When will the Arctic Go Ice Free?

[glennbuck]

Guy McPherson has left science behind for apocalypse-drama and personal gain. He benefits deniers with his unscientific predictions. I recommend to keep away from his publications.

Oh ok, does not help that the IPCC is very conservative with there projections for 2100, happening in last few years many of there late projections, i think the Siberia weather this year was not projected until 2080-2100 by the IPCC! Both ends of the spectrum i suppose.

Siberia’s heatwave reflects temperature changes that weren’t generally forecast to occur until the end of the century.

Russia's state weather authority confirmed that the temperature at the small town of Verkhoyansk — which sits about 70 miles north of the Arctic Circle and boasts the Pole of Cold District Museum of Local Lore as its only tourist attraction listed on Tripadvisor — hit 100.4 degrees Fahrenheit on June 20.

https://www.bloomberg.com/opinion/articles/2020-07-05/siberia-heatwave-climate-change-really-is-big-oil-industry-risk

https://www.forbes.com/sites/trevornace/2020/06/22/the-arctic-circle-hit-101f-saturday-its-hottest-temperature-ever/#65e013be4eb6

[anthropocene]

I would be interested on peoples views on the consequences of when the Arctic ocean becomes ice free? Here is a peer reviewed paper by Guy R,McPherson in June 2020.

What has led you to the conclusion that it is a peer reviewed paper? What quantitative measurements or predictions in the article could be peer reviewed? (I'm interested in how the general public assesses the quality of "scientific" writing - especially articles online  (both climate denial and doomerism)). 

[glennbuck]

I would be interested on peoples views on the consequences of when the Arctic ocean becomes ice free? Here is a peer reviewed paper by Guy R,McPherson in June 2020.

What has led you to the conclusion that it is a peer reviewed paper? What quantitative measurements or predictions in the article could be peer reviewed? (I'm interested in how the general public assesses the quality of "scientific" writing - especially articles online  (both climate denial and doomerism)).

Doomerism or Realism

 All signs point to ever more powerful assaults on biodiversity in the next two decades, painting a dismal picture of the future of life, including human life.

Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines

Gerardo Ceballos, Paul R. Ehrlich, and Rodolfo Dirzo
PNAS July 25, 2017 114 (30) E6089-E6096; first published July 10, 2017 https://doi.org/10.1073/pnas.1704949114

    Contributed by Paul R. Ehrlich, May 23, 2017 (sent for review March 28, 2017; reviewed by Thomas E. Lovejoy and Peter H. Raven)

https://www.pnas.org/content/114/30/E6089

[gerontocrat]

Doomerism or Realism

 All signs point to ever more powerful assaults on biodiversity in the next two decades, painting a dismal picture of the future of life, including human life.

Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines

Gerardo Ceballos, Paul R. Ehrlich, and Rodolfo Dirzo
PNAS July 25, 2017 114 (30) E6089-E6096; first published July 10, 2017 https://doi.org/10.1073/pnas.1704949114

    Contributed by Paul R. Ehrlich, May 23, 2017 (sent for review March 28, 2017; reviewed by Thomas E. Lovejoy and Peter H. Raven)

https://www.pnas.org/content/114/30/E6089

There is a thread... the Holocene Extinction
 - https://forum.arctic-sea-ice.net/index.php/topic,2305.0.html

There is a thread... The Climatic Effects of a Blue Ocean Event
https://forum.arctic-sea-ice.net/index.php/topic,2800.0.html

[Stephan]

It is time for the monthly update of my extrapolation when the extent [Ausdehnung], volume [Volumen], thickness [Dicke] and area [Fläche] will reach zero. The extrapolation occured linearly and by a logarithmic function; the latter one almost constantly resulting in earlier times (valid for volume and thickness, not for extent and area in the winter months). The July value now includes 2020.
Volume in July 2020 is close to the long term trend, thickness for July 2020 lies well above the long term trend lines, whereas extent (lowest on record) and area (lowest on record) dip below it. The "BOE numbers" increased by averaged 6 years (volume) and decreased by 2 years (extent) or by 5 years (area) compared to July 2019. Thickness "BOE number" did not change.
So there is a further conversion between the "late values" (area, extent) and the "early value" (volume).
The order (earlier → later BOE) generally is volume < thickness < area < extent.

