PIOMAS March 2013

Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center:

Excellent news! The trend line has crept up some more and 2013 now has 133 km3 more ice than 2012 and is virtually tied with 2011. It seems the cold of the past weeks has thickened the ice pack considerably. I was getting worried about the coming melting season, especially with those huge cracks already opening up, so this is definitely a relief.

Here is Wipneus' version with the calculated "expected" 2013 values (dotted lines), based on the same date values of 1979-2011 and an exponential trend.
A caveat from Wipneus: "Note that the statistical error bars are quite large."

I didn't think it would happen, but the anomaly trend has shot up and reached the 1 STD zone, just like in 2011 and 2012:

And how about average thickness? Here's the PICT (PIOMAS volume divided by CT area) graph:

The rise looks remarkably steady and if it weren't for the 2012 dip, this year's average thickness would still be well below previous years. Here's average thickness for March 1st (in m):

• 2005: 1.70
• 2006: 1.81
• 2007: 1.67
• 2008: 1.66
• 2009: 1.66
• 2010: 1.59
• 2011: 1.56
• 2012: 1.49
• 2013: 1.45

The thickness graph from the Polar Science Center is basically showing the same, except that here 2012's dip has put this year and last year on a par too:

So thickness is still lowest, but at least volume is back to abnormal. That should give us something to hold onto when the melting season starts.

Comments

[Chris Reynolds]

1) Take time series of Min to Mar 1 volume change and min volume. 1980 to 2012.

2) Detrend using interannual differences.

3) Calculate correlation of previous year's Min to Mar 1 volume change, to the following summer's min. i.e. both in the same year.

Correlation 0.511 for 1979 to 2012 (stat sig 95%). For post 2007 it's 0.810 (stat sig 99.5%).

So there is a correlation between high growth of volume from minimum until 1/3/xx and this correlation seems to be stronger post 2007.

However key to this issue is what has caused the volume increase. It is thickening or loss of thickening that will have a greater impact on seasonal melt. Extension of ice at the sides puts ice in areas where it will melt out. Not within the Arctic Basin, where the minimum is set.

Both PIOMAS thickness and thickness calculated from CT Area and PIOMAS volume do not support thickening.

[Neven]

Okay, another dinner is behind me (literally tomorrow). Time to calculate the thickness.

Chris, do you think most of the volume was created on the fringes (Barentsz and Kara for instance, who have much higher SIA than last year)? It was mighty cold in the centre for a couple of weeks.

[Chris Reynolds]

I suspect so. I'd have expected to see thickness rising to join 2011/12 but it's the 2012 thickness plot that dropped to 2013's level. The behaviour of calculated thickness is useful in this respect. I've found that it helps sort out volume loss from area loss and thinning. In this instance calculated thickness is running smack below 2011/12. So I don't think thickening is happening, I think it's gain of area, which we've seen in CT area increases. I presume extent metrics are climbing - but as you know I don't bother wit extent.

I still think we'll see a record sharp spring volume loss in PIOMAS and a record June Area anomaly crash in CT. I still think we'll see a new record. We'll know by July.

Damn, I'm writing down everything I'm writing into my blog post...

[Dave C]

Chris- Thickness did increase significantly last month.

http://psc.apl.washington.edu/wordpress/wp-content/uploads/schweiger/ice_volume/Bpiomas_plot_daily_heff.2sst.png

It looks like we are almost exactly in the same place we were last year with respect to volume, thickness and area.

For those keeping track, 16.4 in 2008 was the previous largest volume gain through March 1st. This years volume gain has been 16.7 through March 1st. As we all know, 2008 was the only year this decade with a volume recovery, finishing 600k km3 higher than 2007. Winter ice gain has a large effect on summer minimums.

When ice cracks during the winter this opens up water and results in even more ice. We clearly saw this in February. We still have another month for ice to gain even further. Volume peaks in April.
It seems that the most likely mechanism for cracks resulting in melt would be increased ice transport. But these cracks are a long ways from the fram strait or eastern edge that ice mostly gets transported to.
Also, ice transport by volume through the fram has been remarkably steady over the years. It seems like increased ice mobility is being balanced out by decreased ice volume available to flow through the strait.

https://sites.google.com/site/arctischepinguin/home/piomas/grf/fram.png

We can also look at melt volume for the last 5 years. Admittedly I know very little about physical changes in the ice. But statistical trends do not seem to point to a record breaking volume melt this summer. I would be surprised if melt was much above 19.
18.1, 18.2, 19.0, 17.9, 18.7.

It's possible that there will be record melt this summer to counteract the record ice gain, but I don't see any strong theoretical reason to count on this. Partly as a nod to the similarity in conditions, my current prediction for volume minimum this year is 3.26.

[I Ballantinegray1]

We do have the 'growth' at the edges but also the fill in ice as the cracks have opened. Neither of these areas of 'growth' should fill us will confidence for the melt season to come?

I know we have to be hopeful for some kind of recovery over the coming months but I have tried this since 07' only to find myself burned again come each ice min.

My reality remains one of a basin with a majority of thin young ice with even the older ice merely a 'Sheep in Wolf's clothing' ( being a skim of older ice underlain by a keel of FYI.....) and a basin that is able to see off 2m plus FYI before the start of Aug even with 'average' weather.

[Neven]

It seems that the most likely mechanism for cracks resulting in melt would be increased ice transport.

Actually, I would think that if the thin ice in those cracks persist and the cracks don't close, that ice will melt out very fast once the Sun starts pounding it, this will cause open water between thicker floes, absorbing more heat.

If the cracks cause faster melt, this would in theory be the way, I think.

Damn, I'm writing down everything I'm writing into my blog post...

Give us a link when your blog post is up. I will then go over there and say that you've already said that in your comment over here. ;-p

[Dave C]

Looking at an arctic insolation diagram seems to indicate that the sun is not a large factor until April.

http://2.bp.blogspot.com/-k_S7N0VlMRg/UH4RNvJ3cjI/AAAAAAAAFjk/lqjQhGqLWOk/s1600/insolation_latitude.gif

My guess is that the ice cracks before it melts every year. But if the sun isn't shining then it seems that it would not make a difference whether the ice cracks in February or April.

I could be wrong on all three of these, but they seem like reasonable guesses.

Using another quick metric- Volume peaks on April 15th. Ice is approximately distributed from the 60th to 90th parallel. It's likely that volume is shrinking on April 15th below the 75th parallel but still growing above that. So it would seem that ice in the Beaufort area would have another 30-45 days for ice growth.

I guess we'll have a better idea in a few months.

[Neven]

My guess is that the ice cracks before it melts every year. But if the sun isn't shining then it seems that it would not make a difference whether the ice cracks in February or April.

It depends on how large the cracks are and whether they then close up again. The current cracks are pretty large, I'd say.

Imagine that becoming open water. Hopefully it closes up again.

[Espen Olsen]

Dave,

Yes cracks are common this time of the year, but not in this magnitude, and of course it adds to both extend,area and maybe perversely volume , but it also give room for more potential melt due to increased melt surface, it is very much like watching the last hours of a persons life.

[Chris Reynolds]

"Chris- Thickness did increase significantly last month."

Sorry Dave, I think you're seriously wrong on that. Look again at that graph, 2012 levels and meets 2013, 2013 does not increase to meet 2012 or 2011. Indeed 2012 and 2011 are parallel.

I've mentioned you in my latest blog post:
http://dosbat.blogspot.co.uk/
Mainly because you're drawing the sort of flak I used to but also because I think you raise a point worth addressing.

To add the one point made over there that's not been made here:
http://farm9.staticflickr.com/8103/8481914926_1c34bd0f27_o.jpg

"I also note that since the 2010 volume loss every year has shown a drop on the previous year's volume minimum, in fact since 2001 every year has been a year on year drop apart from 2007. 2012 may have soundly beat 2007 but in the PIOMAS volume realm it is a slight event compared to both 2010 and 2007."

