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In Which Decade will the Arctic Sea Ice Extent experience its LAST September with a minimum ABOVE 1X10^6 km^2?

2020-2030
67 (48.9%)
2030-2040
36 (26.3%)
2040-2050
13 (9.5%)
2050-2060
6 (4.4%)
2060-2070
6 (4.4%)
2070-2080
0 (0%)
2080-2090
0 (0%)
> 2090
9 (6.6%)

Total Members Voted: 128

Voting closed: May 29, 2017, 07:46:52 PM

Author Topic: Poll: When Will the Arctic Experience THE LAST Year With Sept. Sea Ice Extent  (Read 48245 times)

Michael Hauber

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Even under worst case rcp8.5 the multi-model mean for September ice extent will still be 0.5m in 2100.  That would allow a high chance that some years would still be above 1m. 

The chances of there not being at least some years > 1m extent between 2100 and 2200 seem very slim to me.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

Hyperion

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I wouldn't be surprised at all if the last year above 1m was 2016. 50/50 I Reckon.

Quote
reforestation and agricultural practices do not have the capability to remove CO2 fast enough so industrial activities must be engaged.  However there are chemical and technical processes for removing CO2 they do not exist are not currently in operation because we do not have a reimbursement mechanism to make them worthwhile.  I believe it would take a cost of carbon over $1,000 per metric tonne. 

Can't entirely agree with you there Jai. Widespread sugarcane and Kelp farming combined with pyrolysis and biochar soil remediation is both highly profitable and up to the job. Even if you just burn the Pyrolysis gas and liquid as fuel you can bury at least 100 tonC of carbon per hectare grown per year, eliminating fertilizer needs instantly and vastly improving soil productivity and health. The addition of the biochar to any soil will cause ongoing extra sequestration of fresh carbon, and a vast reduction in irrigation requirements. Sugarcane has over 1000x less water requirement than pasture anyway. Therefore up to 4x carbon negative energy can be achieved by anyone in their backyard with centuries old village level technology. In fact it is very easy and arguably also centuries old village level tech to use Pyrolysis oils as adhesives and timber treatment and coating systems. This allows substitution of steel and concrete construction systems with natural fibre/lumber/aggregate bioglue laminated beams, panels, and polymer concrete structural solutions. Far higher performance and lower cost than the extremely CO2 producing steel and concrete.
This immediately lobs you into 10x carbon negative territory. And rapidly back on the path to the several thousand tons C per hectare of living soil and above ground biomass that we used to have in our forests. Reduced to max 10-30 tons per hectare in todays agricultural practice. Here in New Zealand we have the worst environmental record per capita in the world. Over 900% deforestation in two centuries with over 20 million hectares reduced from about 2000 ton C pHa living biomass to 10 ton C/hectare. We are about 100 times as bad as Americans sad to say, in turning our living biomass in to CO2 polution of the air and oceans.
But if we do as suggested above with just 1 million hectares of our 25million land and 450million sea territory, we could sequester a couple of hundred million Ton C per year here and we are not a big country.
Why is it not happening? Big money won't do it because you cant patent it and hog all the power and profit. Small people are brainwashed into thinking that you can't do anything in this world without BIG MONEY.
False. The rich and powerful never change the world. Its always the little people.
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
https://en.wikipedia.org/wiki/McGillicuddy_Serious_Party

dj

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I wouldn't be surprised at all if the last year above 1m was 2016. 50/50 I Reckon.

Quote
reforestation and agricultural practices do not have the capability to remove CO2 fast enough so industrial activities must be engaged.  However there are chemical and technical processes for removing CO2 they do not exist are not currently in operation because we do not have a reimbursement mechanism to make them worthwhile.  I believe it would take a cost of carbon over $1,000 per metric tonne. 

Can't entirely agree with you there Jai. Widespread sugarcane and Kelp farming combined with pyrolysis and biochar soil remediation is both highly profitable and up to the job. Even if you just burn the Pyrolysis gas and liquid as fuel you can bury at least 100 tonC of carbon per hectare grown per year, eliminating fertilizer needs instantly and vastly improving soil productivity and health.

Would you have any references regarding the figure for 100 tonsC per hectare.  I would like to do some further reading on that estimate.

jai mitchell

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 http://www.globalcarbonproject.org/global/pdf/pep/Pan.etal.science.Forest_Sink.pdf

The current C stock in the world’s forests is estimated to be 861 +/- 66 Pg C  -  we need to drawdown 1,000 Pg of C
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Bruce Steele

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Maybe pyrolysis and converting forests & kelp into charcoal is better suited to the policy & solutions page. Converting even a small fraction of the 861 +- 66  Pg C of current forests would add to rather than solve our human impacts on planetary ecosystems. Planting and coppicing wood crops has more promise but crop land and water resources are not limitless.
 Jai, why the need to draw down 1,000 Pg C ?  We are only now surpassing 600 Gt C in total accumulated emissions.

http://www.trillionthtonne.org

2020-2030. First year < 1m.  Maybe sooner
Late year requires some prediction on the loss of the halocline...  Much later I would guess
2060-2070
« Last Edit: April 18, 2017, 06:42:55 AM by Bruce Steele »

oren

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I find my poll choice is not editable. Could Neven work his magic here?