Please note that this is not a forecast but a trend!
See attached table, now widened to see the linear function value (y-AA) at t = 0. stg = slope.

Click to enlarge it.

[Juan C. García]

This post is good enough to be here. In "The 2020 melting season" thread, the post will be lost in a week (too many posts there).

Following a heads up from a certain Mr. Watts I bring you news of an interesting new article in Nature Climate Change:

https://GreatWhiteCon.info/2020/08/past-evidence-supports-complete-loss-of-arctic-sea-ice-by-2035/

Allegedly:

Using the [UK Met Office’s Hadley Centre climate] model to look at Arctic sea ice during the last interglacial, the team concludes that the impact of intense springtime sunshine created many melt ponds, which played a crucial role in sea-ice melt.  A simulation of the future using the same model indicates that the Arctic may become sea ice-free by 2035.

https://www.bas.ac.uk/media-post/past-evidence-supports-complete-loss-of-arctic-sea-ice-by-2035/

[dnem]

It is not entirely clear from the press release, but the Nature CC paper concludes: "Here, we show that the latest version of the fully coupled UK Hadley Center climate model (HadGEM3) simulates a more accurate Arctic LIG climate, including elevated temperatures. Improved model physics, including a sophisticated sea-ice melt-pond scheme, result in a complete simulated loss of Arctic sea ice in summer during the LIG, which has yet to be simulated in past generations of models."

[Richard Rathbone]

This model (HadGEM3) has had a really dire performance in predicting the September concentration in past years SIPN entries, so it could use something to improve it. It doesn't look like its changed much though, last year it was making predictions near the top of SIPN entries and its in almost exactly the same place relative to the other models that make SIPN predictions in 2020 as it was in 2019.

4.6 was June entry, 4.7 in July despite record levels of melt ponds in May. I don't know what they assumed the climate could be like in 2035, but HadGEM3 still thinks a BoE is long way from happening under 2020 conditions.

[glennbuck]

Dr. Peter Wadhams speaks out. Arctic Sea Ice, Methane and more.

Welcome Dr. Peter Wadhams who spoke to Jennifer Hynes and Sandy Schoelles on August 11, 2020.  Peter is currently teaching in Italy, but we were fortunate enough to catch up with him for a candid discussion regarding the Scientists Warning articles and subsequent videos that painted Peter and his work with an "alarmist" brush.   With 50 years of Arctic Sea Ice Research to Peter's credit, he spoke to us about his reaction to the material as well as his extremely well researched views on the future of arctic ice and methane.

[The Walrus]

Peter Wadhams again?  When does he predict the Arctic will be ice-free this time?

[nanning]

Peter Wadhams again?  When does he predict the Arctic will be ice-free this time?

Aha The Walrus, I suspect that you forgot for a moment that you're on the ASIF and that you have let us (again) see into your cards.
Your cards don't belong here.

glennbuck, thanks for the video link. Much appreciated. Wadhams is always interesting and one with an enormous amount of scientific field experience and professional respect. An hour of new and recent Wadhams video! yummy!

[Rodius]

Peter Wadhams again?  When does he predict the Arctic will be ice-free this time?

As of August this year, he said this year is still a possible BOE... and if not this year, next year.

While I respect him, he really needs to stop making predictions like that... he complains about people not being scientific in one sentence then makes a prediction that isn't supported by facts (as in, where will all the energy come from to melt out this years remaining ice?)

[glennbuck]

Peter Wadhams again?  When does he predict the Arctic will be ice-free this time?

As of August this year, he said this year is still a possible BOE... and if not this year, next year.

