When will Arctic Extent dip below 1,000,000 Km^2 (2022 poll)

[crandles]

Metric is JAXA extent
currently at https://ads.nipr.ac.jp/vishop.ver1/data/graph/plot_extent_n_v2.csv
but this may need to change if this data becomes unavailable.

Reasoning in comments is encouraged.
Different ranges in comments also acceptable.



The last poll was 4 years ago
https://forum.arctic-sea-ice.net/index.php/topic,2348.0.html

So seemed time for a new one

1 vote per user
poll runs 20 days
Can change vote (within 20 day poll period I assume)
Result visible after voting

Any changes that should be made to poll?

[Paul]

No idea if you want any analysis on why I voted for what I did(2051-2070) but I'll give some reasons.

To reach under 1 million, the ice has to melt where it has never melted before, this is over the CAB and towards the CAA, I think the deep waters over that part of the basin and the fact that area still retains multi year ice means it will take something exceptional to melt this part of the basin. 2020 was the warmest summer on record and yet it did not break the September records.

The melt season is also quite short reletively speaking in that part of the world so any late cold or even average weather is going to create a negative feedback to get the ice to retreat that much.

Winter extent/volume also has to reduce quite a fair bit also imo. An ice free Bering/Bering straight/Kara/Barants would be a good test for the ice but to still go under 1 million will be a huge ask but if the world keeps on warming then it will happen one year but not as quick as some on here may think.

[trm1958]

I voted 31-35. I interpret the question as being the first time it dips below 1Msk. This will probably occur as a result of some oddball circumstances, like 2012 did, with each year needing circumstances a little less odd than the one before. Eventually, it will get easy enough that the first BOE happens, maybe (my guess) in ten or twelve years. But there will still be some nonBOEs for awhile, it won't be till, say the 2040s that all years are ice-free.

[Jim Hunt]

Other - It depends on the weather 

You may also wish to specify precisely which "extent" metric to watch, given the possibility of a close run thing?

[crandles]

Other - It depends on the weather 

You may also wish to specify precisely which "extent" metric to watch, given the possibility of a close run thing?

Weather or different date ranges - post your own range in comments with or without your reasons.

Is NSIDC ok?
Hmm I have forgotten how to get into
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/

[oren]

I take the vote's meaning to be JAXA extent. And I'd be surprised if it doesn't happen for the first time by 2030. One of these years the factors will align.
BTW the easiest way to melt the CAB ice is in the Greenland Sea, following some strong export dipole coupled with a WAA.

[Stephan]

I went for the 2031-2035 bin. It seems the most likely for me. Until then there will be more greenhose gases in the atmosphere and thus the temperature on our planet will get very close to 1.5°C above preindustrial. And the Arctic amplification will also increase and be even more relevant than today.

[Richard Rathbone]

I don't expect the current record to be broken inside the first two bins, let alone 1M.

There's a window of opportunity in the 2040s, if GHGs stick at BAU for long enough, but I think renewables have got too cheap and its not going to happen.

[Michael Hauber]

After 2100 is my vote, on the basis of long term average moving below 1 million.  I believe we are on a reasonable path to mitigate climate change impacts and that long term decline in Arctic ice has significantly slowed after the dramatic losses between about 2000 and 2012.

For the first year 2050-2070.  No noticeable reduction is evident since 2012 (not meaning the trend has gone but rather that it is slow enough that it cannot be detected above noise in a 10 year period).  Between now and 2070 is 50 years and that's a lot of dice rolls to get one very unusual year which will push minimum under 1 million.  And by 2050 the average ice conditions should be obviously lower than the 2010s.  And then likely a decade or more before the next repeat and then gradually becoming more frequent after that.

[Aluminium]

Any changes that should be made to poll?

I would like to see 2022 as a separate option.

[Paul]

You honestly think there is a chance of a BOE this year!?

[Jim Hunt]

Is NSIDC ok?

Does the strikethrough indicate that you've already solved the problem?

You need a username & password to access most NSIDC data these days, and browsers don't support FTP any more:

https://forum.arctic-sea-ice.net/index.php/topic,143.msg308617.html#msg308617

[Aluminium]

You honestly think there is a chance of a BOE this year!?

I voted 2041-2050. However, there is always a chance. And 2022 looks very different compared to what can be expected in 2023-2025.

[icy voyeur2]

Other - It depends on the weather 

You may also wish to specify precisely which "extent" metric to watch, given the possibility of a close run thing?

My gut said 2025 but I voted 26-30. This is based on speculation for an a-typical, especially bad year. A bad year will follow a winter with anomalously high Fram export that will continue over the summer.

So a high Canadian heat wave in June. An early crack over Greenland, and an early July that exports rubble. Yup, it's down to especially bad weather but, in a wholly irrational way, I think we're due for an evil weather year.

