year and how you’re reducing it. That fuel use is your carbon footprint.
The single cheapest way to quit being disgusted is to improve your own behavior and be a good example.
off topic regarding the cars:
manufacturing and transporting a car are very energy intensive … I’ve heard numbers in the 50% range … in the live of the car, 50% of all emissions are due to the manufacturing process. Having 7 is not the same as having 1.
Does anyone here have numbers on sea ice area more recent than 28th August? Or access to the daily numbers charted in the graphs at Cryosphere Today? It looks as if area has levelled out at 3M sq km, while the NSIDC site shows the extent is still dropping. Both are around 60% of the 1979-2000 average for this date.
My impression is that in a typical year the core ice pack would be at 100% concentration, and melt around the edges would mean that the whole extent had 70% ice cover. This year, we’re down to just the core ice pack, and that’s at 70%. As others have observed, there is thick ice north of Greenland, and the rest is thin and melting.
My entirely amateur prediction is that the freeze will go slowly, winter ice area will be a record low around 10-11 M sq km, there will be late-winter rain in Svalbard, and a record low and early start to the melt season in March. Where it goes from there depends critically on the winds and currents in the spring and early summer, and what they do to this core multi-year pack north of Greenland. Some of it will flush out down the east coast, as it does every year. But how much. The rest will all melt. Anyone up for a sweepstake on the date for the NWP opening in 2008?
John, look at the graphics (recent topic in “Open Mind” — see the link on the right hand column under “Other Opinions”). There are so many different measures that it does help to look at them as graphics, and Tamino is just now collecting that information in one place.
Also of course see http://www.globalwarmingart.com/
Those may both be listed also under the “Start Here” link.
Re #386:
“manufacturing and transporting a car are very energy intensive … I’ve heard numbers in the 50% range … in the live of the car, 50% of all emissions are due to the manufacturing process.”
– John P.
Motor gasoline usage in the USA is nearly 10 million barrels per day (according to the EIA, http://www.eia.doe.gov). This is about 50% of all oil consumed by the USA and about 20% of all energy consumed by the USA. The manufacturing sector uses about 32% of all energy used in the USA, so I really doubt if auto manufacturing alone uses 20%.
Many here will already know this, but folks should be aware that Steve Sadlov is a denialist who often just makes stuff up.
Re #298: Paul Ehrlich suggests “Arbustocene” as an alternative to Anthropocene.
Well the Canada Ice Center has come out with a report of ice conditions for the Canadian Arctic.
Update on the Canadian Arctic
The report has some information information, but their appears to be some caution on declaring the arctic ice in the Canadian Arctic at a minimun.
At the end, their is an intersting writeup on how Cryosphere Today tends to underestimate ice concentration, for low concentrations of ice.
Regardless, Global warming knows no national boundary, and if you draw a straigt line from Alaska thru the North Pole to Russia, you will see that most of the Ice favors the North American side anyways, due to winds and Arctic currents.
Im actually amazed that their is not more ice in the Canadian Arctic, but it appears that the arctic ice, being pushed in is melting out before it can clog the shipping channels of the sourthern portion of the Canadian Arctic.
Environment Canada has also that no new ice will start forming until the last week of September in their 30 day ice forecast.
Re. #386 and #389, the peer reviewed studies that have been done on the subject put the percentage of a car’s lifecycle emissions that are due to the combined manufacturing and disposal processes at around 15%, the other 85% being due to the vehicle’s operation. E.g. see MacLean and Lave .
RE: #391 – “At the end, their is an intersting writeup on how Cryosphere Today tends to underestimate ice concentration, for low concentrations of ice.”
I agree. I also suspect NSIDC have similar issues. It may be an artifact of the whole passive microwave paradigm.
RE: #390 – Wrong Bloom. I am a responsible, scientifically informed environmentalist. I want facts. Science. Numbers. Accuracy. I abhor politics, blather, hype, feelings-based decision making, etc. Is it too much to ask?
Re #394: Oh there is ever so much evidence. We could start with the recent thread over at RP Sr.’s blog where you started out claiming the Arctic sea ice trend was being influence by Siberian dams, falling back on Siberian river diversions afer it was pointed out that there aren’t any dams, falling back on fact-free questioning of Soviet-era precip figures after it was pointed out that there aren’t any river diversions, and finally just disappearing in a puff of smoke. Will you link that or shall I? But really, all one has to do is read up this thread to see several instances of your wishful thinking.
Anyway, I don’t especially care about this stuff since I’m obviously well aware of your habits. What concerns me is that someone new to this site might believe one of your factoids.
But why don’t you just nip the problem in the bud and stop, at least on this blog? Obviously you’ve got free reign to say whatever you want over at Climate Audit where it doesn’t do any harm. I don’t see why that shouldn’t suffice.
Thanks for the Canada Ice Centre report Larry, very interesting. If anything it makes me more pessimistic about the near term future of Arctic sea ice, the dramatic reduction in multi-year ice and its description as ‘rotten’ should make for an interesting few years!
Sadlov,
You seem to claim on CA that all of the ice is being forced, by currents and prevailing winds, up against Greenland. However reports from that area seem to say that the ice is 5m thick. I would think that given the amount of ice you say is being carried there that the ice would be much, much, thicker. But, it doesn’t seem to be. How do you explain that?
Citing Canadian ice reports (or even NOAA ice reports for the Arctic Ocean), which you claim that crabbers rely upon — NOT! mainly because they fish S of the Bering Strait along the Western Coast and Alutien islands… The advisories out of Anchorage are advisories for mariners, but I find it hard to think of any commercial fisherman (maybe native whalers) who venture into that part of the arctic.
Please note that the Canadian ice reports mainly relate to the area between the Canadian mainland and Greenland. This is an important area, but it is hardly the entire arctic ocean. Your constant weather reports do not provide a whole picture of the ice extent in the arctic. You should be more inclusive in your reports — even the maps that you link to show a severe loss of sea ice extent. Just what do you think is happening up there?
#391 Nansen correctly used vectors in order to explain ice movement, currently there is an was a High pressure system in the SW quadrant of the North American Pole sector. Combine this with the Arctic Ocean Gyre, and you get a stronger gyre circulation overriding the Southwards Canadian Archipelago 2 nm a day channels current . ….
With retrospect, models themselves may give a clue of what just cause this massive extra ice melt. RC readers may recall Polar Amplification Article:
https://www.realclimate.org/index.php/archives/2006/01/polar-amplification/
Of which several dozen GCM’s forecasting distant in the future Polar ST’s equal with current temperatures in the Arctic, the projections were inaccurate temporally, but were very accurate with respect to the trend direction (severe warming). This goes likewise with Met Office Ice coverage projections (again off by several decades), this probably means that the common denominator between Polar amplification models and Ice extent projections (despite different GCM codes) is more am atmospheric trend calculation error rather than sea temperatures , even if sea and atmosphere are severely intertwined, its probably easier to model sea temperatures since they don’t change as quickly as the air, and this years melt was driven by High pressure cloud free weather.
and this years melt was driven by High pressure cloud free weather.
Naive question: is the presence of high pressure, cloud free weather an incidental or is it a consequence of past warming?
Does anyone know the age of the physical ice itself in the oldest multi-year ice in the arctic? (I’m not looking for the age of the multi-year ice phenomenon, but the age of the actual ice) In 2007, in addition to young ice, have we been melting off multi-year ice that is tens, hundreds, or thousands of years old? Likewise, is the remaining multi-year ice north of Canada and Greenland a few years old, 10 years, or hundreds?
Another question: how long does it take to grow 3 to 5 meter thick multi-year ice?