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When will the arctic go below 1 million square kilometers on one day in a single summer?

2025-2035
34 (33.3%)
2030-2040
27 (26.5%)
2035-2045
13 (12.7%)
2040-2050
7 (6.9%)
2045-2055
2 (2%)
2050-2060
2 (2%)
2055-2065
1 (1%)
2060-2070
1 (1%)
2065-2075
0 (0%)
2070-2080
0 (0%)
2075-2085
0 (0%)
2080-2090
2 (2%)
2085-2095
0 (0%)
2090-2100
0 (0%)
2095-2105
0 (0%)
2100+
10 (9.8%)
2024-2034
3 (2.9%)

Total Members Voted: 102

Voting closed: January 22, 2024, 12:43:47 AM

Author Topic: When will the Arctic go ice free? 2023  (Read 24540 times)

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When will the Arctic go ice free? 2023
« on: October 15, 2023, 01:43:47 AM »
The last poll for this was five years old.
« Last Edit: October 17, 2023, 05:48:25 PM by oren »

HapHazard

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Re: When will the artic go ice free? 2023
« Reply #1 on: October 15, 2023, 03:40:01 AM »
'35-'45 imo

sooner if another 2012 outlier year
If I call you out but go no further, the reason is Brandolini's law.

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Re: When will the artic go ice free? 2023
« Reply #2 on: October 15, 2023, 07:15:46 AM »
'35-'45 imo

sooner if another 2012 outlier year
Maybe check your vote that is what I voted and I see only 1.

oren

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Re: When will the artic go ice free? 2023
« Reply #3 on: October 15, 2023, 07:42:08 AM »
Thanks for opening this, interstitial. Sorry for not responding to your request of putting the various polls/threads in order.
I prefer that long term discussions continue in the original "when will the Arctic go ice free" thread. Discussions relevant to the current voting belong here.

oren

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Re: When will the artic go ice free? 2023
« Reply #4 on: October 15, 2023, 07:44:49 AM »
I voted 2030-2040. I think with AGW marching on and with high weather volatility, the Arctic could go ice free in any year, but my chosen bin has the highest cumulative probability.

Richard Rathbone

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Re: When will the artic go ice free? 2023
« Reply #5 on: October 15, 2023, 08:17:33 AM »
Essentially no chance before 2040, I think there's a decent chance 2012 still holds the record then. Maybe sometime 2060-80 if cutting emissions is too slow, but I think it will happen fast enough for the ice to stay over 1m all century.

Stephan

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Re: When will the artic go ice free? 2023
« Reply #6 on: October 15, 2023, 01:16:25 PM »
I also voted for 2030-2040, relying on my regular analysis which says that September ice volume will go to 0 first in the 2030s either with a linear or a logarithmic extrapolation of the data.
It is too late just to be concerned about Climate Change

Paul

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Re: When will the artic go ice free? 2023
« Reply #7 on: October 15, 2023, 03:12:06 PM »
Going for much longer than the other predictions in here. Mainly because the basin melt season is just not long enough to support a BOE anytime soon given the current ice thicknesses.

It takes a large part of the summer to melt out the largely first year ice that is close to the landmasses to begin with nevermind attacking the ice in the CAB. Plus 2020 was the warmest on record but did not break the record low in September because the Beaufort was more average that year(all the warmth was on the Siberian side)  so whilst t you can have a warm summer overall, there be parts of the basin which won't receive such warmth(as weather always tries to balance the airmasses). Also the ice from the pole towards the CAA tends to have thicker ice so if it takes alot of energy and warmth just to the melt out the first year ice, then how is that ice going to melt away in late summer?

I think it will happen but my theory always has been the variability will increase as we gradually goes downwards, it only takes one 'cool' summer to slow the progress down again.

kassy

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Re: When will the artic go ice free? 2023
« Reply #8 on: October 15, 2023, 06:15:22 PM »
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

The Walrus

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Re: When will the artic go ice free? 2023
« Reply #9 on: October 15, 2023, 07:39:35 PM »
https://forum.arctic-sea-ice.net/index.php/topic,3717.0.html

This was last years poll.