While I respect him, he really needs to stop making predictions like that... he complains about people not being scientific in one sentence then makes a prediction that isn't supported by facts (as in, where will all the energy come from to melt out this years remaining ice?)

I think he got mixed up and was talking about past predictions, later in the interview he says several years from 2021 and that the North Pole will be ice free first and msm will call it a BOE before an actual BOE below 1 million km^2.

There is hardly any MYI left and Thickness is very low compared to the past. North Greenland open water expanding is a worry, so i feel he will not be far off a BOE happening between 2021-2025 in September. Some scientists now say around 2035. Back to the future is getting closer to the near future.

[The Walrus]

Peter Wadhams again?  When does he predict the Arctic will be ice-free this time?

As of August this year, he said this year is still a possible BOE... and if not this year, next year.

While I respect him, he really needs to stop making predictions like that... he complains about people not being scientific in one sentence then makes a prediction that isn't supported by facts (as in, where will all the energy come from to melt out this years remaining ice?)

Agreed.  Those failed predictions just feed the flames of his opponents.  All he seems to do is add three years to his previous predictions.  First it was 2013, then 2016, followed by 2019.  I guess he changed his practice, as he changed to this year or next, instead of 2022.  The fact is that the September minimum has not dropped anywhere near an ice-free state, even with the decline in MYI.  There appears to be more to it than just drawing straight live curves on a small dataset.

[The Walrus]

Peter Wadhams again?  When does he predict the Arctic will be ice-free this time?

Aha The Walrus, I suspect that you forgot for a moment that you're on the ASIF and that you have let us (again) see into your cards.
Your cards don't belong here.

Funny, I thought this was a scientific forum, and one should use scientific "cards."  Apparently, you think that the only "cards" that belong here are those espousing rhetoric, instead of science.

[Richard Rathbone]

Peter Wadhams again?  When does he predict the Arctic will be ice-free this time?

As of August this year, he said this year is still a possible BOE... and if not this year, next year.

While I respect him, he really needs to stop making predictions like that... he complains about people not being scientific in one sentence then makes a prediction that isn't supported by facts (as in, where will all the energy come from to melt out this years remaining ice?)

Agreed.  Those failed predictions just feed the flames of his opponents.  All he seems to do is add three years to his previous predictions.  First it was 2013, then 2016, followed by 2019.  I guess he changed his practice, as he changed to this year or next, instead of 2022.  The fact is that the September minimum has not dropped anywhere near an ice-free state, even with the decline in MYI.  There appears to be more to it than just drawing straight live curves on a small dataset.

Wadhams August 2015 SIPN entry https://www.arcus.org/sipn/sea-ice-outlook/2015/august

Wadhams (Sea Ice and Polar Oceanography Group), 0.98, Heuristic (same as June)
We use entirely statistical extrapolation methods based on measured values of sea ice extent (from satellites) and sea ice thickness (from submarine voyages). [Editor's Note: Upon review by the SIPN team, this outlook has been listed as heuristic in the Sea Ice Outlook report.]

Wadhams has been thinking the ice was due to vanish in 2015 since 2012 and has been ignoring data since 2012 in order to keep thinking that way. Maybe its because his expertise is in old ice, and the old ice has virtually all gone and he can't bring himself to understand an Arctic where the ice has a 2 year lifespan rather than the 10 year lifespan of the ice in the Arctic he studied.

[miki]

Wadhams has been thinking the ice was due to vanish in 2015 since 2012 and has been ignoring data since 2012 in order to keep thinking that way. Maybe its because his expertise is in old ice, and the old ice has virtually all gone and he can't bring himself to understand an Arctic where the ice has a 2 year lifespan rather than the 10 year lifespan of the ice in the Arctic he studied.

Probably Wadhams is right, after all. The Arctic is already unrecognizable for those who loved it 40/30/20 years ago. Maybe the BOE we are all waiting for to happen in the near future, has just occurred under our deceived eyes. And what we are witnessing right now, is just the destroyed ice world shedding its last spoils.

