Support the Arctic Sea Ice Forum and Blog

Author Topic: How soon could we go ice free?  (Read 66034 times)

Shared Humanity

  • Guest
Re: How soon could we go ice free?
« Reply #200 on: June 30, 2018, 05:20:38 PM »
Nice article at https://www.carbonbrief.org/atlantification-arctic-sea-tipping-towards-new-climate-regime

Specifically on the process of Atlantification of the Barents Sea. It seems that the process that inhibits winter re-freeze is the key. I attach a graph that seems to illustrate that (though 2018 bucked the trend).

And I've added an image from the article.

Barents bucking the trend could be due to ice transport not freezing. Did we see significant ice transport from the CAB into the Barents this winter?

Pagophilus

  • Grease ice
  • Posts: 705
    • View Profile
  • Liked: 434
  • Likes Given: 581
Re: How soon could we go ice free?
« Reply #201 on: June 30, 2018, 08:58:56 PM »
Thanks for the useful graph gerontocrat. 

2018 might also seem to 'buck the trend' since it is an individual year plot, which could be expected to show more variability than a multi-year average plot.  2018 seems firmly back on track now... (and indeed all the plots smooth out after May).

Nice article at https://www.carbonbrief.org/atlantification-arctic-sea-tipping-towards-new-climate-regime

Specifically on the process of Atlantification of the Barents Sea. It seems that the process that inhibits winter re-freeze is the key. I attach a graph that seems to illustrate that (though 2018 bucked the trend).

Barents bucking the trend could be due to ice transport not freezing. Did we see significant ice transport from the CAB into the Barents this winter?
You may delay, but time will not.   Benjamin Franklin.

Ned W

  • Guest
Re: How soon could we go ice free?
« Reply #202 on: September 07, 2018, 01:57:58 PM »
[Moved from the 2018 area & extent data thread]


Earlier this summer I posted four scenarios for extent loss:

https://forum.arctic-sea-ice.net/index.php/topic,2057.msg158764.html#msg158764

In one of them, extent doesn't approach zero until the 2070s.  At the opposite extreme it happens around 2022.  I mildly prefer the 2035 scenario, but it could be much earlier or much later.

Here are the scenarios, see the earlier post for comments:








For 2018, one can mentally add an additional point at the end of each of those graphs, at or slightly above the value of the previous endpoint (2017).

Dharma Rupa

  • Frazil ice
  • Posts: 493
    • View Profile
  • Liked: 52
  • Likes Given: 26
Re: How soon could we go ice free?
« Reply #203 on: September 07, 2018, 03:05:08 PM »
[Moved from the 2018 area & extent data thread]


Earlier this summer I posted four scenarios for extent loss:

https://forum.arctic-sea-ice.net/index.php/topic,2057.msg158764.html#msg158764


I think it will be some variant of scenario 4, except I wouldn't know which year.  I think "the end" will come suddenly, and I don't think anyone has a handle on when that end will happen.

Basically, I expect the Arctic Cell collapsing and the CAB becoming part of the Atlantic to happen at the same time -- I just don't know the time.

jdallen

  • Young ice
  • Posts: 3410
    • View Profile
  • Liked: 650
  • Likes Given: 244
Re: How soon could we go ice free?
« Reply #204 on: September 07, 2018, 04:59:07 PM »
[Moved from the 2018 area & extent data thread]


Earlier this summer I posted four scenarios for extent loss:

https://forum.arctic-sea-ice.net/index.php/topic,2057.msg158764.html#msg158764


I think it will be some variant of scenario 4, except I wouldn't know which year.  I think "the end" will come suddenly, and I don't think anyone has a handle on when that end will happen.

Basically, I expect the Arctic Cell collapsing and the CAB becoming part of the Atlantic to happen at the same time -- I just don't know the time.
Good arguments behind that happening.  It would be a natural follow-on from a point I made earlier.  Once the enthalpy in the Arctic builds up to a sufficiently high level we could easily see major changes in heat transport that will rapidly flip the system into an entirely new state.
This space for Rent.

Dharma Rupa

  • Frazil ice
  • Posts: 493
    • View Profile
  • Liked: 52
  • Likes Given: 26
Re: How soon could we go ice free?
« Reply #205 on: September 07, 2018, 08:36:02 PM »
[Moved from the 2018 area & extent data thread]


Earlier this summer I posted four scenarios for extent loss:

https://forum.arctic-sea-ice.net/index.php/topic,2057.msg158764.html#msg158764


I think it will be some variant of scenario 4, except I wouldn't know which year.  I think "the end" will come suddenly, and I don't think anyone has a handle on when that end will happen.

Basically, I expect the Arctic Cell collapsing and the CAB becoming part of the Atlantic to happen at the same time -- I just don't know the time.
Good arguments behind that happening.  It would be a natural follow-on from a point I made earlier.  Once the enthalpy in the Arctic builds up to a sufficiently high level we could easily see major changes in heat transport that will rapidly flip the system into an entirely new state.

