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anonymous

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W.Meier on Conservative Scientists
« on: July 30, 2013, 03:13:07 PM »
Probably induced by comments recently published by the Guardian like: Arctic expert predicts final collapse of sea ice within four years the NSIDC Icelights series just added an entry written by W.Meier titled: Are scientists conservative about sea ice?

Am I the only one wondering how the NSIDC manages to ignore the development of sea ice thickness given the wealth of data from buoys, moorings, submarines and IceBridge hosted there documenting a steeper decline of volume than of extent?
« Last Edit: July 30, 2013, 03:27:48 PM by arcticio »

Vergent

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Re: W.Meier on Conservative Scientists
« Reply #1 on: July 30, 2013, 04:22:08 PM »
Quote
Climate models indicate that sea ice will decline more slowly than recent observations.





The NSIDC article is incredibly deceptive, you would think that we just had a couple of bad years(2007 & 2012). The graph they used obscures the observed in model runs that show false extents well below 6M in the 1900-2000 era. Its like they threw a tantrum and scribbled on the graph with a crayon, and erased 2012.

Vergent

edit; fixed image link and added "erased"
 
« Last Edit: July 30, 2013, 04:35:19 PM by Vergent »

Nightvid Cole

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Re: W.Meier on Conservative Scientists
« Reply #2 on: July 30, 2013, 05:11:26 PM »
Probably induced by comments recently published by the Guardian like: Arctic expert predicts final collapse of sea ice within four years the NSIDC Icelights series just added an entry written by W.Meier titled: Are scientists conservative about sea ice?

Am I the only one wondering how the NSIDC manages to ignore the development of sea ice thickness given the wealth of data from buoys, moorings, submarines and IceBridge hosted there documenting a steeper decline of volume than of extent?

Extent is the NSIDC's idol.

ChrisReynolds

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Re: W.Meier on Conservative Scientists
« Reply #3 on: July 30, 2013, 06:46:32 PM »
I disagree with Dr Meir's reference to GCMs, I think there are good grounds to view them as overly, and unrealistically, conservative.

However when he refers to the thickness/growth feedback I think he may have a point.
Quote
Likewise, there are also negative feedbacks that will slow the loss of ice. One of these results from the fact that ice grows more rapidly when there is no ice or thin ice than when thick ice is present under the same air temperatures. Thus in fall when the sun goes down and the atmosphere gets cold, open water areas grow ice quickly allowing such regions to “catch up” to thicker ice regions.

That noted, by September I may have changed my opinion from this year not telling us anything about the future because of the weather (Unusual weather having retarded the melt). To this year telling us we're on the fast track because of the weather: 2013 may beat 2007/2011 and could come close to 2012, and if it happens this would be in spite of weather not conducive to melt. Thus indicating that ice dynamics are the primary force in the post 2010 years.

If that turns out to be the case then blaming the current loss rate on 'weather' (stochastic variation) will be even more unsupportable than I find it now. With ice dynamics in the lead the only thing that could retard loss would be a maintenance of winter thickness, and this would be the thickness/growth feedback.

anonymous

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Re: W.Meier on Conservative Scientists
« Reply #4 on: July 30, 2013, 08:16:06 PM »
Actually it is that growth paragraph which forced me posting here. It is the same recovery logic sceptics present each November and will repeat after new records until the Arctic is ice free year round. Surely ice growth is huge in places where ice melted out in summer. But how is this a feedback, I call that winter.

Vergent

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Re: W.Meier on Conservative Scientists
« Reply #5 on: July 30, 2013, 08:55:55 PM »


I just can not get over the way they pumped up the 20th century variability from lows around 4.0 M to highs around 10.0 M for a +/- of 3.0 M around the mean. The actual data has a +/- 900k. If you go back to the 70s and 80s, its much less than that. He must be going out more than 3 standard deviations. Is there any reason to do that other than to obscure the divergence of the models from reality?

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Neven

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Re: W.Meier on Conservative Scientists
« Reply #6 on: July 30, 2013, 09:35:56 PM »
Quote
That noted, by September I may have changed my opinion from this year not telling us anything about the future because of the weather (Unusual weather having retarded the melt). To this year telling us we're on the fast track because of the weather: 2013 may beat 2007/2011 and could come close to 2012, and if it happens this would be in spite of weather not conducive to melt. Thus indicating that ice dynamics are the primary force in the post 2010 years.

Well said, Chris. You just summed up this year's story.
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lochbryn

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Re: W.Meier on Conservative Scientists
« Reply #7 on: July 30, 2013, 09:43:59 PM »
Vergent,

The striking thing about that graph is that the only unusual year with respect to the long-term (40-year) trend is 2007.  The last six years have had the lowest mean September sea-ice extent, but the curve was already bending down.  It would be astounding to reach, or even approach, pre-2007 levels again.

There is a built-in conservatism to science in that scientists are wary of making predictive assertions, preferring to test hypotheses and validate models that may already not fit the current environment.  When a system is rapidly moving from one state to another unknown state, it is very hard for science to keep up.

Reports such as the IPCC suffer a greater barrier to breaking out of the conservative mold in that they require consensus, making bold predictions that much more difficult. But we have the tools for individual scientists and informed amateurs to make educated hypotheses that may prove to be more cutting edge, and I would argue, with a rapidly changing system, more accurate.

dorlomin

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Re: W.Meier on Conservative Scientists
« Reply #8 on: July 31, 2013, 12:20:27 AM »
It is clear I will not be making friends with this but here is a question:

If scientists are seen as being 'too conservative' because the sea ice decline models have been behind the physical reality.

Are scientists 'too alarmists' because atmospheric temperatures are behind the projections?

This is a very serious question. How can I go and start hammering the pseudo skeptics for not taking the whole picture into account when they make claims based on models not being 100% accurate then do the same thing myself.

Science has developed over 600 years and faced all kinds of attacks, from burning of Bruno to the  mob attacks on Priestly, from the Scopes monkey trials to Cuccinelli's email trawling. It is a system of gathering knowledge that works, it works incredibly well. But it is not perfect. Even the almighty Principa Mathematica would have failed a blogger audit (especially on Mercury's orbit.)

There are missing variables or not fully understood processes in both the ocean\atmosphere system and the sea ice.

Scientists are not "alarmist" because the failed to nail the atmospheric temperature increase correctly nor are they "conservative"  because they have not got the sea ice retreat correct. They simply lack the final definitive model of those systems. 

Until we have a lot more information on what has caused this rapid retreat we cannot be certain that those processes will not reverse and the sea ice decline slow. We have to communicate this to the public. But uncertainty works in both directions, we cannot\ no must not, rule out sea ice disappearing in August by 2018.

Science is hard. It takes years and even decades to master one small part of it. Nothing in the world is as humbling as trying to tease out meaning from data and make projections. I am not a 'scientist' but I work with 'scientists' to turn data into information.


All I can say is I am not over enamored with the idea we can dismiss the huge amount of work to create projections of either temperature or sea ice cover without doing the huge amount of work necessary to create something better to replace it. This goes for the sea ice blog every bit as much as the climate fraudit website types.
Take it for granted you are wrong.
Just try to work out what about and why.

Peter Ellis

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Re: W.Meier on Conservative Scientists
« Reply #9 on: July 31, 2013, 12:34:36 AM »
All I can say is I am not over enamored with the idea we can dismiss the huge amount of work to create projections of either temperature or sea ice cover without doing the huge amount of work necessary to create something better to replace it. This goes for the sea ice blog every bit as much as the climate fraudit website types.
I would go further.  The arrogance, contempt and sheer rudeness towards the scientific community shown in some of the posts above unfortunately tells me that elements of this site are no better than the contrarian blogs, just wearing alternative clothing.  It's deeply distressing: I thought we were above this and had a genuine respect for the scientists working in this area.