Neven

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And presto, you can change your vote.  ;)
The enemy is within
Don't confuse me with him

E. Smith

seaicesailor

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Personally, I think anyone that voted anything other than 2020-2030 in the poll above is a denialist, consciously or not.


Wow Thank you!
And
What the hell do you know?

AndrewB

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Jai,
I think it's interesting to compare this poll to your previous June 2015 poll on more or less the same theme: When Will We See <1,000,000 km2 Arctic Sea Ice Extent?

http://forum.arctic-sea-ice.net/index.php/topic,1269.0.html

There are many excellent comments in your previous poll thread, among others this one is probably my favorite:

Why no option for "not in this millennium"? RE: This paper contains projections of arctic for RCP 4.5 - with 9 out of 14 models becoming ice free by 2069, and 3 of the models never becoming ice free.
...

Because, "aliens will arrive and fix our global energy imbalance problem" didn't seem like a realistic answer???

What changed between June 2015 and now (mid-April 2017)? Lots of things, but nothing good and no sign of aliens arriving here and fixing our global energy imbalance problem either.

Actually, this happened* that nobody had predicted, not even here on ASIF:

jai mitchell

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Andrew,

The time span between first and last years with < 1X 10^6 km^2 may not be as narrow as you think.  (I am not saying that you are wrong on this - just that they are different questions).

In retrospect, you are right.  I was being far too conservative for conservatism's sake.   Interesting, you caught me self-censoring my answer.  changed from 2040-2050 to 2030-2040.
« Last Edit: April 18, 2017, 12:31:25 PM by jai mitchell »
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jai mitchell

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Bruce.

It really depends on our emission scenarios, we are currently emitting about 10 Pg of Carbon per year with much of this going into the oceans.  As we draw down below 400 ppmv the oceans will begin return this Carbon to the atmosphere.  Also, between now and 2100 I expect an additional 300 Pg from carbon cycle feedbacks.  Of course the 1,000 Pg estimate is a rough one and based on what we do in emissions between now and 2050.

If we reach 4C the 1,000Pg of Carbon will be a gross underestimation due to the release of the same amount of carbon from global permafrost alone (over the next 200 years).
Haiku of Futures Passed
My "burning embers"
are not tri-color bar graphs
+3C today

Pmt111500

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Large part of Southern ocean started to conform wrt sea ice with northern warming which was also very pronounced im the aftermath of large El Nino. The possibility of another high melt year does not mean the southern ocean will behave the same the next southern spring.

I'm not too sure of the future behavior of North Atlantic Drift and Arctic extensions of the same, and the changing snowfall amounts in the northern seas. Still I'm not of the opinion of some scientists arguing this still takes generations.


AndrewB

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Andrew,

The time span between first and last years with < 1X 10^6 km^2 may not be as narrow as you think.  (I am not saying that you are wrong on this - just that they are different questions).

Jai, thanks for your reply. But isn't that a moot point at this stage? I mean, the exact year or decade at which Arctic see ice goes below an arbitrary threshold and whether it can (by means of alien intervention, natural variability, carbon sequestration technology, etc) eventually crawl up again above that same arbitrary threshold, isn't that relatively unimportant? I mean, we already know and even Axel Schweiger, one of the Ding et al 2017 "natural variability attribution" paper co-authors admits, that we have already lost > 80% of the September Arctic sea ice volume (which as you know, is more representative of the real loss than extent).

The disaster is already upon us, actually it's already in the past now.

There is a good possibility that we are wasting precious time discussing* the minutiae of the last chaotic spasms of an entire ecosystem that we have already allowed to die. I somehow feel we should accept the responsibility over what happened and move on to a discussion on how to mitigate the serious consequences of this disaster.

* even though it makes for an interesting discussion.
« Last Edit: April 18, 2017, 12:40:59 PM by AndrewB »

oren

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Thank you Neven!
AndrewB - Each thread has its own subject. If you feel we should be discussing other stuff instead, why not post about it in the thread related to that subject?
(I generally do agree that the disaster is upon us, but I still like to post about a variety of subjects, which probably won't save us but are interesting nevertheless).
For the record, I have changed my vote form 2020-2030 to 2030-2040, as I expect some variablity to continue. A cold winter such as 2013 could come along again.
« Last Edit: April 18, 2017, 02:40:35 PM by oren »

Bruce Steele

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Jai, Planning on further increases in total emissions to 1000 Gt or more is likely or worse inevitable.
I still think there is uncertainty in whether current anthropogenic emission trends or feedbacks are feeding CO2 atmospheric levels. Probably some of each. Rboyd posted a EIA revision in China's contributions that illustrates our problems with parsing out anthro from feedbacks.