What I am saying here is that 2007 isn't like 2012. 2012 was a horizontal volume loss in an already thinned pack. 2007 involved the destruction of a lot of thick ice over a large area. So 2008 rebounded because 2007 was so far below the equilibrium. Since then the equilibrium has moved on. 2012 really wasn't much of an event in the longer trend.

Insolation isn't a factor until March - when peripheral ice starts to retreat. However ice in the Arctic Ocean continues to thicken until April, keeping volume going up and delaying the volume peak until that month.

[Robert Fanney]

Lots of thin ice just North of Barrow...

Looks to me, when analyzing the ice distribution via the US Navy thickness map that most of the thicker ice this year is in the region of the Barents and Kara Seas. So this, somewhat thicker ice, is in more danger of melting out. Looking at the region of thicker ice just north of the Arctic Archipelago and Greenland, this area seems to be thinner and less widely distributed than during the same period of 2012.

So I'm not sure what to read into overall volume measures from PIOMAS touching the 2012 baseline or just slightly exceeding it.

Overall, I think Chris probably has the forecast correct. Will be very interesting to see when melt starts and for how long those volume figures hold.

[Danny Lane Anderson]

Greetings Neven and thank you for this fascinating weblog and discussion platform! I enjoy devouring it fairly often! :o)

"I was getting worried about the coming melting season, especially with those huge cracks already opening up, so this is definitely a relief."

Neven, I'm glad to hear you're not worried now. But what was there to possibly really worry about in any case? If you wish to entertain ideas of worry sometimes, that's valid and ok. But imho there is no need to allow oneself to be in a state of worry. Why worry about something that is done and inevitable.. It is done. the entire Arctic Ocean is a vast solar radiation-absorbing, warming, moisture-sourcing, Gulf-Stream-gulping, sparkling blue ocean as entirely open as the mid-Atlantic.

Whether the experience of this incredible shift is this year or in three years, it is immanent and can be considered done within the illusion of "time", as you know. It's not easy to imagine avoiding it at this point. Possible unpleasant outcomes of this aside, I certainly look forward to the immanent ice-free Arctic Ocean with excitement, awe and wonder. I'm trying to not worry about unpleasant possibilities and instead focus on the positive aspects about this. What a thrilling mystery it is.

In my understanding, the outcome is still a largely unpredictable unknown. It could be the quick start of an Ewing & Donn-style new Ice age from colossal ocean-effect snows (still a possibility if you ask me!) Another outcome imho is the start of a Late-Eocene-like stable very warm climate state worldwide. Or most of us may enjoy some surprising - maybe pleasantly surprising - unforeseen outcome (my favourite) of an ice-free Arctic Ocean and the likely attendant methane releases. Why even begin to worry anyways, considering that you are an eternal being with nothing to truly be afraid of? (at least I know you are an eternal being, whether you believe this or not) :o)

[Neven]

Thanks, Danny, now I feel even better. :-)

Until we hit another record, of course... ;-)

[Danny Lane Anderson]

You're very welcome, Neven! :o)

[Wayne Kernochan]

@Neven: if volume is "per abnormal" but average thickness is down at this time of year, that probably means additional ice at lower latitudes, which will melt out early anyway, plus less thickness than usual further north.

I'm afraid I'm not reassured by this at all ...

[Dave C]

Chris Reynolds-
It looks to be increasing to me. I guess we could disagree about the meaning of the word "significantly". My main point was that the gap between 2012 and 2013 significantly decreased, which seems clear.

My general hypothesis is that 2007 permanently changed ice patterns in the arctic. Because of this I believe that you should overweight melt and gain data from 07 onwards. If you do this, then the trend lines(relative to 10 or 30 year) for ice melt are decreased since we have been on a slight ice melt plateau over the last 5 years.

I also tend to look at the big picture using the easily measurable metrics. I'm sure some details are important but in
general I assume that various less measurable tendencies will be roughly reflected in the primary numbers. This could be falling prey to the availability fallacy, but to adequately look at every factor would be a full time job. This could certainly change in the future, but in the last few years the statistical predictors seem to have done better than the "measure all the details" predictors.

You are correct that 2007 was much further below the trend line than 2012 and that ice gains are somewhat countercyclical. Winter gain is countercyclical to the previous summer's loss. However, summer loss does not seem to be countercyclical to the previous winter's gain. Summer loss seems to follow long term trends more closely than winter gain. Those trends predict about 18.5 to 19.0 of summer loss this year. In any case, I am not predicting a 2008 level of gain. 2008 gained 600k km3. I am predicting about a 0 gain or loss for 2013.

I could be wrong, but if I am right then a lot of people here might be surprised at how high the volume minimum is this year.

[Nightvid Cole]

Is there a good reason to think the volume gain cannot simply be a result of the ice going out Fram Strait now being so much FYI and thus less volume export than normal?

[Tom Lyons]

I believe we will see a greater loss this year than last, as long as snow cover indicates an ever earlier retreat to facilitate that loss than last years. 2012 surprised me when it came so close to 2011 this time of the year, so it is not changing my predictions of a BIG drop in the record minimum ice volume...

[scarlet p.]

Danny Lane Anderson's comment was actually quite inspiring - Nevertheless the Last Days are Here...

That is, the last days of my freeway slogan contest!

http://www.freewayblogger.blogspot.com/2013/01/second-annual-slogan-contest.html

Deadline's March 15th. Best entry so far: "Worst. Ancestors. Ever."

[jonthed]

Surprised you genuinely seem pleased with the volume increase Neven. As Danny has already pointed out, the arctic is already gone, and as Espen says, it's like watching someone on their death bed, and getting excited that one particular painful gasp of breath was less rattly than the last one. The ice is gone, the climate still has a long way to go to reach equilibrium again even if we stopped emitting tomorrow.

I must say I think that another record breaking year and new low for the arctic may be more beneficial to the climate than a debatable "recovery". We need action ASAP, disappearing arctic ice may be our best shot at getting enough people concerned. I don't want the skeptics to have more fuel for the doubt machine, that would only delay action, and not save the arctic anyway.

This is bad news to me, but I still think we'll be in for a new low this year, so we'll see what the public make of it then.

Keep up the good work, and I love that slogan Scarlet P!

[Robert Fanney]

One month of slightly above record low values does not a recovery make...

For me, the Arctic is the canary. I really hope people are taking the warning. Responding when Greenland melt is seriously underway would be quite late.

[Neven]

Surprised you genuinely seem pleased with the volume increase Neven.

Sorry about that, jonthed, it's the Alarmist's dilemma. To melt or not to melt?

[idunno]

It seems to me very expected that volume should increase significantly after the very cold snap.

As Dave C has imnvho correctly noted on another thread, this suggests that 2013 may be a recovery year.

I wonder if very cold ice is more brittle? Anyone?

This might help to explain the cracks...

If the ice is colder, with surface air temps of -40C, then the top surface of the ice should be down towards -40C; if the SAT is -20C, the ice surface should be closer to -20C.

Given that the ice is still thin, then if colder ice is more brittle, or less able to flex, this would make it more prone to cracking. Yes? No? Maybe? Wrong thread?

[Steve Bloom]

New paper (open access; Jennifer Francis co-author): "Cold winter extremes in northern continents linked to Arctic sea ice loss"

[John Christensen]

On hopefullness:

Let me side with Neven that volume gain is a positive relief, even if the patient is still dying.

I have downloaded the daily PIOMAS data since 1979, and if anyone care to analyze this, you would see that the Arctic ice was doomed already by 1979 - this did not happen in the 80's, 90's or 00's.

That also leads to some hope for me, as there will need to be agreement that AGW was less of a factor in 1979 (when we had temporary cooling due to aerosols negating CO2 effect, etc.), but the ice volume was nosediving already, so doing that for another reason.

I took PIOMAS data creating a 14-day running average, and when comparing the main freeze period to the main melting period, the melting was substantially stronger than the freeze, in every single year, without any exceptions.

Daily freeze hardly ever reached 120km3/day at any point since 1979, but in every year since 1979, the strongest melting period of three-four weeks exceeded 200km3/day.