Neven

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Re: W.Meier on Conservative Scientists
« Reply #10 on: July 31, 2013, 12:47:53 AM »
I don't think it has much to do with respect. AGW isn't just a fun scientific riddle, you know. It's serious, and if things are worse than they are portrayed by scientists because they have a tendency to be conservative (because of human nature or the way science works or whatever), then people will get emotional over that.

Dorlomin, your analogy is again apples and oranges. Model projections for surface air temperature never said that from now on every decade will show a warming of 0.2 exactly degrees. Furthermore, there are a couple of explanations for the decrease in rate of warming for the past 15-20 years: dominance of La Niña, decreased solar activity, aerosol increase from BRIC countries, etc. These lulls show up in models, but can't be predicted.

The models have a very difficult time reconstructing the decline in Arctic sea ice cover and volume, let alone project what is going to happen under a BAU scenario. No one actually has a clue as to what's happened exactly, and no one (except for Maslowski and Wadhams) saw 2007, 2011 and 2012 coming. No one knows what's coming next, whereas for global surface air temperatures we can be pretty certain that increased solar activity and a switch in ENSO dominance will result in a warming that will exceed the decadal projection of 0.2 °C.

Conservatism and scientific reticence are the easy way. I know they are, because my feelings of responsibility for the credibility of the ASIB compel me to choose the same route.
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Richard Rathbone

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Re: W.Meier on Conservative Scientists
« Reply #11 on: July 31, 2013, 12:49:53 AM »
I don't think you can say the models are wrong on temperature yet. I think its another 10-20 years or so of level temperatures before the deviation below trend is sufficiently large.

See the annual models versus observations comparison at realclimate for detailed discussion on this.
 http://www.realclimate.org/index.php/archives/2013/02/2012-updates-to-model-observation-comparions/ and links

deep octopus

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Re: W.Meier on Conservative Scientists
« Reply #12 on: July 31, 2013, 12:52:41 AM »
The honest answer to this is that there's simply not a neat and simple answer. Climate systems are notoriously complex. I would hazard to guess that the Arctic is the most capricious ecosystem on the planet, so its complexity is magnified.

An axiom: Science should converge on actual observations as best as possible. Otherwise, a conclusion's logical extension has very little distance, and it is inevitably going to be taken over by a better conclusion to describe something's physical, chemical, or biological nature. This, by simple definition, is science. This would go both ways whether models were generally too low or too high. As early as 2005, the Arctic sea ice was flashing red flags that it was melting faster than expected. On the CMIP5 models of sea ice extent, it was clear from 2007 forward that models were falling behind. By 2012, observed sea ice had stayed more than an entire standard deviation (and then some) below the ensemble mean. Charles Miller of NASA was maybe the first scientist to bring this to my attention. It's fair and proper to ask the question of why this is the case. And if we have the correct frame of mind, it shouldn't be misconstrued as in some way denigrating scientists or attacking them with ad hominem or Dunning-Kruger fallacies. It's a fair question to ask why there's a discrepancy?

I agree, the question of asking how "conservative" a scientist is is a bit obtuse and banal. Even models, a product of scientists, shouldn't be dismissed as having a bias one way or the other. If it's conservative, it's only through hindsight, I think. We don't need to Monday morning quarterback this issue. The point of all this would be that this divergence suggests that the Arctic is behaving in ways that suggest it is far, far more vulnerable to global warming than was expected. And scientists have noticed and have been working to factor in this vulnerability. As for global surface temperature data, scientists have already begun to uncover many of the oceanic variations that influence surface temperatures. Evidently, temperature projections have been closer to the mark thus far, especially from data with high global coverage like GISS. It absolutely goes both ways, but this is not the fault of scientists, but of our collective and unending--albeit shrinking--ignorance, and our strive to understand more about the universe.

Richard Rathbone

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Re: W.Meier on Conservative Scientists
« Reply #13 on: July 31, 2013, 01:04:35 AM »

That noted, by September I may have changed my opinion from this year not telling us anything about the future because of the weather (Unusual weather having retarded the melt). To this year telling us we're on the fast track because of the weather: 2013 may beat 2007/2011 and could come close to 2012, and if it happens this would be in spite of weather not conducive to melt. Thus indicating that ice dynamics are the primary force in the post 2010 years.


Chris,

Have you got a way of quantifying whether weather is good or bad for melt before seeing what the melt actually was?

I could do with one because in practice my definition of "good melt weather" is "PIOMAS showed faster melt than trend". While I have some rough idea of whether I think the July weather was good for melt (I do), if PIOMAS reports a higher volume of remaining ice at the end of July than I am expecting, I'll put that down to my weather sense being out.

I also don't think this is definitely a bad melt weather year yet. The first part of the season was bad, but I don't think it was so bad that it can't be brought back to neutral by favourable August as well as July. 

Peter Ellis

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Re: W.Meier on Conservative Scientists
« Reply #14 on: July 31, 2013, 01:11:23 AM »
I don't think it has much to do with respect.
It has everything to do with respect.  In this thread, Dr Meier's article was described as "deceptive".  Not "mistaken", "wrong", "over-cautious" or what-have-you.  Deceptive.  That is a direct claim that the scientists are lying.  It is unworthy of this forum and this community.

anonymous

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Re: W.Meier on Conservative Scientists
« Reply #15 on: July 31, 2013, 01:32:09 AM »
Peter, you are missing the point and your one dimensional bashing is beyond discussion.

What I expect from the NSDIC is expertise and responsibility. The number in question is the range of predictions regarding an ice free Arctic. This range is known, there is at least one paper analyzing it in detail and my impression is everybody involved feels uncomfortable about for good reasons.

The interesting part is all these predictions are based on science and made by scientists. And it tells a lot if one scientist blogs about on a high profile web site and fails to mention the full range of the discussion, that kind of perspective is given in any scientific paper.

One option to handle this problem is to ignore it, that's what W.Meier did in the article. Another one would be to tackle it and ask how can the scientific community overcome this problem and present actually useful predictions to the public? I know there are multiple high level initiatives (WMO, etc.) along this path, the strategy is basically more reliable data and W.Meier is an active part of the initiatives preparing the needed cyberstructure.

So, again, and the question is allowed at this point: Why does the NSIDC insists on extent as the only sea ice measurement to tell the future?

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Re: W.Meier on Conservative Scientists
« Reply #16 on: July 31, 2013, 02:49:34 AM »
I don't think it has much to do with respect.
It has everything to do with respect.  In this thread, Dr Meier's article was described as "deceptive".  Not "mistaken", "wrong", "over-cautious" or what-have-you.  Deceptive.  That is a direct claim that the scientists are lying.  It is unworthy of this forum and this community.

Quote
Sea ice models, though far from perfect, are the best tools we have to understand and project the future changes in sea ice.



The models(orange) have been outperformed by statistical approaches(blue) and combined approaches(green) for some time now, so this statement is false. The models have been performing horribly. The modelers recently came out with a big study proclaiming that the arctic would not go ice free till 2053-2058 time frame. I feel like I am on that Spanish train and the modelers have decided it is up to them to drive the train. Excuse me, aren't we going a little fast?

Quote
Nonetheless, given the complexity of the sea ice system, the large year-to-year variations observed, and potential negative feedbacks that can act to slow the ice loss, most scientists feel a conservative estimate of the future ice changes is probably warranted.