"Energy-content-based coal consumption from 2000 to 2013 is up to 14% higher than previously reported, while coal production is up to 7% higher"

https://www.eia.gov/todayinenergy/detail.php?id=22952

We should assume other countries fudge their emission figures as well and any reports of a flattening of anthro CO2 is premature. If on the other hand feedbacks are in majority the reason we see continued atmospheric CO2 increases the 1000 Gt number may far short of what is necessary to somehow drawdown, whenever we figure out how to do so.
 I also agree the ocean will give back what CO2 it has absorbed but the timeframe of that release may be in the thousand year timeframe. Remember also that the ocean has more ability to hold CO2 at cold temperatures so as we heat the oceans they will actually return more CO2 than what it has absorbed .
The amount of the return from the oceans is dependent on the gas partial pressure difference  between the ocean and the atmosphere like you stated.

Sterks

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Nobody wants to talk or mention, or even think about the bathymetry of the Arctic Ocean? In my eyes, I'd say it is the number one factor influencing the minimum ice extent shape in September.
How much extra heat makes for keeping same excess heat on the surface, if it badly tends to sink and sink? It's a very physical discussion.
Voted 2060-2070.

gerontocrat

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I look at 2012 and think "circa 15 years ahead of schedule" and 2013 "circa 5 years behind schedule" (cf with nsidc linear fit). That is a 20 year difference possible between years. So if an ice-free september arrives within the next 5 years being a 15 year outlier, it is possible for a +1m km2 year for a goodly number of years after. OR maybe not as this assumes that the slow-motion train wreck continues very much as in recent years.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

AndrewB

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Thank you Neven!
AndrewB - Each thread has its own subject. If you feel we should be discussing other stuff instead, why not post about it in the thread related to that subject?
(I generally do agree that the disaster is upon us, but I still like to post about a variety of subjects, which probably won't save us but are interesting nevertheless).
For the record, I have changed my vote form 2020-2030 to 2030-2040, as I expect some variablity to continue. A cold winter such as 2013 could come along again.

Oren,
When I wrote "we" above I meant our society, politicians, scientists, policy makers and others concerned with AGW. And by "discussion" I wasn't referring to just this thread, but rather the whole debate about Arctic sea ice.

Or you could put it this way: if Jai could edit the poll above, I would ask him to add two categories.
- before 2020.
- It doesn't matter. >80% of the September sea ice is gone already, and the rest can't be saved.

Or if you want to use the metaphor of the slow-motion train wreck movie, that gerontocrat just used in his comment: we are watching the last couple of seconds of the reel, and wondering if the locomotive that has already derailed a minute ago will stop moving at point x or two meters further away.
« Last Edit: April 18, 2017, 07:31:34 PM by AndrewB »

Jim Williams

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...locomotive that has already derailed a minute ago will stop moving at point x or two meters further away.
More like 57 meters...

But what is a few inches between friends?

AndrewB

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...locomotive that has already derailed a minute ago will stop moving at point x or two meters further away.
More like 57 meters...

But what is a few inches between friends?
Does it matter?
Sticking to the train wreck metaphor, does it change the cost of the disaster? Or the number of victims? Shouldn't we (and I mean, we as in humanity/civilization) rush to help the victims instead of wasting time with overanalyzing the path of the locomotive in the remaining two seconds of the reel, and how much water and coal were still left before it crashed, etc, etc, etc?

Perhaps we are just happy with watching Arctic sea ice melt away (and just in case you haven't noticed, I am quoting you, Jim Williams "I come here to watch the sea ice melt") because it's very much an abstract thing, and so huge a disaster that our minds cannot quite apprehend it.

But the fact is, some of us in this excellent forum (myself included) publicly complained to Dr. Ding about his "detachment" from the Arctic sea ice melt disaster. Aren't we (and this time I mean the vast majority of users of this excellent forum) in a similar way just as irresponsible?
« Last Edit: April 22, 2017, 03:41:16 PM by AndrewB »

jai mitchell

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Jai, Planning on further increases in total emissions to 1000 Gt or more is likely or worse inevitable.
I still think there is uncertainty in whether current anthropogenic emission trends or feedbacks are feeding CO2 atmospheric levels. Probably some of each. Rboyd posted a EIA revision in China's contributions that illustrates our problems with parsing out anthro from feedbacks.


"Energy-content-based coal consumption from 2000 to 2013 is up to 14% higher than previously reported, while coal production is up to 7% higher"

https://www.eia.gov/todayinenergy/detail.php?id=22952

We should assume other countries fudge their emission figures as well and any reports of a flattening of anthro CO2 is premature. If on the other hand feedbacks are in majority the reason we see continued atmospheric CO2 increases the 1000 Gt number may far short of what is necessary to somehow drawdown, whenever we figure out how to do so.
 I also agree the ocean will give back what CO2 it has absorbed but the timeframe of that release may be in the thousand year timeframe. Remember also that the ocean has more ability to hold CO2 at cold temperatures so as we heat the oceans they will actually return more CO2 than what it has absorbed .
The amount of the return from the oceans is dependent on the gas partial pressure difference  between the ocean and the atmosphere like you stated.