Water currents..

[John Christensen]

@idunno:

Yes, frost cracking.

[Al Rodger]

John Christensen.
If you analyse global temperature data as you did the 1979 PIOMAS data, you will note than the present warming began before 1979. Indeed, it can be seen from 1976. It may be that 1976 within its time can be considered as 'just another wobble' in a non-warming world, but it was a warming wobble and thus has all that is required to have Arctic-melting abilities. If PIOMAS covered 1976, it would surely show melting on an annual timescale for that year.

The Arctic Ice was not doomed because of 1976 or 1979. It is doomed because 1976 has proved to be more than 'just another wobble,' being the start of a world experiencing AGW.

[crandles]

>"the melting was substantially stronger than the freeze, in every single year, without any exceptions."

Um, maybe I misunderstand but you have realised that the volume max is in April and the volume min is in September so 5 months of melt and 7 months of freeze. Therefore if the volume is anywhere close to being in balance, the melt has to be lot stronger than the freeze.

In top right graph of
https://sites.google.com/site/arcticseaicegraphs/longterm
I count 8 occasions where the volume gain exceeded volume lost. Probably/possibly that is getting less frequent.

[A-Team]

The ice is changing character (aka pre-melting) already out on the central Arctic first year ice and has been for some time. You can see that by looking at the subtle pinkish blue cast of unretouched Jaxa color radar (upper left), comparing to areas of known melt in SE Greenland, Kamchatka, NE Alaska, Barents etc.

Or not, 9% of euro males have some form of colorblindness affecting the OPN1MW cluster on chrX 153,108,088. For you, the next image (upper right) shows what happens when the Gimp color picker is initialized off a single blueish pink pixel (color space radius of 15) off Kamchatka. That's filled in with solid pink (lower left). Pink in the original image can also be enhanced (lower right).

Results will vary according to the initial pixel (or small block of pixels), tolerance in color space, anti-aliasing, feathering and so forth. However the outcome is fairly robust -- the pinkish blue cast of unretouched ice has very similar radar characteristics to the first ice about to melt at lower latitudes.

This Jaxa color radar only goes back to July 2012 so multi-year comparisons are problematic. From animating the last 6 months, minimum pinkish blue occured in early February.

[John Christensen]

Al,

Please see the data below:

1980: 11381 (94), 15875 (131)
1981: 10752 (89), 17720 (146)
1982: 11651 (96), 15276 (126)
1983: 12065 (100), 15264 (126)
1984: 10538 (87), 15508 (128)
1985: 11647 (96), 16269 (134)
1986: 11737 (97), 14817 (122)

Explanation:

The first number is the 14-day running average daily ice volume increase, totaled for day 305 until day 60, i.e. winter ice volume increase.

The second number is the 14-day running average daily ice volume decrease, totaled for day 120 to day 240, i.e. summer ice volume decrease.

In parenthesis you see the average daily value for winter and summer (again from the 120 day periods).

As you see the winter ice volume gain is no match for the summer melting, and with the summer melting in 1980 being already 39.5% more than the 1979/80 winter volume gain - as well as the steadiness of the inequilibirum, there is no chance that there was a state of balance just a few years earlier as I see it.

As the debate is developing, it is becoming clear that volume is a much better predictor than SIA or SIE of what is going on in the Arctic - and what will happen in the next few years, which is why I started looking at PIOMAS data in more detail.

However, I know the topic of AGW is quite political, but thought that there should be scientific interest in trying to understand the reasons for ice volume development, as it does seem to suggest an underlying, ;-) , factor of significant importance other than air temperature increase.

[John Christensen]

crandles,

You are right; I was just looking at the numbers and had not yet considered the period of melting vs freezing. I was struck by the difference in volume change for the heaviest freeze/melting.

The difference in duration definitely changes everything.

Another item I noticed, was that strong melting in recent years starts earlier in the season, but also ends earlier (E.g. melting of more than 100km3/day or more than 200km3/day.

I am interpreting that to indicate that current volume is so low that strong volume decline ends earlier in the summer, since we have a very small ice pack remaining at a high latitude. Thoughts?

[sofouuk]

I know we don't have a lot of historic volume data, but I'd kind of assumed it had been in slow decline since the 1800s (vague memories of early submarines struggling to get through the Bering straits, etc) in line with increasing mean global surface temperature. I mean, volume didn't 'start' dropping in 1976, even if the rate of decrease did start to accelerate from around then

[Jim_pettit]

I've seen the 'R' word thrown around here a bit IRT Piomas sea volume, but to be honest, I'm not quite sure why. Some facts:

For all of January 2012, SIV was higher than it was on the same day in 2011.

For much of March 2012, SIV was higher than it was on the same day in 2011.

For a goof part of April and May 2012, SIV was higher than it was on the same day in 2011.

In fact, 2012 volume was higher than same-day 2011 volume on all but 35 of the first 130 days of the year.

The point being, it's neither logical nor historically valid to speak of a recovery based solely on Q1 data.

No, I'm afraid that, much as some may wish otherwisee, there simply are no reliable signs of an incipient recovery.

[Robert Fanney]

@John Christensen

Long term temperature increase had been occurring since the 1900s. The fact that from the 1940s to the 1970s, there was a relative plateau doesn't deny the fact that air temps were still higher than in previous decades.

Looking at the GISS temp graph, you see temps on a plateau about .4 degree C higher than the low point at around 1910 and .3 degree C higher than the average of 1880 through 1930.

http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A2.gif

And looking at the period from the mid 1940s to 1980, you don't find cooling at all. Just temperature stabilization.

Given the inertia of the ice sheets, it would make sense that melt would continue for some time after a higher temperature was reached with a certain amount of melt being locked in at a given temp.

Notable sea ice recession began in the 1940s and the period of the 1940s to 1979 showed gradual (compared to now) melt. So one wonders if the sustained higher temps were driving the long-term melt at that time.

Also, ocean heat uptake was likely still ramping up at this time and adding its impact to the sea ice.

As for 'other factors' you'll have to find serious evidence to rule out AGW... I've seen a number of oddities in this realm currently (one is claiming that erosion of the electro-magnetic field is causing warming, not AGW). And all have nothing in the way of hard science to back them up. Just ideas and suppositions loosely strung together.

Recovery year... With ice melt having been so rapid during springs and summers during recent years, it's quite possible that this year will not be a recovery year. But there's nothing wrong with hoping. I don't think anyone likes to see the ice cap going.

On the other hand, those most concerned about the broad and ongoing impacts of AGW hope for a response and for a reason to make deniers and policy makers listen. So a recovery year would likely result in another year of heads in the sand and media pandering to new and whacky theories as to why AGW 'isn't valid.'

[Al Rodger]

sofouuk.
As the one who first mentioned 1976 as the time of the melty 'kick-off,' I will chip in.
(Of the struggles of early submarines in the Arctic I know not. However, I do do a good line in early ice breakers in the Arctic. And also the foolishness of the Royal Navy in the century before.)

Prior to 1976 there were during recent times decades with rising temperatures, although prior to that again over millennial timescales global temperatures have been falling since the Holocene Thermal Maximum some time 7,000+ years ago according to the latest 12,000 year hockey stick.
This suggests Arctic ice would have been slowly increasing for 7,000 years up to some point about 150 years ago. Yet ice hockey sticks like this one here (whose provenance was not provided when posted on a blog recently. There was an apology that the 2012 data was not included.) and the more wobbly ice hockey stick in Kannard et al 2011 suggest the timing of that point of maximum freeze was about 1910. But these ice hockey sticks also seem to agree (see Kannard 2011 fig 2) that the melt beginning in earnest in the mid-1970s.

[Robert Fanney]

@ Jim Pettit

Have to mostly agree with this analysis. While it's probably still possible that we'll experience a 'recovery year' or two adding noise to the overall melt trend, it's tough to make a compelling case for a 2013 recovery from a few days of slightly above record low values.

Since 2000, we've had a number of years where March, April and May values have been above the previous record lows, but final summer melt still came in as a new record. I seem to remember a number of people, at about this time last year, also arguing for recovery.