Here he is actually implying that some unnamed negative feedbacks are going to come along and restore the ice cap. So don't worry be happy. We have plenty of time to fix it. "most scientists" Really?

The only way you can be comfortable with ice free in the distant future is if you ignore thickness and volume.



Thanks to Jim Pettit for this graph. No scientist can look at this graph and be comfortable with the "conservative" 40 year estimates.

Vergent
« Last Edit: July 31, 2013, 02:59:00 AM by Vergent »

Juan C. García

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Re: W.Meier on Conservative Scientists
« Reply #17 on: July 31, 2013, 04:09:55 AM »
First, I want to start my comment by expressing that I am very glad that a*** has open this topic.
Second and changing a little the subject, I believe that this Forum is having a great success, and in this regard I just want to highlight that one month ago we were celebrating that the Forum reached one million pages views. Now, just one month and a couple of days more, the Forum is close to reach the 1.5 million page views. With this trend, I am sure that the Forum will reach two million page views before the end of August.
Why I highlight this? Well, 15 months ago, I found Neven’s ASI Blog and I found unbelievable that NSIDC was talking about ice-free Arctic after 2030, when there are so much evidence (analyzing volume) that the collapse could be before 2020. So later in this Forum, I opened two polls about when the members expect ice-free Arctic (With NSIDC SIE and CT SIA) just to have the proof of the Forum’s opinion. I also have expressed my concern of the “Conservative Scientists”, to the level that I wrote something like “Nobel institutions like the IPCC are failing to express the real situation on the Arctic”.
So why I be happy? Well, let’s say that if the IPCC and the NSIDC are inadequatly showing the real danger of what will happen in the Arctic, the Forum success and the Forum members in general, are making the job that IPCC and NSIDC are failing to do (and I'm sorry for expresing this, but this is the way I feel it).
So again, I am very glad that we have a Forum in which we can express freely our ideas and in which we can learn what is happening at the Arctic.
I want to make a last observation. In this Forum I tried to transform knowledge into action, but I found answers like we should avoid making messages that look like “we ought to…”. Well, the true is that we (humans) are going to face huge problems in the near future and we should look to avoid them, so from my point of view, there is no harm with messages that look like “we ought to…”.
At the beginning of 2007, four scientists of the NSIDC and one of the National Center for Atmospheric Research (all at the University of Boulder, Colorado) wrote the article “Arctic sea ice decline: Faster than forecast” (1). This article showed that the models developed by IPCC overvalue the stability of the Arctic sea ice extent (SIE), so that the real melting of sea ice was faster than what the IPCC models were forecasting. They also published a graph that has become a continuous reference, showing the IPCC SIE models versus the real decline of sea ice. (Graph 1)
It is important to emphasize that this article was made six months before the new September 2007 SIE record, which means that the values of 2005-2006 trigger this criticism to the IPCC models.
After six years, having new 2007 and 2012 SIE records, they are developing new models but they continue to underestimate the actual melt. From my point of view, it is unacceptable that almost all the models put the Arctic sea ice free after 2100. Only the worst scenario has a sea ice free at 2060 (according to the definition of Arctic sea ice free happens when NSIDC SIE average is less than one million km2) (Graph 2) (2).
But instead of trying to change the IPCC forecast, I would like to propose another action. Now the USA National Climate Assessment and Development Advisory Committee (NCADAC) has a draft document to comment and it will become the Third Climate Assessment Report. So I want to propose that we seek to include a forecast of Arctic sea ice free, based on PIOMAS volume. The reviewing deadline is April 12, 2013.
What do you think? Do you agree that the IPCC models, as they are right now, are worthless? Would you like to make the effort to include a PIOMAS volume forecast on the USA Third Climate Assessment Report?

 
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Peter Ellis

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Re: W.Meier on Conservative Scientists
« Reply #18 on: July 31, 2013, 10:27:51 AM »
Here he is actually implying that some unnamed negative feedbacks are going to come along and restore the ice cap. So don't worry be happy.
They're not unnamed, and we're watching them in operation as we speak!  How can you say that?  Remember back in March when the "buzz" was that the cracking in the Beaufort was a harbinger of doom, that "Crackopalypse" would mean the Beaufort melted out early, allowed much more sunshine to be absorbed, and would mean a final collapse down to ~1 million or less this year?  I think it's fair to say the models are way outperforming that prediction right now. 

To be explicit about the feedback: new ice rapidly formed in the open leads, thickened quickly to near the full first year ice thickness, and so the cracking actually increased overall ice volume.  We saw this in the April and May PIOMAS model, and also in the way the Beaufort's been slower to melt this year than of late.  More open water during winter leading to increased ice formation, meaning that winter area + volume don't drop as fast as the summer levels. It's visible on a gigantic scale right here and now.

The current dogma on this board is that the ice is worse condition than previous years and that some kind of collapse is imminent in the next 2-3 weeks which will let us catch up to or overtake 2012.  No chance.  Go back and look at the IJIS and MODIS data for the northern Chukchi and ESAS last year.  Concentration was way down, pretty much mirroring what we see on the Atlantic side this year - and then the GAC came along to smash it.  The ice is currently half a million above 2012, and it will take another GAC even to stay that far behind.

My initial prediction for the year was a recovery to somewhere between 2012 and 2007.  Right now, it's looking more like we will end up around the 2008/2010 level.  2010 is in fact an interesting comparison - we had the early spring crash, but then the weather turned and the curve flattened, before bottom melt took over in August and kept things dropping.  Well this year we've had the similar bad weather, but we also didn't get the spring crash, so crucial insolation never got through.  The waters are colder and bottom melt will likely be less, at least in the Beaufort and Chukchi.  It's possible therefore that we'll end up above even 2010. 

Another few years like this year will bend those exponential predictions right out to the 2020s or 2030s - and we must not forget that this year's weather is (I believe, Chris Reynolds can confirm) much closer to the historical average.  In the long run, it may well be that 2007-2012 are outliers with anomalous spring weather.  Time will tell.

anonymous

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Re: W.Meier on Conservative Scientists
« Reply #19 on: July 31, 2013, 02:11:45 PM »
My initial prediction for the year was a recovery to somewhere between 2012 and 2007.

Like that phrase, 6 years ago 2007 was an unforeseen dramatic record low, now it looks like a recovery.  :o

Peter, make sure your screen is not upside down while looking at the trend!

Nightvid Cole

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Re: W.Meier on Conservative Scientists
« Reply #20 on: July 31, 2013, 03:36:52 PM »
Here he is actually implying that some unnamed negative feedbacks are going to come along and restore the ice cap. So don't worry be happy.
They're not unnamed, and we're watching them in operation as we speak!  How can you say that?  Remember back in March when the "buzz" was that the cracking in the Beaufort was a harbinger of doom, that "Crackopalypse" would mean the Beaufort melted out early, allowed much more sunshine to be absorbed, and would mean a final collapse down to ~1 million or less this year?  I think it's fair to say the models are way outperforming that prediction right now. 

To be explicit about the feedback: new ice rapidly formed in the open leads, thickened quickly to near the full first year ice thickness, and so the cracking actually increased overall ice volume.  We saw this in the April and May PIOMAS model, and also in the way the Beaufort's been slower to melt this year than of late.  More open water during winter leading to increased ice formation, meaning that winter area + volume don't drop as fast as the summer levels. It's visible on a gigantic scale right here and now.

