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viddaloo

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Re: Arctic Summer Sea Ice transition
« Reply #100 on: November 04, 2014, 05:23:12 AM »
For what its worth, Peter Wadhams gave a presentation today, making his case for a an ice free month in 2020.

An excerpt follows:

"No models here," Peter Wadhams, professor of applied mathematics and theoretical physics at the University of Cambridge in England, told the Arctic Circle Assembly on Sunday. "This is data."

Wadhams has access to data not only on the extent of ice covering the Arctic, but on the thickness of that ice. The latter comes from submarines that have been beneath the ice collecting measurements every year since 1979.

This data shows ice volume "is accelerating downward," Wadhams said. "There doesn't seem to be anything to stop it from going down to zero.

"By 2020, one would expect the summer sea ice to disappear. By summer, we mean September. ... (but) not many years after, the neighboring months would also become ice-free."

See: http://www.adn.com/article/20141102/expert-predicts-ice-free-arctic-2020-un-releases-climate-report

I second that.
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jai mitchell

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Re: Arctic Summer Sea Ice transition
« Reply #101 on: November 04, 2014, 05:58:42 AM »


http://www.pnas.org/content/early/2014/10/29/1413640111

Far-infrared surface emissivity and climate
We also describe a previously unidentified mechanism that amplifies high-latitude and high-altitude warming in finding significantly lower values of far-IR emissivity for ocean and desert surfaces than for sea ice and snow. This leads to a decrease in surface emission at far-IR wavelengths, reduced cooling to space, and warmer radiative surface temperatures.

Quote
In the Arctic, the simulations found that open oceans hold more far-infrared energy than sea ice, resulting in warmer oceans, melting sea ice, and a 2-degree Celsius increase in the polar climate after only a 25-year run.

This could help explain why polar warming is most pronounced during the three-month winter when there is no sun. It also complements a process in which darker oceans absorb more solar energy than sea ice.


 Read more at: http://phys.org/news/2014-11-berkeley-lab-scientists-driver-arctic.html
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Michael Hauber

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Re: Arctic Summer Sea Ice transition
« Reply #102 on: November 04, 2014, 08:46:32 AM »
To answer your question from the solar radiation thread, the 2 degree difference is between a model with and without the adjustment for far right infra red.  However it is a maximum, and is not uniform.  There are also significant areas where the difference is negative, some in the Bering Strait area, but mostly in the rest of the globe - the Arctic average still looks to be significantly positive with the strongest +1 to +2 differences over an area stretching from Kara/Barents sea through to Greenland.
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wili

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Re: Arctic Summer Sea Ice transition
« Reply #103 on: November 04, 2014, 10:04:15 AM »
"2 degree difference is between a model with and without the adjustment for far right infra red"

That was my impression, too.
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crandles

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Re: Arctic Summer Sea Ice transition
« Reply #104 on: November 04, 2014, 12:48:07 PM »
Crandles,

in your new best fit curve for PIOMAS volume, what if 20,000 KM^3 is a winter tipping point where by winter ice formation becomes radically slower, resulting in earlier and earlier summer ice free states.  This is more akin to the tipping point effects that both Vid and I see as resulting from large scale systemic enthalpy increases.

What if, as September becomes ice free and winter volumes become sufficiently thin that a rapid winter decline occurs due to compounding summer enthalpy effects, say around 2025, where would your winter curve go then (assuming summer stays the same (I think it will plateau a bit at the end).

I hope tipping points are fairly rare, but they are certainly a possibility which would throw any curve extrapolation off.

>where by winter ice formation becomes radically slower

umm why would that happen?

Graph from Thorndike 1975 from Chris Reynolds slow transition thread


The evidence therefore seems clear that as you get less ice volume it is thinner and it thickens much more quickly. This is why I am expecting the slope of the volume decline to be slower than it has been recently. Models also show a slowing down.

>large scale systemic enthalpy increases
When the ice thickness is zero, the rate of heat loss from the system is 13cm of ice formation per day. So even if you heated the top metre of water to 20C, that heat would be gone in something like 20 days and there is still plenty of time left for the ice to grow to over a metre thick. Where then is your systemic enthalpy increase?

OK I will accept that some of the heat mixes down low enough that it isn't given up before ice formation starts. But I would suggest this has already been happening and I don't see it causing a sudden accelerating shift in the system. Nor do models show such an accelerating shift as we get nearer to ice free.

jai mitchell

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Re: Arctic Summer Sea Ice transition
« Reply #105 on: November 04, 2014, 05:07:17 PM »
>where by winter ice formation becomes radically slower

umm why would that happen?


residual heat and (now) reduced emissivity of open water in the far infrared.

I guess the best way to check this would be to track October ice volume accumulation rates over time as Viddaloo has been doing with other months in this thread.
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crandles

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Re: Arctic Summer Sea Ice transition
« Reply #106 on: November 05, 2014, 12:05:10 AM »


If it was significant, I think you would expect to see longer delays on the way back up than on the way down. Counting the little dots on the 5m km^2 line, the earliest we have got down to 6m Km^2 is 9 dots earlier than the 2000s average. On the way back up it is 11 dots later than the 2000s average so there seems a slight effect there. I am not denying there is more heat in the water just that vast majority of it is lost to space by the time the water has frozen over. If we go up to the 8m km^2 line, I count 8 dots earlier and later than 2000s average. That seems like an effect of lower ice levels at all times rather than effect of heat being retained significantly slowing the reforming of ice.

By the 10m Km^2 line, the delay and drop seem less than on the way down.