[SimonF92]

After 2100 is my vote, on the basis of long term average moving below 1 million.  I believe we are on a reasonable path to mitigate climate change impacts and that long term decline in Arctic ice has significantly slowed after the dramatic losses between about 2000 and 2012.

For the first year 2050-2070.  No noticeable reduction is evident since 2012 (not meaning the trend has gone but rather that it is slow enough that it cannot be detected above noise in a 10 year period).  Between now and 2070 is 50 years and that's a lot of dice rolls to get one very unusual year which will push minimum under 1 million.  And by 2050 the average ice conditions should be obviously lower than the 2010s.  And then likely a decade or more before the next repeat and then gradually becoming more frequent after that.

You may be right, but keep in mind that variables keeping the system in check at the moment may not extend past the near future.

Personally, I went 2036-2040, because fundamentally it was the middle choice (by category) and I feel getting this prediction correct boils down to guessing. All of these advanced models were already shown to be wrong by >1SD anyway.

[crandles]

Is NSIDC ok?

Does the strikethrough indicate that you've already solved the problem?

You need a username & password to access most NSIDC data these days, and browsers don't support FTP any more:

https://forum.arctic-sea-ice.net/index.php/topic,143.msg308617.html#msg308617

Strikethrough indicates I solved the problem by opting for JAXA extent as Oren suggested and have edited this into first post.

Thanks for the reply

[gerontocrat]

  from Jim Hunt
You need a username & password to access most NSIDC data these days, and browsers don't support FTP any more:

I access NSIDC data files by going to https://nsidc.org/arcticseaicenews/sea-ice-tools/

Then I scroll down until I see the list of available files...

1. All daily (single day and five-day trailing average) extent values in one file, updated daily (Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx)
2, Monthly sea ice average extent and area, and rankings (Sea_Ice_Index_Monthly_Data_with_Statistics_G02135_v3.0.xlsx)
3. Sea ice extent and area organized by year (Sea_Ice_Index_Monthly_Data_by_Year_G02135_v3.0.xlsx)
4. Minimum and maximum extent values and dates for each month and year, with rankings (Sea_Ice_Index_Min_Max_Rankings_G02135_v3.0.xlsx)
5. Sea ice extent rates of change (Sea_Ice_Index_Rates_of_Change_G02135_v3.0.xlsx)
6. Daily sea ice extent, by region (N_Sea_Ice_Index_Regional_Daily_Data_G02135_v3.0.xlsx and S_Sea_Ice_Index_Regional_Daily_Data_G02135_v3.0.xlsx)
7. Monthly sea ice extent, by region (N_Sea_Ice_Index_Regional_Monthly_Data_G02135_v3.0.xlsx and S_Sea_Ice_Index_Regional_Monthly_Data_G02135_v3.0.xlsx)
8. Daily sea ice extent 1981-2010 climatology (N_seaice_extent_climatology_1981-2010_v3.0.csv and S_seaice_extent_climatology_1981-2010_v3.0.csv)

Click on the one(s) you want and they automatically download as Excel files.

This avoids any problems with ftp, and passwords etc are not required.

ps: To add the the condfusion I believe at one time a BOE was defined as the September average sea ice extent being below 1 million km2; (or was it every day in September below 1 million km2?).
This is a much stiffer target to meet than just one day below 1 million km2.

[crandles]

I access NSIDC data files by going to https://nsidc.org/arcticseaicenews/sea-ice-tools/

Thank you.

Perhaps the Actic sea ice graphs page should link to that rather than

"NSIDC sea ice extent daily data" linking to ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/

This is a much stiffer target to meet than just one day below 1 million km2.

That is true, but I wanted to stick with the same question as last time and as this question says dips below and doesn't mention BOE it seems that one day will suffice if it is correctly measured not some glitch in the system for calculating the the extent.

I also don't think it is worth adding a 2022 only poll option which was suggested earlier.

[Tor Bejnar]

I'm guessing a monster El Nino or the year following one could produce the next record low ice autumn. Maybe the monster El Nino following the next will reduce ice extent to a mere million (km²). So ... 8 years from now?

[The Walrus]

I'm guessing a monster El Nino or the year following one could produce the next record low ice autumn. Maybe the monster El Nino following the next will reduce ice extent to a mere million (km²). So ... 8 years from now?

Historically, the biggest drop in extent minimu was from 2006 to 2007, which amount to 1.62 M km2.  However, that was largely due to 2006 being above the trendline.  The 2011 extent was well below the trendline, so the one-year drop was slightly less than 1 M km2.  Had 2011 fallen exactly on the long term trend line, the one-year drop would have been 1.64 M km2, which would be the largest deviation from the [linear] trend.  Projecting the trend forward. and using 1.64 M has the largest negative deviation from the trend, 2042 is the first year that could potentially drop below 1 M km2.  Any year prior would require an unprecedented decrease in minimum extent.

