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When will the Arctic Extent dip below 1,000,000 Km^2

2018-2019
12 (17.9%)
2020-2025
21 (31.3%)
2026-2030
13 (19.4%)
2031-2040
15 (22.4%)
2041-2060
2 (3%)
2061-2080
0 (0%)
2081-2099
1 (1.5%)
2100-beyond
3 (4.5%)

Total Members Voted: 64

Voting closed: July 27, 2018, 07:46:32 AM

Author Topic: When will the Arctic Go Ice Free?  (Read 187565 times)

The Walrus

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Re: When will the Arctic Go Ice Free?
« Reply #1650 on: June 30, 2020, 11:05:28 PM »
I would agree gerontocrat.  As we approach zero, conventional wisdom no longer holds.

JNap

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Re: When will the Arctic Go Ice Free?
« Reply #1651 on: July 07, 2020, 04:16:34 AM »
It will be interesting to observe the overall effects of the strong arctic High pressure that has been centered over the CAB for the past 7 days -- and forecasted to continue for at least the next 5+ days.  At this point, it seems as though the GAH (Great Arctic High as I think that Freegrass labeled it) seems increasingly likely to be the event that defines the 2020 melt season. 

Looking beyond 2020, weather events like this that drive such a high level of solar insolation during peak solar season will happen again.  (Tealight may need to extend the AWP scale of his graphs.)  If it does happen during a year where we start with a lower volume and extent AND have an early melt in the high arctic peripheral seas with the lower albedo, it sets the stage to break the 2012 low.  Such an event would likely have a number of people rethink / revise their estimates of the first year of a BOE.     
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Rod

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Re: When will the Arctic Go Ice Free?
« Reply #1652 on: July 07, 2020, 04:27:06 AM »
JNap, I’m not disagreeing with what you said, but don’t forget that big arctic high we had in late May.

There were lots of images showing surface melting. That caused a lot of preconditioning that is likely making the current conditions even worse for the ice.   

Phoenix

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Re: When will the Arctic Go Ice Free?
« Reply #1653 on: July 07, 2020, 05:46:57 AM »
It will be interesting to observe the overall effects of the strong arctic High pressure that has been centered over the CAB for the past 7 days -- and forecasted to continue for at least the next 5+ days.  At this point, it seems as though the GAH (Great Arctic High as I think that Freegrass labeled it) seems increasingly likely to be the event that defines the 2020 melt season. 

Looking beyond 2020, weather events like this that drive such a high level of solar insolation during peak solar season will happen again.  (Tealight may need to extend the AWP scale of his graphs.)  If it does happen during a year where we start with a lower volume and extent AND have an early melt in the high arctic peripheral seas with the lower albedo, it sets the stage to break the 2012 low.  Such an event would likely have a number of people rethink / revise their estimates of the first year of a BOE.   

There are going to be a lot of defining events for this melting season, some of which we don't know yet because we have a couple of months to go.

Certainly, the current peak melting situation is a big freaking deal and makes even people on the hopeful side like myself less confident about the future.

This will also be known as the year when covid potentially accelerated warming potential by a bunch of years via BAU interruption of atmospheric aerosols.

Another leading candidate is the incredible explosion of Siberian warming which has been widely publicized in mainstream media.

The early warming in May and the 1055+ hpa high pressure back then is also an important part of the story. There was also a crazy 1070 hpa high in March that didn't get much notice.

On the other hand, you'll have all of these above reasons why melting is so extreme and likely no record and perhaps we will better appreciate the importance of all the factors that go into setting a record. Perhaps there will be the greater appreciation for the importance of the relatively excellent 2019-2020 freezing season and the importance of consistency if the Beaufort continues to buck the overall trend and has the highest regional minimum of the century.

So far....I think 3-4 months of winter below 21st century average and a March dip below 1960's average temperature should share top billing with the current weather, Siberian heat explosion and aerosol reduction. A couple more months to go to still and more headlines to come.

It's all a crap shoot at this point and seemingly dependent on where the polar air mass decides to move around.


JNap

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Re: When will the Arctic Go Ice Free?
« Reply #1654 on: July 07, 2020, 08:35:01 PM »
Phoenix, my intent was not to dismiss the other events from earlier this year that you pointed out have helped to set up the current situation (e.g. early warming in May and the heat coming from Russia), rather it was to simply highlight the ice impact of the long run High Pressure during peak insolation.  IMHO, I am guessing that this High Pressure streak will be the event that most people will remember for the 2020 melt season -- unless something even more dramatic occurs later this summer.