Are you expecting the lines in future to both drop and bulge out on the right hand side much more than has been seen in the past? If so why would it happen in the future but not much in the past?


viddaloo

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Re: Arctic Summer Sea Ice transition
« Reply #107 on: November 05, 2014, 02:00:07 AM »
October refreeze 1979–2014 (2014 estimate by viddaloo).

While likely, I think we have to wait a few years before any new Autumn refreeze trend becomes apparent in the data.

So far, only April and September have changed significantly in this respect: September from being a net Gain month to a net Loss month, and April (soon) from being a net Gain month to a net Loss month (2007, 2010, 2013).
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viddaloo

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Re: Arctic Summer Sea Ice transition
« Reply #108 on: November 05, 2014, 04:30:25 AM »
It seems fair to say that for the first 3–4 weeks of October, the volume gain is on average slower than in the late 20th century, but for October all in all, the gain is faster. To me, that means the ocean/air is now much warmer way into October, and this effect for the large part of the month outweighs the potentially faster refreeze because you have more open water left over from September.

It would be interesting to look at a trendline for October 15th, though. Pmt111500, maybe we need Sami months here? :)
« Last Edit: November 05, 2014, 04:45:31 AM by viddaloo »
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viddaloo

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Re: Arctic Summer Sea Ice transition
« Reply #109 on: November 12, 2014, 02:55:52 PM »
Last week I was waiting for the PIOMAS data to arrive, so this will be a 2–week update.

The November extent refreeze has been 250 000 km² slower than the 2002–2013 average, but extent is still higher than last year. The last fortnight has therefore seen a slight increase in Yearly Average Extent, from just below the 10.3 mark to 10.306 yesterday. To date we've still lost some 115 000 km² from yearly averages, though, since the Big Descent began on January 5th 2014. The 2014/13 YAE gap is unmatched in 2009/08, so we have to proceed to 2010/09 to find a similar gap on May 29th, making the YAE descent 199 days 'ahead of schedule'.

Yearly Average Volume is expected to peak in early March of 2015, then start a big 1000–day descent. That makes it 14 months late compared to the current Big Descent in Yearly Average Extent, or, if you will, about 7 months late judging from the 2014/13 and 2009/08 YAV gaps.

The big disconnect in onsets of the descents may throw some doubts at the very existence of a 5–year cycle, and to be honest, I am one of those doubters. Yet it's really not essential to the hypothesis when a descent starts, and there are very good physical reasons for the discrepancy with regard to the YAV development: The slide in extent is ongoing because the Southern areas melt out earlier and refreeze later, whilst the awaited slide in volume is lagging because of the Northern MYI in the CAB. It will catch up, and then we'll see really dramatic collapse of the Arctic sea ice, during those 1000 days.

(The hypothesis can be considered falsified and dead the minute the yellow 2012–2016 line crosses the red 2007—2011 line, or later, if necessary, if we don't see a major crash in 2017 and a subsequent Yearly Average rebound in 2018—2019.)

First graph below shows 2014 + 2009 detail. The second and third present the general overview.

2015 is expected to be the 'new 2010' according to the hypothesis. 2010 not only connects the pre–2010 years with the post–2010 years — by crossing the graph for 2014 YAV — because of its overwhelming melt, it also holds the current record in melted ice volume: 19 693 km³. (Incidentally only 1 km³ more than 2012). It also set new records for April, May and June melts (genuine hat–trick), individually and for Spring totals.

My question to all of you is thus: Do you think 2015 will set a new record in total ice melt? And will April, May and June records fall? Why or why not? :)
« Last Edit: November 12, 2014, 03:13:57 PM by viddaloo »
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viddaloo

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Re: Arctic Summer Sea Ice transition
« Reply #110 on: November 28, 2014, 12:37:38 PM »
So Viddaloo says (about) 2039  I say (about) 2065 and Chris says beyond 2100 for a year-around ice free arctic.

I think you'll find I say about 2031, but let me moderate that: 1) At the moment the YAV Collapse curve is on a peak, which yields later collapse estimates. The next time it's at a bottom, it could easily point to 2028 or 2029 for zero ice. 2) As I've pointed out rather thoroughly, and shown by estimate testing, simple curve–fitting is too conservative. In the real world, this means that rapid feedbacks that still haven't started or still are quite weak, will start without those feedbacks being predictable by this simple statistical analysis. This means an all ice–free Arctic ocean all year round is more likely to happen somewhere between 2025 and 2030 than in the year 2031.

Also, there seems to still be a disagreement about statistics and maths, in that some people on this forum seem to claim that an average cannot be calculated when one or more values hit zero. This makes absolutely no sense to me. Mind you, I'm not saying I'm not listening to your arguments, it's just that those arguments make absolutely no sense to me. Practically speaking, then, those arguments would have to be better, or maybe better explained, in order for them to impact my opinion of the mathematical ability or 'right' to calculate average values.

If Bruce has 1 apple, Bob none and Adam 8 apples, they still have an average of 3 apples each. Even though Bob has no apple. Maths doesn't stop working just because Bob has no apple.
« Last Edit: November 28, 2014, 01:28:56 PM by viddaloo »
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crandles

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Re: Arctic Summer Sea Ice transition
« Reply #111 on: November 28, 2014, 01:43:12 PM »
2) As I've pointed out rather thoroughly, and shown by estimate testing, simple curve–fitting is too conservative.

thoroughly? Sorry but hand waving is a more accurate description.