[Steven]

My guess is 2041-2050.

We have been nowhere near a Blue Ocean Event yet.  2012 was more than 2 million km2 above the BOE threshold and the other years more than 2.5 million km2.

I would ignore volume extrapolations and rather use a simple extent or area extrapolation to get a rough estimate for the date of BOE.  There are some indications that the rate of loss has been slowing down in recent years, but that may just be natural variability.

Summer weather patterns in the late 2000s and early 2010s were conductive to strong melting, whereas weather conditions since 2013 have generally been more favorable for ice retention.  Big question is if that is just natural variability, or if there is a negative feedback at play that is causing lower air pressure, more clouds and less WAA in the peak insolation months.

[FishOutofWater]

The Temperature and Heat flux from the north Atlantic into the Arctic across the Iceland/Scotland ridges and channels declined after 2014. This is a major factor in the stabilization of sea ice extent and thickness over the past decade.

The extraordinary warming and salinity-increase during 1995–2004 have been studied extensively both in the AI and the SPNA (Bersch et al., 2002; Hatun et al., 2005; Häkkinen et al., 2011). They highlight the dynamics of the SPG in controlling the composition and strength of the AI through shifts in the subpolar front and advective pathways toward the Iceland-Scotland Ridge. Specifically, a weakening and westward contraction of the SPG, opening the gateway for throughput of warm water from the STG. Hatun et al. (2005) for example, showed that the salinity-increase of the AI on the Iceland-Scotland Ridge and thus the warming captured later in the Svinøy section, coincided with a decline of the SPG circulation with a 1-year time lag, using an altimetry-based gyre index (Häkkinen & Rhines, 2004). However, the gyre index continued to decline until 2015, despite a cooling of the eastern SPNA from 2005. Considering that, Foukal and Lozier (2017), (2018) found that the properties of the eastern SPNA do not covary with the SPG size and suggested that the SPG dynamics do not control the strength of the inter-gyre throughput.

The most intriguing development of the AI-temperature is the cooling from an absolute maximum in 2014 to a subsequent minimum in 2018 (Figure 3b). This cooling starts 3–4 years after the extraordinarily freshening event in the Newfoundland Basin during 2012–2016, explained as an outbreak of Arctic water from the Labrador Current into the Newfoundland Basin (Holliday et al., 2020). The anomaly joined the NAC and propagated eastward and subsequently northward being identified as a salinity/temperature anomaly in the Iceland Basin during 2014–2018 (Reverdin et al., 2018), before entering the Nordic Seas. However, this interpretation has been questioned by Kenigson and Timmermans (2021), arguing that also this freshening can be explained by the SPG dynamics. The conflicting views of the mechanism behind the water-properties of the eastern SPNA and thus the AI, demonstrates that the complexity of the underlying mechanisms is not fully resolved.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2021GL096427

[gerontocrat]

I'm guessing a monster El Nino or the year following one could produce the next record low ice autumn. Maybe the monster El Nino following the next will reduce ice extent to a mere million (km²). So ... 8 years from now?

You've stolen my thoughts - or at least some of them..

I go for the El Nino after the next one because...

- going below one million km2 extent for one day is an easier target,

- I was listening to a climate scientist on BBC's Radio4. He pointed out that England having a new record max temperature of above 40 celsius was not expected for a good few years yet. (It was also not confined to one of the usual hotspots but spread over a largish area of England for a good few hours) He also mentioned the Canadian heatwave last year that was also way outside any reasonable expectations. He said that these have caused alarm amongst many climate scientists, some of whom are now wondering if the climate models that assume a broadly linear increase in AGW as greenhouse gas concentrations increase may be inadequate.

- a third year of Al Nina seems likely. One consequence of that seems to be to increase heat capture by the oceans, which maybe in an El Nino year could be matched by a large heat transfer from the oceans to the atmosphere.

- add to that the likelihood of CO2 emissions increasing for a few years yet plus increased methane from fossil fuel use (natural gas and coal mining) plus the increased methane emissions from other sources.

- And a speculation. This year I have been looking at Antarctic sea ice a lot. It seems to me that since around 2007 the variation between years of high sea ice and those of low sea ice are getting wider and wider, which suggests to me widening instability. (This year the sea ice 365 day average is falling like a stone). Everything is connected - they call it teleconnections? - perhaps that instability will be reflected in the Arctic sea ice.

So I say
- An El Nino in 2024,
- 5 to 7 years later another El Nino that administers the  coup de grâce - 2030

[Rodius]

I keep seeing people who think the process is linear.