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Phoenix

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Re: When will the Arctic Go Ice Free?
« Reply #1655 on: July 07, 2020, 09:18:41 PM »
Phoenix, my intent was not to dismiss the other events from earlier this year that you pointed out have helped to set up the current situation (e.g. early warming in May and the heat coming from Russia), rather it was to simply highlight the ice impact of the long run High Pressure during peak insolation.  IMHO, I am guessing that this High Pressure streak will be the event that most people will remember for the 2020 melt season -- unless something even more dramatic occurs later this summer.

I'm not trying to imply that there was anything wrong with your intent JNap.

I think you may be right in terms of how the ASIF community remembers the 2020 season as the community conversation heavily emphasizes extreme melting conditions.

There is not nearly the same level of interest here in winter weather which will arguably have a bigger impact on the 2020 outcome than the current high pressure environment. What took place in early March was pretty anomalous and there was almost no discussion of it as it was taking place. It's understandable in that ice growing in cold weather is relatively uneventful and unexciting. There aren't many moving parts to talk about as there are in summer. Same with the Beaufort story where the lack of action thus far is the noteworthy issue.

The world at large that doesn't follow the Arctic weather closely probably won't have much connection to the current high pressure environment. The kind of headlines that crack the average person's bandwidth so far are the 100F temp barrier in the Arctic Circle, scientists alarmed by Siberian heat and the permafrost driven oil spill in Russia.

JNap

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Re: When will the Arctic Go Ice Free?
« Reply #1656 on: July 07, 2020, 09:55:39 PM »
Totally agree with your point on the general population.   Maybe they become aware of 100 degree day in Siberia, maybe.  For the forum, there does seem be a focus on the melt season vs. the freezing season.
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oren

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Re: When will the Arctic Go Ice Free?
« Reply #1657 on: July 08, 2020, 06:09:27 AM »
...winter weather which will arguably have a bigger impact on the 2020 outcome than the current high pressure environment.
The 2020 winter gave an extra 20 cm average thickness to CAB ice (some of which was in the form of extra-thick ice near the Fram exit), partly at the price of too-thin ice on the Siberian side. 10 cm of this extra CAB thickness was already gone by the end of June, according to PIOMAS data.
Posts made on the melting season thread, which I am unable to personally verify, mentioned possible losses of several cm and up to 10cm per day, resulting from the heat dome and clear skies during peak insolation period - while the ice is at very low albedo thanks to its preconditioning in May and June.
Additional cold winter days contribute less and less to ice thickening due to the thermodynamics involved - freezing occurs at the bottom of the ice and is impeded by the insulation of the ice and snow layer - thus there is a negative feedback loop. Not that winter is unimportant, but there is a limit to its effect. On the other hand, additional sunny summer days contribute directly to ice thinning, as melting occurs at the top. In addition, continuous insolation reduces ice albedo (and also warms the water below the ice) and thus there is a positive feedback loop. This makes summer-induced variability potentially higher than winter-induced variability, should a stuck weather pattern come along. Note the above description does not include transport and export, which further complicates the issue.
So which can have the bigger impact, winter weather or summer weather? I think it's both. And when an unprecedented HP sits over the CAB at peak insolation, maybe it's best to wait for its outcome and only then reassess what we know of variabilities.

Some charts and statistics of past years, click to enlarge. Each line starts at day 266 (late Sep). All units in 1000s of km3. Will 2020 break volume loss records for late summer? We will know soon.
« Last Edit: July 08, 2020, 06:32:10 AM by oren »

Phoenix

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Re: When will the Arctic Go Ice Free?
« Reply #1658 on: July 08, 2020, 07:55:30 AM »
...winter weather which will arguably have a bigger impact on the 2020 outcome than the current high pressure environment.
The 2020 winter gave an extra 20 cm average thickness to CAB ice (some of which was in the form of extra-thick ice near the Fram exit), partly at the price of too-thin ice on the Siberian side. 10 cm of this extra CAB thickness was already gone by the end of June, according to PIOMAS data.
Posts made on the melting season thread, which I am unable to personally verify, mentioned possible losses of several cm and up to 10cm per day, resulting from the heat dome and clear skies during peak insolation period - while the ice is at very low albedo thanks to its preconditioning in May and June.
Additional cold winter days contribute less and less to ice thickening due to the thermodynamics involved - freezing occurs at the bottom of the ice and is impeded by the insulation of the ice and snow layer - thus there is a negative feedback loop. Not that winter is unimportant, but there is a limit to its effect. On the other hand, additional sunny summer days contribute directly to ice thinning, as melting occurs at the top. In addition, continuous insolation reduces ice albedo (and also warms the water below the ice) and thus there is a positive feedback loop. This makes summer-induced variability potentially higher than winter-induced variability, should a stuck weather pattern come along. Note the above description does not include transport and export, which further complicates the issue.
So which can have the bigger impact, winter weather or summer weather? I think it's both. And when an unprecedented HP sits over the CAB at peak insolation, maybe it's best to wait for its outcome and only then reassess what we know of variabilities.