Bruce,

thank you for posting that EIA bit.  I was looking for it yesterday.  There is some discussion that the drop in per unit coal consumption but the continuity of energy use from coal is a strong indicator of China moving toward cleaner coal types and processes as part of their 3-year aggressive aerosol reduction program.

The projections are not showing what is happening today but the expectation is that this process is ramping up significantly and the apparent results since December 2015 appear to be MASSIVE on a global atmospheric circulation scale.

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Jim Williams

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...locomotive that has already derailed a minute ago will stop moving at point x or two meters further away.
More like 57 meters...

But what is a few inches between friends?
Does it matter?
Sticking to the train wreck metaphor, does it change the cost of the disaster? Or the number of victims? Shouldn't we (and I mean, we as in humanity/civilization) rush to help the victims instead of wasting time with overanalyzing the path of the locomotive in the remaining two seconds of the reel, and how much water and coal were still left before it crashed, etc, etc, etc?

Perhaps we are just happy with watching Arctic sea ice melt away because it's very much an abstract thing, and so huge a disaster that our minds cannot quite apprehend it.

But the fact is, some of us in this excellent forum (myself included) publicly complained to Dr. Ding about his "detachment" from the Arctic sea ice melt disaster. Aren't we (and this time I mean the vast majority of users of this excellent forum) in a similar way just as irresponsible?
Actually you are proposing that I have a specific valuation upon a certain kind of life.  I do not.  I am here watching what is a very interesting change in the global climate -- I am not here assigning a valuation upon that change.

In fact, I find the watchers who are also excited and then end with some sort of disclaimer rather annoying.

AndrewB

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...

In fact, I find the watchers who are also excited and then end with some sort of disclaimer rather annoying.


Well, I suppose that's what the "ignore" function is for...  :P

Coffee Drinker

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I vote for 2090 or later.

Think we will get very close the coming years but wont reach the threshold that constitutes ice free.

Overall I expected a substantial recovery of the arctic sea ice in the next decades due to solar minimum and natural variation of the arctic climate. Maybe add one or two major volcanic eruptions to further sustain the recovery.

Once those factors diminish, I expect a complete collapse of the arctic sea ice around 2090 with largely ice free summers and slow ice formation in late autumn and winter without a complete refreeze.

Neven

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Welcome to the ASIF, Coffee Drinker, your profile has been released.
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I believe that each summer has the potential to see complete melt out, it just demands an extreme, and consistent , summer melt season of high melt,high export.

Over time I have seen the 'extreme conditions' , needed for melt out, reduce in intensity meaning we no longer need as extreme an event as we did only 10 years ago?

This means we can arrive at a point that even though we have ice in the water in August the body of open water, and its melting potential, will mean the loss of that remaining ice no matter the weather conditions.

We may well sail very close to that point this year esp. if we find high melt conditions over the high insolation months?

Winter has already giving us a flying start by keeping ice level low and ( relatively?) warm. We now need to see how this first phase of melt season pans out. If we see high losses beginning to rack up before June things will become very interesting ( and very busy on here!!!).
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Lennart van der Linde

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I believe that each summer has the potential to see complete melt out, it just demands an extreme, and consistent, summer melt season of high melt,high export.

Almost 40 yrs ago Arctic sea ice volume varied on average a little over 15,000 km3 between yearly maximum and minimum:
https://04da4be4-a-62cb3a1a-s-sites.googlegroups.com/site/marclimategraphs/collection/G14.jpg?attachauth=ANoY7cqMx9S8RVR_Ydp_-i4nWDWIvSCkMBjZj5uagJjsJ-GC216EsfLKPwHqz7lHU4E4Wwmj_rgogyRsBPNf7Pb6kbho7zKc9-2ZFlJGsbL0_39ewpLJPtiA1f8BodCEz86LyL6Gg9qwnfNXEtTiuAMHey2q3T7GuKQ1Fcu_VOkrFVthmP8-SlZnjkT22CwtjlAtVdHtNIo1ctlg9d22U5z_Dt0pavps_lWNu4edUUmUucw0gdEoxow%3D&attredirects=0

Minima were close to 15,000 km3 and could vary as much as 4,000 km3 within a few years. Now almost 20,000 km3 is being melted each year between maximum and minimum, and the minimum is little more than 4,000 km3, so indeed in a good melting year, we could get to zero volume any year now, it seems.

Lennart van der Linde

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Tor Bejnar

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This graph shows the same [sad] story even better:
...
... especially knowing that the blue line (max) in 2017 will likely drop below the "21" (x1000 km3) line.  During recent years, melt has been in the rage of 19.5 (in 2010 and 2012) to 16.5 (2014), so less than 2,000 km3 remaining is a real possibility, but not a 'sure thing'.

I won't be particularly surprised if we have a record melt (20,000 km3 - the Arctic has been prepped for it) or a modest one (17,000 km3 - the High Arctic's short melting season makes it tough, even with thin ice).