The current dogma on this board is that the ice is worse condition than previous years and that some kind of collapse is imminent in the next 2-3 weeks which will let us catch up to or overtake 2012.  No chance.  Go back and look at the IJIS and MODIS data for the northern Chukchi and ESAS last year.  Concentration was way down, pretty much mirroring what we see on the Atlantic side this year - and then the GAC came along to smash it.  The ice is currently half a million above 2012, and it will take another GAC even to stay that far behind.

My initial prediction for the year was a recovery to somewhere between 2012 and 2007.  Right now, it's looking more like we will end up around the 2008/2010 level.  2010 is in fact an interesting comparison - we had the early spring crash, but then the weather turned and the curve flattened, before bottom melt took over in August and kept things dropping.  Well this year we've had the similar bad weather, but we also didn't get the spring crash, so crucial insolation never got through.  The waters are colder and bottom melt will likely be less, at least in the Beaufort and Chukchi.  It's possible therefore that we'll end up above even 2010. 

Another few years like this year will bend those exponential predictions right out to the 2020s or 2030s - and we must not forget that this year's weather is (I believe, Chris Reynolds can confirm) much closer to the historical average.  In the long run, it may well be that 2007-2012 are outliers with anomalous spring weather.  Time will tell.

I would be extremely surprised to see this year not end up below 2007, and actually, I expect it to be a new record low. This is due to HYCOM's concentration, thickness, and SST maps which, when looking at the CAB , are clearly doing consistently worse this year than any previous year, including last year.

werther

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Re: W.Meier on Conservative Scientists
« Reply #21 on: July 31, 2013, 03:43:45 PM »
What’s the work done, Peter?

How much cloud coverage there’s actually been compared to other years?
What makes the difference between DMI +80dN and NCEP/NCAR data on 2m+SL Temperature?
Are SST’s really lower all through the Arctic Ocean?
Is the set-up more like the climatologic trend this year?
Is the supposed change in NH atmospheric pattern creating a positive feedback for the ice, while creating extremities in the mid-latitudes?

So many questions have risen this season.

Need time to analyse in the aftermath.
It’s not that obvious, you know… or maybe it is when the final numbers come in and some will say “…I told you”…, others “…nothing to see, just go on…”

Vergent

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Re: W.Meier on Conservative Scientists
« Reply #22 on: July 31, 2013, 06:07:04 PM »



This is what the "recovery" is going to look like in a few days. DMI sys we have had a negative temperature anomaly for the last 100 days in the high arctic, yet the eastern CAB melt out is historic. What would this look like had it been warm?

The danger is an Atlantic surface water inrush into the CAB. This would be up to a million km^3 of 7C water, that would eventually convect and start melting ice. A sci-fi fantasy?



TOPAZ4 is the third coupled model to model such an event(preceded by PIPS2, and the Met office global). The warm water goes down to 1000m and is convecting up to the surface. On the modeled concentration map, you can see two polynyas in the area that are the result. On the 5m temps, you can see the beginning of the convection.



Is this actually happening? I think not. Unfortunately, there are no ITPs in the area. But I do not see evidence of this in the surrounding ITPs.

But this will happen, the arctic basin water is denser than the adjacent Atlantic water. All that is needed is for the lens of low density water that surrounds the ice to get pushed back, and the Atlantic water will flow in While the dense cold water gushes out the Fram taking ice and fresh water with it.

A decade ago I figured out that this could happen, and time and again physics based models agree.

This mechanism cannot be in these climate models, they never show the ice abruptly going to zero. Last January the Met office global model showed a 200km polynya opening up near the pole before they reset it.

The danger of the climate models is what they are missing! They are just place holders for what we should have. When the ice is going south and the climate models are going east, the models are just paper dolls, a distraction from what we should be doing.

What we should be doing is figuring out who is in danger if the ice is gone in mid summer. This could be as soon as next summer, that is what TOPAZ4 is telling us.

Vergent




Espen

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Re: W.Meier on Conservative Scientists
« Reply #23 on: July 31, 2013, 06:18:18 PM »
You Aint Seen Nothing Yet :

Have a ice day!

ChrisReynolds

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Re: W.Meier on Conservative Scientists
« Reply #24 on: July 31, 2013, 07:28:53 PM »
Actually it is that growth paragraph which forced me posting here. It is the same recovery logic sceptics present each November and will repeat after new records until the Arctic is ice free year round. Surely ice growth is huge in places where ice melted out in summer. But how is this a feedback, I call that winter.

Arcticio,

Consider this graph.



Once average thinning equals average annual maximum thickness there is predominant open ocean at the end of the year. Average seasonal thinning has increased in recent years, however this may be a limited process as it probably depends on the transition to FYI from MYI. Average maximum April thickness is declining and it is at this point that the consideration of autumn/winter ice growth comes in to play.

The PIOMAS volume gain from minimum to 1 March is increasing as CT Area declines.



The trend line should not be taken to have a physical basis, nor should its extension. However the message from the data is clear - that autumn/winter volume gain is increasing. This could mean that the winter thickness decline in the first figure will come to a halt. This is especially the case given that it is only in recent years that the loss of volume has ceased to come from thickest ice categories and has started to occur from thinner younger ice.



That is a plot of thickness categories (along the bottom) which contribute volumes to the total volume (per year in the coloured part of the table). It can be seen that by 2010 the long term decline in ice over 3.5m thick has reached a de facto conclusion, and that after this the thickness profiles of the ice thin.

Due to the relationship in the second graph of this comment the autumn/winter ice growth has the potential to retard the April thinning shown in the first graph.

ChrisReynolds

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Re: W.Meier on Conservative Scientists
« Reply #25 on: July 31, 2013, 07:45:36 PM »
Have you got a way of quantifying whether weather is good or bad for melt before seeing what the melt actually was?

I could do with one because in practice my definition of "good melt weather" is "PIOMAS showed faster melt than trend".

The 'method' I'm using is simply the lack of development of the new summer circulation pattern.


This pattern develops a dipole anomaly over the Siberian side of the Arctic, with high pressure over the central Arctic and the CAA. That dipole anomaly is discussed in Overland et al "The recent shift in early summer Arctic atmospheric circulation." The question this year may help to answer is the relative strengths of sea ice dynamics (which have changed with thinning) and the AD, both seem likely to be playing a role in the greater annual range of CT Area and extent since 2007.

The problem with using PIOMAS volume as an indicator of how conducive weather is to melt is that it neglects the role of ice dynamics.

ChrisReynolds

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Re: W.Meier on Conservative Scientists
« Reply #26 on: July 31, 2013, 07:54:55 PM »
Are scientists 'too alarmists' because atmospheric temperatures are behind the projections?

...Until we have a lot more information on what has caused this rapid retreat we cannot be certain that those processes will not reverse and the sea ice decline slow.

As has been stated above it's too early to say if the atmospheric trend has been broken. However there is a levelling of temperatures and this has been explained.

Foster & Rahmstorf, 2011, Global temperature evolution 1979–2010.
Quote
When the data are adjusted to remove the estimated impact of known factors on short-term temperature variations (El Niño/southern oscillation, volcanic aerosols and solar variability), the global warming signal becomes even more evident as noise is reduced.. ..The adjusted data show warming at very similar rates to the unadjusted data, with smaller probable errors, and the warming rate is steady over the whole time interval. In all adjusted series, the two hottest years are 2009 and 2010

Kaufman et al, 2011, Reconciling anthropogenic climate change with observed temperature 1998–2008.
http://www.pnas.org/content/108/29/11790.full
Quote
We find that this hiatus in warming coincides with a period of little increase in the sum of anthropogenic and natural forcings. Declining solar insolation as part of a normal eleven-year cycle, and a cyclical change from an El Nino to a La Nina dominate our measure of anthropogenic effects because rapid growth in short-lived sulfur emissions partially offsets rising greenhouse gas concentrations. As such, we find that recent global temperature records are consistent with the existing understanding...