OK.  We agree on the what, but what about the when?  I am inclined to think it will be soon, but so far I have seen nothing persuasive to argue sooner or later.  I think it will be soon simply because the Industrial Revolution started in the early 1800s; which is not a good argument for timing.  I think asking for timing from the global models is simply casting bones.

magnamentis

  • Guest
Re: How soon could we go ice free?
« Reply #206 on: September 07, 2018, 08:49:17 PM »
[Moved from the 2018 area & extent data thread]


Earlier this summer I posted four scenarios for extent loss:

https://forum.arctic-sea-ice.net/index.php/topic,2057.msg158764.html#msg158764


I think it will be some variant of scenario 4, except I wouldn't know which year.  I think "the end" will come suddenly, and I don't think anyone has a handle on when that end will happen.

Basically, I expect the Arctic Cell collapsing and the CAB becoming part of the Atlantic to happen at the same time -- I just don't know the time.
Good arguments behind that happening.  It would be a natural follow-on from a point I made earlier.  Once the enthalpy in the Arctic builds up to a sufficiently high level we could easily see major changes in heat transport that will rapidly flip the system into an entirely new state.

in this thread i agree 100%, just not in the "year round thread" ;) ;)

5 years are still pessimistic (considering we don't WANT to see a BOE any time soon) but as you say, the possibility for a sudden death of summer sea-ice cannot be entirely discarded.


Tor Bejnar

  • Young ice
  • Posts: 4606
    • View Profile
  • Liked: 879
  • Likes Given: 826
Re: How soon could we go ice free?
« Reply #207 on: September 07, 2018, 08:52:48 PM »
An alternative: we could try actually casting bones! ;D ::) :P
If they float, BOE this year; if they land, BOE in a geologic 'instant'.
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

karl dubhe2

  • New ice
  • Posts: 82
    • View Profile
  • Liked: 27
  • Likes Given: 31
Re: How soon could we go ice free?
« Reply #208 on: September 07, 2018, 09:16:22 PM »
I do believe that it could go ice free this year, iff there was an incoming large asteroid that happened to hit  the floating ice at the North Pole.  :)  That would melt the stuff, mix up the ocean's water, and be one heck of a disaster.

Needless to say, that's an unlikely scenario.  Maybe I should pitch it to Hollywood...

Dharma Rupa

  • Frazil ice
  • Posts: 493
    • View Profile
  • Liked: 52
  • Likes Given: 26
Re: How soon could we go ice free?
« Reply #209 on: September 07, 2018, 09:37:43 PM »
[Moved from the 2018 area & extent data thread]


Earlier this summer I posted four scenarios for extent loss:

https://forum.arctic-sea-ice.net/index.php/topic,2057.msg158764.html#msg158764


I think it will be some variant of scenario 4, except I wouldn't know which year.  I think "the end" will come suddenly, and I don't think anyone has a handle on when that end will happen.

Basically, I expect the Arctic Cell collapsing and the CAB becoming part of the Atlantic to happen at the same time -- I just don't know the time.
Good arguments behind that happening.  It would be a natural follow-on from a point I made earlier.  Once the enthalpy in the Arctic builds up to a sufficiently high level we could easily see major changes in heat transport that will rapidly flip the system into an entirely new state.

in this thread i agree 100%, just not in the "year round thread" ;) ;)

5 years are still pessimistic (considering we don't WANT to see a BOE any time soon) but as you say, the possibility for a sudden death of summer sea-ice cannot be entirely discarded.

I don't care to predict the end of Summer Ice, since I don't think anyone has any real handle on that, but I say that when the Summer Ice goes the Winter Ice will soon, if not immediately, follow.

The collapse of the Arctic cell and Atlantification will feed each other to end it.

P.S.  I am only talking about the CAB.  Ice near the continents might keep showing up for decades.
« Last Edit: September 07, 2018, 09:43:51 PM by Dharma Rupa »

Klondike Kat

  • Grease ice
  • Posts: 842
    • View Profile
  • Liked: 40
  • Likes Given: 56
Re: How soon could we go ice free?
« Reply #210 on: September 08, 2018, 02:16:06 PM »
[Moved from the 2018 area & extent data thread]


Earlier this summer I posted four scenarios for extent loss:

https://forum.arctic-sea-ice.net/index.php/topic,2057.msg158764.html#msg158764


I think it will be some variant of scenario 4, except I wouldn't know which year.  I think "the end" will come suddenly, and I don't think anyone has a handle on when that end will happen.

Basically, I expect the Arctic Cell collapsing and the CAB becoming part of the Atlantic to happen at the same time -- I just don't know the time.
Good arguments behind that happening.  It would be a natural follow-on from a point I made earlier.  Once the enthalpy in the Arctic builds up to a sufficiently high level we could easily see major changes in heat transport that will rapidly flip the system into an entirely new state.

in this thread i agree 100%, just not in the "year round thread" ;) ;)

5 years are still pessimistic (considering we don't WANT to see a BOE any time soon) but as you say, the possibility for a sudden death of summer sea-ice cannot be entirely discarded.

I don't care to predict the end of Summer Ice, since I don't think anyone has any real handle on that, but I say that when the Summer Ice goes the Winter Ice will soon, if not immediately, follow.

The collapse of the Arctic cell and Atlantification will feed each other to end it.

P.S.  I am only talking about the CAB.  Ice near the continents might keep showing up for decades.

I cannot say that I agree.  Why would the ice in the center of the ocean make that much more difference than the ice near shore?  The ice will retreat slowly (sometimes more rapidly) towards land.  I would expect the effects of this to be roughly proportion to the amount of ice present.  Why would the loss of 80% of the ice make that much more difference than 60%?