[metalreflectslime]

What happens after a BOE happens?

I hear crops will fail due to heat.

What else happens?

[oren]

Welcome mfc. This question belongs in a different thread, this one deals with when, not with what happens after.

There is a thread... The Climatic Effects of a Blue Ocean Event
https://forum.arctic-sea-ice.net/index.php/topic,2800.0.html

[Tony Mcleod]

Peter Wadhams again?  When does he predict the Arctic will be ice-free this time?

As of August this year, he said this year is still a possible BOE... and if not this year, next year.

While I respect him, he really needs to stop making predictions like that... he complains about people not being scientific in one sentence then makes a prediction that isn't supported by facts (as in, where will all the energy come from to melt out this years remaining ice?)

2020 declared Blue Ocean Event
The area of the Arctic is 14.06 million km², we are already under 4 million km² of sea-ice. Look at the ratio of blue water to white sea-ice, the blue so outweighs the white that I'm declaring 2020 a BOE year, the second (after 2012). All it took in 2012 was a storm, this year it took bugger all. Because the remaining ice is nothing but a vestigial skin, next year, only freakish cold will prevent another one. Wadhams was wrong because he was late, not early.

[Tom_Mazanec]

Tony, my understanding of BOE is 1 million square kilometers, not 4 million.

[oren]

Tony, while you are correct that ice loss in the Arctic ocean has important effects long before the blue ocean event, and that the basin has been severely hit, as it was in 2012 (and 2016), still as Tom wrote this thread is about the classic definition of 1 million km2.

[Archimid]

I believe he refers to the melt ponding in the arctic. A ship cruising certain regions of the central Arctic could easily think that there was nothing but blue ocean.


I can see that being true from the perspective of a scientist that studied the old Arctic like Wadhams.

But a blue ocean event is much more than just blue ocean to the naked eye. In a blue ocean event the Sun has time to raise sea surface temperatures high enough that the air surface temperature in the central, coldest Arctic departs typical summer variability.
 
See DMI N80.

http://ocean.dmi.dk/arctic/meant80n.uk.php

Right now DMI N80 is "merely" failing to cool during the trasition from the Arctic day to the Arctic night. In a true BOE, DMI N80 departs its summer natural variability that is usually fixed to the temperature/humidity of the ice.

[SimonF92]

Peter Wadhams again?  When does he predict the Arctic will be ice-free this time?

As of August this year, he said this year is still a possible BOE... and if not this year, next year.

While I respect him, he really needs to stop making predictions like that... he complains about people not being scientific in one sentence then makes a prediction that isn't supported by facts (as in, where will all the energy come from to melt out this years remaining ice?)

2020 declared Blue Ocean Event
The area of the Arctic is 14.06 million km², we are already under 4 million km² of sea-ice. Look at the ratio of blue water to white sea-ice, the blue so outweighs the white that I'm declaring 2020 a BOE year, the second (after 2012). All it took in 2012 was a storm, this year it took bugger all. Because the remaining ice is nothing but a vestigial skin, next year, only freakish cold will prevent another one. Wadhams was wrong because he was late, not early.

I wonder how many people said 2013 would be a BOE

[Tony Mcleod]

Wadhams' prediction was for an ice-free "central basin". He didn't count on it all being blown to one side leaving one hemisphere blue. (I know that is not exactly what happened...but...)

In the 80s sea-ice area summer minimum was over 50% of the basin. In 2012 'blue' water reaches 78%. As of today, with ice under 4 million km², its 72% and rising. Yes, I'm being tongue in cheek, but I'm also pointing out that 75% blue water is quite blue. Next year will be short odds to beat 2012, volume numbers are even worse, so poof the year after.

[Freegrass]

We're not gonna go from 4M Km² to 1M Km² in one years time. And if that would happen, it would happen at the end of the melting season.

Someone else told me that when the DMI 80N goes above the green line, that this would be a sign of a BOE.