Nature doesn't work like that.
It tends to look like nothing is happening and then, suddenly, a sudden collapse occurs and everyone is surprised.

It is like a landslide, an earthquake, a tsunami, hurricanes, heatwaves, viruses, and more.
It happens all the time.

And for at least a decade, the climate science community has kept looking at older projections saying the events are happening much faster than expected. It is almost cliche to hear them saying that.

Nature doesnt work linearly.
It tends to be exponential.
We just think it is linear because it looks like it for a short time... until it becomes obvious. Shouldnt we just assume it is exponential until it has been proven to be linear?

I put down 2022 to 2025.
I don't honestly think it will happen then (too much ice and from what I can tell the physics tells us that not enough heat is entering the Arctic to melt all of the ice for that to happen) but I also wouldn't be surprised if it did happen in that timeframe due to export or some other event I am not aware of (which means that are many things that can happen that can do the job)

If I was to put money on it, I would go 2026 to 2030... mostly because an El Nino is getting close, and the ice is thinner than before already.

Someone said they ignore the volume, which makes no sense to me because that is probably the key metric but also the most inaccurate.
Looking at ice from above looks good regardless of whether it is 1cm thick or 400cm thick.

I can see a lot of area and extend data dropping like a brick well before many people think.

[Jim Hunt]

I access NSIDC data files by going to https://nsidc.org/arcticseaicenews/sea-ice-tools/

Thank you.

Perhaps the Arctic sea ice graphs page should link to that

That FTP link still works if you have an FTP client. However HTTPS is undoubtedly easier for most people.

I wonder if the ASIG management are watching?

[The Walrus]

My guess is 2041-2050.

We have been nowhere near a Blue Ocean Event yet.  2012 was more than 2 million km2 above the BOE threshold and the other years more than 2.5 million km2.

I would ignore volume extrapolations and rather use a simple extent or area extrapolation to get a rough estimate for the date of BOE.  There are some indications that the rate of loss has been slowing down in recent years, but that may just be natural variability.

Summer weather patterns in the late 2000s and early 2010s were conductive to strong melting, whereas weather conditions since 2013 have generally been more favorable for ice retention.  Big question is if that is just natural variability, or if there is a negative feedback at play that is causing lower air pressure, more clouds and less WAA in the peak insolation months.

It it was just a few years, then I might attribute it to natural variability.  However, after a decade, it ceases to be variability and becomes a new trend.  As you state, we are nowhere new a BOE right now.  It would take a major change, much more than a strong el nino, to break the barrier.

[crandles]

I'm guessing a monster El Nino or the year following one could produce the next record low ice autumn. Maybe the monster El Nino following the next will reduce ice extent to a mere million (km²). So ... 8 years from now?

You've stolen my thoughts - or at least some of them..

I go for the El Nino after the next one because...

Where are the strong el ninos before 2007 and 2012?
 


strong La Ninas maybe?

Umm No, that seems to come after 2007 minimum and about 18 months before 2012 minimum

Multivariate ENSO Index:

Code: [Select]

2004 .332 .37 -.036 .358 .558 .315 .571 .617 .558 .492 .794 .684
2005 .325 .816 1.057 .626 .885 .589 .519 .343 .296 -.179 -.385 -.55
2006 -.428 -.414 -.521 -.571 .045 .526 .716 .748 .8 .939 1.272 .965
2007 .985 .537 .125 .026 .348 -.155 -.248 -.442 -1.197 -1.217 -1.155 -1.178
2008 -1.006 -1.371 -1.552 -.858 -.345 .142 .088 -.269 -.58 -.699 -.588 -.646
2009 -.714 -.69 -.705 -.106 .326 .751 1.06 1.05 .707 .883 1.107 1.059
2010 1.066 1.526 1.462 .978 .658 -.228 -1.103 -1.671 -1.879 -1.892 -1.477 -1.558
2011 -1.719 -1.544 -1.554 -1.387 -.199 -.003 -.193 -.517 -.778 -.939 -.938 -.945
2012 -.98 -.675 -.382 .11 .757 .842 1.126 .607 .316 .069 .127 .111
2013 .103 -.068 -.026 .09 .205 -.094 -.314 -.481 -.155 .115 -.053 -.234
2014 -.27 -.259 .018 .295 1.001 1.046 .915 .937 .557 .421 .754 .566
2015 .417 .464 .614 .916 1.583 2.097 1.981 2.334 2.479 2.201 2.271 2.12
2016 2.216 2.17 1.963 2.094 1.752 1.053 .352 .167 -.118 -.385 -.209 -.11
2017 -.052 -.043 -.08 .744 1.445 1.039 .456 .009 -.478 -.568 -.285 -.576
2018 -.623 -.731 -.502 -.432 .465 .469 .076 .132 .509 .468 .698
Thought we had decided there seemed no significant correlation.