Thus far, the voters are choosing later dates than last year, although less than half the number of voters have cast their preferences.  Nobody chose sooner than 2025 this time around, compared to 7.3% last year.  The next two lowest bind are also trending lower.  Difficult to get an exact comparison as this year there are overlapping bins.  Later years are running slightly higher, but could be the result of fewer voters.  It will interesting to see that transpires when more voters respond.

gerontocrat

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Re: When will the artic go ice free? 2023
« Reply #10 on: October 15, 2023, 08:05:52 PM »
I still reckon the slow transition thing will get busted sometime in the next few years - not in this El Nino but the one after or the 2nd after this one - say 2029 or 2035. Later than my last poll vote (la Nina slowed things down?)

What can happen in the Antarctic can happen in the Arctic.
« Last Edit: October 16, 2023, 12:48:51 AM by gerontocrat »
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Re: When will the artic go ice free? 2023
« Reply #11 on: October 15, 2023, 09:00:14 PM »
There's just not enough examples of drastic ice losses to do reliable statistics on this one, yes. And as it looks like El Ninos may have an effect on either mostly in southern or in northern hemisphere wrt to high temperatures on ocean and on land and the effect may manifest itself more than half a year afterwards, there's absolutely no possibility to prove slow transition wrong until it is wrong. Then remembered reading once of a ten year warm spell on some sediment data somewhere in the world and that sort of thing tends to change things quite quickly.

John_the_Younger

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Re: When will the artic go ice free? 2023
« Reply #12 on: October 15, 2023, 09:05:35 PM »
With the 2025-35 bin the most popular (as of this post), I wonder if anybody would have chosen 2024 if it was a possibility...  8)

After all, I'm still rooting for 2019.  :P  :-\   ::)

oren

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Re: When will the artic go ice free? 2023
« Reply #13 on: October 15, 2023, 09:47:34 PM »
I didn't notice the first bin was the same length as the others. I will move my vote to it.
2024 is a good point though. It would be kinda funny if all voters here turn out wrong.

icy voyeur2

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Re: When will the artic go ice free? 2023
« Reply #14 on: October 15, 2023, 11:47:45 PM »
I'm 25-35  :'( after watching how mobile the ice has become. I'd love to be wrong.

I fear a year like parts of this last year with a number of week long gales driving ice out the Fram. What we want to cheer for is the winds blowing ice up against Greenland and CAA, piling it into tall drifts with fresh ice forming off Russia, and wind blowing into CAB from the Atlantic side. Maybe that could restore a more coherent pack.
$0.02

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Re: When will the artic go ice free? 2023
« Reply #15 on: October 16, 2023, 06:53:56 AM »
I did not consider 2024 very likely and it kept all the bins the same size. If people want me to change it let me know. I went with a decade per bin because with weather I think that is about the best resolution one can hope to guess.

kiwichick16

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Re: When will the artic go ice free? 2023
« Reply #16 on: October 16, 2023, 07:56:28 AM »
2024 - 2029

The Walrus

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Re: When will the artic go ice free? 2023
« Reply #17 on: October 16, 2023, 09:27:21 PM »
'35-'45 imo

sooner if another 2012 outlier year

The Arctic sea ice extent in 2012 was 27% below the trend line.  The largest deviation from the trend in the 44-year NSIDC history (2007 was the only other year which was greater than 20% below the trend).  Another 2012-like year would reduce the Septmeber minimum extent to about three million km2.  It would take three more such years just to get close to one million. 

It will take more than that for the Arctic to go ice-free.

oren

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Re: When will the artic go ice free? 2023
« Reply #18 on: October 16, 2023, 11:42:45 PM »
You are not here to shoot down other voters, but to state your own vote.