Dharma Rupa

  • Frazil ice
  • Posts: 493
    • View Profile
  • Liked: 52
  • Likes Given: 26
Re: How soon could we go ice free?
« Reply #211 on: September 08, 2018, 02:30:54 PM »
...
I don't care to predict the end of Summer Ice, since I don't think anyone has any real handle on that, but I say that when the Summer Ice goes the Winter Ice will soon, if not immediately, follow.

The collapse of the Arctic cell and Atlantification will feed each other to end it.

P.S.  I am only talking about the CAB.  Ice near the continents might keep showing up for decades.

I cannot say that I agree.  Why would the ice in the center of the ocean make that much more difference than the ice near shore?  The ice will retreat slowly (sometimes more rapidly) towards land.  I would expect the effects of this to be roughly proportion to the amount of ice present.  Why would the loss of 80% of the ice make that much more difference than 60%?

The Arctic Cell is already in the process of collapsing.  That is what all the Jet Stream talk is about.  It is collapsing because of the reduction in sea ice.  When it collapses completely then the climate over the Arctic Ocean will be much like that over the North Atlantic, reinforcing the end of the Arctic Cell and the sea ice.

The continents are not going to warm in Winter nearly as quickly, therefore you are likely to find ice near (surrounded by) land.


Pmt111500

  • Guest
Re: How soon could we go ice free?
« Reply #212 on: September 08, 2018, 03:04:12 PM »
... iff there was an incoming large asteroid that happened to hit  the floating ice at the North Pole.  ....
Needless to say, that's an unlikely scenario.  Maybe I should pitch it to Hollywood...
 

::) ;D :D ;)

jdallen

  • Young ice
  • Posts: 3410
    • View Profile
  • Liked: 650
  • Likes Given: 244
Re: How soon could we go ice free?
« Reply #213 on: September 08, 2018, 08:45:04 PM »
An alternative: we could try actually casting bones! ;D ::) :P
If they float, BOE this year; if they land, BOE in a geologic 'instant'.
Tor, you owe me screen cleaning tools.  ;D
This space for Rent.

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #214 on: September 13, 2018, 09:27:55 PM »
OPEN WATER SEAS
A Blue Ocean Event is when the Arctic Seas (even for one day) become an open water sea. We all look at the ice , when perhaps we should be looking at the change to Open Water Seas with a maritime climate as opposed to ice-covered deserts. This is what this series of posts is all about.

Ice Area is the measure that best shows for each of the 14 Arctic Seas (and the Arctic Seas in total) the amount of each sea covered by ice. It is that measure as a proportion of the area of each sea (and the total area of the Arctic seas) that indicates the balance between a maritime or sea-ice climate environment. So the area of each sea is the measure against which sea ice area is measured.

Measuring the Open Water proportion is a simple calculation.
1.    Average Daily Ice Area for each year = Sum of the sea ice area for the 365 days of the year and  divide by 365
2.   Divide by the area of the sea to give the proportion of sea covered by ice during the year.
3.   Then Open Water Percentage is 1 minus the proportion of sea covered by ice during the year expressed as a percentage.

This has also been done for
- March, when sea ice is at the maximum,
- September, when sea ice is at the minimum,
- The year to date.
________________________________________________________________________
The Arctic Seas are in very different environments. I have done some rough groupings. This first grouping is about bbr's favorite part of the world - Hudson Bay, the Baffin Sea, and the Canadian Archipelago (CAA). The graphs are attached.

The most striking feature is that the average open water of all three seas has changed very little over the 4 decades. One would think AGW has passed them by. Baffin and Hudson Bay are "Blue Ocean" seas for the month and September (and longer) while the CAA is between 60 to 70 percent open water in this minimum month.

On average, the CAA is only 20-30% open water, very much an ice desert, completely so in winter.
The Baffin Sea (includes the Labrador Sea) is around 70% open water on average, and 40% during the minimum month. On balance, very much an open water sea.
Hudson Bay is around 50% open water on average, and almost zro during the minimum month. On balance, neither one nor the other.

One wonders when increasing Arctic temperatures will really impact these seas.
« Last Edit: September 13, 2018, 09:40:18 PM by gerontocrat »
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Archimid

  • Young ice
  • Posts: 3511
    • View Profile
  • Liked: 899
  • Likes Given: 206
Re: How soon could we go ice free?
« Reply #215 on: September 14, 2018, 12:03:47 AM »
I though the BOE was going to happen in 2016, concurrent with peak global temperatures. It didn’t happen.

When will it happen depends on whether global temperatures enter another hiatus or they keep climbing. If we enter another hiatus we may have a decade until the next peak planetary temperature destroys the Arctic. If temperatures keep climbing it will happen much sooner.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

johnm33

  • Guest
Re: How soon could we go ice free?
« Reply #216 on: September 14, 2018, 11:54:52 AM »
"One wonders when increasing Arctic temperatures will really impact these seas."
A significant fraction of the Arctics freshwater passes through these seas, the more the CAA melts the larger that fraction. I think a good proxy for this flow are the sea levels on the eastern seaboard, the inert arctic waters pressing hard against the continent as they move south, sufficient to slow the Gulf stream. With less ice there may be a threshold when the Russian rivers form their own seasonal freshwater current, think of the Amazons penetration into the Atlantic, that reaches the CAA. These seas may well be the last refuge for ice.