Some charts and statistics of past years, click to enlarge. Each line starts at day 266 (late Sep). All units in 1000s of km3. Will 2020 break volume loss records for late summer? We will know soon.

I agree with you completely Oren that there are diminishing returns to temperature variance in the winter which are not applicable to summer. The return on investment is continually shrinking.

But the volume in the CAB went from 2nd place at the minimum to 9th place at the beginning of the melt season and put on an extra 700 km3 or 20 cm / m2 which created a nice buffer for the melt season to work through. So far, that buffer is proving useful in determining relative position. The winter was not just relevant in the CAB, but also in the Beaufort Sea and the knock on effects associated with the extra ice there from the winter might potentially make a world of difference in the outcome there as well.

I also agree that its best to wait until the outcome of 2020 is known before we reach any conclusions. If you read my comments to JNap, you will see my remarks to that effect.

I am not the originator here of the comments which aim to proclaim the top story of the season in advance. I am trying to come up with a list of all the important story lines that I can think are relevant and adding my personal emphasis on some things which I think are not naturally focused on here because they are not as exciting as unprecedented melting weeks.

The peak melt is very important though. Achieving a new level raises the vulnerability level to a real blowout. If we have the same melting season after a warmish winter and don't get lucky in the Beaufort, it's definitely a major disaster. It's important to try and understand the root causes of the new level which is why the covid / aerosol story is important and also to understand how much is related to the NH wind circulation breaking down.

Ultimately, this is all connected to human systems and there is going to be some reaction which may alter the trajectory of the ice in the future. I'm trying to find the elusive spot which conveys the seriousness and gravity of the AGW predicament without squashing the hope that something can be salvaged. I push back against both deniers and doomers. My contribution at ASIF should be interpreted as someone who is committed to hoping for a positive outcome.

oren

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Re: When will the Arctic Go Ice Free?
« Reply #1659 on: July 08, 2020, 08:50:43 AM »
Fine with all, but this hope (or doom for that matter) does not belong in the Cryosphere section. We follow the ice and the science objectively. Hope should be applied in policy and solutions, politics, and other social and economic issues on this site.

Stephan

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Re: When will the Arctic Go Ice Free?
« Reply #1660 on: July 12, 2020, 05:11:30 PM »
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 June value now includes 2020.
Volume, area and thickness for June 2020 lie a little bit above the long term trend lines, extent is at the trend line. The "BOE numbers" increased by averaged 2 years (area) and 1 year (volume) and decreased by 1 year (thickness) and 2 years (extent) compared to June 2019.
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. stg = slope.
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jens

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Re: When will the Arctic Go Ice Free?
« Reply #1661 on: July 14, 2020, 08:01:38 PM »
To look at the gradual step-by-step process of moving towards ice-free Arctic, I think we are bound to be very near a tipping point in which 3M km2 becomes the new "normal" and it would be unlikely to have years above 4M km2 any more. A bit like how recently the expectation has been to have a low 4M outcome and the last time a season ended up above 5M km2 was in 2009. Well, guess that's not going to happen any more.

So perhaps by late 2020's the further new normal could be around 2M km2 at the minimum with then a decent chance that a more intense outlier would end up at 1M.

That 1M dividing line is a bit artificial anyway and ultimately it wouldn't be a big difference if a year ended up being at 0.9M or 1.1M km2. I'm more interested in overall trends although each individual season is different and either above or below current "normal".

Climate change is speeding up and this does of course complicate the predictions somewhat. In accordance to this melting rates should accelerate too, but it's difficult to guess at which rate would this happen.

igs

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Re: When will the Arctic Go Ice Free?
« Reply #1662 on: July 14, 2020, 10:42:33 PM »
That 1M dividing line is a bit artificial anyway and ultimately it wouldn't be a big difference if a year ended up being at 0.9M or 1.1M km2. I'm more interested in overall trends although each individual season is different and either above or below current "normal".

I fully agree with this, it's totally arbitratrary and because it will be a huge difference between 1M km2 and i.e. 0.1 km2 I strictly oppose a threshold that is so far away/above a far worse real blue ocean.

I followed the discusstion when it started and it went like so often, a respected person came up with the proposal, the minors barely dared to contradict and by sheer repetition and discarding those with opinionion it stuck.
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gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #1663 on: July 14, 2020, 11:08:48 PM »
That 1M dividing line is a bit artificial anyway and ultimately it wouldn't be a big difference if a year ended up being at 0.9M or 1.1M km2. I'm more interested in overall trends although each individual season is different and either above or below current "normal".