Perhaps it is fair to say that recovery is slightly more possible now with values approaching 2012, 2011 and not remaining in record low territory year-round (which would point to a much more rapid collapse). But that possibility still seems less likely than another year of record melt.

[Craig Merry]

Do the graphs in the original post discern between ice age? I would expect th MYI would show a decline at least.

Perhaps it's easier for the ice to form when it's closer to freezing or a streak of temperatures in certain near-freezing areas to cause a overall reading of more ice? In a way the volume uptick does not surprise me. There's a lot of variables to consider in projections - but I think we're headed to a ice-free arctic this year or next.

[John Christensen]

@Robert Fanney,

Please see e.g.

Tracing Atlantic Water Signature in the Arctic Sea Ice Cover East of Svalbard from 'Advances in Meteorology', vol. 2012, page 6:

The data from the Arctic and Antarctic Research Institute (AARI) collection were used [30]. We consider two water layers: 100–200m and 200–300m (Figure 7). This choice is explained by the features
of AW transformation in the AIW discussed in Section 2.
Provided that the concept of AW intensive mixing in the upper part is correct the layer shallower than ∼200m initially contains the heat, which is totally released upwards and laterally during the FSBW transit from Fram Strait to the Laptev Sea. The layer below ∼200m retains a large portion of its initial heat content up to where the AIW terminates its full circuit around the Arctic Ocean interior. Within the considered time interval (1979–2011) the temperature in both AW layers coherently increased. However, this increase
was not monotonic, but rather cyclic with an 8–10-year period. The background positive trend is 1.5◦ per 32 years in the upper layer and 1.25◦ per 32 years in the lower layer. It is worth mentioning that after the most recent temperature increase, which culminated in 2007, the temperature did not drop back to the initial point as happened earlier, but remained about 1◦C higher in both layers, leading to the
conclusion that AW in the Arctic Ocean is shifting to a new warmer state [31, 32]. Hence, there is no doubt that the heat
input to the Arctic Ocean interior has substantially increased since the end of the 1990s. The question is has this increased heat input provided the major forcing of the documented change in ice properties in the WNB?

The article then moves to conclude:

Time series of FSBW temperature in Fram Strait feature a monotonic increase after the mid-1990s, consistent with shrinking ice cover. This coincidence provides solid ground for the hypothesis that a substantial amount of the AW heat in the WNB is able to reach the under-ice layer and contribute to the ice melting from below.

I have previously referred to another article that also documents an increase in temperature for the AW inflow on the Fram Strait Branch starting in the 1860's, and DMI has an article that the increase in glacier speed for the Jacobshavn Glacier is due to multi-decadal changes in the temperature of the Irminger Stream, and is not linked to AGW.

As I have stated before I am not denying the effect of CO2, but I fear the world at large will not be much bothered once we have the first ice free Arctic summer - which will be soon.

Therefore, my vain hope is that other factors are at play as well, as we are otherwise just headed in the wrong direction much too fast..

[Aaron Lewis]

However wonderful PIOMAS is, it is a model based on limited data. Error bars are from internal consistency, rather than armies of samplers fanning out across the ice to field check the data.

Data quality going into the PIOMAS is marginal - and that is the fault of congress not investing in better remote sensing.

We do not have funding for appropriate, real time, field checking of sea ice conditions.

The Arctic weather is doing things we have never seen before. I would not pin my hopes on a couple of month's results.

[Al Rodger]

John Christensen.
The 'G' in AGW stands for 'global'. The poles climatically act as massive heat sinks, receiving heat from lower latitudes and radiating it out into space. That transfer of heat from lower latitudes into the Arctic can only increase under AGW. Warmer air temperatures & warmer ocean currents are the primary cause of ice loss and rising Arctic temperatures which are amplified by lower albedo due to melted ice and wetter air over the now exposed warming oceans.
The Arctic is certainly not the fastest warming region of the planet because of a 40% increase in atmospheric CO2 over the last century-and-a-half.

[John Christensen]

Al,

So AGW has warmed the Atlantic water currents into the Arctic by 1.25-1.5 degree celcius in 32 years, and also caused a temperature increase of the same magnitude in the Fram Strait inflow back in the 1860's? And DMI, which certainly is not a GW skeptic institution, is just wrong when they link warming ocean currents to multi-decadal cycles rather than AGW?

[Robert Fanney]

@ John Christensen

Too fast...

This is what is most alarming to me. And I can certainly sympathize with wanting for hopes -- vain or otherwise.

Fram Straight/Laptev paper references and other factors...

This paper would seem to point toward an 8-10 year melt amplification phase in this region moving back toward a cooler/steadier phase afterward. But even this paper shows that after 2007 heat increase was greater than a regular cycle would indicate. For my part, this seems to give little comfort. If we are on the 'cool cycle' there now, what happens after 2015-2017?

Irminger Stream and other non AGW melt factors...

I would think that as CO2 forcing continues to increase, natural variability and local influences like these would tend to become more skewed -- riding on top of the overall pattern of human forcing. This is not to say that AGW is the primary factor in all increases in melt. But just that it is the net over-riding factor. It would push natural re-freeze phases to freeze less or to not freeze at all. And it would tend to amplify natural heating phases (in most but probably not all cases).

Context...

And this is what I'm really not happy about and have tended to gripe the most about. We're sitting at nearly 400 ppm CO2. And we have CO2 rising at a background rate more than ten times faster than anything science can clearly perceive in the geologic past.

This is TOO FAST. And this too fast driver is, likely, the reason changes are happening faster than they should. I hope that this is not the case. But, all things being equal, it seems the most likely case.

A rather rudimentary meta-analysis of current CO2 levels puts us in conditions comparable to those observed in the Pliocene (3-4 degrees C hotter and sea levels 75 feet higher) over centuries IN A STEADY STATE CLIMATE (Please excuse the emphasis. I am not shouting at anyone, just trying to highlight a point).

The problem here is that we are not in a steady state climate. The current level of CO2 is only the initial forcing and the environment has yet to respond fully. Further, we're adding 2.2 ppm CO2 to that initial forcing each year.

So this is the current, larger, AGW problem and it seems pretty huge and difficult to me. And I think it likely that we've pushed the current climate beyond much hope for a comfortable, linear trend. So it is my opinion (likely as flawed as any), given this analysis of the evidence, that it is the primary driver of the very rapid changes we observe.

All Sea Ice Melt, Feedbacks, and Greenland...

You'd mentioned that we probably won't have much to talk about once Arctic Sea ice goes. Well, once summer sea ice goes, then we have spring and fall sea ice. Then, last of all, winter.

Unfortunately, as this trend takes hold, Greenland plays a larger and larger role.

And Greenland presents far more dangerous and volatile problems. Once the sea ice goes, Greenland loses a big insulator. The heating energy that went into reducing sea ice now goes to turning water into vapor and warming the environment around Greenland. This, in turn, amplifies Greenland melt.

Greenland melt means more rapidly increasing sea level rise. But it also means negative feedbacks in the Arctic. All that cold, fresh water increases the freezing temps of local sea water. It may perturb the Gulf Stream and reduce heat transport. And this means huge temp differentials in a strange location. Hansen has warned of a period of very dangerous storms as a result. Maybe the local cooling pushes a degree of sea ice recovery in certain regions. Depends on how powerful the human forcing and other feedbacks are in relationship to the negative feedback produced by the melt.

Regardless, still quite a lot to talk about. Not reassuring talk at all. But talk nonetheless. And, for my part, I hope we don't have to get there before there's a large policy response to the problem.

Just two last points and I will shut up. AGW means added heat energy. What we've failed to do so far is describe, accurately, how that heat energy goes to work. What does it do and in what proportion? Melt ice? Heat oceans? Heat the atmosphere? Set in motion feedbacks? Once these questions are more accurately answered, then I think we'll have a better picture.