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #217 on: September 14, 2018, 12:50:15 PM »
OPEN WATER SEAS
A Blue Ocean Event is when the Arctic Seas (even for one day) become an open water sea. We all look at the ice , when perhaps we should be looking at the change to Open Water Seas with a maritime climate as opposed to ice-covered deserts. This is what this series of posts is all about.

The graphs look at open water (i.e. free of ice) as a percentage of the area of each sea. The sea ice measure used is NSIDC ice area
________________________________________________________________________
The Arctic Seas are in very different environments. I have invented some rough groupings. This second grouping I have named the Pacific Gateway, being the Bering and Chukchi seas. The graphs are attached.

The Bering Sea was around 80% ice free, with minimum open water during March of around 40% until the late 2000's.
From 1979 the sea has been ice free for 3 or more months of the year. 

Then in 2012 something very strange happened. While the Arctic as a whole was undergoing record melt, the reverse happened in this sea, the average ice free percentage dropping to around 55%, minimum open water during March down to less than 10%.

Since then ice has rapidly declined. Open water during the sea ice maximum sea ice month of March has risen from less than 10% in 2012 to over 80% in 2018. Average open water for 2018 looks set to be above 90%.

This is new. Is the Bering Sea going through a permanent sea change towards a truly open water maritime climate sea?

The Chukchi Sea
An open Bering Sea, in theory, promotes ocean warmth entering the Arctic Ocean which in turn assists melting of the Chukchi. Does the data support this, i.e. changes in the Bering apparent in the Chukchi ? Not really - until 2012.

Until 2012, average open water gradually increased over time from 20% to 40%, maximum open water in September from around 60% to nearly 100%, and minimum open water in March at around 5% or less. However, in 2012 there was a significant drop in open water average to 35%, and a more significant drop in maximum open water from 100% to 85%. Since that date, the upward trend in open water has been restored.

If the Bering Sea continues the trend to year round open water maybe the consequences for the sea ice in the Chukchi will be significant.

"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Shared Humanity

  • Guest
Re: How soon could we go ice free?
« Reply #218 on: September 14, 2018, 02:54:07 PM »
While the Bering Sea at max was 80% open water, the longer term trend does not rule out the past couple of years as anomalous.

I love these charts by the way. It captures very clearly the degradation of the ice cover across the Arctic and does it in a way not previously tracked.

Shared Humanity

  • Guest
Re: How soon could we go ice free?
« Reply #219 on: September 14, 2018, 03:01:08 PM »

________________________________________________________________________
The Arctic Seas are in very different environments. I have done some rough groupings. This first grouping is about bbr's favorite part of the world - Hudson Bay, the Baffin Sea, and the Canadian Archipelago (CAA). The graphs are attached.

The most striking feature is that the average open water of all three seas has changed very little over the 4 decades. One would think AGW has passed them by. Baffin and Hudson Bay are "Blue Ocean" seas for the month and September (and longer) while the CAA is between 60 to 70 percent open water in this minimum month.

On average, the CAA is only 20-30% open water, very much an ice desert, completely so in winter.
The Baffin Sea (includes the Labrador Sea) is around 70% open water on average, and 40% during the minimum month. On balance, very much an open water sea.
Hudson Bay is around 50% open water on average, and almost zro during the minimum month. On balance, neither one nor the other.

One wonders when increasing Arctic temperatures will really impact these seas.

While the impact is far less than other seas, there is still a slight, very noticeable increase in the annual open water percent.

Shared Humanity

  • Guest
Re: How soon could we go ice free?
« Reply #220 on: September 14, 2018, 03:11:17 PM »
Basically, I expect the Arctic Cell collapsing and the CAB becoming part of the Atlantic to happen at the same time -- I just don't know the time.

This isn't happening in the Chukchi which is more or less ice free for extended periods and has increasing salinity due to mixing and intrusion from the Bering. The long, dark, frigid Arctic winters will continue to cause ice to form after the first BOE.

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: How soon could we go ice free?
« Reply #221 on: September 14, 2018, 05:13:51 PM »
Now, I don't know if this one makes sense or even if it belongs here, but I attach a chart showing sunspot numbers (proxy for insolation) and arctic winter temperatures (here shown as a 3 yr moving average). It seems that low sunspot numbers "lead to" higher winter temperatures while high sunspot numbers "cause" lower winter temperatures (correlation for the past 30yrs: -0,55). We have just had the 3 warmest winters in the arctic and also, we are around the lows of the current solar cycle. If the above holds, we should not see much more warming in the winters in the arctic for the next few years (same as 2009-15).

Is this utterly stupid or just completely?

Archimid

  • Young ice
  • Posts: 3511
    • View Profile
  • Liked: 899
  • Likes Given: 206
Re: How soon could we go ice free?
« Reply #222 on: September 14, 2018, 05:50:06 PM »
Quote
Is this utterly stupid or just completely?
I think the weak correlation you see is a form of echo. The difference between maximum sunspots and minimum sunspots is minimal relative to the total energy of the Sun is almost trivial.