I fully agree with this, it's totally arbitratrary and because it will be a huge difference between 1M km2 and i.e. 0.1 km2 I strictly oppose a threshold that is so far away/above a far worse real blue ocean.

I followed the discusstion when it started and it went like so often, a respected person came up with the proposal, the minors barely dared to contradict and by sheer repetition and discarding those with opinionion it stuck.
The 1 million km2 originally came from the IPCC  reports (I think)., and is in pretty much universal use.
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KiwiGriff

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Re: When will the Arctic Go Ice Free?
« Reply #1664 on: July 15, 2020, 02:43:40 AM »
If they used 0 as the base line you can just imagine the usual suspects and "look over there it's a chunk of sea ice in the artic"so we are not there yet and scientists are just alarmist bullshiters

Sebastian Jones

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Re: When will the Arctic Go Ice Free?
« Reply #1665 on: July 15, 2020, 07:23:52 AM »
If they used 0 as the base line you can just imagine the usual suspects and "look over there it's a chunk of sea ice in the artic"so we are not there yet and scientists are just alarmist bullshiters

That's part of it of course, but as I recall 1M was chosen because it was reckoned that that was the threshold at which the Arctic Ocean would start to behave like an ocean rather than like a frozen pond. Wind driven Eckman pumping mixing up the layers of water, for example.
1m km2 is considered a tipping point.

igs

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Re: When will the Arctic Go Ice Free?
« Reply #1666 on: July 15, 2020, 09:01:09 PM »
That 1M dividing line is a bit artificial anyway and ultimately it wouldn't be a big difference if a year ended up being at 0.9M or 1.1M km2. I'm more interested in overall trends although each individual season is different and either above or below current "normal".

I fully agree with this, it's totally arbitratrary and because it will be a huge difference between 1M km2 and i.e. 0.1 km2 I strictly oppose a threshold that is so far away/above a far worse real blue ocean.

I followed the discusstion when it started and it went like so often, a respected person came up with the proposal, the minors barely dared to contradict and by sheer repetition and discarding those with opinionion it stuck.
The 1 million km2 originally came from the IPCC  reports (I think)., and is in pretty much universal use.


Universal use does not make it more correct. IMO it's outright false and i also did not hint at any specific source because it does not matter and certainly I'm aware that the value was not created here. It's an "Universal" pattern how such values develop over and over again.


IPCC is huge body that is prone to interest groups, funding sources and political influence. Not a source I trust AT ALL and with good reason as can be seen on a day to day base.

Once they declare the arctic ice-free or a BOE and people look at sat-images and see a lot of ice left, this will be the point in time when the value will get changed or frowned upon by EVERYONE while not it's just a few.
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wili

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Re: When will the Arctic Go Ice Free?
« Reply #1667 on: July 15, 2020, 09:47:58 PM »
"Universal use does not make it more correct"

Actually, in language, which is pretty much what we are talking about (the definition of a term), it pretty much does.

You might not like it, but if everyone else says that a duck is something that quacks, waddles, and swims as well as flies...that's pretty much the definition of what a duck is, no matter how much you might not like it.
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The Walrus

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Re: When will the Arctic Go Ice Free?
« Reply #1668 on: July 15, 2020, 10:35:57 PM »
wili, I agree.  Years ago, ice-free was defined as less than 1 million square km, and has been the benchmark ever since.  One could argue that it has less significance than another benchmark with regards to weather, albedo, future warming, etc.  It was not entirely arbitrary as every year since measurements have been made have exceeded one million, and the first to fall short would be a milestone.  In the same way, we distinguish a millionaire from someone in the UMC.  In reality, there is little difference between a million and 900k, but the milestone has been broken.  At this point, everyone understands its usage, and there is little point arguing about it.

igs

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Re: When will the Arctic Go Ice Free?
« Reply #1669 on: July 15, 2020, 11:02:46 PM »
"Universal use does not make it more correct"

Actually, in language, which is pretty much what we are talking about (the definition of a term), it pretty much does.

You might not like it, but if everyone else says that a duck is something that quacks, waddles, and swims as well as flies...that's pretty much the definition of what a duck is, no matter how much you might not like it.


That's exactly who this planet has been brought to the verge of destruction. There are thousands of examples where the vast majority shared the same opinion and said the same and was totally wrong. One of the worst reasons I've ever heard.


In facte a wise man once said that if there is too much agreement on a debatable topic one shoud be alarmed. Somehow this is not important enough to go that far and I for my part will end it here.