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Re: When will the artic go ice free? 2023
« Reply #19 on: October 17, 2023, 12:44:53 AM »
If a BOE occurs in 2035 over 80% of the voters will be right.

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Re: When will the artic go ice free? 2023
« Reply #20 on: October 17, 2023, 02:17:24 AM »
2035-2045 from me

I suppose "ice free" means "below 1 million km² for at least a single day in a single summer"; not the official definition, where we have to get this for five years in a row, or something crazy like no ice all year long.

I have recently said how much Fram export has worried me this past season. I can see how that (together with other stuff, of course) may get us to below 3 million km² regularly, maybe even close to 2 million. Something else has to happen to get much lower than that.
Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level.

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Re: When will the artic go ice free? 2023
« Reply #21 on: October 17, 2023, 02:47:28 AM »
I added below 1 million square kilometers to make that clear.
I personally consider that 1 day in a single season. I think most others do as well because that adds a minimum of 5 years making the earliest mathematically possible date 2029. I am not sure why the official line became 5 years. To me it seems like a stalling tactic like saying preindustrial includes 1949. But I am not an expert so I will just say that for my poll that is not what I mean. I updated the poll question to reflect that.

The Walrus

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Re: When will the artic go ice free? 2023
« Reply #22 on: October 17, 2023, 03:10:39 AM »
I think people would agree that we are talking about the first instance of the sea ice extent falling below one million km2.

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Re: When will the artic go ice free? 2023
« Reply #23 on: October 17, 2023, 05:48:00 AM »
Here’s what the IPCC stated in the Special Report on the Ocean and Cryosphere in a Changing Climate in 2019:

Quote
It is very likely that projected Arctic warming will result in continued loss of sea ice and snow on land, and reductions in the mass of glaciers. Important differences in the trajectories of loss emerge from 2050 onwards, depending on mitigation measures taken (high confidence). For stabilised global warming of 1.5°C, an approximately 1% chance of a given September being sea ice free at the end of century is projected; for stabilised warming at a 2°C increase, this rises to 10–35% (high confidence). The potential for reduced (further 5–10%) but stabilised Arctic autumn and spring snow extent by mid-century for Representative Concentration Pathway (RCP)2.6 contrasts with continued loss under RCP8.5 (a further 15–25% reduction to end of century) (high confidence). Projected mass reductions for polar glaciers between 2015 and 2100 range from 16 ± 7% for RCP2.6 to 33 ± 11% for RCP8.5 (medium confidence). {3.2.2; 3.3.2; 3.4.2, Cross-Chapter Box 6 in Chapter 2}

This was updated in the AR6 Working Group 1 (Physical Sciences) report in 2021:

Quote
B.2.5 Additional warming is projected to further amplify permafrost thawing and loss of seasonal snow cover, of land ice and of Arctic sea ice (high confidence). The Arctic is likely to be practically sea ice-free in September at least once before 2050 under the five illustrative scenarios considered in this report, with more frequent occurrences for higher warming levels. There is low confidence in the projected decrease of Antarctic sea ice.

I voted for 2030 to 2040.

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Re: When will the artic go ice free? 2023
« Reply #24 on: October 17, 2023, 07:35:17 AM »
I was reading the statement of given 1.5 degree warming the chance of ice free by end of the century is 1% and thought no way. Then I thought limiting warming to 2 degrees is unrealistic now. I kept reading and ice free at least by 2050 is in agreement with my expectations. My guesses for sea ice have not been great so there is that.

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Re: When will the artic go ice free? 2023
« Reply #25 on: October 17, 2023, 07:39:34 AM »
I increased the 2024 range to see if that makes a difference.

FredBear

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Re: When will the artic go ice free? 2023
« Reply #26 on: October 17, 2023, 09:19:40 AM »
I voted "anytime soon" as everyone needs to be ready for a warning sign!(?)