Results indicate that net anthropogenic forcing rises slower than previous decades because the cooling effects of sulfur emissions grow in tandem with the warming effects greenhouse gas concentrations. This slow-down, along with declining solar insolation and a change from El Nino to La Nina conditions, enables the model to simulate the lack of warming after 1998.

ChrisReynolds

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Re: W.Meier on Conservative Scientists
« Reply #27 on: July 31, 2013, 08:07:14 PM »
...and we must not forget that this year's weather is (I believe, Chris Reynolds can confirm) much closer to the historical average.

Yes I can confirm that. 2013's summer so far is quite unlike the other post 2007 years (with the minor exception of July 2010).
e.g. June SLP fields.
http://dosbat.blogspot.co.uk/2013/07/june-status-part-2a-atmosphere-slp.html
2013 so far has looked more like a pre-2007 year in terms of the atmosphere. That it does so in some respects with regards ice is no coincidence. However I still see ice dynamics as a big factor this year - much more FYI.

For what it's worth I agree with your concerns regards the anti-scientist hyperbole around here. I'm glad someone else is seeing WUWT or even Goddard in a mirror.

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Re: W.Meier on Conservative Scientists
« Reply #28 on: July 31, 2013, 08:25:42 PM »
I disagree that there is an "anti-scientist" bent here.  There is disagreement about some findings by some scientists.  Science is a slow process - hypotheses, data gathering, analysis, review by peers, not to mention fundraising, all take time, and each step forward is only one piece of the puzzle, and one subject to further review at that.  I have nothing but the highest regard for scientists in general and those who are expanding our understanding of how AGW works in particular.

Unfortunately, global climate is changing faster than science can keep up.  I am sure it makes it an exciting time to be a climatologist.  But it may be frustrating for those seeking to nudge the policy debate not to have clearer answers now. It also raises the temptation (I am pointing the finger at myself!) to play armchair scientist.  There are many here, though, who have a lot to add to the debate, not all of whom hold a doctorate or have published work in peer-reviewed journals.

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Re: W.Meier on Conservative Scientists
« Reply #29 on: July 31, 2013, 08:54:39 PM »
Are scientists 'too alarmists' because atmospheric temperatures are behind the projections?

...Until we have a lot more information on what has caused this rapid retreat we cannot be certain that those processes will not reverse and the sea ice decline slow.

As has been stated above it's too early to say if the atmospheric trend has been broken. However there is a levelling of temperatures and this has been explained.

Foster & Rahmstorf, 2011, Global temperature evolution 1979–2010.

Chris, I am pretty sure Dorlomin is aware of that.  One of the points he was making (I think) is that many of these underlying processes like ENSO, variations in ocean currents, ocean heat content, etc, act on a decadal scale.  Some decades have better conditions for global surface warming than others.

Similarly, some decades (or shorter time periods) may have better conditions for Arctic sea ice melt than others.

I'm not an expert on atmospheric patterns or ocean heat transfer to the Arctic.  But from what I see here on the forum, it seems that 2007-2012 and in particular 2010-2012 had favorable conditions for the Arctic sea ice to melt.

The model runs suggest that it's not unusual to have periods of steep decline in Arctic sea ice, followed by slower periods.  It's perfectly possible that we just had a period of steep decline to be followed by a slowdown.

In fact, I think that favorable melting conditions in the last few years made the aggressive volume trends, like the exponential trend for PIOMAS, look more realistic than they truly are.  I see no physical motivation for using an extrapolation of such a trend.  This could only be valid if the positive feedbacks in the Arctic are so powerful that the negative ones will hardly play any role.  But that is not what we are seeing this year, as Peter explained in his last post.
« Last Edit: August 01, 2013, 02:48:01 AM by Steven »

danp

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Re: W.Meier on Conservative Scientists
« Reply #30 on: July 31, 2013, 09:24:25 PM »

How much cloud coverage there’s actually been compared to other years?
What makes the difference between DMI +80dN and NCEP/NCAR data on 2m+SL Temperature?
Are SST’s really lower all through the Arctic Ocean?
Is the set-up more like the climatologic trend this year?
Is the supposed change in NH atmospheric pattern creating a positive feedback for the ice, while creating extremities in the mid-latitudes?

So many questions have risen this season.

Need time to analyse in the aftermath.
It’s not that obvious, you know… or maybe it is when the final numbers come in and some will say “…I told you”…, others “…nothing to see, just go on…”

I agree.  To me nothing looks obvious at all about analyzing this season, and while I am no Arctic expert I find it exhilarating as that's always the most scientifically exciting place to be.  Peter's observation about the Beaufort cracks may well be a highly important factor this season and it is not at all what I expected to happen.  It's wonderful to be surprised, particularly by something that may be positive news.  But as I understand it, regrowth around cracking involves much more detailed ice dynamics than the thinness->regrowth negative feedback the models the models have pushed, even though it's fair to put it in the same category.  After all, there were perfectly plausible physical reasons that many folks on the forum thought it would go the other way.

I disagree that there is an "anti-scientist" bent here.  There is disagreement about some findings by some scientists.  Science is a slow process - hypotheses, data gathering, analysis, review by peers, not to mention fundraising, all take time, and each step forward is only one piece of the puzzle, and one subject to further review at that.  I have nothing but the highest regard for scientists in general and those who are expanding our understanding of how AGW works in particular.

Unfortunately, global climate is changing faster than science can keep up.  I am sure it makes it an exciting time to be a climatologist.  But it may be frustrating for those seeking to nudge the policy debate not to have clearer answers now. It also raises the temptation (I am pointing the finger at myself!) to play armchair scientist.  There are many here, though, who have a lot to add to the debate, not all of whom hold a doctorate or have published work in peer-reviewed journals.

Exactly my feelings.  On these boards there is certainly the kind of arrogance that comes from stepping into someone else's field without having quite appreciated how much effort the trained scientists have devoted to the work they've produced so far.  As a scientist in an unrelated field I'm frankly humbled at how generous and open individual scientists have been with their time and energies when folks here have asked them for information about their work.

I also appreciate the scientists' resource limitations as well as the natural pressures that lead to conservatism when it comes to places where their best models are doing poorly.  The kind of messy, phenomenological, observational-based open science that keeps me coming to these forums is time-intensive and may never lead easily to well-defined models predictive models, but nonetheless I constantly find amazing insights from everyone here that complement my erratic learning from the published literature. 

There's no way to avoid people getting grumpy when it comes to prediction time:  there's a reason we all are here as a community, and it's not because the Arctic is just some abstract scientific system we don't understand.  Since Arctic ice is the vanguard of visible climate change and the poster child for possible excess conservatism in past scientific predictions, any predictions come along with a host of policy and political baggage that gains weight with the stature of the person delivering it.  I certainly have my moments of being upset with excess scientific reticence, and Meier's comments irked me for some of the reasons others commented on.

But in the end it's just a matter of time; the ice will do what it will do over the next few years, and we'll be learning quickly about our new Arctic.  Global warming is vastly depressing, but the Arctic is a subsystem in which I've found some scientific excitement as consolation.  So for the moment I'm just sticking to the old arctic sea ice blog mantra:  keep our eyes on the ice.