However, that "almost trivial" energy difference has been operating in an ~11 years cycle since before life emerged. In a chaotic system, if you introduce very small perturbations for a very, very long time you can shift the system in a way that it develops a correlation to the very small but constant force, essentially decreasing chaos.

I think Sunspots are correlated with some Earth system phenomena because over the course of billions of years the constant regularity of solar cycles makes the system have a memory of solar cycles.

Disturbances like CO2 warming eventually overwhelm that constant regularity to transform the climate system into something new. The biosphere is probably very much aligned with these cycles. It will suck to lose that alignment.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #223 on: September 14, 2018, 07:24:49 PM »
OPEN WATER SEAS
A Blue Ocean Event is when the Arctic Seas (even for one day) become an open water sea. We all look at the ice , when perhaps we should be looking at the change to Open Water Seas with a maritime climate as opposed to ice-covered deserts. This is what this series of posts is all about.

The graphs look at open water (i.e. free of ice) as a percentage of the area of each sea. The sea ice measure used is NSIDC ice area
________________________________________________________________________
The Arctic Seas are in very different environments. I have invented some rough groupings. This third grouping I have named the AtlanticGateway

Group 3 :- the Atlantic Gateway, being the Greenland, Barents, Kara & Laptev and seas.
The Atlantic Gateway dwarfs the Pacific Gateway, being many times wider and deeper. As global ocean heat content and high latitude air temperatures remorselessly increase, one might expect sea ice in these seas to respond accordingly. It is these seas that started the conversation on “Atlantification” of the Arctic (and me to embark on this little (ha-ha) exercise – thanks A-Team).

The Greenland Sea is affected by export of sea ice from the Central Arctic (The CAB) down the Fram Strait, and warming air and ocean from the south. In years when that export of ice is high, one might expect higher levels of ice in this sea. The decline of multi-year (MYI) and thick ice in the CAB in recent years has led to a reduction in ice export.

Yearly average open water has increased from around 50% to approaching 70%.

In March (maximum sea ice) open water has increased from just over 30% to just over 50%.

In contrast, in the 3 months of August to October (minimum ice) open water has increased by a more modest 10%, from around 75% to 85%.

Volatility from year to year is also high, though moderating in recent years, perhaps reflecting variations in Fram export.

The Barents Sea is regarded very much as the poster child for “Atlantification”.

Yearly average open water has increased from around 55% to around 90% from 1980 to date.

In the 3 months of August to October (minimum ice) open water has increased from around 95% open water to 100% in most years since 2008.

March open water (the month of maximum ice) has increased from 30% to 70%.

This is now a sea that just has a bit of ice for a bit of the year. It is now a maritime sea especially as it has lost most of its winter ice.

However, despite being totally ice free for long periods, this has only reduced winter sea ice forming. It gives every sign of gradual transformation, and no sign of abrupt total loss of winter sea ice.

The Kara Sea is again in a unique environment. To the north the island of Novaya Zemla blocks warmth from the Atlantic; to the south, western Siberia can be somewhat cold in winter and very hot in summer.

Yearly average open water has increased from around 25% to around 50% from 1980 to date.

In the 3 months of August to October (minimum ice) open water has increased from around 70% to 95% in most years since 2006.

March open water (maximum ice) has increased from under 10% to around 15% since 2012 despite ice to the south in the Barents and the frigid Russian winter . Volatility has also increased.

This is also a sea that shows the impact of the 2012 great melt.

In 1980 this sea was an ice sea for most of the year. It is now approaching 50-50 status.

The Laptev Sea is totally surrounded by ice in winter to the north, and Central Siberia to the south – sometimes even colder than the Arctic in winter. This is evidenced by no change in open water in March – more or less none.

Yearly average open water has increased from just under 20% to around 30% from 1980 to date.

In the 3 months of August to October (minimum ice) open water has increased from around 45% to around 80% in most years since 2006.

March open water (maximum ice) has not increased from under 10%

The most striking feature of the Laptev is the extreme volatility of the maximum open water months August to October.

In 1980 this sea was an ice sea for most of the year. It still is, apart from the period late summer to autumn.
« Last Edit: September 15, 2018, 03:34:51 PM by gerontocrat »
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #224 on: September 14, 2018, 07:49:24 PM »
Now, I don't know if this one makes sense or even if it belongs here, but I attach a chart showing sunspot numbers (proxy for insolation) and arctic winter temperatures (here shown as a 3 yr moving average). It seems that low sunspot numbers "lead to" higher winter temperatures while high sunspot numbers "cause" lower winter temperatures (correlation for the past 30yrs: -0,55). We have just had the 3 warmest winters in the arctic and also, we are around the lows of the current solar cycle. If the above holds, we should not see much more warming in the winters in the arctic for the next few years (same as 2009-15).

Is this utterly stupid or just completely?
If I remember rightly, it was a Russian Scientist, an authority on sunspot cycles (but not on Global atmospherics) who re-ignited this debate. I know very little about it except for that lovely butterfly graph.

I might be a bit more convinced if someone chucked the data into an excel spreadsheet as an x-Y graph and told excel to put in various trendlines (easy to also tell excel to automatically do the correlations).

Some individual seas show little or no decrease in winter sea ice, others a lot. It seems to me that their vulnerability to increasing temperatures (air and ocean) all depends on their location that determines their climatic environment.