The Passenger Pigeon was the most numerous bird on earth - until it didn't exist.
A tropical island had massive palm trees until the new inhabitants became impoverished -
Easter Island (apparently used as a sheep farm by foreign investors since its discovery!).

We have many warnings from the past - what earth will we leave for our heirs (think Amazon Jungle)?

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Re: When will the artic go ice free? 2023
« Reply #27 on: October 17, 2023, 11:18:17 AM »
I missed a C in the title but I can not edit it now.

Burnrate

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Re: When will the artic go ice free? 2023
« Reply #28 on: October 17, 2023, 03:24:07 PM »
I would say, specifically, 2032.

kassy

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Re: When will the artic go ice free? 2023
« Reply #29 on: October 17, 2023, 04:28:27 PM »
Thus far, the voters are choosing later dates than last year

Time for an update.  ;)
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oren

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Re: When will the artic go ice free? 2023
« Reply #30 on: October 17, 2023, 05:48:53 PM »
I missed a C in the title but I can not edit it now.
Fixed.

The Walrus

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Re: When will the artic go ice free? 2023
« Reply #31 on: October 17, 2023, 09:01:01 PM »
Thus far, the voters are choosing later dates than last year

Time for an update.  ;)

With 51 voters, almost on par with the previous poll now.  Overallapping bins make exact comparisons a little tenuous, but arbitrarily throwing half into each bin yields the following:

                   Previous     New Poll
<2025             49%            -
2026-2040       41%          78%
2041-2060        3%           16%
2061-2080        0%            2%
2081-2100        2%            0%
2100+              5%            4%

The biggest change is the number of voters opting for after 2040 compared to before (22% compared to 10%).   

Pavel

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Re: When will the Arctic go ice free? 2023
« Reply #32 on: October 18, 2023, 06:42:42 AM »
2100+
 I don't think it's really possible to melt out the ice North of 80

gerontocrat

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Re: When will the Arctic go ice free? 2023
« Reply #33 on: October 18, 2023, 12:21:08 PM »
2100+
 I don't think it's really possible to melt out the ice North of 80
In late February 2018, i.e. mid-Winter, extrordinary warmth from Southerly winds created a large area of open water North of Greenland. If that had happened in late Spring or early Summer....?

https://forum.arctic-sea-ice.net/index.php/topic,2141.msg143541.html#msg143541
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Glen Koehler

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Re: When will the Arctic go ice free? 2023
« Reply #34 on: October 19, 2023, 02:34:06 PM »
     I voted for 2030-2040 based on some simplified calculations, but I think they are accurate enough to make a reasonable guess.  Global average surface temperature anomaly as of 2022 is at +1.3C over the preindustrial proxy (1850-1900).  The decadal rate of increase starting around 1970 was about 0.18C -- until recently.  James Hansen says we should expect the next couple of decades to increase that rate to 0.27 to 0.36C per decade.  (2023 is already way above that trend, but it is just one year).
   
    Notz and Stroeve 2018 calculated that at a temperature anomaly of +1.68 C, the ASI will be in equilibrium with <1M km2 Extent in Septembers.

     So with 0.38 C more warming the planet will be at the temperature where (long term) we would expect ~1M km2 September ASI Extent in most years.  At the decadal rate proposed by Hansen that will only take about 11-14 years starting from 2022, thus the 1.68C anomaly would be reached by 2033 - 2036. 

     It does not seem likely that the 1M km2 equilibrium response would occur the first year that the anomaly reaches +1.68 C.  And research indicates that the "Slow Transition" negative feedback probably still has a few years left before winter warming overwhelms increased heat loss from increased open water heading into winter, but it could start to gradually weaken by 2030.