Here is some evidence that these aggressive curves do not play out in reality and these simple curve fittings are being shown to be too aggressive not too conservative.


Where is your evidence? (Please assume that waffle about the feedbacks you expect to happen doesn't count as evidence.)


They each eat an apple a day if they have them available. Two days later, is their average now (3-1per day*2days)=1 apple? No their average is 2, more than the 1 because the average has declined slower. Heat/ice volume works the same way because vast majority of excess heat is vented to atmosphere and space in autumn each year so the negative numbers get reset with each winter maximum having similar volume despite extra heat (negative volume) being created each year.

It rather begs the question are you trolling?
 
« Last Edit: November 28, 2014, 01:52:17 PM by crandles »

viddaloo

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Re: Arctic Summer Sea Ice transition
« Reply #112 on: November 28, 2014, 02:04:03 PM »
2) As I've pointed out rather thoroughly, and shown by estimate testing, simple curve–fitting is too conservative.

thoroughly? Sorry but hand waving is a more accurate description.

Crandles, I'm sorry if you haven't seen or understood my pointing it out and demonstrating it through a thorough estimate testing. It is all in my signature link, so feel free to give it another try when you feel that you are ready for it.

Here is some evidence that these aggressive curves do not play out in reality and these simple curve fittings are being shown to be too aggressive not too conservative.


Where is your evidence? (Please assume that waffle about the feedbacks you expect to happen doesn't count as evidence.)

See above. Ignoring my evidence doesn't really give you an upper–hand here, it only shows you are ignoring my evidence. Feel free to continue to do so, as I only really care about arguments from people who are willing to study the evidence. The rest I can chit–chat with about the weather or other things, but it doesn't concern the matter we are discussing.

Staying on focus I believe helps us to understand things faster than constantly running in all other directions. I may be in a minority there, and there may be good reasons to not want to reach an understanding faster, but then those reasons should also be brought out in the open, IMO.
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crandles

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Re: Arctic Summer Sea Ice transition
« Reply #113 on: November 28, 2014, 04:27:29 PM »
Sorry about the handwaving comment, I hadn't seen the link in your signature comment. My mistake.

Your polynomial curve (cubic?) on %melt has been less aggressive than Wipneus' exponential extrapolations and it looks like reality has so far proved more aggressive than your formula, at least on your one year ahead testing. To claim it is thorough testing, I would expect to see more than this: One year ahead is likely dominated by noise, whereas several years ahead is likely to see systematic error emerging above the noise.

It is the systematic error from the curve type we want to see. Wipneus' graph does it nicely I think. (Notice how we are now firmly on the less aggressive side of the first couple of extrapolated curves.)

Besides this, you have in no way (that I have seen) shown that the curve shouldn't be more like:

PIOMASVolumemax&minExtrapolatebelievable by crandles2011, on Flickr

If data roughly follows the downward slopes then eventually all the actual data several years ahead will end up on the less aggressive side of your extrapolated curves from several years before.

There are lots of curves that fit the data but go off in different directions. Assuming your curve type is right without any physics to back it up is a bit of a wild game and more so when people are pointing out physics that make your curve type unlikely eg Chris Reynolds slow transition blog post and thread on this forum.


viddaloo

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Re: Arctic Summer Sea Ice transition
« Reply #114 on: November 28, 2014, 04:40:55 PM »
I understand CR has a blog post with a theory. That doesn't mean it's correct or that all math tools immediately stop giving meaningful results. I, for one, don't think CR is correct about the Arctic sea ice collapse. I think others have a better understanding of the forces at play here.
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crandles

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Re: Arctic Summer Sea Ice transition
« Reply #115 on: November 28, 2014, 06:19:20 PM »
I understand CR has a blog post with a theory.

You are showing your ignorance. In science things don't get better than being a theory.

So the maths tool that I used to see if the data is showing any signs of leveling out, the 4 parameter gompertz fit posted above which does find some leveling out, if fact so much that it levels out immediately is a maths tool that keeps working according to the logic you just gave.




jai mitchell

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Re: Arctic Summer Sea Ice transition
« Reply #116 on: November 28, 2014, 06:55:18 PM »
Crandles, Vid

You know, I can see a lot of good points here from both of you.

1.  There will be feedbacks that are currently not being experienced, with greater and greater intensity, as the arctic warms and the jet stream becomes more erratic - Vid

2.  Using an average on a time-dependent depletion model is not the best methodology, (but given the above uncertainty, might be a pretty good fit nonetheless).

3.  Mathematic models and theories are really all we are working with to predict the future.  In this exercise a bit of "common sense" has to be incorporated, or at least an "educated guess".  This is why crandles' 4th power Gompertz curve is tongue-in-cheek (because it is SO UNLIKELY)

4.  the above is also why I expect a gompertz curve finish, because I am simply hedging my bets.

5.  If VID is right and intensely powerful positive feedbacks occur as soon as we approach ice fre conditions, then he is going to get the steep curve dropoff that he is predicting.  this isn't hand waving, it is a possibility.