For the Arctic as a whole, increase in winter open water / decrease in winter sea ice seems a much more gradual and even process. Graph attached

"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Dharma Rupa

  • Frazil ice
  • Posts: 493
    • View Profile
  • Liked: 52
  • Likes Given: 26
Re: How soon could we go ice free?
« Reply #225 on: September 14, 2018, 09:02:47 PM »
OPEN WATER SEAS

I'm hoping, and half expecting that you are going to follow with grouped analyses and a general conclusion.  I am impressed with what this measure is showing so far -- though it isn't clear it portends my predictions.  Seems to hint more at a slow Oceanification, rather than a sudden one.

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: How soon could we go ice free?
« Reply #226 on: September 14, 2018, 09:12:59 PM »
It seems that low sunspot numbers "lead to" higher winter temperatures while high sunspot numbers "cause" lower winter temperatures (correlation for the past 30yrs: -0,55). We have just had the 3 warmest winters in the arctic and also, we are around the lows of the current solar cycle. If the above holds, we should not see much more warming in the winters in the arctic for the next few years (same as 2009-15).

Is this utterly stupid or just completely?
If I remember rightly, it was a Russian Scientist, an authority on sunspot cycles (but not on Global atmospherics) who re-ignited this debate.

For the Arctic as a whole, increase in winter open water / decrease in winter sea ice seems a much more gradual and even process. Graph attached

The point I wanted to make is that although obviously greenhouse gases define the long term temperature trend (up),but short term winter temperature oscillation might somehow be influenced by solar output (dont know how). If this is true, then  the next few winters should not be warmer than the past 3 very warm ones, as the "solar downswing" would be balanced by the ongoing greenhouse gas forcing. If this is true then the next "window of opportunity" for an ice free arctic would be the bottom of the next solar cycle, some time around 2030...

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #227 on: September 14, 2018, 09:35:25 PM »

The point I wanted to make is that although obviously greenhouse gases define the long term temperature trend (up),but short term winter temperature oscillation might somehow be influenced by solar output (dont know how). If this is true, then  the next few winters should not be warmer than the past 3 very warm ones, as the "solar downswing" would be balanced by the ongoing greenhouse gas forcing. If this is true then the next "window of opportunity" for an ice free arctic would be the bottom of the next solar cycle, some time around 2030...

Increasing CO2 ppm might well force more air and ocean temperature increase than  any -ve effect from decreased solar radiation. How does one separate these two effects ? Add in a possible change in ocean currents that could either chuck loads of extra heat from the Atlantic ocean at the Arctic (or vice-versa) and you are talking big math and big computers.

I and my laptop retire from the field. Wait and see becomes my plan of action, if I live that long. (My epitaph - "damn, I wanted to see what happened next")
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #228 on: September 14, 2018, 09:40:11 PM »
OPEN WATER SEAS

I'm hoping, and half expecting that you are going to follow with grouped analyses and a general conclusion.  I am impressed with what this measure is showing so far -- though it isn't clear it portends my predictions.  Seems to hint more at a slow Oceanification, rather than a sudden one.

The grouped analyses will be a pig. Simple averages will not do, need to weight by area involved etc.
Patience, Dharma, I did not realise what I was letting myself into, starting this.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Dharma Rupa

  • Frazil ice
  • Posts: 493
    • View Profile
  • Liked: 52
  • Likes Given: 26
Re: How soon could we go ice free?
« Reply #229 on: September 14, 2018, 10:00:58 PM »
OPEN WATER SEAS

I'm hoping, and half expecting that you are going to follow with grouped analyses and a general conclusion.  I am impressed with what this measure is showing so far -- though it isn't clear it portends my predictions.  Seems to hint more at a slow Oceanification, rather than a sudden one.

The grouped analyses will be a pig. Simple averages will not do, need to weight by area involved etc.
Patience, Dharma, I did not realise what I was letting myself into, starting this.
My poor suffering slave.

It looks really good so far!

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #230 on: September 15, 2018, 04:05:05 PM »
OPEN WATER SEAS
A Blue Ocean Event is when the Arctic Seas (even for one day) become an open water sea. We all look at the ice , when perhaps we should be looking at the change to Open Water Seas with a maritime climate as opposed to ice-covered deserts. This is what this series of posts is all about.

The graphs look at open water (i.e. free of ice) as a percentage of the area of each sea. The sea ice measure used is NSIDC ice area

The Arctic Seas are in very different environments. I have invented some rough groupings. This fourth grouping I have named the Central Arctic Basin Protected Seas
________________________________________________________________________
Group 4 :- the protected seas of the Central Arctic Basin – being the Beaufort, Eastern Siberia and Central Arctic Seas
In winter, these seas are bounded by frozen land and/or frozen water, and are the last to be exposed to open water. It is often assumed that they will be the last to lose their ice.

The Beaufort Sea, bounded by Alaska and Canada to the South, the Chukchi to the West, and the Central Arctic to the North and East.

Yearly average open water has increased from around 15% to 30%.

In March (maximum sea ice) open water has decreased from around 5% almost zero.

In contrast, in the 3 months of August to October (minimum ice) open water has increased more than doubled, from around 35% to 75%.