But do not forget that the problems we are facing with the climate are based on human behavior and what we are discussing is interpretation of the symptoms. That means whenever someone brings up an underlaying flaw in human behavior it's very much ON TOPIC and the resistance of most people's subconsious minds is basically proof that something's not quite right.


I did not hear one real reason why 1M should be THE number and yes, the diff. between 0.9 and 1M is small but the diff. between 1M and 0.1 is huge, which is when the human eye will agree to the term "ice-free" or "blue-ocean"

I'm too old to see that day most probably but remember when it happens and observe the dispute about whether that much ice can be considered ice-free and pay special attention to all the excuses that will pop up to explain why it was inevitable to be wrong.
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Ken Feldman

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Re: When will the Arctic Go Ice Free?
« Reply #1670 on: July 15, 2020, 11:15:30 PM »
The "ice free" definition was set at less than 1 million square km because there will be many years when the thick ice near Greenland and the CAA won't melt out but the rest of the Arctic will be ice free.  So you'll have deniers claiming that a BOE isn't a BOE because there's still 100,000 to 900,000 of ice around the fringes.

https://en.wikipedia.org/wiki/Arctic_sea_ice_decline#cite_note-AR5-4

Quote
An "ice-free" Arctic Ocean is often defined as "having less than 1 million square kilometers of sea ice", because it is very difficult to melt the thick ice around the Canadian Arctic Archipelago.[20][21][22] The IPCC AR5 defines "nearly ice-free conditions" as sea ice extent less than 106 km2 for at least five consecutive years.[4]


HapHazard

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Re: When will the Arctic Go Ice Free?
« Reply #1671 on: July 15, 2020, 11:25:30 PM »
So I guess dictionaries are useless. Concrete definitions should be abolished, and I should remove the lines on my tape measure and speedometer.

C'mon.

oren

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Re: When will the Arctic Go Ice Free?
« Reply #1672 on: July 15, 2020, 11:44:20 PM »
Let's not get bogged too much in definitions. This thread is about when will the Arctic be virtually ice-free, less than 1M km2, for the first year. Not the updated and poliltically-motivated IPCC definition of 5 consecutive years, and not the layman zero ice definition.
Whoever wants to discuss when the Arctic will be totally ice free, zero, is welcome to discuss this separately.

Glen Koehler

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Re: When will the Arctic Go Ice Free?
« Reply #1673 on: July 16, 2020, 12:51:36 AM »
Let's not get bogged too much in definitions.
    At the cost of adding one more distracting message, I feel compelled to congratulate and thank Oren for superb moderator service during what is turning out to be quite a rodeo this year as the ASI appears to enter the next phase.  You've handled the usual food fights, occassional personality disorders, and the inevitable cases of topic drift with a diplomatic and effective aplomb.

Hefaistos

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Re: When will the Arctic Go Ice Free?
« Reply #1674 on: July 16, 2020, 06:27:22 AM »


Quote
An "ice-free" Arctic Ocean is often defined as "having less than 1 million square kilometers of sea ice", because it is very difficult to melt the thick ice around the Canadian Arctic Archipelago.[20][21][22] The IPCC AR5 defines "nearly ice-free conditions" as sea ice extent less than 106 km2 for at least five consecutive years.[4]

10^6 km2

jens

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Re: When will the Arctic Go Ice Free?
« Reply #1675 on: July 16, 2020, 09:18:47 AM »
That's part of it of course, but as I recall 1M was chosen because it was reckoned that that was the threshold at which the Arctic Ocean would start to behave like an ocean rather than like a frozen pond. Wind driven Eckman pumping mixing up the layers of water, for example.
1m km2 is considered a tipping point.

1M is just a nice round number for humans to operate with. But nature doesn't operate with "nice round numbers". Whether the real tipping point would be at 1.489M, 1.221M or 0.897 km2 nobody knows.

Of course we as humans simplify matters a bit and then we discuss about 1M km2 here in this topic too. Well, I guess it makes more sense than discussing when would Arctic be below 1.159 km2. Fair enough. But at the very least let's not pretend that a nice round number is how nature actually operates. That's all I'm saying. It's just a threshold for human mind to try to make sense of the world.

The Walrus

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Re: When will the Arctic Go Ice Free?
« Reply #1676 on: July 16, 2020, 03:40:12 PM »
Well put jens.  Why don't we all just agree and leave it at that.  If anyone wants to discuss a different value, start a new thread.

Glen Koehler

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Re: When will the Arctic Go Ice Free?
« Reply #1677 on: July 19, 2020, 03:35:48 AM »
Vox_mundi posted a Navy Arctic Roadmap https://forum.arctic-sea-ice.net/index.php/topic,3183.msg275158.html#msg275158
   That document has an interesting graphic showing projected of ASI Extent in 2030 vs 2012. 
    A rough eyeball comparison of the area for their 2030 area suggests that it is about 30% of the 2012 area. 
    Given that 2012 JAXA & NSIDC Exent minimums were 3.18 and 3.41 million km2, respectively, the 2030 Navy projection at ~30% of 2012, is a pretty close fit to what a 1 million km2 September minimum BOE event would look like.