[Yeah, my comment may belong in the melting thread - but this isn't a 'major' thread, so I don't expect Neven to get out his axe, but because of this note he might  :D.]
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

AndrewB

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This graph shows the same story even better:
...
Indeed there are similar versions of this chart floating around, some with smoothed data, some not, etc.
The main point of this chart is that, when the trendlines meet is when total summer melt = total Arctic sea ice from previous winter(s). In other words, a zero sea ice Arctic.

Chris Reynolds used a version of this chart to predict zero ice by the mid 2020's, but he was assuming a small, linear drop in maximum (April) Arctic sea ice volume after 2014. Unfortunately he posited a "slow transition" (see the thread by the same name here on ASIF) to a sea ice free Arctic based on this small, linear drop in maximum (April) Arctic sea ice, itself based on a simple thermodynamic negative feedback (heat loss during Arctic winter getting higher and higher as the ice gets thinner and thinner, hence the ice thickening being faster and stronger after a summer with more melt).

2017 is showing that AGW and positive feedbacks resulted in a record, step drop in Arctic sea ice volume at the end of March / beginning of April (see the PIOMAS thread). In other words, positive feedbacks have largely overwhelmed the negative feedback described by Chris in the winter 2016/2017 and the two (quadratic) trendlines should meet sooner than the mid 2020's.

Another way of stating what is happening in 2017 is to say that we have just entered a new Arctic climate regime which will stabilize when we get a year-round, totally ice free Arctic ocean, and the transition from the current state should be quite fast. No "slow transition", but rather, an abrupt one.

Quoting from Tamino's blog: "The loss of Arctic sea ice is so great, so rapid, so alarming and surprising, it’s powerful evidence of dramatic man-made climate change."

(from https://tamino.wordpress.com/2016/09/28/its-the-ice-stupid/ )
« Last Edit: April 20, 2017, 02:09:34 AM by AndrewB »

Jim Williams

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This graph shows the same story even better:
...
Indeed there are similar versions of this chart floating around, some with smoothed data, some not, etc.
The main point of this chart is that, when the trendlines meet is when total summer melt = total Arctic sea ice from previous winter(s).

Chris Reynolds used a version of this chart to predict zero ice by the mid 2020's, but he was assuming a small, linear drop in maximum (April) Arctic sea ice volume. Unfortunately he posited a "slow transition" (see the thread by the same name here on ASIF) to a sea ice free Arctic based on this small, linear drop in maximum (April) Arctic sea ice, itself based on a simple thermodynamic negative feedback (heat loss during Arctic winter getting higher and higher as the ice gets thinner and thinner, hence the ice thickening being faster and stronger after a summer with more melt).

2017 is showing that AGW and positive feedbacks resulted in a record, step drop in Arctic sea ice volume at the end of March / beginning of April (see the PIOMAS thread). In other words, positive feedbacks have largely overwhelmed the negative feedback described by Chris in the winter 2016/2017 and the two (quadratic) trendlines should meet sooner than the mid 2020's.

Another way of stating what is happening in 2017 is to say that we have just entered a new Arctic climate regime which will stabilize when we get a year-round, totally ice free Arctic ocean, and the transition from the current state should be quite fast. No "slow transition", but rather, an abrupt one.

Quoting from Tamino's blog: "The loss of Arctic sea ice is so great, so rapid, so alarming and surprising, it’s powerful evidence of dramatic man-made climate change."

(from https://tamino.wordpress.com/2016/09/28/its-the-ice-stupid/ )

The transition from a desert to a maritime climate happened in late December 2015.

AndrewB

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...
The transition from a desert to a maritime climate happened in late December 2015.

Well, if we consider that >80% of Arctic summer sea ice is already gone in the last 39 years or so, then the transition began a long time ago, and nowadays we are just going through its last stages.
But I believe there was a clear step change in November/December 2016 (I don't see anything special happening in December 2015, though), that's what this (excellent, from Wipneus as usual) chart tells me:


seaicesailor

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The transition from a desert to a maritime climate happened in late December 2015.

Based on what? On some plumes of humidity over the Arctic? You don't know if that is an annual variation, or decadal, or what. You know as much as I do or any around (except maybe the owner of the site, Rob, Dr. Ding and a handful more), which is nothing.

Based on a graph???? Lol. Based on clairvoyance, a vision in dreams or what?

In September 2012 "a tipping point was crossed", in November Sandy . But Did we? Or didn't we? Cause 2013 and 2014 were pretty unispiring seasons for some that shut their mouth for a good and nice while.
Same we heard when Katrina in 2005 "We will never come back to past seasons". Well, in what respects to Atlantic hurricanes, we are back to old times.

2017? Does not look good, if you ask me even worse than 2016, but how I wish it was otherwise.

Jim Williams

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The transition from a desert to a maritime climate happened in late December 2015.

Based on what? On some plumes of humidity over the Arctic? You don't know if that is an annual variation, or decadal, or what. You know as much as I do or any around (except maybe the owner of the site, Rob, Dr. Ding and a handful more), which is nothing.