     And positive feedbacks are on the increase -- including more rain, storm activity, wave activity to break up pack ice and bring up subsurface heat, ice fracturing for more mobility and export, and thinner ice that melts faster.  Those positive feedback influences are still small relative to the melt resistance of the current ASI Volume, Area, Extent, and Thickness.  But as they increase they will become increasingly synergistic.  For example, thinning of the average ice thickness from 1.8 to 1.7M does not change the melt rate nearly as much as thinning from 0.8 to 0.7M.  Thinner ice breaks into smaller pieces with more surface area exposed to >0C seawater and air, and are more vulnerable to export. 

     Even if the endpoint estimate is for BOE to become possible/increasingly likely starting around 2035, the stall in the long-term downward trends that we have seen since 2012 may continue for a few more years.  We all remember when the climate change deniers made a big fuss about the 15-year-long global warming "hiatus" between 1998 to 2013.  Watch for increasing references to the "unchanging Arctic". 
    (Of course, as Carl Mears who manages the RSS satellite data said, "If you start riding a bike on the top of a hill you are guaranteed to go downhill for a while", which is why the deniers chose to start their interest in global temperature trend at 1998, the year of a very strong El Nino temperature bump.)

     It would not be surprising for the current ASI decline "hiatus" to last another 4 years to also reach 15+ years in 2027-2030.  But eventually, the increasingly warm winters preceding/following increasingly warm, rainy, wavy, stormy summers working against progressively thinner, more fractured, more mobile ice will kick into high gear.  Then we will all be surprised at how fast the previously slow pace of ASI evolution kicks into a high-speed transition that delivers the first BOE before 2040. 

    While we like to discuss when the "big change" will come, it is important to realize that a BIG change has already happened.   Look at the September ASI thickness map for 1985 vs. 2023.  There are many ecological and other ramifications of 4+ year old thicker vs. <1 year old thinner ice.  The old Arctic that Inuit elders and folks like Peter Wadhams banged around in during their younger days already only exists in memory, and for the rest of us in data.  It's hard enough to fathom such a fundamental change in data, but it must be heartbreaking for those with a more intimate physical experience of the now-deceased "old" Arctic. 

Image from https://forum.arctic-sea-ice.net/index.php/topic,2348.msg384557.html#msg384557


     It is happening so fast that one does not have to be an elder to see the Arctic world shifting.  The late David Barber (1960-2022) noted that the Arctic he studied in grad school (late 1980s-early 90s) was no longer there.  My son worked in interior Alaska a few years ago.  Young Yupik villagers could point out changes in vegetation, wildlife, and in the reliability of the frozen Yukon River as the road to the coast, that had evolved in just the previous 10 years.  When the river begins to thaw that ice road becomes hazardous, which had already cost some village inhabitants their lives.
« Last Edit: October 20, 2023, 08:18:36 PM by Glen Koehler »
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Paul

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Re: When will the Arctic go ice free? 2023
« Reply #35 on: October 19, 2023, 04:09:50 PM »
2100+
 I don't think it's really possible to melt out the ice North of 80
In late February 2018, i.e. mid-Winter, extrordinary warmth from Southerly winds created a large area of open water North of Greenland. If that had happened in late Spring or early Summer....?

https://forum.arctic-sea-ice.net/inde
x.php/topic,2141.msg143541.html#msg143541

That was all down to the winds and you won't get such a strong jet stream in summer to create such strong winds to move the ice like that. Probably what happened in the summer of that year could be more comparable but in that area, the sea currents will always try and push the ice towards Greenland in anycase hence the predictions that would be the last area for any ice to survive.

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Re: When will the Arctic go ice free? 2023
« Reply #36 on: October 19, 2023, 05:38:06 PM »
That post by gero was accompanied with the paper that stated:

"By quantifying these three terms for each of the past 42 years, we find that multiyear ice loss primarily occurred through two stepwise reductions, with the budget otherwise generally being in balance.  The first loss occurred in 1989 due to anomalously high export, while the second loss occurred between 2006 and 2008 through a confluence of anomalously high export and melt and low replenishment."