I am grateful for both of your contributions to this forum!  I have benefitted greatly from your work in greater understanding and perspectives!
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LRC1962

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Re: Arctic Summer Sea Ice transition
« Reply #117 on: November 28, 2014, 08:02:06 PM »
Other then the last 2 years we have seen a massive drop in ASI in the last 10 yrs or os. At the same time we have seen a "pause" in global temperatures. Noting: There are those who disagree with this in that under reported temperature areas are warming faster then calculated those still giving a rise in temperatures. The main culprit for this is pointed at the Pacific Ocean which has been under te influence of a -PDO thereby driving down temps in that area. These last few months have seen a major change going on in the PO.
The one thing that did not occur for a La Nina to happen was the necessary atmospheric changes. A point to ponder: could it be that the PO waters are rising rapidly, but in such a way that it is occurring so generally that the normal wind patterns are weakening such has happened with the jet stream and therefore the long term weather patterns in the Pacific are stagnating. Note: a heating up of the PO still could give rise to nasty typhoons as we have seen IMO and a farther indication of a general PO heating would be haw much farther north those storms are tracking.
What you may justly ask is my point? If the global temps start rising at a rate that gets it back on the curve pre 1998, plus see a return of a +PDO as a few have argued, could not we see a collapse of ASI such as we saw in '07 or '12, and thereby seeing a possible ice free time sooner rather then later?
The reason I bring this up is that although the Atlantic Ocean weather systems seem to have greater impact on the Arctic, the PO is known to have the greatest impact on a global scale including the North Atlantic Ocean.
As I have no education on this I may be terribly wrong and wish to be edified on my statements.
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crandles

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Re: Arctic Summer Sea Ice transition
« Reply #118 on: November 28, 2014, 08:26:33 PM »
3.  Mathematic models and theories are really all we are working with to predict the future.  In this exercise a bit of "common sense" has to be incorporated, or at least an "educated guess".  This is why crandles' 4th power Gompertz curve is tongue-in-cheek (because it is SO UNLIKELY)

Yes it is very unlikely, I don't believe it.

(BTW it is a 4 parameter gompertz curve rather than '4th power'.)

This curve type clearly asks if there is a slow down in the rate of decline and the fit is showing yes there is. This doesn't mean the curve type is correct, I am clearly saying it is wrong. It does show some evidence for a slow down in rate of decline otherwise the best fit would continue downwards for some way before levelling off. By showing more than 1 curve type I am also showing that there are many curve types than can fit the data and then go off in different directions.

Given this situation, it is difficult to defend choosing quite an aggressive trend and saying this trend is too conservative. At best it may be a possibility.

Chris Reynolds work seem well researched giving due consideration to the published literature on the subject. Consequently there seems far better support for what Chris Reynolds is saying.

Viddaloo may not like it, but the onus is on him to show that what he believes is better supported.
Otherwise sensible people should prefer to study the scientific literature on the subject. Criticising the literature without replacing it with something better is not a defensible position.

viddaloo

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Re: Arctic Summer Sea Ice transition
« Reply #119 on: November 28, 2014, 08:47:06 PM »
It is natural to be afraid in the face of such massive changes to our living environment, Crandles, and therefore I don't blame you or anyone who react this way.

If I recall correctly I use a 2nd order polynomial trendline for my Arctic sea ice collapse graph (posted above). I don't automatically assume the graph will take off violently in any other direction than it has until now. Rather, I assume it will follow the same path further down.

Thirteen thousand one hundred days of observational data DO a trend make.
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jai mitchell

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Re: Arctic Summer Sea Ice transition
« Reply #120 on: November 28, 2014, 10:35:47 PM »
Chris Reynolds work seem well researched giving due consideration to the published literature on the subject. Consequently there seems far better support for what Chris Reynolds is saying.

I disagree, I believe I have shown quite clearly earlier in this thread as well as in his thread on the other subject heading that he has overemphasized the winter heat loss rate with an overly simplistic model that disregards atmospheric moisture as well as far infrared heat emissivity reductions of open water and observed increases in average October barrow Alaska temperatures over the last decade.

In addition, he has severely underestimated the temperature increase associated with a summer ice free state as well as a significant underestimation in enthalpy accumulation during the midnight sun on ice free conditions.

In effect, he has duplicated the Tistche et. al. paper's models, the same one that has the problems that I have outlined above.  (from my, obviously, armchair amateur's perspective)  but, I quoted significant paper resources in both threads to back up my claims.
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crandles

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Re: Arctic Summer Sea Ice transition
« Reply #121 on: November 29, 2014, 01:24:39 AM »
Chris Reynolds work seem well researched giving due consideration to the published literature on the subject. Consequently there seems far better support for what Chris Reynolds is saying.

I disagree, I believe I have shown quite clearly earlier in this thread as well as in his thread on the other subject heading that he has overemphasized the winter heat loss rate with an overly simplistic model that disregards atmospheric moisture as well as far infrared heat emissivity reductions of open water and observed increases in average October barrow Alaska temperatures over the last decade.

In addition, he has severely underestimated the temperature increase associated with a summer ice free state as well as a significant underestimation in enthalpy accumulation during the midnight sun on ice free conditions.

In effect, he has duplicated the Tistche et. al. paper's models, the same one that has the problems that I have outlined above.  (from my, obviously, armchair amateur's perspective)  but, I quoted significant paper resources in both threads to back up my claims.

I don't believe far infrared heat emissivity is a huge model error. William Connolley wrote
Quote
And if I were dumping this into a model I’d ramp it up to the limit of what could be possible, just to get something you could see in the model. The real effect, if it pans out, could be much smaller. Plus as you say there could be spin-up effects

So we disagree of the size of this and what I have provided isn't very much.

Passing a temperature threshold which allows much more moisture in the atmosphere sounds a plausible tipping point effect. This is a very different beast than curve extrapolation. I really don't trust my intuition once we get past a month of ice free conditions. The chances of a tipping point like this are obviously much greater once we are talking that far ahead than when we are taking of the next decade or up to two decades.

> I believe I have shown quite clearly earlier in this thread ...