Based on a graph???? Lol. Based on clairvoyance, a vision in dreams or what?

In September 2012 "a tipping point was crossed", in November Sandy . But Did we? Or didn't we? Cause 2013 and 2014 were pretty unispiring seasons for some that shut their mouth for a good and nice while.
Same we heard when Katrina in 2005 "We will never come back to past seasons". Well, in what respects to Atlantic hurricanes, we are back to old times.

2017? Does not look good, if you ask me even worse than 2016, but how I wish it was otherwise.
The DMI 80N prior to 2015 all look pretty much the same as all but the last few days of 2015.  The DMI 80N for 2016, and so far in 2017 have the interesting characteristic that the wintertime temperatures NEVER fall to the long term mean.

In this timeframe, the discussion here was about the remarkable number of storms entering the Arctic.

Gray-Wolf

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If we have not totally mangled the workings of the N. Hemisphere's atmosphere then we will still have 'natural variability' sat on top ( when working with AGW and not offsetting it) of the Human forcing and so we may well find 'Nature' throws us a curve ball well before the current trend line hits 1 million?

I have been fearing the results of the return of the 'Perfect Melt Storm' synoptic over the basin. As time went forward I saw the weather over the basin over melt season become ever more 'average' with low pressure keeping it cloudy over the high insolation months. So should I fear Mother Natures rhythms more than mankind's melt pressures?

If Nature, adding into man's forcings, leads to our first sub million pack then it will be ahead of most of our predictions as such 'natural' events are hard to pin down. But then will the first sub million event make repeats of the same far more likely in the short term?
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AndrewB

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The DMI 80N prior to 2015 all look pretty much the same as all but the last few days of 2015.  The DMI 80N for 2016, and so far in 2017 have the interesting characteristic that the wintertime temperatures NEVER fall to the long term mean.
...

Jim, you are absolutely correct, although the temperature anomaly is much more marked in the winter of 2016/2017 than in the winter of 2015/2016, leading to the exceptional Arctic sea ice volume deficit this year, that I already mentioned.

And needless to say, I don't think there is any "natural variability" in the observed remarkable temperature anomalies in the winters of 2015/2016 and 2016/2017. This is AGW + Arctic amplification.

Charts below from: http://ocean.dmi.dk/arctic/meant80n.uk.php

jai mitchell

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But I believe there was a clear step change in November/December 2016 (I don't see anything special happening in December 2015, though)

https://www.nasa.gov/feature/goddard/2016/extremely-warm-2015-16-winter-cyclone-weakened-arctic-sea-ice-pack
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jai mitchell

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The transition from a desert to a maritime climate happened in late December 2015.

Based on what? On some plumes of humidity over the Arctic? You don't know if that is an annual variation, or decadal, or what. You know as much as I do or any around (except maybe the owner of the site, Rob, Dr. Ding and a handful more), which is nothing.

Based on a graph???? Lol. Based on clairvoyance, a vision in dreams or what?


The primary indicator of a global atmospheric transition at that time:

Water Vapor Anomaly
http://data.remss.com/vapor/monthly_1deg/tpw_v07r01_198801_201703.time_series.txt

Figure 1 Attached



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AndrewB

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But I believe there was a clear step change in November/December 2016 (I don't see anything special happening in December 2015, though)

https://www.nasa.gov/feature/goddard/2016/extremely-warm-2015-16-winter-cyclone-weakened-arctic-sea-ice-pack

What I meant - perhaps my phrase was not precise enough - is that I can't see anything special happening at the end of 2015 when it comes to Arctic sea ice volume as measured by PIOMAS, on the chart that I included in my post.

Yes, we can see an extraordinary peak in temperature right at the end of December 2015, probably due to the warm winter cyclone that you refer to. It doesn't seem to have impacted Arctic sea ice volume in January 2016 that much though. I guess it took the really long period of extraordinary warmth during the months of October, November, December 2016 and January, February and March 2017 to build up the deficit in PIOMAS that we have now. Wipneus posted an interesting chart about that in the PIOMAS thread which I am reproducing here, hoping he doesn't mind:


AndrewB

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It's interesting that the poll is basically about when the Arctic's transition to a new climate state will be essentially complete (and I am positing that the transition will be abrupt and come within the next 5 years), but the discussion also raises the question of when this transition really began - and again I am positing that it began probably many years before we crossed the 350ppm CO2 threshold.

Off topic but these days the Keeling Curve shows CO2 concentration > 410ppm.  :'(


Jim Williams

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It's interesting that the poll is basically about when the Arctic's transition to a new climate state will be essentially complete (and I am positing that the transition will be abrupt and come within the next 5 years), but the discussion also raises the question of when this transition really began - and again I am positing that it began probably many years before we crossed the 350ppm CO2 threshold.

Off topic but these days the Keeling Curve shows CO2 concentration > 410ppm.  :'(

The transition began 8,000 years ago, but exponential functions have a habit of starting out very flat and then getting extremely steep.

I'll agree about the 5 years (or less).