It is therefore entirely a story about summer melting. It is still very much an “ice desert” sea.

The Eastern Siberian Sea (ESS)
has the Central Arctic Sea to the North, the Chukchi to the East, the Laptev to the West, and Central- Eastern Siberia to the South. It is, on occasion, vulnerable to Atlantic winds and currents when the Laptev has melted out.

Yearly average open water has increased from just under 10% just under 30% from 1980 to date.

In the 3 months of August to October (minimum ice) open water more than doubled  from around 30% open water to 75%. In these months volatility from year to year is also very high.

March open water (the month of maximum ice is zero as near as makes no difference.

It is therefore entirely a story about summer melting. It is still very much an “ice desert” sea.

The Central Arctic Sea
is the largest sea by far, at 3.2 million km2 and over 20% of the total area of the Arctic Seas. Centred on the North Pole, t is bounded by the CAA, Beaufort, Chukchi, ESS, Latev, Kara, Barents, and Greenland Seas plus North Greenland and Canadian Islands.

Yearly average open water has increased from around 5% to around 10% from 1980 to date. Most of this increase happened abruptly, at around 2006.

In the 3 months of August to October (minimum ice) open water has increased from around 15% to 30%  Again, most of this increase happened abruptly, at around 2006. At that time annual volatility also increased markedly.

March open water (maximum ice) has increased from nearly zero to approaching 5% since 2012.

At an average open water percentage during the year of 10%, it is still very much an “ice desert” sea. This sea is never ice free, and at current rates of decline, it will be many years before it is ice free even in the month of minimum ice area.

The graph makes it clear how much of that sea is permanently ice covered
« Last Edit: September 15, 2018, 04:12:59 PM by gerontocrat »
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Dharma Rupa

  • Frazil ice
  • Posts: 493
    • View Profile
  • Liked: 52
  • Likes Given: 26
Re: How soon could we go ice free?
« Reply #231 on: September 15, 2018, 05:48:01 PM »
That's a pretty shocking change in the CAB in 2006-7...  When was the term Atlantification invented?

Stephan

  • Young ice
  • Posts: 2649
    • View Profile
  • Liked: 758
  • Likes Given: 459
Re: How soon could we go ice free?
« Reply #232 on: September 15, 2018, 07:50:11 PM »
A simple question: Is the summer increase of open water in CAB since 2006/7 directly or mainly caused by a more northern ice boundary N of Svalbard and FJL?
It is too late just to be concerned about Climate Change

El Cid

  • Young ice
  • Posts: 2507
    • View Profile
  • Liked: 923
  • Likes Given: 225
Re: How soon could we go ice free?
« Reply #233 on: September 15, 2018, 08:01:02 PM »
great charts gerontocrat, they show a "systemic change" in 2006-7 but no seismic shifts since then

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #234 on: September 15, 2018, 08:24:33 PM »
A simple question: Is the summer increase of open water in CAB since 2006/7 directly or mainly caused by a more northern ice boundary N of Svalbard and FJL?
I don't know,but in 2006 there is a general burp upwards in the Laptev but not the Kara, and a burp up int winter sea ice decline in the Barents on the Atlantic side, and a general upwards burp in the Chukchi, Beaufort and East Siberian on the Pacific side.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #235 on: September 16, 2018, 05:35:04 PM »
OPEN WATER SEAS
A Blue Ocean Event is when the Arctic Seas (even for one day) become an open water sea. We all look at the ice , when perhaps we should be looking at the change to Open Water Seas with a maritime climate as opposed to ice-covered deserts. This is what this series of posts is all about.

The graphs look at open water (i.e. free of ice) as a percentage of the area of each sea. The sea ice measure used is NSIDC ice area

The Arctic Seas are in very different environments. I have invented some rough groupings. This fifth grouping I have named the Seas south of the Arctic Ocean – being the Okhotsk, and the St. Lawrence
________________________________________________________________________

Group 5 :- Seas south of the Arctic Ocean – being the Okhotsk, and the St. Lawrence

The Okhotsk Sea, at around 50o North has no connection with the Arctic Ocean, and the St Lawrence, at around 52o North, very little. They form part of the NSIDC analyses and so they are included.

The Okhotsk Sea area is 1.583 million km2. This analysis uses 1.617 km2, the maximum extent in the NSIDC record since 1979. This is because the NSIDC grid includes part of the Sea of Japan. The 1.617 km2 figure is probably too low, but I do not have the technical skills to establish the size of the grid used by NSIDC, and NSIDC do not have the data readily available. (This also applies to a few other seas but is not significant).

Yearly average open water has gradually increased from around 80% to around 90% from 1980 to date.

In the 3 months of August to October (minimum ice) open water is always 100%, often more than 95% open water for more than 6 months

March open water (maximum ice) has increased from under 40% to over 60%. That percentage plunged downwards from 1997 to 2001, recovered to the upward trend by 2006, but has not changed much since then.

Yet another sea that shows no sign of being unable to reform sea ice in winter.

The St. Lawrence
Yearly average open water has gradually increased from around 90% to around 95% from 1980 to date.

In the 3 months of August to October (minimum ice) open water is always 100%, often more than 95% open water for more than 6 months. Apart from two years (’87 and ’88), ice was less than 5% of maximum for between 180 and 184 days – remarkably consistent.