     When that happens, it will be a headline for a day, and the ice will begin winter increase shortly thereafter, and humanity will go back to ignoring planetray climate disruption.  Or perhaps we will be wiser by then.  A lot can happen in 10 years.  It certainly will for the Arctic ice.  The question is whether human response will evolve accordingly.  Vote Climate as if your life depended on it.  Annoy your famiy and friends by harping on it.  They will love you for it later.

« Last Edit: July 19, 2020, 04:07:18 AM by Glen Koehler »

Archimid

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Re: When will the Arctic Go Ice Free?
« Reply #1678 on: July 19, 2020, 06:12:39 AM »
 Lately, I've come to think of the BOE as different event than an ice free arctic. I think a BOE implies more than just a small area of ice. A BOE implies a shift from arctic conditions to oceanic conditions across all the arctic ocean. That can only be achieved after an ice free arctic is achieved early in the melting season.  A late ice free arctic will not immidiatly cause a BOE.

There have been discussions in the past that defines a BOE as an N80 average surface temperature well above the historic average. The arctic becomes a "warm" ocean layer, not a frozen dry desert layer. An ice-free arctic as defined by Oren above seems like the prelude to the first BOE, not a BOE.

It is worth trying to guess if and when it will happen.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

prokaryotes

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Re: When will the Arctic Go Ice Free?
« Reply #1679 on: July 21, 2020, 01:14:03 AM »
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Tony Mcleod

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Re: When will the Arctic Go Ice Free?
« Reply #1680 on: July 21, 2020, 02:51:49 AM »
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 June value now includes 2020.
Volume, area and thickness for June 2020 lie a little bit above the long term trend lines, extent is at the trend line. The "BOE numbers" increased by averaged 2 years (area) and 1 year (volume) and decreased by 1 year (thickness) and 2 years (extent) compared to June 2019.
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. stg = slope.

Hi Stephen, I would like to understand your table better could you please explain it in a little more detail.

Tony Mcleod

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Re: When will the Arctic Go Ice Free?
« Reply #1681 on: July 21, 2020, 03:25:52 AM »
If they used 0 as the base line you can just imagine the usual suspects and "look over there it's a chunk of sea ice in the artic"so we are not there yet and scientists are just alarmist bullshiters

That is exactly the sort of fodder the paid deniers look for to conjure up doubt and disinformation. It spreads to the echo chambers, confirms the biases and ends up on Fox adding to the polarisation. It is already primed via the "they said it would be ice free by xxxx..." meme.

One way to minimize this is to always frame it in terms of a BOE. You can see blue ocean with your own two eyes, very soon there will be lots of it and no denying. Using the term "ice free", whatever your definition, will attract denial because it can reverse for a year or three then cherry-pickers will prove you're wrong: "they told us the ice was gone...". Events are less final so there is nothing to deny.

IMHO "When will there be a BOE?" would be a much better title for this thread.

oren

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Re: When will the Arctic Go Ice Free?
« Reply #1682 on: July 21, 2020, 03:56:08 AM »
To do some justice, the official term by the IPCC is "nearly ice free".

Stephan

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Re: When will the Arctic Go Ice Free?
« Reply #1683 on: July 21, 2020, 07:37:04 PM »
Hi Stephen, I would like to understand your table better could you please explain it in a little more detail.

Hi Tony,

I collect all monthly averages from NSIDC and PIOMAS in four individual spreadsheets. Then I create the plots of area, extent, volume and thickness vs. time.

I then select every data row (one for each month) and apply a linear and a logarithmic function for each of these four values (area, extent, volume and thickness) for every month. Then I calculate when these functions reach zero (the x axis, this is my "BOE number"). These values are then summarized in the big colourful table I present here every month. In addition I add the slope of the linear function into that big table. From this you can see that the slope is much steeper in the summer and autumn months than for the rest of the year.

Every month a new set of values is included into the spreadsheets and then I recalculate the BOE number and compare it to the value I had calculated a year ago. These differences are usually very small (we are in the 42nd year of satellite observation), but they are not negligible.

In the end once volume disappears in the mid 2020s the other values (area, extent and thickness) also tend to zero. This discrepancy (or mismatch) has been widely discussed in this thread about 2 years ago.