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Even under worst case rcp8.5 the multi-model mean for September ice extent will still be 0.5m in 2100.  That would allow a high chance that some years would still be above 1m. 

The chances of there not being at least some years > 1m extent between 2100 and 2200 seem very slim to me.
Wasn't there a great paper recently that showed the model mean was only about half the observed decreased in Arctic sea-ice?

The graph is http://nsidc.org/arcticseaicenews/files/2016/12/Figure6.png with discussion at http://nsidc.org/arcticseaicenews/2016/12/arctic-and-antarctic-at-record-low-levels/

I find that graph from Stroeve (2016) to be quite convincing, though you could argue that recent years seem to be departing somewhat from a linear fit. Using the graph I would argue that the last year with a >1 million extent would be around about when cumulative emissions reach 2400 Gt CO2. Annual emissions are currently about 36 Gt CO2 per year. Call it 900 Gt CO2 to go, that's 25 years from 2015, ie 2040. (I'm not expecting drastic cuts in CO2 emissions, alas, but they have at least stabilised for the last couple of years).

If we take the linear model to be on the conservative side then I go for the 2030-2040 decade.

If I had been asked this question a few years ago I would have gone for the 2020-2030 decade with few doubts, but I have been surprised that the positive feedbacks have not been as strong as I had expected, and have not rendered weather variability entirely moot in the short-term.

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In the absence of geoengineering activities, when do you think the Arctic will experience its LAST year with a Sept minimum sea ice extent ABOVE 1 million square km? 

This is looking at human lifetime scales, not century or epoch scales so no, it won't be the absolute last unless the sun explodes.  Just global warming impacts, not nuclear winter etc.
Unless my english is really off the wording specifies LAST time ABOVE. That is NOT the same as the FIRST time ABOVE. That means to me all you need as one cold summer and you can have ice hanging around all summer. Maybe not much above 1M km2 but still above.
Therefore based on that interpretation I do see a chance of having a cold enough summer to have ice lasting all summer long.
 As for the exponential vs Gompertz argument.  Gompertz has a big problem because it only works if the melt is only as a result of sun influence. The real results are that as the  thins the it becomes much easier for the wind and waves attack and move around the thick ice. That means it will then get broken up and moved out of the Arctic. Bye bye Gompertz chart. As for exponential. It all depends on how steep you make that curve. To get below 1M you need not only high enough temperatures, but favourable wind and wave action for that first ice free summer. We are close enough to 2020 with still enough ice that we still may see ice after 2020, but based on condition of the ice right now, all it will take is a 2007 or 2012 summer and it will be all gone.
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AndrewB

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Even under worst case rcp8.5 the multi-model mean for September ice extent will still be 0.5m in 2100.  That would allow a high chance that some years would still be above 1m. 

The chances of there not being at least some years > 1m extent between 2100 and 2200 seem very slim to me.
Wasn't there a great paper recently that showed the model mean was only about half the observed decreased in Arctic sea-ice?

The graph is http://nsidc.org/arcticseaicenews/files/2016/12/Figure6.png with discussion at http://nsidc.org/arcticseaicenews/2016/12/arctic-and-antarctic-at-record-low-levels/

I find that graph from Stroeve (2016) to be quite convincing, though you could argue that recent years seem to be departing somewhat from a linear fit. Using the graph I would argue that the last year with a >1 million extent would be around about when cumulative emissions reach 2400 Gt CO2. Annual emissions are currently about 36 Gt CO2 per year. Call it 900 Gt CO2 to go, that's 25 years from 2015, ie 2040. (I'm not expecting drastic cuts in CO2 emissions, alas, but they have at least stabilised for the last couple of years).

If we take the linear model to be on the conservative side then I go for the 2030-2040 decade.

If I had been asked this question a few years ago I would have gone for the 2020-2030 decade with few doubts, but I have been surprised that the positive feedbacks have not been as strong as I had expected, and have not rendered weather variability entirely moot in the short-term.

Hi misfratz,
The Nots & Stroeve 2016 paper is freely available here: http://www.ncaor.gov.in/files/Science_News/Arctic%20news-0811-16.pdf

The authors themselves admit that their estimate is "very conservative":
Quote
it  is a  very  conservative  estimate  of  the  cumulative emissions at which the annual minimum sea-ice area  drops  below  1  million  km2 for  the  first  time.
(emphasis mine)

The takeaway from the Notz & Stroeve 2016 paper is that 1) most current climate models vastly underestimate the sensitivity of Arctic sea ice to cumulative emissions and 2) we should reduce emissions as fast as possible, and far faster than the 2C target implies.

As discussed above, the positive feedbacks seem to have overtaken natural variability and negative feedbacks just this past winter. The confirmation of this would be a new record low September sea ice extent / volume this coming summer. Not much to wait now (I would say things should be very clear around the end of August, in a little more than 4 months).

Sterks

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Bathymetry, bathymetry, bathymetry, BATHYMETRY!!!
Inconvenient truth to ignore?