[oren]

Indeed crandles, I thought the same. But I think 2016 gave people some ammunition.
We'll see when the next one comes along.

[Simon]

I voted 31 - 35 based on a casual look at April sea ice volume and annual average ice volume loss. To me, this suggests that once the maximum sea ice volume dips below 19,000km2 then the Arctic will be under threat of sea ice collapse in early September. I think that although there exists the possibility of a large BOE this decade, I think it unlikely though early next decade, chances of a dip in 1,000,000km extent are better than 50 - 50.

[jdallen]

Haven't changed the estimate I've had for years.

[Steven]

Nature doesnt work linearly.
It tends to be exponential.
We just think it is linear because it looks like it for a short time... until it becomes obvious. Shouldnt we just assume it is exponential until it has been proven to be linear?

...

Someone said they ignore the volume, which makes no sense to me because that is probably the key metric but also the most inaccurate.
Looking at ice from above looks good regardless of whether it is 1cm thick or 400cm thick.

Exponential volume extrapolations were popular in the early days of this forum, but they have aged very poorly.  The Arctic should have been ice-free already by 2015 according to those projections.  Obviously that didn't happen.  Apart from Sam Carana, nobody seems to be using such exponential trendlines anymore.

Linear volume extrapolations are still being used on the forum.  But I suspect that in a few years it will be obvious that they suffer from the same problem as the exponential ones: they go to zero too quickly.  The linear volume trend for 1979-2021 projects a record low volume for September 2022 (which is obviously not going to happen) and then even lower values for the next years until reaching BOE levels (<1000 km3) by 2029 or earlier.  Not going to happen IMHO.

[The Walrus]

Nature doesnt work linearly.
It tends to be exponential.
We just think it is linear because it looks like it for a short time... until it becomes obvious. Shouldnt we just assume it is exponential until it has been proven to be linear?

...

Someone said they ignore the volume, which makes no sense to me because that is probably the key metric but also the most inaccurate.
Looking at ice from above looks good regardless of whether it is 1cm thick or 400cm thick.

Exponential volume extrapolations were popular in the early days of this forum, but they have aged very poorly.  The Arctic should have been ice-free already by 2015 according to those projections.  Obviously that didn't happen.  Apart from Sam Carana, nobody seems to be using such exponential trendlines anymore.

Linear volume extrapolations are still being used on the forum.  But I suspect that in a few years it will be obvious that they suffer from the same problem as the exponential ones: they go to zero too quickly.  The linear volume trend for 1979-2021 projects a record low volume for September 2022 (which is obviously not going to happen) and then even lower values for the next years until reaching BOE levels (<1000 km3) by 2029 or earlier.  Not going to happen IMHO.

Exponential changes are unsustainable.  Eventually, they revert to linear or slower rates of change.  Global population is a prime example.  It was growing exponentially until about 1960, when it started to slow towards a linear growth rate.  Projections are for that to slow even further in the coming decades.

[VeliAlbertKallio]

Back in February 2007 the Arctic Council prepared its "Arctic Impact Report" with three scenarios (a copy shown here:    https://www.academia.edu/50061072/Moon_Flight_Crew_Interview_of_Veli_Albert_Kallio_Step_3_for_SpaceX_2023_Lunar_Mission

From the above source you could see a massive early melting against the three projections given:

2040-2070 minimum sea ice extent ---> level was reached almost immediately, by August 2007
2070-2100 minimum sea ice extent ---> level was reached by August 2012
2150 totally ice free Arctic Ocean ------> not yet reached

As a result of these many people saw that the models were not capturing the rapidity of ice losses. Leading to extremely gloomy projections how ice was going to vanish, making the experts to appear as if fools at the time. I was one of them at the time (and quite a few years afterwards as well). When I cited in September 2007 that ice might disappear by turn of that decade, that was not exponential but linear drop from amount of ice extent reduction from 2006 to 2007 to be continued at same rate of reduction each year to reach ice free ocean around 2010. Peter Wadhams made his newspaper front page that Arctic Ocean was becoming ice free by 2012. Wiesław Masłowski was another early bird promising such an early ice apocalypse as well as John Davies of Friends of the Earth. I recall how the Parliament's Select Committee on Environmental Audit redacted its report on Arctic and waited until end of melting season after hearing Arctic Methane Emergency Group Presentation by John Nissen, Peter Wadhams and Stephen Salter. Clearly, at that moment it was a shock as the neat Steady Climate Change had turned into Abrupt Climate Change for Met Office. Seymour Laxton at the University College London forecast all sea ice gone by 2020.