ChrisReynolds

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Re: W.Meier on Conservative Scientists
« Reply #31 on: July 31, 2013, 09:28:09 PM »
Steven,

The post 2010 period has been notable in terms of both CT Area and PIOMAS as being favourable for ice melt. However to date I have been unable to find an explanation for this in terms of the atmosphere. This leaves ice dynamics, and in particular the volume loss in 2010 and associated thinning causing the post 2010 behaviour. I can go into detail if you need. But the bottom line is that the post 2010 volume losses are probably due to ice dynamics, not weather. Even in 2013 there was still a damped spring melt, not as aggressive as 2010 to 2012, but present nonetheless.



Which is remarkable considering the weather.

The overall 2007 to 2010 period is more problematic. 2007 lead to a substantial thinning of the pack, and 'open water formation efficiency' will have been increased leading to the larger seasonal cycle in volume area and extent post 2007. However the dipole anomaly has been shown to have a causal role in record minima pre-2007 and from 2007 to 2012 there has been a strong dipole set up by a wider atmospheric pattern, so it is reasonable to see the dipole as having had a role in the greater seasonal cycle.

The question that is crucial is whether this atmospheric set up will continue. This pattern has not occurred in the summer average from 1948 to 2006, yet in June/July/August 2007 to 2012 it is present to a greater or lesser degree. This strongly suggests that it is reasonable to view it as related to sea ice, since the post 2007 sea ice has been markedly different to the preceding years. 

This year we have had a cold May and June, as detailed in this blog post:
http://dosbat.blogspot.co.uk/2013/07/june-status-part-2b-atmosphere-and-ice.html
Melt from the Siberian sector has been slow in June.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.9.html
This is something I see as relevant because part of the puzzle is a paper by Bluthgen describing a feedback between atmosphere and ice in the summer of 2007 that persisted the dipole anomaly generally agreed to have been a big player in the crash of that year. That didn't happen this year because of the slow start in that region, I suspect it did happen in 2007 to 2012.

So what I'm getting round to saying is that I don't consider this year to be the start of a run of cold years.

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Re: W.Meier on Conservative Scientists
« Reply #33 on: July 31, 2013, 11:18:12 PM »
Chris, I'm completely aware of at least two or three reasons sea ice decline might go horizontal until enough energy accumulated in the atmosphere to even do harm to an ice pack mostly consisting of first year ice.

But that's a question for another thread. I don't see how this helps to understand why the NSIDC promotes extent more than it deserves. Let's collect points why extent might be superior or not and bring back the necessary objectiveness the W.M. article lacks. I opened this thread to find out what might qualify extent to tell the future and declare all other parameters excrescent.

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Re: W.Meier on Conservative Scientists
« Reply #34 on: July 31, 2013, 11:55:00 PM »
I want to add another two cents, the last ones because I'm too busy, so have to move on.

I don't mind scientists being conservative (like I said, I've become more conservative and reticent myself since I started blogging because I know my limits and feel responsible for the ASIB's credibility), but I do have problems with the way some of them sometimes communicate. It's almost as if they're eager to dispel any worst case scenario that might pop up, and they pop up a lot because there are things happening in the Arctic that nobody saw coming, and the Arctic is an incredibly important factor in keeping things stable for the Northern Hemisphere. My guess is that they fear the fake skeptic drums, as fake skeptics have been so successful at intimidating scientists, eating them up as it were, as if they're cannibals. And so our beloved scientists walk through the jungle and say: hush, hush, lest the cannibals hear us and start beating their drums to warn each other of our presence.  ;)

I understand all of this, but still, I don't understand why they can't put worst case scenarios in perspective AND at the same time emphasize that there are potentially very serious risks involved with Arctic sea ice (and summer snow cover) loss. Something along the lines of: "Arctic sea ice loss could very well have, and perhaps already is having, serious consequences. The trends are very clear and have been dropping much faster than anticipated. Combine this fact with our lack of knowledge and thus relatively large uncertainty, and it's clear that there's a distinct possibility of unpleasant surprises occurring. HOWEVER, in the case of methane burps, there is no or very little direct evidence that such an event could take place in the near future. We don't see it in paleoclimatic data or in the field. Yet. Given the risks, we need to increase our knowledge on this subject so that we can constrain uncertainty and determine what the worst case scenario could look like."

I've just re-read Walt Meier's piece and you just don't see anything of that, except towards the very end, very weakly in the last sentence: "One thing that all scientists who study sea ice agree upon is that under increasing temperatures, the overall long-term declining trend will continue and some summer in the future, we will look down on the North Pole and see a blue Arctic Ocean. It’s not a matter of if, but when." Ah, so that's the consequence? A blue Arctic Ocean? Well, that doesn't sound too bad! Reminds me a bit of the Bahamas! Mind you, I'm a fan of Walt Meier and think he does a very good job practically all of the time, but his piece only tells half the story.

Never mind the really subjective stuff by folks like Andy Revkin and Jason Samenow who really seem to get a kick out of bashing the alarmists. Unfortunately, their arguments are full of holes and they fail to emphasize that the combination of the rate of change, lack of knowledge, bad track record so far for predicting events in the Arctic, calls for a lot of caution and increased research. They will say: "Oh, but I just said that last week in another piece". And I say: "No, you have to say it every time, because that's the story of the Arctic. Tell the whole story, every time."

There, that's what I wanted to say. Back to building now.
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dorlomin

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Re: W.Meier on Conservative Scientists
« Reply #35 on: August 01, 2013, 12:10:28 AM »
Sod this. Too many self appointed experts indulging in hand waving and sneering at actual scientists.

You all want your methane dooms and abrupt sea level rises taken seriously? Get into the field and collect some data or use what is public domain to write a real paper. Then submit it for peer review. You will rapidly learn why the Eschenbachs and Tisdales of this world stick to blog publishing.

People round here think you can do novel science by skim reading abstracts or looking (eyeballing for gods sakes) maps of methane levels and jumping to conclusions.

You want to play citizen scientist without earning the maths and physics? Cool, join the queue with Watts and friends.

Clearly I am walking in a different direction to the one this forum wants to take. I am from Glasgow. We dont do polite, we do do brutally frank and unvarnished. If I stand my ground round here it will be seen as studs showing over the ball type tackles. (This forum was launched with Cruyff so footballing analogies are fair game), so have fun folks. I will be below the line the in the UK press dishing out the hammer to deniers.



Take it for granted you are wrong.
Just try to work out what about and why.

Neven

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Re: W.Meier on Conservative Scientists
« Reply #36 on: August 01, 2013, 12:24:09 AM »
I don't know if you're tackle was directed to my shins, dorlomin, but if so, please re-read my comment. I'm talking about the conservatism bleeding into the communication. I'm fine with dispelling extreme worst case scenarios or alarmism by putting them in the scientific perspective, but I want to see the other half of the story as well: trend + lack of knowledge = risky business

One thing doesn't exclude the other. On the contrary. When you've got Anthony Watts agreeing with you, you're obviously doing something wrong.

BTW, just a guess: You're probably a Rangers fan, aren't you? What division do they play in? And do you still support them?  ;D
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Re: W.Meier on Conservative Scientists
« Reply #37 on: August 01, 2013, 12:45:56 AM »
> You all want your methane dooms and abrupt sea level rises taken seriously?

No, I want the Arctic future communicated with a confidence level which makes it serious.

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Re: W.Meier on Conservative Scientists
« Reply #38 on: August 01, 2013, 07:52:38 AM »
Sod this. Too many self appointed experts indulging in hand waving and sneering at actual scientists.