We'll we're at the end of the season, and we're staying well beyond the green line after popping above it for a while earlier on in the season. Melting season is effectively extended. A drastic change. IMHO the beginning of a BOE. BOE version 0.1

[igs]

We're not gonna go from 4M Km² to 1M Km² in one years time. And if that would happen, it would happen at the end of the melting season.

Someone else told me that when the DMI 80N goes above the green line, that this would be a sign of a BOE.

We'll we're at the end of the season, and we're staying well beyond the green line after popping above it for a while earlier on in the season. Melting season is effectively extended. A drastic change. IMHO the beginning of a BOE. BOE version 0.1

What is meant is:

ABOVE the green line AND ABOVE Zero and not just for a day but for longer and not just 0.5C above 0C and green-line but 3, 4, 5 - 10C

Temps are every year many days above the greenline but rarely when temps are above 0C.

That means in short that the green-line is irrelevant, it's about how much air-temps over the ice that is currently mostly above 80N, is reaching above 0C and that has been normal this year as well as it is now not significantly higher the 0C if at all for longer than a day or two.

The ice keeps temps right above around 0C and once there won't be ice the waters will heat up and the inblowing warmer air will be able to keep it's temp longer.

[Tor Bejnar]

FYI:  there is a Poll.

Where will the last Arctic Sea Ice be located?

Read the first entry before you cast your vote(s) ... (unless you don't want to).

[Freegrass]

I understand what you're saying Igs, and I agree that a BOE 1.0 is exactly what you describe. But you can't ignore the fact that the temperature above 80N is staying rather high for this time of year, and that this is most likely due to heat on land and in the ice free ocean around it. For a real BOE 1.0 the ice 80N will have to disappear, but right now almost all the ice around 80N is gone. Thats why I will start calling it a BOE 0.1. Not a real BOE 1.0! But a transition phase with a changing thermocline and the possible end of MYI.

[igs]

I understand what you're saying Igs, and I agree that a BOE 1.0 is exactly what you describe. But you can't ignore the fact that the temperature above 80N is staying rather high for this time of year, and that this is most likely due to heat on land and in the ice free ocean around it. For a real BOE 1.0 the ice 80N will have to disappear, but right now almost all the ice around 80N is gone. Thats why I will start calling it a BOE 0.1. Not a real BOE 1.0! But a transition phase with a changing thermocline and the possible end of MYI.

No, of course I can't ignore and as far as I'm aware I didn't make the slightest attempt to ignore it

 

I just went a bit to to lenght to explain why the green line that is an average is irrelevent in that context and most certainly so once the green line is below 0C.

BTW, talking about the current temps above 80N, beside the fact what already has materialized, according to the forecasts it will continue in a similar way, expecting a very flat sloap before probably dropping once of a sudden once the highs and lows favour a cool down.

[D-Penguin]

Peter Wadhams again?  When does he predict the Arctic will be ice-free this time?

Aha The Walrus, I suspect that you forgot for a moment that you're on the ASIF and that you have let us (again) see into your cards.
Your cards don't belong here.

Funny, I thought this was a scientific forum, and one should use scientific "cards."  Apparently, you think that the only "cards" that belong here are those espousing rhetoric, instead of science.

The science no longer represents the actuality of events; it has failed to 'connect the dots' and is too far behind the curve. Informed opinions are now more relevant than the science in the context of policy formulation in preparation for a BOE, the pre-cursor of an ice free Arctic ocean and the global implications that will follow.

[Alison]

The science no longer represents the actuality of events

Surprised to read this here. I do take encouragement from the numbers this year - despite a serious assault from adverse weather and eight years more global warming, the ice has been resilient enough to stay above the 2012 minimum.

To me, this demonstrates the extraordinary amount of energy needed to melt ice and suggests a BOA is decades, not years away... and I don’t expect to be abandoning science any time soon

[Alison]

The state of mind of your post is what I call "defense mode", which makes even legit views kind of emotional and with a tendency to exaggeration.