Natural variability, on the other hand, I think would have to provide a very high degree of inertia to overcome the current forcing. And the evidences for non-linear responses in the geologic past do not make a good case for natural variability holding large or even moderate to small forcings in check. And, in this case, the forcing is very large and more rapid than anything we've seen before.

Best to everyone. And thanks for indulging my worries.

[John Christensen]

On DMI and ocean currents, see especially page 5 of this article from Nature:

http://ocean.dmi.dk/staff/mhri/Docs/Holland_et_al_NatureGeoscience2008.pdf

[Chris Reynolds]

I'd like to recommend the following satellite image from Environment Canada.
http://farm9.staticflickr.com/8230/8555615612_7eb91243dc_o.jpg
Further words would be superfluous.

[John Christensen]

@Robert,

Agree that we are witnessing an unprecedented gamble with our environment.

Still, I live in a country - Denmark - where only a couple of percent of the land surface has remained unchanged by man, everything else having been turned into utility for man.

How are we to know how to respect the environment, if we have none left?

We buy some rain forest shares, so that others cannot do what we did, but we do not stop what we are doing at all. Wind power fields are established, but we open a new oil field as well.

I anticipate this experiment will only end when fossil fuel is gone, - the wealthy will surely survive and we no longer appreciate what remains to be lost.

[SATire]

Robert Fanny,

I am with you and agree on nearly every point you made. I only want to put one more on top: Since CO2 stays ~100 years in atmosphere and radiative forcing is a heating rate instead of a heat - that means, we are increasing the fire every day while knowing, that we can not reduce it for the next 100 years. It will heat 100 years even if we stop emission to zero now. So, temperatures or melt will increase still, if we do not emitt CO2. But we still do emit CO2. And we even increase emittion - so turning the heating know further while knowing, that we can not turn it back for 100 years. How duffy we are...

[Chris Reynolds]

Dave C,

I think we'll have to agree to disagree on what thickness is doing. I can't add to what I've said above.

I do agree that post 2007 is a new regime in the Arctic and therefore has to be treated as such, and behaviours within that period given precedence over past periods. This is why I gave the correlation for that period and noted that it's higher.

I'm not convinced by your argument that the 'plateau' means we can lessen the loss trend. See the following graphic.
http://farm9.staticflickr.com/8103/8481914926_3f4b4511eb_o.jpg

I've just changed that so everything is on the same axis, it was orginally done to show a specific point ages ago and I've been using it too generally, just updating as new data came in.

But I'll leave it at that until the weekend - work pressures.

[Steve Bloom]

John, I think you're straining way too hard to find a large role for natural variability. Among other things, don't forget that much of the increasing AW heat flow comes from the tropical Indian Ocean via the shifting Agulhas current, a crystal-clear AGW effect.

Re the Irminger warming, did the DMI article affirmatively exclude a role for AGW? That's contrary to my understanding. Reference?

[Steve Bloom]

Very useful graph, Chris, thanks. The prematurity of declaring a plateau is made obvious.

[Chris Reynolds]

Steve,

Well the plateau in the annual range is clear - post 2007 there's a step increase in annual range. But the volume loss continues.

[Steve Bloom]

Oh, sorry, John, I guess that last link was the DMI reference?

Note that the data stopped 7 years ago and that in the concluding paragraph they make no prediction about the future. What's happened since? IIRC there's been a fair amount of subsequent work.

As a general matter, AGW layered on top of natural variability will often produce this sort of behavior. It's just that when the time comes in the natural cycle for things to shift back, they won't.

[Steve Bloom]

Tweet just now received: "#IceBridge will be conducting their first project test flight on the P-3 tomorrow to check out the ATM laser altimeter."

[Steve Bloom]

Right, Chris. To restate the bleedin' obvious in case anyone is confused on this point (not you, obviously), that "plateau" is purely an artifact of the maxima and minima dropping together over that period. IOW, it's an indication that things are worse, not better (noting e.g. that if the maxima were not also dropping the range would show a distinct increase).

[Chris Reynolds]

John Christensen,

AW intrusion is real. The warming it has brought is due to AGW because AGW is responsible for ocean warming. However the role for AW in Arctic sea ice loss is highly speculative.

Here is the AW layer:
http://www.whoi.edu/page/preview.do?pid=111896

You can see that the warm AW layer is restricted to roughly 150m to 400m down. Above it water temperature is much colder. This situation is maintained because despite being warmer, the AW is denser due to higher salinity.

Anyone wanting to show strong interplay between AW and sea ice must produce not only hypothetical mechanism, but must address the data from the WHOI profiling buoys.

Please note I have chosen ITP57 because it started off in Kara, and proceeded right through the region where AW drops out of contact with surface waters after passing the abyssal deep boundary poleward of Svalbard/Franz Josef etc.

Bear in mind that in modelling studies it has been found that formation of new ice produces cold dense brine which interferes with Arctic stratification and draws in AW: Holland et al "Future abrupt reductions in the summer Arctic sea ice" - see blockquote at end. So the conclusion that Ivanov et al come to - that increased AW coincident with sea ice retreat, may not actually indicate AW is the cause of sea ice retreat. It may indicate that ice retreat is the cause of increased AW.

[14] Increasing ocean heat transport to the Arctic occurs even while the North Atlantic receives less poleward heat transport with a weakening meridional overturning circulation. These increases are related to strengthened ocean currents and warmer waters entering the Arctic Ocean from southern latitudes. Previous studies [Bitz et al., 2006] suggest that such increases in future climate projections are associated with the changing ice cover. As the ice cover thins, it becomes a weaker insulator resulting in larger ice production during the autumn/winter. The consequent increase in winter brine rejection drives ocean ventilation, and strengthens the inflow of warm Atlantic waters.

[Glacierchange.wordpress.com]

Just returned from the Arctic Workshop and was not encouraged by the data presented. Climate Central is only a week behind your notice on fracturing ice, that why we come here first. Dexterity Fjord Icecap is losing on the ice volume battle too.

[Steve Bloom]

Yep, there are feedback loops everywhere, although note that this suggested mechanism does not exclude a primary role of warmer AW in starting the process. The upshot is that the inflow, regardless of precise mechanism, is going to melt more sea ice.

IIRC some prior work has pinned the distinctive Laptev region sea ice retreat to warming AW. I wonder how strong the mechanism suggested by Bitz et al. could have been there. OTOH what is true in the Central Basin may not be true (or as true) in the peripheral seas.

[Steve Bloom]

"However the role for AW in Arctic sea ice loss is highly speculative."

So perhaps better to say that it's the mechanism that's speculative.

[SATire]

Chris Reynolds and Dave C,

somehow I have to agree to both of you - since 2007 something changed and there is something like a plateau of melt volume/PIOMAS annual range. The plateau is nothing else but a maximum of 17-19 k km3 melt every year. It will hold until summer volume is zero and start to drop soon, therefore. Once there is no old ice left to melt, only volume froozen in the previous winter is there to melt. That is pure logic without any theory... A maximum is always looking like a plateau if you are sitting on it.

No volume gain of any cold February can ever stop that trend - nature is unstoppable on its way to the new equilibrium, that may be looking like a Pliocene clima or any other clima appropriate to 400 ppm...

My prediction for minimum ice volume is: less than last year. That is a quite save bet ;-)
An about 50:50 bet would be: 1k km3 less than last year. That will hold until min. volume is 0 - so for about 3 years. After that date, nobody would predict -1 kkm3 min. volume :-)

[Robert Fanney]

@Chris

That satellite picture is certainly something to look at. Is there any corollary for such a large crack-up happening in the past at this time of year?

@John

I don't know about the wealthy and continued carbon exploitation. Thousands of gigatons of potential fossil fuel carbon (if you include all unconventional fossil fuels along with methane hydrates) is a very stiff order considering the trouble we already have at +880gtc. I'm not too certain the public will be tolerant of the wealthy's continued prosperity if they push for carbon exploitation and shifting the harm caused by it via ice melt/climate change onto them.