You all want your methane dooms and abrupt sea level rises taken seriously? Get into the field and collect some data or use what is public domain to write a real paper. Then submit it for peer review. You will rapidly learn why the Eschenbachs and Tisdales of this world stick to blog publishing.

People round here think you can do novel science by skim reading abstracts or looking (eyeballing for gods sakes) maps of methane levels and jumping to conclusions.

You want to play citizen scientist without earning the maths and physics? Cool, join the queue with Watts and friends.

Clearly I am walking in a different direction to the one this forum wants to take. I am from Glasgow. We dont do polite, we do do brutally frank and unvarnished. If I stand my ground round here it will be seen as studs showing over the ball type tackles. (This forum was launched with Cruyff so footballing analogies are fair game), so have fun folks. I will be below the line the in the UK press dishing out the hammer to deniers.
Don't go anywhere, dorlomin. I enjoy your perspective and appreciate what you bring to the discussions.

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Re: W.Meier on Conservative Scientists
« Reply #39 on: August 01, 2013, 07:07:08 PM »
I posted a quick summary in the blog about this under Arctic Time Bombs.

The idea is that the Albedo variable feedback component for climate sensitivity is directly affected by the loss of arctic sea ice.  The current projections of sea ice loss go into that sensitivity calculation.  The acceleration of sea ice loss radically increases the short term sensitivity since loss of arctic sea ice in June 1 will lead to increases in local temperatures by over 5C during that period.

This variable feedback component to climate sensitivity radically increases the 2XCO2 sensitivity to >4.5C  and the sensitivity to current CO2 burdens goes up from 1.2 to over 3C.

In addition, the long term equilibrium sensitivity based on an ice free arctic created at current CO2 levels leads to a longer and larger positive feedback from arctic methane release and pushes the long term sensitivity even further out.

We are looking at a carbon dioxide sensitivity adjustment of over 3C based on simply having lost the arctic 60 years before the models said we would.  This arctic amplification wasn't supposed to happen until CO2 concentrations reached 540PPMv. (and some time after that when temperatures approached equilibrium).

That is why this conservatism is so very impactful.

Thankfully, some scientists are currently adjusting their sensitivity analyses, they have not adjusted for this yet: 

  http://www.sciencemag.org/content/340/6129/183
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Re: W.Meier on Conservative Scientists
« Reply #40 on: August 01, 2013, 09:14:00 PM »
Chris, I'm completely aware of at least two or three reasons sea ice decline might go horizontal until enough energy accumulated in the atmosphere to even do harm to an ice pack mostly consisting of first year ice.

But that's a question for another thread. I don't see how this helps to understand why the NSIDC promotes extent more than it deserves.

Why not ask NSIDC or Dr Meir?

Let's collect points why extent might be superior or not and bring back the necessary objectiveness the W.M. article lacks. I opened this thread to find out what might qualify extent to tell the future and declare all other parameters excrescent.

I'm out of this discussion then. I consider extent to be a clumsy near useless metric, prefer CT Area, and as I've gone over repeatedly see volume as driving the process of the decline of the pack.
e.g. http://dosbat.blogspot.co.uk/2013/05/summer-acceleration.html

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Re: W.Meier on Conservative Scientists
« Reply #41 on: August 01, 2013, 10:22:54 PM »
I don't see how this helps to understand why the NSIDC promotes extent more than it deserves. Let's collect points why extent might be superior or not...
1) Extent is what matters to ships. They need to know which areas are ice-free, which areas are impassable, and which areas are loose pack "proceed with caution"

2) Extent is what matters to the public, visually. It's a simple "you can see it / you can't see it" metric.

3) There is good historical data for extent which (with care) can be integrated across multiple sources from passive microwave satellite data to radar data to ships' logs.  There is much less data for area, and it's hopelessly confounded by melt ponding.  There is next to no historical data for volume, comparatively.

4) Extent is what he was asked to comment on. He was addressing the question of when the Arctic will melt out.  That is intrinsically a question of extent, i.e. whether the Arctic ocean is covered with ice or not!  It seems particularly perverse therefore to slate him for saying (paraphrased) "According to our best guess, this much of the Arctic will still be ice covered up until 2030".


All the above are fairly simple, obvious answers which make sense to me.  However, above and beyond that, you're missing a key point about that article.  The claims Walt makes for the date of Arctic melt-out are not based on extent: the claims are based on the GCMs.  The predicted extents are the output, not the input.  The GCMs model as much as they can, in as much detail as they can, and that includes volume - in fact, the better ones model the water, ice and atmosphere together.  If you look at the papers, you'll see that the GCMs also model the ice as becoming thinner, i.e. the volume drop precedes the extent drop - but that wasn't  the question he was being asked to comment on. 

Finally, his article (if you bother to read it in detail) makes the important point that while the model ensemble predicts ice hanging on for a couple of decades yet, individual model runs frequently show rapid ice loss events over the course of a few years.  Any individual model run might well have a period of 5-6 years which appears at least as dramatic as 2006-2012, but then slow back down again. Since the real world is the equivalent of a single model run, scientifically we simply cannot say whether the trend is wrong, or whether we've just had an unusually sharp "downward wiggle" in a trend that will ultimately zero out in the 2030s.  The best guess based on the GCMs is the latter.

It would be very interesting to look at some of the data for individual model runs, rather than the complete ensemble, and have Tamino, Wipneus and all the rest run Gompertz fits (and linear, and exponential...) for individual runs.  Possibly the most important question would be the long-term autocorrelation of the runs: whether individual runs that show a sharp early dip are also the runs that zero out soonest, or whether they return reasonably rapidly to the average trend.  It might be (for example) that the world was indeed on a trend set to zero out in 2030, but that the recent spell of several bad melt years in a row has tipped us into a more rapid regime of melt-out.  Tietsche et al looked at this after imposing artificial perturbations (removing all sea ice) and found that it took about 3 years to "decay" back to the long-term trend: it would be interesting to know if the same applied to internal fluctuations within the model itself.

...and bring back the necessary objectiveness the W.M. article lacks.
This is what I mean by a lack of respect.

I opened this thread to find out what might qualify extent to tell the future and declare all other parameters excrescent.
And you would have a point if Dr Meier was doing a naive extrapolation of the extent figures with no underlying model for how climate works.  He's not doing that - however that is what a lot of people here are doing with the volume figures.

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Re: W.Meier on Conservative Scientists
« Reply #42 on: August 01, 2013, 10:40:45 PM »
Why not ask NSIDC or Dr Meir?
Sure, that was another reason starting this, I'm collecting points since the US draft climate assessment. Sorry to read you're out.

Richard Rathbone

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Re: W.Meier on Conservative Scientists
« Reply #43 on: August 01, 2013, 11:07:44 PM »
Peter,

According to one lot of modellers, the best guess on their model is that the model is wrong about the arctic. There might be a slow down in loss, but they looked at why their model showed slowdown, looked for any evidence that the processes responsible for slowdown were actually occurring, and concluded that the slowdown observed in their model was unlikely to occur in the actual arctic to any significant degree.

A. E. West et al.: Mechanisms causing reduced Arctic sea ice loss,

http://www.the-cryosphere.net/7/555/2013/tc-7-555-2013.html

You'll need to read the paper to see this quote from their conclusions, rather than the abstract I linked, but its not paywalled.

"Given the causes discovered, we cannot conclude, from the HadGEM1 projections, that a slowdown in ice loss is to be expected soon,"

While the claims Walt makes for the date of Arctic melt-out are based on the GCMs, they are claims that that at least the Hadley centre modellers regard as not supported by their model.