The trend since the last step is a mere 14,000 km2 per year.  At that rate, the multi-year ice will not decrease below one millino until 2064.  It will take another step-wise reduction to reduce the multi-year ice significantly.  The last two occurred 18 years apart.  Perhaps we are due in 2025.  That would knock the multi-year ice down to about half a million km2.  That could set the stage for a summer BOE.

kiwichick16

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Re: When will the Arctic go ice free? 2023
« Reply #37 on: October 19, 2023, 09:36:42 PM »
@  the walrus .....not sure the ice knows about due dates  ......but apart from the ongoing, in my opinion impressive , rollout of renewable energy , and improvements in energy efficiency, i'm struggling to think of other factors which are helping to maintain ice coverage

kiwichick16

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Re: When will the Arctic go ice free? 2023
« Reply #38 on: October 19, 2023, 09:39:25 PM »
i forgot electric cars

oren

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Re: When will the Arctic go ice free? 2023
« Reply #39 on: October 19, 2023, 10:31:07 PM »
We are sliding off topic. Renewables and electric cars don't belong here. And folks should preferably state their own vote (Walrus), and avoid criticizing other votes (all).

HapHazard

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Re: When will the Arctic go ice free? 2023
« Reply #40 on: October 19, 2023, 10:50:06 PM »
Title should've been more like "POLL: When will the Arctic experience its first BOE? (2023 edition)"
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Re: When will the Arctic go ice free? 2023
« Reply #41 on: October 19, 2023, 11:21:34 PM »
Title should've been more like "POLL: When will the Arctic experience its first BOE? (2023 edition)"

It originally was, until the title was changed (to be more specific). See the discussion above.
Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level.

HapHazard

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Re: When will the Arctic go ice free? 2023
« Reply #42 on: October 20, 2023, 12:55:53 AM »
It wasn't really, I read the discussion, but whatever it doesn't matter.
If I call you out but go no further, the reason is Brandolini's law.

interstitial

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Re: When will the Arctic go ice free? 2023
« Reply #43 on: October 20, 2023, 02:06:25 AM »
It wasn't really, I read the discussion, but whatever it doesn't matter.
The question was more specific but not the title.

Chuck

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Re: When will the Arctic go ice free? 2023
« Reply #44 on: October 20, 2023, 02:43:33 AM »
Is predicting when sea ice will go below 1 million square kilometers anything more than guesswork?

Richard Rathbone

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Re: When will the Arctic go ice free? 2023
« Reply #45 on: October 20, 2023, 04:23:53 AM »
Is predicting when sea ice will go below 1 million square kilometers anything more than guesswork?

The link between CO2 and long term average (e.g. 60 month running mean) is pretty strong.

However there's an awful lot of poorly understood variability between that trend and what happens on any given day. Plus what happens to CO2 in future decades will be a consequence of political choices yet to be made.

However, people can take a view on variability, can take a view on politics and can do calculations to come up with the consequence for BOE. And if the facts change, they can change their views and redo their calculations. Educated guesswork.

Cherrypicking also happens. Variability is huge, so anything could happen on any given day, and that day will be tomorrow (Or December 25th 2307).

My view on variability is that a long period portion of it switched from a phase where it was driving summer ice further below the long term trend to one where it is pulling it back a decade ago, and its got another couple of decades or so to go before it switches again and yet more decades after that to return to the phase it was in around 2007-2012. https://www.nature.com/articles/s41561-018-0256-8
I think thats plenty of time for the economics of solar and wind to drive fossil fuels out of business despite the political friends they have at the moment and I expect the CO2 trend to bend before summer ice gets within range of 1m in a freak melt year. I'd put a freak melt year at about 3m for the 2020s with below 3m becoming a bit less freakish in the 2030s and the lower bound not shifting much until the 2040s  even under BAU for CO2.