[Chris Reynolds]

Steve,

IMO there is clearly a role in Atlantic Sector retreat. However this has been less than in other sectors due to the drop off out of contact with surface ice that the AW shows as it enters the Arctic Ocean. Note that this drop off does not happen in Barents/Kara due to shallower bathymetry.

The greatest retreat of ice has been in the Siberian sector, next in the Beaufort/Chuckchi sector. What I don't think has been demonstrated as strongly as some here seem to think is a role for AW in the retreat in these sectors.

It is also worth noting that PIOMAS forcing does not include explicit ocean warming. Any such effect is a result of NCEP/NCAR forcing, as Schwieger et al 2011 state:

Daily mean NCEP/NCAR reanalysis data are used as atmospheric forcing, i.e., 10-m surface winds, 2-m surface air temperature (SAT), specific humidity, precipitation, evaporation, downwelling longwave radiation, sea level pressure, and cloud fraction. Cloud fraction is used to calculate downwelling shortwave radiation following Parkinson and Washington [1979].

So if increased AW is causing a large part of the PIOMAS volume loss it must be directly due to those atmospheric indices. The ice component of PIOMAS lies upon an ocean model, which is capable of producing the ocean response to this forcing.

I don't think it's just the mechanism that's speculative, although I do concede that 'highly speculative' may be overstating somewhat. But the demonstrable fact remains that as the AW falls off the edge of the Abyssal deep into the Nansen and Eurasian Basins it drops out of direct contact with the sea ice:

Bathymetry of the Arctic.
http://commons.wikimedia.org/wiki/File:Arctic_Ocean_bathymetric_features.png

So at present ocean heat flux from AW is largely out of contact with the ice. And we are left with internal ice dynamics (transition fro MYI to FYI), ice albedo, and atmospheric heat fluxes as more readily supportable explanations of ice loss.

I'm not dismissing AW, but I don't think it's justified to point the finger at AW when other processes are acting against ice survival and there is as yet no strong link between AW and sea ice. And before someone posts a link to something that's old hat to me - I include Catlin and the double diffusion issue in that.

[Robert Fanney]

@ SATire

I would think we are pretty darn duffy at this point in the game.

[Chris Reynolds]

SATire,

"The plateau is nothing else but a maximum of 17-19 k km3 melt every year. It will hold until summer volume is zero and start to drop soon, therefore"

Actually I think this is a key part of the transition. To get a seasonally sea ice free state you'd need to have massively accelerated losses between April and Sept. This is what is happening. Once the ice has started to become seasonally sea ice free then we get to see what effect that has on winter growth. I don't know if a seasonally sea ice free state is stable.

Robert Fanney,

I don't know how unusual it is. I have posted on my blog (Dosbat) about one aspect being unusual - that was the Arc fracturing that (I now think) started the event, despite earlier fracturing. I still stick to that, but with regards the wider cracking I'm not so sure. I've come across images and papers suggesting fracturing of the ice isn't unusual - this backs up my recollections. I've been following the ice increasingly since 2007.

Unusual or not it is very impressive, and I thought that image was the best I've seen from that satellite. It often gets cloudy when it gets interesting.

[wili]

AW = ?

[Neven]

Atlantic Water, wili. I wrote a piece on it last year.

[Dave C]

Chris- I understand your points, but remain suspicious of non-quantifiable factors. I guess we will find out a lot more by the end of this melting season.

That is a pretty impressive picture.

Does anyone here know if there are images from previous years available?

[wili]

Thanks, Neven. That makes sense.

[SATire]

Chris,

"Once the ice has started to become seasonally sea ice free then we get to see what effect that has on winter growth. I don't know if a seasonally sea ice free state is stable."
I agree - that state might not be stable. An ice-free arctic would result in a hugh amount of evaporation since dry could air from siberia will get warm there. Salinity will increase and since the atlantic is larger than the arctic basin, an increase drift will also go in that direction - it could jump to all-year ice-free state making Ellesmere island comfortable for camels once more...

[Steve Bloom]

"But the demonstrable fact remains that as the AW falls off the edge of the Abyssal deep into the Nansen and Eurasian Basins it drops out of direct contact with the sea ice."

So then we are talking slow diffusion, which must be happening unless it flows right back out of the Arctic (unlikely to my knowledge).

The Laptev reference is from memory, may well be Barents/Kara rather.

IIRC Shakhova or one of her colleagues noted a few years ago that ESS retreat was primarily because of warm water encroachment onto the shallow shelf. Is that AW at the end of its journey? I should look it up.

[John Christensen]

An article discussing how warmer Atlantic Water started entering the Arctic from 1860's, but that SST in the Fram Strait did not increase before around 1950:

(Werner, Kirstin, Spielhagen, Robert F., Bauch, Dorothea, Hass, H. Christian, Kandiano, Evgeniya, Zamelczyk, Katarzyna, Atlantic Water advection to the eastern Fram Strait – multiproxy evidence for late Holocene variability,
Palaeogeography (2011)):

After ca 1750 AD decreasing planktic foraminifer fluxes indicate very cold conditions. High IRD contents are attributed to heavy sea ice conditions found also in historical observations and instrumental records. IRD may have also been produced by melting Svalbard glaciers. Subpolar planktic foraminifers in the 150-250 µm fraction and planktic δ 18O values indicate strengthened Atlantic Water inflow after ca 1860 AD. However, low fluxes and planktic foraminifer assemblages of the 100-250 µm fraction suggest cool surface water conditions until the mid of the 20th century. Changes in all studied proxies indicate warmer temperatures for the past few decades (see Spielhagen et al., 2011) and coincide with positive Atlantic Water temperature anomalies and a retreating sea ice margin for the ca last 100 years (Divine and Dick, 2006; Polyakov et al., 2004, 2005).

[John Christensen]

@Steve Bloom,

Regarding the Irminger Current and natural variability vs AGW:

As you have seen on images for the Jacobshavn Glacier, there were significant periods of glacier retreat between 1851 and 1931, where roughly half of the glacier tongue was lost, the other half lost since 1931.

What is your take on that?

[Klon Jay]

In case anyone doesn't know about this imagery site:
http://www.weatheroffice.gc.ca/satellite/index_e.html
Scroll down to HRPT. I like the very first link below that...
Can see some smaller fracturing on Siberian side now.

[Steve Bloom]

IIRC there was a paper on that earlier JI retreat in the last year or so that seemed to provide a definitive answer, not AGW, but I would just point out to you that you need to take the present trend in the context of everything else happening in the region. As the paper you quoted notes, it's all moving in the same direction now, and that was certainly not the case in the older period of record.

Also, John, please provide links to the papers you quote. Thanks.

[Kevin McKinney]

Just my opinion, and shouldn't be mistaken for Science (or even science), but I think it's naive to assume that intrusions of AW, or other advections of warm water into the Arctic, are independent of AGW.

Don't mean to dump on any sources of hope here, but we know that AGW changes circulation in the atmosphere--why not oceanic circulation as well? That was the essence of the Broecker hypothesis about the NA conveyer, and though that idea was oversold, it wasn't--we think!--invalid.

That Arctic sea ice melt 'just happens' to start to take off at just the same time that the AGW signal started to show is a hell of a coincidence, if you ask me.

[John Christensen]

@Steve and Kevin,

Sorry Steve, the Fram Strait article has multiple links. One is:
http://oceanrep.geomar.de/11885/

This article argues that there is a strong connection between changes in ocean currents and Artic surface cryospheric conditions (centered around Svalbard here, where the effect is most pronounced).

AGW of course started back when we started changing our landscape, clearing forest cover, building dams, and changing water flows centuries ago, and that should have had some impact on climate and weather patterns.

However, to say

it's naive to assume that intrusions of AW, or other advections of warm water into the Arctic, are independent of AGW.

is unreasonable simply because it has been shown in the article above as well as the DMI article above that changes in currents and intrusion of warmer water has had measurable impact in the 1930's (both in Western Grenland and Fram Strait), in the 1860's, and sooner, where we must agree that AGW related to CO2 cannot have been a factor.