That seems a very odd summary to me. You claimed a 400% increase rather than a 20% increase and when Chris Reynolds asked for your calculations you seemed to talk your way through what calculations would be necessary. Maybe I misunderstood but I could imagine a slight increase from 20% arising but am still lost as to how 400% comes about. Then the conversation moved on to ice free conditions at 1 June and you pointed to some papers, which I admit I don't think I have read, but I didn't see any indication of how this showed that Chris Reynolds 'has overemphasized the winter heat loss rate' or 'underestimated the temperature increase associated with a summer ice free state'.

You clearly believe Chris Reynolds has overemphasized... and underestimated..... but that is different from having 'shown quite clearly'. If you can show it, I would be interested to see it.

crandles

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Re: Arctic Summer Sea Ice transition
« Reply #122 on: November 29, 2014, 01:41:14 AM »
It is natural to be afraid in the face of such massive changes to our living environment, Crandles, and therefore I don't blame you or anyone who react this way.

If I recall correctly I use a 2nd order polynomial trendline for my Arctic sea ice collapse graph (posted above). I don't automatically assume the graph will take off violently in any other direction than it has until now. Rather, I assume it will follow the same path further down.

Thirteen thousand one hundred days of observational data DO a trend make.

What has fear got to do with assessing the scientific merit of your extrapolations?

2nd order polynomial cannot find an increase in the rate followed by a decrease in the rate of decline. So you are closing your mind to that possibility. You need to consider more of the curves that fit the data but when extrapolated go off in different directions.

DO a trend make? yes
Does this make extrapolation easy? No, there are lots of curves that fit the data but then go off in different directions.

I am thinking we have done this over and over. If you are not getting it then you are simply not going to learn and it is pointless me trying to help you learn.

jai mitchell

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Re: Arctic Summer Sea Ice transition
« Reply #123 on: November 29, 2014, 07:38:30 AM »

I don't believe far infrared heat emissivity is a huge model error. William Connolley wrote
Quote
And if I were dumping this into a model I’d ramp it up to the limit of what could be possible, just to get something you could see in the model. The real effect, if it pans out, could be much smaller. Plus as you say there could be spin-up effects

as I stated before:  from the paper

Quote
Fig. 4 indicates that the difference between
the unity assumption and an estimate of far-IR surface emissivity
based on land type as shown in Fig. 3 causes CESM to produce
dramatically different results in climate variables, even after only
25 y of integration. Decadally averaged surface temperatures’
change in the 2030s differs in the two integrations by up to 2 °K,
with a systematic increase in temperatures with IGBP emissivity.

note this is globally averaged, of course the arctic is going to respond with a much greater response.  there are several other factors that are included in this. 

> I believe I have shown quite clearly earlier in this thread ...

That seems a very odd summary to me. You claimed a 400% increase rather than a 20% increase and when Chris Reynolds asked for your calculations you seemed to talk your way through what calculations would be necessary. Maybe I misunderstood but I could imagine a slight increase from 20% arising but am still lost as to how 400% comes about. Then the conversation moved on to ice free conditions at 1 June and you pointed to some papers, which I admit I don't think I have read, but I didn't see any indication of how this showed that Chris Reynolds 'has overemphasized the winter heat loss rate' or 'underestimated the temperature increase associated with a summer ice free state'.

You clearly believe Chris Reynolds has overemphasized... and underestimated..... but that is different from having 'shown quite clearly'. If you can show it, I would be interested to see it.

yeah I don't have the matlab or the time to do the hand calculations.  suffice it to say, with increasing solar irradiance based on the previous curve, integrating the time dependent cumulative solar irradiance with latitude from June 1 to September 1 the accumulation of enthalpy is several times higher. not 20%, not even close.



I am sorry if this doesn't make sense by looking at the graph, I don't really know what to tell you.

finally, observational evidence of barrow Alaska October temperature anomalies this last decade indicate a much higher feedback (as well as paleo evidence from svalsberg during hyperthermals.  There is a significant and prolonged release of heat (with associated humidity increases) once a near summer ice free state occurs.
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viddaloo

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Re: Arctic Summer Sea Ice transition
« Reply #124 on: November 29, 2014, 09:12:28 AM »
5.  If VID is right and intensely powerful positive feedbacks occur as soon as we approach ice fre conditions, then he is going to get the steep curve dropoff that he is predicting.  this isn't hand waving, it is a possibility.

You know, I kind of started the other way around: 1) I saw that IPCC was way off in their projections of an ice–free state, 2) then I thought what if we just use a basic poly trendline? When criticizing my own poly trendline, 3) I then looked at how accurate such a trend projection had been in the near past, and on what side it had been wrong. 4) I then found it had been too conservative. 5) The most probable reason it had been too conservative, was the fact that the feedbacks involved in this epic thaw simply overwhelm both the Panel and the statistical analysis with the added trendline.

Basically, there seem to be known unknowns — to use Donald Rumsfeld's famous expression — that force the thaw to be more rapid than even the poly trendline that currently points to an all–Arctic all–year ice–free state beginning in the year 2031.

Knowing far less about the physical basis of these changes than most on this forum, I then simply trust the math — which I DO understand — and gaze humbly at these massive forces that are probably changing our future forever.
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Re: Arctic Summer Sea Ice transition
« Reply #125 on: November 29, 2014, 01:09:45 PM »

as I stated before:  from the paper

Quote
Fig. 4 indicates that the difference between
the unity assumption and an estimate of far-IR surface emissivity
based on land type as shown in Fig. 3 causes CESM to produce
dramatically different results in climate variables, even after only
25 y of integration. Decadally averaged surface temperatures’
change in the 2030s differs in the two integrations by up to 2 °K,
with a systematic increase in temperatures with IGBP emissivity.

note this is globally averaged, of course the arctic is going to respond with a much greater response.  there are several other factors that are included in this. 