This sums up your post nicely, I think. Not personal though...

[The Walrus]

The science no longer represents the actuality of events

Surprised to read this here. I do take encouragement from the numbers this year - despite a serious assault from adverse weather and eight years more global warming, the ice has been resilient enough to stay above the 2012 minimum.

To me, this demonstrates the extraordinary amount of energy needed to melt ice and suggests a BOA is decades, not years away... and I don’t expect to be abandoning science any time soon

As to the science part, he explained very well what was meant hence there is no reason to defend science. If there is no know past event that represents the current state of the ice in the arctic, observation for now beats science IN A CERTAIN WAY i.e. that the models are based on past data and events and cannot represent what is happening right now.

Further, that 2020 will stay above 2012, albeit it's most probable, is a premature statement.

That a BOE "CAN" take a bit longer than some of us fear is a valid opinion but that as well is neither a certainty nor does it justify to go to the other extreme and talk about decades just like that.

Decades means at least 2 decades and I see the probable outcome somewhere between 5-15 years, hence in the middle and certainly not significantly more than 25 years out.

The state of mind of your post is what I call "defense mode", which makes even legit views kind of emotional and with a tendency to exaggeration. Science was not attacked, hence it does not need to be defended and there is nothing wrong at all with science in form of models and expectations based on the past, it's just sometimes not working that way once important parameters have changed once of a sudden and it takes time to adapt things to the new reality/normal.

That said, none of us KNOWS so either way some respect for the unknown is recommended at all times.

I hope this does not come across personal in any way, it shouldn't, it's purely meant as a reply to what you wrote and nothing more.

Best


 

Perhaps, but that statement could have worded much better.  To imply that "informed opinion" is a better metric than science really opens a whole can of worms.  To whose opinion should we be listening?

Observations are science.  Science collects data through measurement and observation, and draws the most likely conclusion.  That conclusion may change as new measurements or observations are observed, but it is still science.  Models are only as good as the observations and measurements inputted.  Modelling, just like extrapolation, too far beyond the dataset is mere speculation.  Anyone can speculation when a BOE will occur; it could be in the next few years, decades, or longer.  A BOE is well beyond the known observations and measurements, so the forces at play as the ice declines may not match those that were monitored prior.

[oren]

To be clear, no one is abandoning science, science is the only thing. However, science includes armchair and hobby science as well as published science. Published science is by definition of its process often too slow to deal with fast moving changes. Hence there is a good niche for this forum and armchair science to complement published science.

That a BOE "CAN" take a bit longer than some of us fear is a valid opinion but that as well is neither a certainty nor does it justify to go to the other extreme and talk about decades just like that.

igs - please don't decide for others what makes sense and what doesn't. No one of us owns the truth. Alison thinks it's decades away, it's a valid position, no reason to consider it extreme, even if (like me) you disagree.

[Shared Humanity]

The science no longer represents the actuality of events

Surprised to read this here. I do take encouragement from the numbers this year - despite a serious assault from adverse weather and eight years more global warming, the ice has been resilient enough to stay above the 2012 minimum.

To me, this demonstrates the extraordinary amount of energy needed to melt ice and suggests a BOA is decades, not years away... and I don’t expect to be abandoning science any time soon

Well, that makes at least one of us. 

[Tor Bejnar]

In 2012 I 'projected' an ice-free Arctic in September 2019.  Last year and thus I consider usArctic ice to be living on borrowed time.  All the better if we are reprieved for another 15 or more years (or, if you like, rounded to 'decades') . 

[Alison]

The state of mind of your post is what I call "defense mode", which makes even legit views kind of emotional and with a tendency to exaggeration.

The state of mind of your post is what I call “attack mode”, which makes event legit views kind of aggressive and with a tendency to mysogeny. Please don’t take this personally

[gerontocrat]

Who needs science when we've got arithmetic.