Since then I agree a lot of things have changed, and as one of the articles discusses, it is difficult to separate whether increased inflow into the Arctic is causing the excessive outflow, or if increase outflow due to melting is causing extra inflow today.

Whichever is the case, the melting and inflow of AW seem to reinforce each other, and who knows: If increased AW inflow has been in place since 1860's, helping to slowly warm the deeper AO water layers, causing a slow and steady increase in vertical heat convection (and vertical water movement, when the temperature exceeds 4C), it may very well last another century, and being reinforced by the increase of CO2, it may also not return to an opposite state as easily - or not at all.

[Glacierchange.wordpress.com]

John: The retreat of Jakobshavn from 1851 to 1931 was quite slow compared to the current context. There is no doubt the emergence from the LIA generated widespread retreat of GIS outlet glaciers, the rate of that retreat here just pails by comparison to the current changes.

[John Christensen]

Glacierchange:

Jacobshavn Glacier retreated 6-8km from 1875-83, i.e. 1km/year, which is quite substantial, given also that air temperatures arguably were lower during that period.

From 1929-31 (where the DMI article refers to a pulse of warm water inflow from the Irminger Current), it retreated 4km in two years - an average of 5.5meters per day for two years.

The retreat almost came to a complete stop from 1964-2001, where the Arctic ice is otherwise showing strong indications of decline. If ocean currents are a small side-effect and AGW impact on atmospheric conditions the main effect, and the two were already strongly correlated, how is this then possible?

Lastly, the glacier reacts to the IC pulse of 1997 with very strong melting, and as the DMI article argues, the fjord stays deep far inland, so there is no reason for the retreat to slow, allthough the projections of course are challenging.

Clearly, we are observing the combined effect of rising temperatures and other factors (DMI argues that NAO is involved with changes in the Irminger Gyre), and while several have pointed to the correlation between melting induced outflow via Fram Strait and AW inflow increase, I have not seen any discussion of a NAO/AGW link, but may have missed that?

[Al Rodger]

John Christensen,
I would suggest you are wrong to state that Werner et al 2011 (full text here) "argues that there is a strong connection between changes in ocean currents and Arctic surface cryospheric conditions." They present evidence of a " strengthened Atlantic Water inflow after ca 1860 AD. However, ... (other data) suggest cool surface water conditions until the mid of the 20th century. Changes in all studied proxies indicate warmer temperatures for the past few decades (see Spielhagen et al., 2011) and coincide with positive Atlantic Water temperature anomalies and a retreating sea ice margin for the ca last 100 years (Divine and Dick, 2006; Polyakov et al., 2004, Polyakov et al 2005).
The writing in Werner et al 2011 is not without ambiguity (I would say rather too much ambiguity) but to attempt to pile on the significance of AW warming in the Arctic prior to the latter half of the 20th century is surely a further misinterpretation of Werner et al 2011 (and his references to boot).

And if you wish to extend the AGW narrative (now truly off topic) to incorporate pre-industrial/non-fossil-fuel-use as "having some impact", it would be good to do more than hint at what level of "some impact" you have in mind.

[Kevin McKinney]

John, we didn't see generalized ice retreat in the 1860s; the past and present effects on Jacobshavn Isbrae are local. Today's persistent retreat of sea ice across the entire Arctic is quite a different kettle of fish.

I suggested that you can't assume that ocean current changes are independent of AGW--and I think that's physical: we know that surface evaporation rates depend upon temperature and humidity, and that they can drive changes in salinity and temperature which in turn drive ocean currents. Wind can drive currents, too, and does so to surprising depths. So, it's unreasonable (IMO!) to assume that AGW will not affect oceanic circulation--even though to my knowledge that subject is not very well explored yet. (Though "to my knowledge," frankly, sets a low bar.)

On the other hand, this does not mean that every current results from AGW--there can be natural variations that result from other causes. That means that the changes in the Irminger gyre in the 1860s do not show that other, subsequent changes in circulation are unrelated to AGW also. Fires start even in the absence of arsonists...

On AGW and the NAO, there's some work. For example, I found this abstract via Google Scholar:

The climate of the Atlantic sector exhibits considerable variability on a wide range of time scales. A substantial portion is associated with the North Atlantic Oscillation (NAO), a hemispheric meridional oscillation in atmospheric mass with centers of action near Iceland and over the subtropical Atlantic. NAO-related impacts on winter climate extend from Florida to Greenland and from northwestern Africa over Europe far into northern Asia. Over the last 3 decades, the phase of the NAO has been shifting from mostly negative to mostly positive index values. Much remains to be learned about the mechanisms that produce such low frequency changes in the North Atlantic climate, but it seems increasingly likely that human activities are playing a significant role.

(Visbeck et al, 2001. PNAS. "The North Atlantic Oscillation: Past, Present and Future.)

Here's the search URL, in case anyone wants to peruse some of the other work (22,500 hits in all):

http://scholar.google.com/scholar?hl=en&q=north+atlantic+oscillation+anthropogenic+climate+change&btnG=&as_sdt=1%2C11&as_sdtp=

[wili]

Good points, Kevin and Al.

The more pressing question is what will be/is now the effect of the loss of Arctic sea ice on ocean currents. We have seen some discussion by Dr. Jennifer Francis and others about the (possible?) effects of sea ice retreat on atmospheric currents. Is there similar work going on about the possibly-even-more-consequential effects on ocean currents? (Apologies if this has been exhaustively discussed somewhere here and I missed it.)

I would vote for not pursuing or addressing any further the absurd notion that AGW, directly and indirectly, is not the major driver of the exponential rate of loss of sea ice volume seen in PIOMAS and confirmed by other measures. There are more important and valid issues to spend the precious time on and for precious unique knowledge base we have here here, imho.

[Kevin McKinney]

OT: Just published an article on "Climate stories to watch in 2013."

Feedback welcomed...

http://doc-snow.hubpages.com/hub/Climate-Stories-To-Watch-In-2013

[Robert Fanney]

@John

To put these things in a metaphorical context, what we have here are a few cherries. But the tree they come from is overwhelmed by AGW kudzu.

Over the past 11,300 years we've seen no temp increase so rapid as the present. There are top scientists who say the current temp increase is even more rapid than the radical swings that occurred in the last ice age.

We have scientific reports showing that Arctic sea ice is now the lowest in 3,000 years. And this is a snapshot of a system in rapid decline.

And we have CO2 levels in the atmosphere not seen in 2-3 million years.

This is the base-line.

Further, the cherries presented for non AGW are only valid when taken in a very narrow and mostly strangled context. The institutes that produced these studies do not use them to refute the overlying, larger impact of AGW. So for anyone to do so belies even the undergirding conclusions of these papers. Papers which, by their nature, focus on localized data and single issue phenomena. They are not impact studies. But you seem to believe they are, making conclusions completely outside those produced by the authors.

So the pieces we're looking at here present no evidence that AGW is not the driving force melting the entire Arctic. Nor do they show that the larger, very rapid Arctic melt is a part of natural variability or that the Arctic has ever experienced anything like this before as a whole. There is no current corollary in the science for the current pace of overall melt or for the number of anomalous melt events occurring at such a high frequency. And there is nothing in the larger science that provides serious evidence to show that AGW is not the over-riding force involved.

To do that one would have do better than to say 'in this year, on this day, in this particular place things were almost as bad 130 years ago' or to say 'this particular ocean current is cyclic and therefore overall warming is not driven by AGW.'

[A-Team]

The designers of the infrared camera on the NOAA-16 satellite went to considerable effort so that the embedded temperature scale on the photos would accurately reflect the surface temperature of the ice. So far we have made little use of that in speculating about the consequences of the unprecedented cracking this year to minimum summer ice volume or extent.

When a fracture forms in winter, the air is so cold that the water soon freezes between the ice walls (if you can call something with a few inches of freeboard a wall). The new ice thickens by freezing already cold water to its bottom, as the heat equation takes over above and below.

However the adjacent ice is doing the same so the new ice never quite attains a matching freeboard, leaving the depression vulnerable to a later melt pond. Nor, as the infrared imagery shows, does it ever get quite as cold.