I hope this explanation helps a little. If you have further questions, don't hesitate to ask further questions.

kind regards from Germany Stephan

PS: I am well aware that "BOE" is defined as an area of 1 M km² and not 0 M km² of ice.
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werther

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Re: When will the Arctic Go Ice Free?
« Reply #1684 on: July 21, 2020, 07:54:10 PM »
On Glen's graphic: that 2020 margin actually corresponds to some excursions in my old CAD-analyses. Based on what I saw this morning through Worldview Manati-star image and the forecasts for the next two weeks I suppose the september minimum will be somewhere between 2.8 and 3.1 Mkm2.
Some Beaufort MYI (2-4 y old), part of the CAA channel ice and the Greenland Sea-tongue included in this forecast. Very deep incursion in the CAB from the ESS sector but not (yet) over the Northpole.

ShortBrutishNasty

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Re: When will the Arctic Go Ice Free?
« Reply #1685 on: July 21, 2020, 11:01:28 PM »
I think we are all indebted to Prokaryotes for his wonderful videos!

I watched his latest vid (this thread July 20, 2020, 06:14:03 PM) and then delved into his ASIF Post History.  That's some website he's pushing

SB&N

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« Last Edit: July 21, 2020, 11:14:44 PM by oren »
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Tony Mcleod

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Re: When will the Arctic Go Ice Free?
« Reply #1686 on: July 22, 2020, 09:58:11 AM »
Hi Stephen, I would like to understand your table better could you please explain it in a little more detail.

Hi Tony,

I collect all monthly averages from NSIDC and PIOMAS in four individual spreadsheets. Then I create the plots of area, extent, volume and thickness vs. time.

I then select every data row (one for each month) and apply a linear and a logarithmic function for each of these four values (area, extent, volume and thickness) for every month. Then I calculate when these functions reach zero (the x axis, this is my "BOE number"). These values are then summarized in the big colourful table I present here every month. In addition I add the slope of the linear function into that big table. From this you can see that the slope is much steeper in the summer and autumn months than for the rest of the year.

Every month a new set of values is included into the spreadsheets and then I recalculate the BOE number and compare it to the value I had calculated a year ago. These differences are usually very small (we are in the 42nd year of satellite observation), but they are not negligible.

In the end once volume disappears in the mid 2020s the other values (area, extent and thickness) also tend to zero. This discrepancy (or mismatch) has been widely discussed in this thread about 2 years ago.

I hope this explanation helps a little. If you have further questions, don't hesitate to ask further questions.

kind regards from Germany Stephan

PS: I am well aware that "BOE" is defined as an area of 1 M km² and not 0 M km² of ice.

Sorry Stephan, I seem to be missing something because try as I might I just do not know how to interpret that table (It might just be me ofcourse :P...). "x axis, this is my "BOE number". I don't see an "x axis" or any "trend lines" or even any years. You mention stg=slope, the slope of what? Maybe if you walk me through an example.

oren

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Re: When will the Arctic Go Ice Free?
« Reply #1687 on: July 22, 2020, 11:15:21 AM »
Let me try to formulate an answer and see if I understand this myself.
X axis is years.
Y axis is each of the monthly-average parameters Stephan tracks (area, extent, volume, thickness).
Slope (negative) is the of the linear trend line of the previous years (1979-2020).
A line is approximated for each parameter, for each month of the year, and its slope is calculated.
BOE value is where the extrapolated line hits zero. For each given line, for Y=0, what X?

Take July volume. The slope of the linear trend is minus 0.359. This is the average loss per year. Given the current value of the trend line (not provided) and the slope, it is calculated to hit zero at year 2034.
Sharper slopes are highlighted with orange and yellow colors.
The same "BOE value" is calculated for a logarithmic trend, however I assume the provided slope is for the linear one.

glennbuck

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Re: When will the Arctic Go Ice Free?
« Reply #1688 on: July 23, 2020, 12:36:45 AM »
I vote 2020-2025 tried to vote on graph but does not seem to work.

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Re: When will the Arctic Go Ice Free?
« Reply #1689 on: July 23, 2020, 01:02:58 AM »
I vote 2020-2025 tried to vote on graph but does not seem to work.
voting closed 2018

Stephan

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Re: When will the Arctic Go Ice Free?
« Reply #1690 on: July 23, 2020, 09:01:58 PM »
Hi Tony,

I attach two of my graphs from which I calculate my BOE number.
Maybe this explains a little bit better what I did.

(sorry that the trend lines are a litle bit too thin, but I hope you can see them)

kind regards Stephan

PS: Oren: You are completely right  :)
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Tony Mcleod

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Re: When will the Arctic Go Ice Free?
« Reply #1691 on: July 24, 2020, 07:13:02 AM »
Hi Tony,

I attach two of my graphs from which I calculate my BOE number.
Maybe this explains a little bit better what I did.