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Re: W.Meier on Conservative Scientists
« Reply #44 on: August 02, 2013, 12:06:37 AM »
Peter,

although - obviously - we do not share the same concept of respect, I appreciate your detailed input. Let me comment point by point:

1) Navigational relevance remains undisputed.

2) I don't get this science should follow common sense logic. I learned before skating on ice, check thickness. Actually I think communicating extent to the public is quite misleading and most people get the significance when confronted with 50% extent loss and 75% volume loss during same time frame.

3) Yes, extent covers nicely the satellite era starting 1979. Submarine draft data hosted at the NSIDC  spans from 1979 to 2004. Check my first post, there is even more data from other sources. Extent is a secondary product of area acquired by satellites, don't know of extent data before area. Due to the 15% threshold it ignores both melting ponds and sea ice concentration. By assuming 100% ice cover beyond the ice edge it integrates nicely with ship logs, but at the cost of physical quality.

4) Sure, when the ice is gone all measurements report zero, zip, nothing and null. The question was what qualifies extent to determine this point in time. Since it ignores concentration and reports same amount of ice whether thickness is 5m or 5cm, it doesn't look very skillful.

> The predicted extents are the output, not the input. 

That's not exactly true, extent is still in use to 'calibrate' models and since there are multiple algorithms with different data sets it is a reason for major headaches, because you'll get different outcome depending on chosen extent data set. Check the literature. In my domain that's called: Garbage in, garbage out.

> individual model runs frequently show rapid ice loss events over the course of a few years

That's true if you look at time spans short enough. IIRC a paper by Stroeve investigated deeper and she hasn't found a single model which was able to reproduce correctly, say, last 100 years.

So, in short, I agree on the application of extent for navigational purposes. Regarding the climate a flat two dimensional model of sea ice is an unacceptable reduction of the physical reality. We are talking about global warming and Arctic amplification, good luck with deriving heat flux changes from sea ice extent time series.



Dromicosuchus

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Re: W.Meier on Conservative Scientists
« Reply #45 on: August 02, 2013, 12:20:12 AM »
I'm very glad that Dr. Meier decided to write this piece, as it's forced us to pay a bit more attention than we usually do to the gulf between the 2016 +- 3 years projection* and what a large number of very intelligent, very competent researchers (who are far more familiar with the field than many of us are) consider probable.  A little soul-searching can only do this community good.

Now, all that said, I'm not sure I can wholeheartedly agree with Dr. Meier's (relatively, of course) optimistic view.  There are, after all, good scientists doing good research who are rather significantly more spooked than the CMIP5 modelers are, and I don't feel safe assuming that they're merely being overly alarmist (although barring something completely and totally unprecedented, Maslowski's 2008 expectation of a 2013 meltout is, ah, not looking all that prescient).  Maybe the CMIP5 projections are right; I hope they are.  Just to be on the safe side, though, I personally am going to try to plan for the future under the assumption that Wadhams et al. are a bit closer to the truth, and a collapse is imminent.  Me for the precautionary principle.

*On that subject, does anyone know of a published paper, pre-2007 melt season, in which total ice destruction in ~2016 (or, at least, pre-2020) was predicted?  I can't seem to find anything along those lines.

slow wing

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Re: W.Meier on Conservative Scientists
« Reply #46 on: August 02, 2013, 02:17:23 AM »
Drom,

Dr Wieslaw Maslowski states that it was around 2003-4 that he first started predicting the *possibility* of melt out by 2013:

Posted on 24 Mar 2008
"...my first presentation where I actually had this projection stated exclusively was about 4 or 5 years ago in San Francisco, at American Geophysical Union poll meeting. So, I'm not actually upgrading my projection, I'm just saying that it may happen sooner but we were one of the early people who were saying that it might happen within the next decade, instead of by the end of this century."
http://bze.org.au/media/radio/dr-wieslaw-maslowski-predicted-2013-ice-free-summer-arctic-five-years-ago-now-he-says-ma


Note his use of the word *might*. It's commonplace on certain websites to claim that was predicted as a certainty and to use that to unfairly discredit the researcher. He seems a competent and reasonable researcher, at least based on what I have read from him.


 His prediction of 2016 +/- 3 (from 2011?) is still looking very good to me and his methodology seems superior to that for many of the predictions for a longer time frame, e.g. just looking at extent and ignoring the observed thinning of the ice.


It is undeniable that minimum ice volume has been falling fast year-by-year and extrapolations of that using simple parameterisations mostly predict an ice-free summer some time later this decade. (See Wipneus' plots from this forum, for example.) Empirical observation and modelling have a respectable role in science in the absence of a defensible quantitative first-principles model to the contrary, which is the case here.

Dromicosuchus

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Re: W.Meier on Conservative Scientists
« Reply #47 on: August 02, 2013, 05:50:38 AM »
Many thanks for the link, Slow Wing.  I did a bit more digging, and finally managed to dig up a link to a specific talk given:  http://www.ametsoc.org/atmospolicy/documents/May032006_Dr.WieslawMaslowski.pdf  Honestly, for the most part I wanted to just have a concrete example of him having made that projection, rather than an offhand recollection given five years later or a reference to an AGU talk that doesn't seem to want to show itself anywhere on teh intarwebz.  As you say, this is less a concrete prediction and more a simple statement that if the trend persists, an ice-free state is inevitable, which...well, it is as it is.

Oh, and for whatever it might be worth, some folks might be interested in the following.  I imagine a fair few of you are familiar with this RASM model, but I wasn't, and I figure there might be others here who would be similarly interested to hear of it:  http://www.oc.nps.edu/NAME/ResearchMedia.EU_Maslowski_highres.pdf

ChrisReynolds

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Re: W.Meier on Conservative Scientists
« Reply #48 on: August 02, 2013, 08:26:36 PM »
Why not ask NSIDC or Dr Meir?
Sure, that was another reason starting this, I'm collecting points since the US draft climate assessment. Sorry to read you're out.

I'll see if I can contribute, but I don't want to just be repeating stuff like a broken record.

Could try this for a start though.



The blue line is the volume of ice due to ice under 2m thick in April. The purple line is the volume of ice due to ice over 2m thick in April. The red line is CT Area at daily minimum. The blog post is here:
http://dosbat.blogspot.co.uk/2013/05/summer-acceleration.html
But to save people reading - I  don't think it is any coincidence that the decline in CT Area tracks the loss of multi-year ice (where ice over 2m thick is assumed to have grown above the thermodynamic thickness for a seasons growth of 2m, therefore ice over 2m thick is a proxy for multi year ice).

It is the loss of volume that is driving the loss of Arctic sea ice, not the loss of extent/area. So to fixate on extent/area is a classic case of the tail wagging the dog.

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Re: W.Meier on Conservative Scientists
« Reply #49 on: August 02, 2013, 10:03:49 PM »
I don't think it is any coincidence that the decline in CT Area tracks the loss of multi-year ice

Of course it isn't. First, consider the fact that the trend in winter maximum is much shallower than the trend in summer minimum, which means that the trend is summer minimum is closely related to the trend in "area melted per year"  Next consider that at the broadest possible level, the Arctic is structured like a doughnut.  The fringes are entirely first-year ice, the middle is a mix of first-year and multi-year ice. During the summer, ice melts from the outsides inwards.  That means that in years when more ice melts, more multi-year ice melts - and, crucially, proportionally more of the melt encompasses multi-year ice.  Finding a strong correlation between the area melted each summer and the amount of multi-year ice lost isn't remotely unexpected, but it's a long way to jump from that to causation.