The image below has the ice colored according to one of 14 temperature categories supplied in the legend of the AVHRR Beaufort Sea picture of 14 March 2013. Note the fractures -- many of which are several weeks old -- are still distinctly warmer than the surrounding ice. The table shows the percentage of each temperature class and the square km that it occupies in total (done by counting pixels and using latitudinal scale).

I found many ways to go astray in making this image (attn: 1000 pixels wide). If the native resolution and orientation are not retained, resizing or rotating will dither the grayscale key too, requiring a fresh one to be stubbed in. The original grayscale bins were 16 units apart, so the diameter of the Gimp/PS color picker has to be set to 15, or some pixels will end up 'falling between the cracks'. If file is saved as jpg etc, it loses all scientific value to the end user (the color picker will no longer work upon download). The usual temperature gradient palettes (roygbv or blackbody) work poorly because it is the similar temperatures that most need to be distinguished.

Finally, the original photo should have included a second key -- a grayscale continuum between temperature extremes so that a color picker pulls out a vertical bar there and so an accurate temperature. This is a fixable error in cartography, unlike the many user-unfixable ones we've been encountering.

[John Christensen]

A-Team,

Wow, this is a great and very detailed image!

If I am reading it right, it seems many of the "fresh" cracks have a temperature of -22.5C, while neighboring ice is 7-9 degrees colder. I was wondering with the ice temperatures displaying like this, if it would be possible to calculate how much heat convection/freezing is going on in those cracks, or if it would be necessary to have air temperatures to assess the heat release?

[Neven]

A-Team, you're outdoing yourself here. Marvelous image. I've posted it in the follow-up post Crack is bad for you (and sea ice).

PS I've had a couple of requests from journalists and the like who wanted to know if they could use your animations. I copied your comment where you said it's all open source. Let me know if that is not okay (or mail me so I have your mail address).

[me.yahoo.com/a/nSjChi4X3vr8X3DRw93GkY1.cerja.8nvWk-]

A-Team,

Wow, this is a great and very detailed image!

If I am reading it right, it seems many of the "fresh" cracks have a temperature of -22.5C, while neighboring ice is 7-9 degrees colder. I was wondering with the ice temperatures displaying like this, if it would be possible to calculate how much heat convection/freezing is going on in those cracks, or if it would be necessary to have air temperatures to assess the heat release?
If you know the conductivity of ice it should be possible to calculate the difference in thickness for example as well as the heat loss.

Phil.

[me.yahoo.com/a/nSjChi4X3vr8X3DRw93GkY1.cerja.8nvWk-]

Based on the Barrow site it's ~1ºC/0.1m of ice, so the fresh cracks should be about 0.7m thinner, assuming no snow. Thermal conductivity of ice is ~2.3W/m K so I make that ~23W/m^2 conducted through the ice.

Phil.

[Robert Fanney]

Wow, A-Team. Amazing understanding of the underlying capabilities of these satellites and use thereof. Well done.

(who are these guys anyway? ;)

[Andy Lee Robinson]

Instead of rendering a full animation, here's just one frame including February's data:

[Andy Lee Robinson]

(I forgot to mention that the image above links to a bigger one of 1280x1024)

[Chris Reynolds]

SATire,

I'm not thinking about a transition to perennially sea ice free in years. It seems to me that even with a rapid establishment of thick cloud and increased atmospheric/ocean heat transport it will take a couple of decades at the very least to warm the Arctic Ocean to the point where it doesn't freeze in winter and no longer acts as a large heat sink in summer.

In "Factors controlling the bifurcation structure of sea ice retreat" by Eisenman:
http://eisenman.ucsd.edu/reprints/Eisenman-2012.pdf
Figure 1 shows a schematic of different sea ice responses to climate forcing. If we're looking towards a non stable seasonally sea ice free state then Scenario II and III are the ones we're interested in. Scenario II is where a transition to perennially ice free (all year) occurs after some years of seasonally ice free. Scenario III is where the transition to perennially ice free occurs rapidly after a seasonally sea ice free state starts.

Eisenman summarises various studies below that figure. It is worth noting that he finds that no GCMs find Scenario III, although some simplified models on a shallow ocean (mixed layer) do. Of possible significance is that Abbot has used a simplified model and a cloud parameterisation to produce Scenario III. However GCMs do simulate Scenario II, where seasonally sea ice free persists for sometime before the final transition. I'd need to do a lot more reading to see if I can support my hunch that ocean warming plays a role, so it remains a hunch.

Steve Bloom,

If there's AW flowing into the Arctic, then water must be flowing out. If the AW layer is growing it would seem to be downwards, as the upper layer being freshened by river discharge and seasonally freshed by ice melt, doesn't seem likely to be growing. Increased ice melt isn't really a significant factor, 2m of surface ice thickness corrsesponds to roughly the same thickness of ocean water, the AW is hundreds of metres down.

[Rob Dekker]

Good news that ice volume is back to 2011/2012 levels ! It seems to me that the cracks actually helped to accomplish this, since open water obviously freezes much faster than a solid slab of ice. Hopefully this (winter cracks) is an indication of a 'negative' feedback, at least on an inter-annual basis.

Of course, if volume at the start of the melting season is unchanged, then the ice minimum in September will be determined by the amount of heat pumped into the Arctic during the melting season itself.

In that regard, it will be very interesting to follow the snow cover trend during April, May and June. If the relentless downward trend of earlier snow melt from the past decade continues
http://climate.rutgers.edu/snowcover/chart_anom.php?ui_set=1&ui_region=nhland&ui_month=6
then common sense will suggest that there will be an increasing amount of heat absorbed in the Arctic during the melting season, which will lead to a new record September minimum EVEN IF the spring volume maximum is the same as in previous years.

[SATire]

Chris,

I think one should at least think about "a transition to perennially sea ice free in years." That might be a possibility following that Eisenman paper. However, that model is simple 1D, ocean currents are not modelled other then as just as a parameter.

In academic sciences, we use 80% of our work to discuss definitions, appropriate time-scales and relevance of specific processes to be modelled - it is a hard way to get to a theory but that way must be gone. Without going that way, any opinion is as interesting as e.g. your hobbies, mainly usefull for late night discussions in the bar after work ;-)

To apply that - we need a base on questions like what is "steady state"? When is a "transition completed"?
Some typical time-scales are: The seasons, AO/ENSO-cycles, solar cycles, ocean cycles.

Since it surely takes several >1000 years for the oceans to get in any steady state - that should be separated first. For the prediction of the time for perennially sea ice free state we do not have to estimate the time needed to heat the arctic basin down to the ground. But that point will be very interesting if we once want to model a possible way back to current ice-ages...

For medium time-scale it would be sufficient to heat upper 100 m of arctic ocean - that could be a matter of 10 years to start (10m/year), but it will not be steady state of course on a 100 years time-scale.
If we use Wipneus-Exponential and would assume, that 50% ice-free time in the arctic would be sufficient to heat that upper layer - that process would start somewhere next decade and would be "completed" about one decade later. However - further surprises are guaranteed ;-)

[Paul]

Would it be terribly remiss of me to put a prediction out for 2.9 total ice volume minimum in spite of the current recovery.

I base this idea off the fact that much of the recovery in ice volume comes from the periphery.

[Jim Williams]

Personally Paul, I think your prediction is about 2.9 too high. I do agree with your assessment of the 'recovery', but I also think there are signs that the halocline may be breaking down.

I admit that I'm being very aggressive in my predictions, but I'm sticking with them at least until mid-summer. This, of course, is just a guess -- but I'm rather sure that some Summer soon the ice is simply going to melt away, and this Summer is as good as any other.

[Paul]

Jim, with regards to the arctic ice melting to a 0 minimum, we can be certain this is going to occur.

We can probably assert this will occur within the next 2-10 years with high degree of surety.

The question is how soon it will occur, and will this event spark some action to finally be taken to ameliorate climate change and attempt to arrest the effects it will unleash. Personally I think it already to late to really have any effect.