Oh come on, notice the 'up to' in what you quoted. Alternatively, look again at fig 4A and you will see that 2K is the maximum temperature difference and there are many areas that are colder. Globally averaged temperature difference will be like 0.2K higher at most. Not that globally averaged matters it is the Arctic we are interested in and that is generally warmer with only a bit of Siberia, ESS, and Chukchi being colder, perhaps an average of 1K warmer.

My guess is they haven't fully spun up the model to have atmosphere and ocean properly in balance and these spin up effects could well be the cause of quite a bit of the differences. Plus as William Connolley says they probably threw in the maximum effect to try to be able to show some effect. William also backed me up on the spin up effects.

crandles

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Re: Arctic Summer Sea Ice transition
« Reply #126 on: November 29, 2014, 01:35:13 PM »

finally, observational evidence of barrow Alaska October temperature anomalies this last decade

But this is what Chris Reynolds and I would expect. The ocean venting heat to the atmosphere in the Autumn.

Why would this create a 'much higher feedback' rather than simply running out of heat a little later? So far we have seen some movement towards a later ice recovery:


but basically very little, maybe a week to 10 days over 12 years shown. OK if we are talking ice free on 1 June then there is a lot of time to accumulate heat and I can see a long delay before ice starts to grow. But for the short term - next decade-ish can you justify expecting the delay to suddenly start growing much more rapidly than it has so far? Why would this start imminently rather than 5 or 10 years ago?

jai mitchell

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Re: Arctic Summer Sea Ice transition
« Reply #127 on: November 30, 2014, 02:30:47 PM »
Indeed,

however, if you slide your attention over to figure 4b you will see a 2030 projection of SIE that is 6-7% LESS than baseline due to the far infrared emissivity.

using a simplistic model based only on ice layer and clear sky heat loss rates is foolhardy and shortsighted.  Model me some increasesing pacific eddy current heat flux under RCP 8.5 and include 300% perturbations in winter humidity by 2030 and we will see where we get. 

The point here being that

1.  climate models failed us in the arctic by only considering TOA emission as a driver of ice loss

and

using a related model based on tietsche's work, without consideration of latent heat and ocean current heating is following along the average arctic sea ice extent under RCP8.5 model's path to perdition.





(note the above and imagine now a june 1st arctic ice-free state)

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crandles

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Re: Arctic Summer Sea Ice transition
« Reply #128 on: November 30, 2014, 04:24:02 PM »
Yes there is an effect when you turn the effect on. Of course, the effect doesn't get turned on in reality, it has always been on. Really need to get the ocean atmosphere and ice into balance by running a pre-industrial climate for a few hundred years then force with 20th Century forcings and then RCP8.5.

That paper does say
Quote
We use several well-established radiative transfer techniques and one stateof-
the-art Earth system model ...
CESM was run with the Representative Concentration Pathway (RCP) 8.5
forcing (35),

What makes you think Tietsche's work didn't consider latent heat or ocean current heating or only use clear sky heat loss rates? That sounds like denier nonsense about GCMs. Of course CESM and other similar state of the art models include latent heat considerations and ocean currents and appropriately cloudy skies.

Tietsche et al 2011 says
Quote
The global AOGCM we use consists of the atmosphere component ECHAM5 [Roeckner et al., 2003] with a T31 horizontal resolution and 19 vertical levels, and the ocean component MPI-OM [Marsland et al., 2003] with a curvilinear grid that has a horizontal resolution of 50–200 km in the Arctic and 40 vertical levels. A dynamic–thermodynamic sea-ice model based on the work by Hibler [1979] is included.



If ice is forming faster than in previous years, the latent heat released has to go somewhere and that is to atmosphere and space. So higher temperatures in late Sept and October while accumulated heat is vented prior to ice formation is expected. Also higher temperatures all the way to Feb as ice forms faster to catch up with previous years ice levels is expected. I don't see what you are pushing with those temperature graphs. Why would there be a stronger feedback than already modelled?

At what temperature changes is your 300% winter humidity increase reached?

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Re: Arctic Summer Sea Ice transition
« Reply #129 on: November 30, 2014, 06:22:19 PM »


doesn't look like any reason to expect sudden acceleration compared to what we have seen at the relevant temperatures.

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Re: Arctic Summer Sea Ice transition
« Reply #130 on: December 02, 2014, 10:09:08 PM »

What makes you think Tietsche's work didn't consider latent heat or ocean current heating or only use clear sky heat loss rates?


Not Tietsche, I am talking about CR's model.


If ice is forming faster than in previous years, the latent heat released has to go somewhere and that is to atmosphere and space. So higher temperatures in late Sept and October

At what temperature changes is your 300% winter humidity increase reached?

The late Sept and October data doesn't play out even in recent years, abnormally high temperatures are being reached throughout the year.

the 300% winter humidity is associated with a June 1st ice free condition.

Thanks for the graph, I can see that the 300% winter humidity increase is reasonably within a regime of variable temperatures where winter averages are close to 10C. 
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Re: Arctic Summer Sea Ice transition
« Reply #131 on: December 17, 2014, 08:01:28 PM »
The bow–shaped graph for annual average volume proves the sea ice collapse is accelerating year by year. For the very bow–shape (of the trend) implies an ever more rapid loss of ice, not a slow–down.