The floor is the limit (except from November 2012 Arctic Sea Ice News)

Research by our colleagues Jamie Morison at the University of Washington Seattle and NASA scientist Son Nghiem suggests that bathymetry (sea floor topography) plays an important role in Arctic sea ice formation and extent by controlling the distribution and mixing of warm and cold waters. At its seasonal minimum extent, the ice edge mainly corresponds to the deep-water/shallow-water boundary (approximately 500-meter depth), suggesting that the ocean floor exerts a dominant control on the ice edge position. However, in some cases, ice survives in the shallower continental shelf regions due to water circulation patterns. For example, the shelf area of the East Greenland Sea is almost always covered with sea ice because the southward-flowing cold Arctic surface water helps to limit melt.

In contrast, ice disappears in shallow areas like the Barents and Chukchi seas that are subject to warm ocean waters and river runoff. River runoff and ice melting have also contributed to changes in the amount and distribution of fresh water in the Arctic.


http://nsidc.org/arcticseaicenews/2012/11/arctic-rapidly-gaining-winter-ice/

seaicesailor

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Removed my last comment, was off-topic.
Sterks, it is a serious and difficult problem indeed. This year might be interesting to see how the floor topography affects the final shape of the pack.
:-)

gerontocrat

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Bathymetry, bathymetry, bathymetry, BATHYMETRY!!!
Inconvenient truth to ignore?

The floor is the limit (except from November 2012 Arctic Sea Ice News)

Research by our colleagues Jamie Morison at the University of Washington Seattle and NASA scientist Son Nghiem suggests that bathymetry (sea floor topography) plays an important role in Arctic sea ice formation and extent by controlling the distribution and mixing of warm and cold waters. At its seasonal minimum extent, the ice edge mainly corresponds to the deep-water/shallow-water boundary (approximately 500-meter depth), suggesting that the ocean floor exerts a dominant control on the ice edge position. However, in some cases, ice survives in the shallower continental shelf regions due to water circulation patterns. For example, the shelf area of the East Greenland Sea is almost always covered with sea ice because the southward-flowing cold Arctic surface water helps to limit melt.

In contrast, ice disappears in shallow areas like the Barents and Chukchi seas that are subject to warm ocean waters and river runoff. River runoff and ice melting have also contributed to changes in the amount and distribution of fresh water in the Arctic.


http://nsidc.org/arcticseaicenews/2012/11/arctic-rapidly-gaining-winter-ice/

I wonder how much bathymetry data is still locked up in the Pentagon collected by all those nuclear subs wandering around under the Arctic during the cold war (and presumably still doing so, especially now Russia is showing its teeth).
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johnm33

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"bathymetry" http://www.arctic.io/maps/bathymetry/
unless someone has a better link

misfratz

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The authors themselves admit that their estimate is "very conservative":
Quote
it  is a  very  conservative  estimate  of  the  cumulative emissions at which the annual minimum sea-ice area  drops  below  1  million  km2 for  the  first  time.
(emphasis mine)
The trend line is quite convincing for the 30-year mean, but of course the variability around that mean will lead to a much earlier first year below 1 million km2.
As discussed above, the positive feedbacks seem to have overtaken natural variability and negative feedbacks just this past winter. The confirmation of this would be a new record low September sea ice extent / volume this coming summer. Not much to wait now (I would say things should be very clear around the end of August, in a little more than 4 months).
I don't see that it follows. Arctic sea-ice extent now is comparable to last year. It's true that PIOMAS volume is down compared to last year, but I was misled by rapid declines in PIOMAS volume in previous years that did not overwhelm short-term natural variability as I had expected they would.

A new record low this September would not be particularly shocking given the current trend, and would not suggest that natural variability was no longer a factor. I would still expect years with September sea-ice above the trend line in following years.

It's worth remembering that declines in September sea-ice extent are not particularly consequential in terms of sea-ice albedo feedback. For that we would look more to declines in May - July extent. For this reason I do not find your argument that there will be a paradigm shift in the Arctic sea-ice following the first year with less than 1 million km2 in September all that convincing.

Once the decline gathers pace in June then the growth in Arctic Ocean heat storage will be much more rapid, and I could envisage dramatic consequences. But I see the declines in September extent as a prelude to this main event. And thus, therefore, still subject to natural variability about the trend in decline.

AndrewB

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... Arctic sea-ice extent now is comparable to last year.
...

You mean that we have had three years in a row of record low maximum winter extent, with 2017 being the lowest on record after 2016?

And that in 2017 we find ourselves with much thinner, much more "rotten" ice than in 2016?

So no, even though Arctic sea ice data shows, as of April 21st, record low extent for this time of the year, this does not give us the whole picture here. PIOMAS is a much better indicator of the poor condition of the ice and how much the warm 2016/2017 winter prevented significant thickening and volume buildup.

As I wrote before, September 2017 will probably continue and confirm the exponential trend in ice volume loss and establish a new record minimum (both volume and extent). That "natural variability" would save the Arctic sea ice from its demise in the coming few years is pure wishful thinking (or denialism).