I am not apologetic about our early enthusiasm of such dramatic declines that did not happen completely to our tone. There were laggards all along the way and I believe it helped to stimulate debate and brain storming in the early years of this group. Sam Carana is still in that pursuit, but I also feel that many other climate factors warrant us to remain in tiptoes and warn the community. There are plenty of people unaware of the gravity of the situation and it is always going to be so. Certainly, there has not been movement fast enough to halt action on climate change beginning from leaders such as Donald Trump (USA), Jair Bolsonaro (Brazil), Mohammed bin Salman (Saudi Arabia), Vladimir Putin (Russia), Scott Morrison (Australia) and many other bad players.

I still would like to draw line even further back in time to the time of The United Nations Conference on Environment and Development (UNCED) also known as the Rio Earth Summit June 3 to June 14, 1992 and the subsequent United Nations General Assembly when Javier Pérez de Cuéllar authorised the First Nations of Americas to table their ethnoclimatology motion on the floor of the UN General Assembly as the closing plea of the opening proceedings of the UN's first Year of Indigenous Peoples (1993) where stipulated end to the northern cryosphere with all ice gone within about a generation -based on the ethnic recollections of how the ice ages came in and went out in Native American Indian ethnoclimatology (quadripartite "Four Mankinds" ethnoclimatology version): https://www.academia.edu/36396474/United_Nations_General_Assembly_Motion_101292_for_UNFCCCs_Talanoa_Dialogue I have been on the call on this ever since with mostly commissioned by South Asian and other nations in Asia-Pacific regions with even some WMO funds.

Summarising the above: We do not know the exact role how methane clathrates will play out this. We do not also have proof how darkened and wet Greenland Ice Sheet behaves especially once ice begins to vanish and the sea water warms rapidly due to ever lower volumes of ice to melt. I also believe there is "discrimination of archaeology" due to fallen sea levels of the Last Glacial Maximum (= methane clathrate depressurisation maximum) and Holocene Thermal Optimum (= permafrost melting maximum) having grave alterations of carbon-14 isotope from these sources making ice melting and sea level rise processes appear stretched. Great Pyramid of Giza has been radiocarbon dated at 34th century BCE (5.4 kyr in geophysicist language). But the tax records, political appointments etc clearly indicate that it was built 902 years later than radiocarbon years obtained. By Santorini eruption 17 century BCE this gap had narrowed to about one century but it still existed. This is because CO2 does not immediately disappear. There are scope for grave errors in systems!

We must remain on alert to these things and Abrupt Climate Change is mathematically highly chaotic. There may be a spectrum of possibilities from Sam Carana to the laggard GCM ends.
Some more details here in my recent interview: https://www.podofgold.world/ghosts-of-climates-past-veli-albert-kallio/ We are an excellent group thanks to Neven and we must brainstorm on it!

Nature doesnt work linearly.
It tends to be exponential.
We just think it is linear because it looks like it for a short time... until it becomes obvious. Shouldnt we just assume it is exponential until it has been proven to be linear?

...

Someone said they ignore the volume, which makes no sense to me because that is probably the key metric but also the most inaccurate.
Looking at ice from above looks good regardless of whether it is 1cm thick or 400cm thick.

Exponential volume extrapolations were popular in the early days of this forum, but they have aged very poorly.  The Arctic should have been ice-free already by 2015 according to those projections.  Obviously that didn't happen.  Apart from Sam Carana, nobody seems to be using such exponential trendlines anymore.

Linear volume extrapolations are still being used on the forum.  But I suspect that in a few years it will be obvious that they suffer from the same problem as the exponential ones: they go to zero too quickly.  The linear volume trend for 1979-2021 projects a record low volume for September 2022 (which is obviously not going to happen) and then even lower values for the next years until reaching BOE levels (<1000 km3) by 2029 or earlier.  Not going to happen IMHO.

[Jim Hunt]

At the 2013 Economist Arctic Summit in Oslo the learned panellists were asked this very question.

Here is a recording I inadvertently made of their answers:

https://soundcloud.com/water-connects-us/ice-free-summer-arctic-numbers

[Tor Bejnar]

I referenced El Ninos because they add a great deal of heat to the Pacific atmosphere and, generally, increase world surface (2m) temperatures.  El Nino years are pretty consistently warmer than Neutral and La Nina years. The specific reference was the year of the next El Nino or the year after.  I've not presumed El Ninos directly cause Arctic ice melt (history says there is no obvious connection), but the years following an El Nino will tend to be warmer than the year(s) before an El Nino, and because there are global circulations (heat/water) and CO2 continually gets added to the atmosphere, I figure a couple major El Ninos will do the trick.  And besides, in 8-10 years, will anybody look back on this thread to see how wrong I'm being? 