2029 BOE - "It was the Volume that got him. Not enough. Couldn't support a great big mult-million km2 ice sheet anymore. He crashed and burned".

Spoken while looking North over the Arctic at the remains from a snow-free hill on Ellesmere Island.

[The Walrus]

So, if volume loss were to accelerate, then we reach a BOE in 2030.  What would happen if the volumetric losses continue on its current trajectory?

[oren]

I believe Gero simply continued the long term volume trend, you call that acceleration since you focus on the last decade only and minima only. Which of these trends is representative of future reality? Honestly hard to know.

[The Walrus]

I believe Gero simply continued the long term volume trend, you call that acceleration since you focus on the last decade only and minima only. Which of these trends is representative of future reality? Honestly hard to know.

No, that is a continuation of the short-term trend - roughly the last 5 years.  The long-term is much less steep.

[oren]

I wonder what you are looking at. Yellow line is volume. Connect 1987 to 2019 and extrapolate.

[miki]

Who needs science when we've got arithmetic.

2029 BOE - "It was the Volume that got him. Not enough. Couldn't support a great big mult-million km2 ice sheet anymore. He crashed and burned".

Spoken while looking North over the Arctic at the remains from a snow-free hill on Ellesmere Island.

Given that Nature never really goes by "average", I put my bet on 2022. Because it could not make up for the losses of 2021.

Of course, I truly, truly hope I'm wrong.
There's just so much heat/energy in the Arctic system, though. Just give it some weather.

[Simon]

I could well be wrong but when I thought about BOE, I came to the conclusion that 2027 +/- 2 years would be when an annual BOE would become a permanent feature and that the length of time this would persist would increase perhaps as much as several months by 2050.

[The Walrus]

I wonder what you are looking at. Yellow line is volume. Connect 1987 to 2019 and extrapolate.

My apologies.  I was looking at the red line.  I now agree with your extrapolation.

[gerontocrat]

I believe Gero simply continued the long term volume trend, you call that acceleration since you focus on the last decade only and minima only. Which of these trends is representative of future reality? Honestly hard to know.

No, that is a continuation of the short-term trend - roughly the last 5 years.  The long-term is much less steep.

I am annoyed.

It would be nice if one was asked what one had done, not told what one had done.
It is the linear trend from 1979 to 2019 projected forward 9 years.

That is an average of about 320 km3 less volume each year, in line with the records of the Polar Science Center.

& that's all I'm going to say about that.

[Stephan]

I wonder what you are looking at. Yellow line is volume. Connect 1987 to 2019 and extrapolate.

And then insert some weather induced negative spikes like 1981, 2007 or 2010-2012, subtract them from the linear trend line and the BOE is reached even earlier than 2029...

[SimonF92]

I could well be wrong but when I thought about BOE, I came to the conclusion that 2027 +/- 2 years would be when an annual BOE would become a permanent feature and that the length of time this would persist would increase perhaps as much as several months by 2050.

Once the inertia of latent heat of melting has been overcome the changes will be rapid and I wouldnt be surprised if the BOE is +2~3 weeks duration for every year after the first one.

[Stephan]

It is time for the monthly update of my extrapolation when the extent [Ausdehnung], volume [Volumen], thickness [Dicke] and area [Fläche] will reach zero. The extrapolation occured linearly and by a logarithmic function; the latter one almost constantly resulting in earlier times (valid for volume and thickness, not for extent and area in the winter months). The August value now includes 2020.
Volume in August 2020 is slightly above the long term trend, thickness for August 2020 lies almost at the long term trend lines, whereas extent and area dip slightly below it. The "BOE numbers" did not change (volume, thickness) and decreased by 1-2 years (extent, area) compared to August 2019.
So there is a tiny further convergence between the "late values" (area, extent) and the "early value" (volume).
The order (earlier → later BOE) generally is volume < thickness < area < extent.

Please note that this is not a forecast but a trend!
See attached table, now widened to see the linear function value (y-AA) at t = 0. stg = slope.

Click to enlarge it.