(sorry that the trend lines are a litle bit too thin, but I hope you can see them)

kind regards Stephan

PS: Oren: You are completely right  :)

Yes thank you Stephen and Oren for clarifying that for me.

Pmt111500

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Re: When will the Arctic Go Ice Free?
« Reply #1692 on: July 24, 2020, 08:03:43 AM »
Thanks Stephan for this look on the volume numbers. Back when I thought area numbers by Ct were directly comparable to reports of other organizations on sea ice did weekly graphs (oh, 7 years have passed, anyway starting from here: https://forum.arctic-sea-ice.net/index.php/topic,194.0.html

Monthly ice volume decrease could give the most accurate estimate of this
Cooling the outside by heat pump.

Glen Koehler

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Re: When will the Arctic Go Ice Free?
« Reply #1693 on: July 24, 2020, 07:10:45 PM »
I attach two of my graphs from which I calculate my BOE number.
      Thanks Stephan.  Can you repost those charts with X year axis going out to 2075 instead of ending at 2025?

     BOE in September is our big marker only because it is the first one up to bat.  But also interesting to see the trend lines for Extent and Volume levels for August, July, June etc. out to 2075.  The decline in ice coverage in those months has a much greater effect on solar radiation absorbtion and is much more important for planetary energy budget.

     Your chart indicates about a 20 lag between June vs. July. If we think 2020 is dramatic, imagine the impact of having the ice in its current condition coinciding with June 21 summer solstice.
« Last Edit: July 24, 2020, 07:22:11 PM by Glen Koehler »

kassy

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Re: When will the Arctic Go Ice Free?
« Reply #1694 on: July 24, 2020, 07:36:35 PM »
I think you are underestimating the carry over heat (interesting growing seasons with specific seas closing later or not at all) and the damage done already. The atlantic waters flowing in where there was ice but now is none and mixing.

Plot the ice that is regrowing in the last few years. Project ahead. Possibly reconsider 2075.
You need like 1m20 or so for a lame season and then having thicker ice around helps.

Excel earth looks healthy compared to our one 100% trustworthy analog.
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Stephan

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Re: When will the Arctic Go Ice Free?
« Reply #1695 on: July 24, 2020, 07:53:00 PM »
Please find the two charts now in the time frame from 1975 to 2100. The trend lines are bolder now for better visibility. (October and August volume trend lines are now superimposed; there is no trend line missing)
Important note: Extrapolations into the far future offer very little guidance. So please do not shout at me when the December volume does not reach zero in 2062 but ten years earlier or later...  ;)
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glennbuck

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Re: When will the Arctic Go Ice Free?
« Reply #1696 on: July 24, 2020, 11:12:50 PM »
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.

Quote below from the paper.

Specifically, the rapidity of environmental change associated with the loss of albedo indicates industrial civilization will fail shortly after the Arctic Ocean becomes ice-free.

Finally, the ongoing release of methane from the relatively shallow seafloor of the Arctic Ocean is expected to accelerate when the ice disappears.  Atmospheric  methane  began  to  rise  exponentially  in  2007 after a 7-year period of near-zero growth [17]. By 2013, it became clear that “significant quantities of methane are escaping the East Siberian Shelf as a result of the degradation of submarine permafrost over thousands of years” [18]

 https://opastonline.com/wp-content/uploads/2020/07/the-role-of-conservation-biology-in-understanding-the-importance-of-arctic-sea-ice-eesrr-20-.pdf

The Walrus

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Re: When will the Arctic Go Ice Free?
« Reply #1697 on: July 24, 2020, 11:20:09 PM »
That was written by Guy McPherson.  He is a noted end-timer, proclaiming the extinction of all life on earth by 2026.  I have not given him much credence.

glennbuck

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Re: When will the Arctic Go Ice Free?
« Reply #1698 on: July 24, 2020, 11:34:53 PM »
That was written by Guy McPherson.  He is a noted end-timer, proclaiming the extinction of all life on earth by 2026.  I have not given him much credence.

Oh ok i do believe we are in trouble and in a climate crisis, climate scientists say we are in a six mass extinction event and as animals become extinct that involves us Humans animals too. If we raise the temperature too much and the Arctic ice free adds a feedback loop to rising temperatures then Famine could kill many Billions of Humans but not necessarily all humans on Earth.

https://www.theguardian.com/environment/2017/jul/10/earths-sixth-mass-extinction-event-already-underway-scientists-warn
« Last Edit: July 24, 2020, 11:56:05 PM by glennbuck »

oren

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Re: When will the Arctic Go Ice Free?
« Reply #1699 on: July 25, 2020, 12:38:58 AM »
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.