[Icegod]

The ice melt has mirrored the temperatures in the Atlantic with the AMO so no I don't think the ice is going to melt out at 2100 or any other year unless something disastrous happens.
AMO peaked out in 2012 that's why you have the anomalous record and it's slowly been cooling ever since. If we are deep in a cold phase and have these numbers then I might be alarmed but the ice started melting when the AMO started to transition in 1980.....

[El Cid]

Linear volume extrapolations are still being used on the forum.  But I suspect that in a few years it will be obvious that they suffer from the same problem as the exponential ones: they go to zero too quickly.  The linear volume trend for 1979-2021 projects a record low volume for September 2022 (which is obviously not going to happen) and then even lower values for the next years until reaching BOE levels (<1000 km3) by 2029 or earlier.  Not going to happen IMHO.

I've often criticized linear projections on many threads from a statistical points of view. I'm still convinced that these linear fits are statistically speaking totally false.

BUT.

We know how many natural systems behave: there is some stability or a weak trend  - then all of a sudden there is a regime change which pushes the system into a new (sort-of) equilibrium. And then that equilibrium holds - until it doesn't.

The arctic had a huge regime change when it lost MYI between 2005-12. Now we seem to have a new "regime" that is somewhat stable and that might continue for any number of years. However, as we keep heating the planet sometime, something will break once again (halocline breakdown, Atlantic waters reaching the NP, anything, IDK) and BOE will suddenly happen.

Therefore it is impossible to forecast when it will happen but in retrospect those linear projections might still look not so bad after all - although methodologically totally wrong

[Jim Hunt]

A recent paper on ENSO effects on the Arctic:

"Record Low Arctic Sea Ice Extent in 2012 Linked to Two-Year La Niña-Driven Sea Surface Temperature Pattern"

By nudging observed tropical SSTs in a state-of-the-art coupled climate model, we identified the impact of tropical SST anomalies on the 2012 record low Arctic SIE. In the case when the tropical SSTs from 2010 to 2012 are nudged to the observations in the model, the dramatic Arctic sea ice loss in 2012 summer is reproduced well. Specifically, our model simulation demonstrates that La Niña conditions in the summer of 2010 and 2011 increased lower tropospheric temperature over the Pacific sector of the Arctic, whereas a negative phase of Pacific Meridional Mode (PMM) in 2012 strengthened the anomalous Greenland high and the associated transpolar drift of sea ice toward the Fram Strait.

[El Cid]

and yet with two years of la nina in 2021-22 the opposite seems to have happened

[Aluminium]

and yet with two years of la nina in 2021-22 the opposite seems to have happened

Not yet. The weather determines outcome more than anything else. August will come soon.

[Rodius]

Nature doesnt work linearly.
It tends to be exponential.
We just think it is linear because it looks like it for a short time... until it becomes obvious. Shouldnt we just assume it is exponential until it has been proven to be linear?

...

Someone said they ignore the volume, which makes no sense to me because that is probably the key metric but also the most inaccurate.
Looking at ice from above looks good regardless of whether it is 1cm thick or 400cm thick.

Exponential volume extrapolations were popular in the early days of this forum, but they have aged very poorly.  The Arctic should have been ice-free already by 2015 according to those projections.  Obviously that didn't happen.  Apart from Sam Carana, nobody seems to be using such exponential trendlines anymore.

Linear volume extrapolations are still being used on the forum.  But I suspect that in a few years it will be obvious that they suffer from the same problem as the exponential ones: they go to zero too quickly.  The linear volume trend for 1979-2021 projects a record low volume for September 2022 (which is obviously not going to happen) and then even lower values for the next years until reaching BOE levels (<1000 km3) by 2029 or earlier.  Not going to happen IMHO.

Exponential changes are unsustainable.  Eventually, they revert to linear or slower rates of change.  Global population is a prime example.  It was growing exponentially until about 1960, when it started to slow towards a linear growth rate.  Projections are for that to slow even further in the coming decades.

Of course they are unsustainable, that's why they stop.

Yet, exponential is how things take off, and they look linear for a while until they are clearly not. Like Covid growth.
And when it is obvious that some things grow exponentially, it should be taken as the default.

Is the Artic ice melting the same way... nobody knows at this point in time. But we will know within ten years.
If the ice hasn't dropped below 1 million, linear.
If it is gone and regularly gone, exponential.

I have no idea which it is, nobody does.
I am just saying that my experience with nature lends itself to exponential. ANd given how surprised the climate scientists seem to be all the time, the events of climate change are probably not linear.

Whether that shows up in the ice, I don't know, but the changing climate if speeding up....

[Rodius]

Nature doesnt work linearly.
It tends to be exponential.
We just think it is linear because it looks like it for a short time... until it becomes obvious. Shouldnt we just assume it is exponential until it has been proven to be linear?

...