Juan C. García

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Re: When will the Arctic go ice free? 2023
« Reply #46 on: October 20, 2023, 07:03:56 AM »
I made a similar poll on July 2013. The poll answers say it all. What surprise me is not that we haven't had an ice free Arctic. It surprise me that in 11 years, the 2012 record has not being broken.

I think it is time to discuss about posible negative feedbaks:
- Does the melt of Greenland ice slows the ASI melt?
- What about the Polar Vortex?
- Other negative feedbacks on the ASI melting?

My bet (now on this poll) is 2040-2050.

https://forum.arctic-sea-ice.net/index.php/topic,414.0.html
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.

The Walrus

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Re: When will the Arctic go ice free? 2023
« Reply #47 on: October 20, 2023, 04:29:15 PM »
That previous poll had several options up to 2030, with just one afterwards.  Consequently, 97% of respondents chose one of the earlier bins, and a mere 3% opted for after 2030. 

Because that poll occurred immediately after the 2012 melting season, the potential for a rapid demise of the sea ice was fresh on everyone's brain.  That probably had a large influence on the mindset of the respondents.  The following graph shows the trend (17 years) for the period of greatest decline crossing 1M km2 at 2030 (red line).  From the poll, it appears that several thought the decline would accelerate prior to then.

Since that large decline, the ice has taken a different path.  The minimum extent has followed the much slower slope (17 years) as shown with the blue line.  Many analysts are calling this the step-wise decline. 

The black line shows the minimum sea trend prior to the step-wise decline.  To paraphrase gerontocrat, my theory that is my own, is that the black line is the sea ice response to warming, and that the red line was an aberration due to local influences.  The blue line is just a correction of that aberration.  My theory is that the ice will continue on the blue line (more or less) until it reaches the black, and will then resume the original downward trend. 

That is why I chose the latest bin for an ice-free Arctic.  I am sure that this will be controversial for several posters, but unless some drastic change occurs in the Arctic (another large influence creating another step-wise decline), I do not see a rapid decline in ice extent anytime soon.

kiwichick16

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Re: When will the Arctic go ice free? 2023
« Reply #48 on: October 20, 2023, 07:14:22 PM »
Couple of years old  ......but covers a lot of factors working against sea ice retention

https://www.carbonbrief.org/state-of-the-climate-how-the-world-warmed-in-2019/

this year, and next year are looking significantly worse

epiphyte

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Re: When will the Arctic go ice free? 2023
« Reply #49 on: October 20, 2023, 11:58:06 PM »
I'm one of the outliers who voted for 2100+, but not because I think the ongoing annual ice decline, or the underlying global warming trend, is not an imminent, existential problem.

In the past I (and I know many others) somehow assumed that a BOE might serve as a warning of dire global consequences to follow. Now I fear that regardless of the overall trend, statistics alone may delay the occurrence of a BOE until long past the time when it must be regarded as a trailing consequence of global changes which will have already taken place.   

Whilst the few who may recall my 2013-2016-era posts on the subject (viz: 'poof') may see this as a complete about-face in contrast to my earlier opinion, I do not see it as such. It's just that now that the multi-year ice is essentially gone, we seem to be in a metastable pattern which will leave at least some un-melted ice, somewhere in the arctic, at the end of every season, for quite a while past the point where most of it melts out, almost every summer.

Over the years of lurking since I last posted, I've noticed much to recommend, and little to discredit, these two rules of thumb:

   - in mid-late winter, where there is no ice, there will very quickly be ice.
   - in summer, where there is no ice, there is no melting, and the more ice there is in any particular place, the slower it melts.

I know it's a lot more complicated than this, but I can't help reducing it to a mangled PT Barnham analogy; in winter, freezing some of the ocean, some of time is enough to end up with a frozen ocean. but in summer, warming some of the ocean, all of the time, will always leave a few chunks somewhere unless you're stirring pretty vigorously.

...and one might speculate that to stir things up that much, so far from the equator, something pretty ugly will likely already be happening at lower latitudes.