Thereby any suggestion that more open water (or more zero ice) year by year for the past decades should somehow have slowed the collapse down is thoroughly falsified. In fact, what such suggestions reveal is a serious thought error. Losing more ice of course isn't slowing the loss of ice, quite the contrary, and the bow–shape confirms this.

Having publicly made such preposterous claims, clearly and very obviously wrong, I can see why their anger is so furious, and why the 'Arctic Sea Ice Collapse' graph is attacked so viciously. The graph illustrates in 10 seconds why any such statements are plain wrong.

Yet while the choice of trendline — a 2nd degree polynomial — for this graph may be criticized (it certainly has been), all the furious attacks on the historical data part — marked by purple colour — of the graph have now quieted down, and critics are now saying 'of course we know what an average is, you don't have to explain that to us'. So for now the 'science is settled' on the purple part of the 'Arctic Sea Ice Collapse' graph.

As a consequence, some people should take the necessary time to realize that their previous claims about more open water hampering the ice loss were plainly and ludicrously wrong. On our way to perennial open water all over the Arctic, there will of course be huge increases in open water area, and these increases will most likely continue to speed up the sea ice collapse, not the other way around.
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Re: Arctic Summer Sea Ice transition
« Reply #132 on: December 17, 2014, 08:24:01 PM »
Can (all)you stop arguing with that graph, the fact is we don't know what does really going on, we know there is a lot of energy in the systeme but would it stay away or impact directly the ice without a gompertz tail...We will have to see how it goes. I  hope your are (all) doing more than seeing, we have to solve that mess...as already said green busyness won't solve the problem, so think twice the green busyness would have to be ecologically sound (I am not sure if it is possible...there is different ways to make so thought). Beside we will have to find ways to reduce our population quickly, softly with as less pain as possible (The question is still pending).

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Re: Arctic Summer Sea Ice transition
« Reply #133 on: December 20, 2014, 10:12:59 PM »
Laurent, anger is still raging and flames licking higher and higher in other parts of this forum related to this graph, so it's fairly obvious certain people feel very threatened. They certainly do not want to see this info, let alone debate it openly.

I guess the best solution is to quell the debate for the holiday season, and then simply hope that people find the time to relax during the quiet weeks and get their heads straight. I'm confident they will see things my way when they do, and that their anger is about me seeing this so early.
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Re: Arctic Summer Sea Ice transition
« Reply #134 on: January 03, 2015, 11:21:30 AM »
It's a 'slow ice day' — IJIS still figuring out how to make a new 2015 column, and PIOMAS still chewing on the December numbers — so let's make a more fact–free philosophical post in the meantime.

I'm trained in 'theory of science' at University — the oldest and most integral discipline within classic philosophy. I'm particularly interested in logic and the construction of valid (and invalid) arguments. My Jungian personality type also makes me more interested in the topic of discussion than in the individual participants, so all hypotheses of an interpersonal focus are thus rendered baseless.

When I review what in everyday language is called a theory, but in more scientific lingo an hypothesis, I focus on the most basic premises it is built on. Logically, if one of these premises is faulty, the entire argument falls. To me the signature or name signing the hypothesis is just unimportant, as the argument has to stand on its own feet (basically its premises).

Now, in one of the many long pieces of prose arguing for a 'slow transition' hypothesis, one such basic premise seems to be that the current downward trend of the CAB winter sea ice would end at zero in the 2030s, 'but surely no–one expects that'. The premise is followed by an exclamation mark, which for me, as a topic–focused analytical person, just isn't very convincing. Also, with regard to the extraordinarily rapid collapse of the Arctic sea ice, it seems more reasonable to me, at least, to 'expect the unexpected'.

Using such very weak basic premises, the entire hypothesis more or less falls, logically, the way I see it. At least it would fall if this was an integral part of the argument for the hypothesis (which I believe, but am not entirely sure, that it is).

In my own work on the collapse of the Arctic sea ice, I have this autumn looked at the different IPCC models and projections, and found them unconvincing. I have also looked into the extensive criticism of said panel, in both the popular and the scientific press over the past few years.

An idea was thus born to dismiss all the models and focus entirely on the recorded sea ice data. A Cambridge professor of ocean physics has since supported me in this choice of focus, so it cannot be entirely unscientific, as I see it.

The most striking result of my efforts is the graph showing sharp decline of the annual average volume of sea ice — displayed in this thread — and its simple polynomial trendline pointing to a July 2029 crash of all sea ice, year–round.

When evaluating the critique of this graph, again, as a highly analytical person, as mentioned above, I only consider the critique that can be said to have merit, that is critique that is not baseless or misunderstood or targeted more at the person and his 'conduct' than at the topic at hand; the physics or math or statistics of the graph.

I'm not impressed by this critique, and consequently it doesn't change my view of the timescale of the rapid collapse of sea ice. Less analytical people, or folks with other Jungian personality types, I'm sure, would be very impressed by this critique with or without any merit, simply because of the sheer social pressure to think differently. A Gary Larson comic on 'peer–pressure at the lab' comes to mind, where 3 already visibly mutated scientists are trying to egg the 4th scientist on to drink the stuff in the test–tube.



I particularly am not impressed by critique that mostly focuses on the year in the conclusion or long–term estimate of my work, 2029, dismissing the whole argument because, like above, 'surely no–one expects that'.