Someone said they ignore the volume, which makes no sense to me because that is probably the key metric but also the most inaccurate.
Looking at ice from above looks good regardless of whether it is 1cm thick or 400cm thick.

Exponential volume extrapolations were popular in the early days of this forum, but they have aged very poorly.  The Arctic should have been ice-free already by 2015 according to those projections.  Obviously that didn't happen.  Apart from Sam Carana, nobody seems to be using such exponential trendlines anymore.

Linear volume extrapolations are still being used on the forum.  But I suspect that in a few years it will be obvious that they suffer from the same problem as the exponential ones: they go to zero too quickly.  The linear volume trend for 1979-2021 projects a record low volume for September 2022 (which is obviously not going to happen) and then even lower values for the next years until reaching BOE levels (<1000 km3) by 2029 or earlier.  Not going to happen IMHO.

Maybe the timelines are too human.

And it could happen before 2029, there are far too many unknowns, and far too many events in the climate that are happening well before predicted to say a full melt out is impossible.

The heat waves in Europe this year shouldn't be happening either, yet, there they are.

[VeliAlbertKallio]

It seems there is a degree of ambiguity on headline statement to some. I just noticed that someone is perhaps referring to the winter time disappearance year 2100 and beyond. That is a completely different thing to summer time as sea ice will keep forming in innumerable winters to come.

The other issue regarding El Nino and the loss of Arctic Sea ice disappearance is the degree to which the former is driver and the latter is respondent, and whether the two events are inseparable or not.

[crandles]

It seems there is a degree of ambiguity on headline statement to some. I just noticed that someone is perhaps referring to the winter time disappearance year 2100 and beyond. That is a completely different thing to summer time as sea ice will keep forming in innumerable winters to come.

The other issue regarding El Nino and the loss of Arctic Sea ice disappearance is the degree to which the former is driver and the latter is respondent, and whether the two events are inseparable or not.

Ultimately everything affects everything but ....

El Nino causes high global average temperature, this is not disputed. But we know much more than that, we can track where the heat is. After the peak, the heat anomaly can be tracked moving North for several months but it is dissipating. Maybe a small amount of that heat continues and reaches the Arctic but the temperature anomaly becomes too small to measure and vast majority of the heat will have dissipated to space rather than to the ice.

You can come up with all sort of relationships - perhaps a stronger el Nino will reach further north so there is a non linear effect or maybe any effect on the ice depends on other oscillations like AO. Once you start doing these sorts of things when combined with the problem of when does it have effect? 12 months later? or 13 to 15 months later? or 9 to 18 months later? Basically there becomes so many places you could look, a correlation could easily be by chance rather than due to the suggested mechanism.

It becomes more sensible to just say if there was a large effect, we would know about it (like with global average temperature and ENSO). A small effect may be there but we are unlikely to be able to show it is significant.

Maybe a longer record of reliable data will help, but I would recommend against holding your breath for this.

If we are unlikely to be able to show it is significant, then it is probably better to move on to something else.

[Phil.]

and yet with two years of la nina in 2021-22 the opposite seems to have happened

Well the two La Niña years were seen as setting up 2012, that would seem to suggest a big loss when we return to normal, maybe next summer?

[trm1958]

It seems there is a degree of ambiguity on headline statement to some. I just noticed that someone is perhaps referring to the winter time disappearance year 2100 and beyond. That is a completely different thing to summer time as sea ice will keep forming in innumerable winters to come.

Good point.
I interpreted the poll as being the September minimum. Does the OP agree? Let's clarify that.

[El Cid]

Not really.

La nina started in mid 2010, this time almost exactly 10 yrs later: mid-2020. 2011 and 2021 were full la nina and then 2012 saw the ice collapse. 2022? not really

[dnem]

I took this poll to be any, at least one-day, dip below the 1 million km^2 mark and I voted 26-30. "The transition will be slow until it's not."

I just think the weather will align and the ice will collapse abruptly obliterating any trend analysis.

[The Walrus]

Little in nature follows a clear mathematical equation.  The exceptions are chemical reactions and physics.  Natural processes can rarely be categorized in this manner.  We gather the data and attempt to draw a connection, but often the complexities render the results approximations at best.  We can analyze what has happened in the past, and guesstimate what will happen in the future, which is what we are doing here.  In all likelihood, thee Ed current trend will change (at least once), before we reach an ice-free state.  Whether that becomes a faster or slower rate of change, I cannot say.  Hence, I opted for a longer timeframe.

[Phil.]

Not really.

La nina started in mid 2010, this time almost exactly 10 yrs later: mid-2020. 2011 and 2021 were full la nina and then 2012 saw the ice collapse. 2022? not really

Well La Niña conditions are expected to continue into this winter if 2023 returns to neutral conditions that will be very similar to 2012.