If you wanted to falsify the conclusion, you would basically either have to wait until 2029, or you would have to logically argue for the dismissal of one of my basic premises. Just saying that you don't 'like' or 'believe' my conclusion does not impress me or make me change my mind. The reason for this apparent 'stubbornness' on my part is exactly the fact that no integral part of my argument has been challenged in anything resembling a logical manner. To me, then, the argument is as good as before the critique of it began.

The best and most logically based critique of my work has in fact come from myself. This may sound self–congratulatory to many, if not most, but it is still a fact. The critique is that an estimate based entirely on the already recorded sea ice data would likely be too conservative, because entirely new and both unknown and (important!) unexperienced feedback mechanisms could still appear and change the path of the sea ice collapse dramatically.

The odds are any such unexperienced feedbacks would be so–called 'positive' feedbacks, ie feedbacks that strengthen and reinforce the already dramatic pace of the ice–cap collapse.
« Last Edit: January 03, 2015, 11:33:17 AM by viddaloo »
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Re: Arctic Summer Sea Ice transition
« Reply #135 on: January 03, 2015, 12:21:18 PM »
Have to agree with your finishing shot Vid ;)

Science knows the end result of continued warming by looking at past analogues of ice levels under similar forcings but appear constantly surprised by the way ice is being lost ( scrabbling to keep up?).

We already know that when we do make the final drop to near ice free that this will bring , or intensify, the transition but how do we spot what would be an 'outlier' in this transition if it were merely a steady drip ,drip event? We are again looking at the vagaries of 'weather' and chaotic coincidence. One more poor winter ice gain followed by perfect melt storm synoptics over melt season and we are there but how to see these condition before times?

2017 is the first possible return to the 07' synoptic ( so we are told) so a poor winter for ice gain in 2016/17 might see us facing the summer when the ice went?

At present export has restarted and we are trading our Atlantic MY 2.5m ice for FY sub 1m ice. Warm air over the Pacific side appears to be limiting growth there so will we see Piomas drop back into the other low ice years in Jan/Feb?

Will export continue into summer? Will we see a warm /average summer this time ( instead of a third , back to back,year of good ice retention?)?

The changes we are measuring in the atmosphere above the basin are, to me, part of the 'normalisation' to ice free conditions and not a pre- condition to ice free conditions? They go hand in hand but only the 'ice free summer' will cement them fully into place? Export, low summer ice and ocean warming are what lie behind the losses that leave the pack vulnerable to the first 'outlier' ice free summer (IMHO).
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Re: Arctic Summer Sea Ice transition
« Reply #136 on: January 03, 2015, 05:35:04 PM »
Laurent, anger is still raging and flames licking higher and higher in other parts of this forum related to this graph, so it's fairly obvious certain people feel very threatened. They certainly do not want to see this info, let alone debate it openly.

I guess the best solution is to quell the debate for the holiday season, and then simply hope that people find the time to relax during the quiet weeks and get their heads straight. I'm confident they will see things my way when they do, and that their anger is about me seeing this so early.

I have been coming to this site for nearly 3 years and this PIOMAS trend chart has been openly and healthily discussed for this entire time. I suggest you read others comments and other threads more closely.

Your increasingly hyperbolic posts suggests that you think you are saving this site from a community of denialists. This is laughable and I have found myself over the last 2 months simply skipping your comments and many responses to them.

To use your own analogy, your posts are producing more smoke  than light.

« Last Edit: January 03, 2015, 05:41:54 PM by Shared Humanity »

jai mitchell

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Re: Arctic Summer Sea Ice transition
« Reply #137 on: January 04, 2015, 10:51:58 PM »
Without the ability to provide counterfactual (before 2029), one must instead look to see if the projections are remotely plausible.

To understand if they are plausible, one must have a good understanding in specific disciplines that are related to the physical systems being predicted.

In addition, a healthy understanding of the physical systems that might also experience relational impact from the predicted final system state would be very helpful.

This is called a "reality check".

to find a sense of reality then, one must either understand what the specific system dynamics necessary to implement the final produced change would look like.  Or, at least, how this system change would impact other interrelated systems.

So, the questions are:

1.  What kind of conditions in the arctic would be necessary to prevent sea ice from forming during the boreal winter 

and

2.  What would these conditions look like in non-arctic areas of the northern hemisphere.

I was trying to lead you in this direction when I asked you about lake ice in the Northern American Great Lakes.  Obviously, for a winter to be so warm that it never reaches -5C in the arctic throughout the cold-dark of February, the Winter temperatures of the areas that DO receive sunlight would have to be similarly warmed.

In other words, a 25C warming of the arctic in winter would be approximated in the mid-latitudes by a 13C (or more!) warming in winter. 

And if this occurred in the winter, what then would the summer look like?  Are we then looking at a globally averaged temperature increase of 15C?

now does this conditional state seem plausible in 2029? Or even before 2100?

Without some other major response, I don't see how it can be.
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Re: Arctic Summer Sea Ice transition
« Reply #138 on: January 04, 2015, 10:59:41 PM »
Quote
If you wanted to falsify the conclusion, you would basically either have to wait until 2029, or you would have to logically argue for the dismissal of one of my basic premises.

you see, that is just it. As far as I can tell you have stated no premise, except the obvious drawn from a projection of a trend.

In fact, it seems that your premise is, "I don't need a premise" (i.e. "no models here")

In addition, you light on Wadham's statement regarding "neighboring months" (to September) as being validation to your year around ice-free curve.  This takes out the context his statement, since "neighboring months would first indicate the months that currently experience similar ice states, not maximums.

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