March open water (maximum ice) has increased from around 60% to over 80%, but volatility from year to year is very high.

Nevertheless, the St. Lawrence is yet another sea that shows no sign of being unable to reform sea ice in winter.

ANALYSIS BY GROUPINGS TO COME NEXT - it may take some time.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

NACK

  • New ice
  • Posts: 26
    • View Profile
  • Liked: 9
  • Likes Given: 1
Re: How soon could we go ice free?
« Reply #236 on: September 17, 2018, 11:39:00 AM »
Gerontocrat,

I really appreciate what your hard work has accomplished. Thanks.

One area of interest is a subset of the CAA; the area south of Devon, Cornwallis, Bathhurst and Mellville Islands - i.e. the Northwest Passages.

The CAA, although geographically an entity, could really be split into two sections; north and south of this line; as they are two dissimilar sections regarding the open water analysis.

A year-round ice-free shipping route appears to be many years in the future but it would be interesting to see the graphs for open water the last several decades.


gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #237 on: September 17, 2018, 04:24:37 PM »
Gerontocrat,

I really appreciate what your hard work has accomplished. Thanks.

One area of interest is a subset of the CAA; the area south of Devon, Cornwallis, Bathhurst and Mellville Islands - i.e. the Northwest Passages.

The CAA, although geographically an entity, could really be split into two sections; north and south of this line; as they are two dissimilar sections regarding the open water analysis.

A year-round ice-free shipping route appears to be many years in the future but it would be interesting to see the graphs for open water the last several decades.
It would, but the NSIDC system does not go down that far. My understanding is that data sent by the satellite is plonked into a matrix that adds a code to say which sea each bit of data belongs to. That is the the code used for the numerical analysis of area and extent for each sea. That code does not split the CAA into sub-sets. (Other codes I presume are used to allow the GIS mapping of area and extent and concentration).

Many wish finer detail was available, especially for the massive Central Arctic Sea so change between, e.g. The Atlantic and Pacific sides could be analysed numerically. But to do so would be a massive exercise to reanalyse the daily matrices from 1979 - all 14,000+ of them.

It ain't going to happen, methinks. Ice-sat2 will produce the data to do it -from 2019. The data will be freely available (I hope), but this person has not the GIS skills to have a go. (I wish I did but there you are).
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #238 on: September 17, 2018, 09:02:28 PM »
OPEN WATER SEAS
A Blue Ocean Event is when the Arctic Seas (even for one day) become an open water sea. We all look at the ice , when perhaps we should be looking at the change to Open Water Seas with a maritime climate as opposed to ice-covered deserts. This is what this series of posts is all about.

The graphs look at open water (i.e. free of ice) as a percentage of the area of each sea. The sea ice measure used is NSIDC ice area

The Arctic Seas are in very different environments. I have invented some rough groupings. This analysis now looks at overall totals for each group
________________________________________________________________________

Group I – Baffin (including Labrador) Seas, Hudson Bay, and The Canadian Archipelago (CAA) - 3.8 million Km2
The most striking feature is that the average open water of all three seas has changed very little over the 4 decades. One would think AGW has passed them by.

I am tired, and it is late. Do it properly tomorrow
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Dharma Rupa

  • Frazil ice
  • Posts: 493
    • View Profile
  • Liked: 52
  • Likes Given: 26
Re: How soon could we go ice free?
« Reply #239 on: September 17, 2018, 09:11:05 PM »
OPEN WATER SEAS
I am tired, and it is late. Do it properly tomorrow

That is fine...are we going to call these continental seas?

oren

  • Moderator
  • First-year ice
  • Posts: 9805
    • View Profile
  • Liked: 3584
  • Likes Given: 3922
Re: How soon could we go ice free?
« Reply #240 on: September 17, 2018, 11:14:58 PM »
I think the gridded data IS available from NSIDC, and at least Wipneus and probably some others can analyze it. I fantasize on being able to do it myself at some point.

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #241 on: September 17, 2018, 11:25:21 PM »
I think the gridded data IS available from NSIDC, and at least Wipneus and probably some others can analyze it. I fantasize on being able to do it myself at some point.
Yes it is, and I read it up. My fantasy duly evaporated.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #242 on: September 18, 2018, 10:50:42 PM »
A better attempt, I hope.

OPEN WATER SEAS
A Blue Ocean Event is when the Arctic Seas (even for one day) become an open water sea. We all look at the ice , when perhaps we should be looking at the change to Open Water Seas with a maritime climate as opposed to ice-covered deserts. This is what this series of posts is all about.

The graphs look at open water (i.e. free of ice) as a percentage of the area of each sea. The sea ice measure used is NSIDC ice area

The Arctic Seas are in very different environments. I have invented some rough groupings. This analysis now looks at overall totals for each group
________________________________________________________________________

Group I – Baffin (including Labrador) Seas, Hudson Bay, and The Canadian Archipelago (CAA) - Area 3.8 million Km2

The most striking feature is that the average open water of all three seas has changed very little over the 4 decades. One would think AGW has passed them by.

Yearly average open water has increased marginally from around 50% in 1980 to around  55% by 2018.

In March (maximum sea ice) open water has stayed at around 20% , i.e. mostly ice-covered.

In the 3 months of August to October (minimum ice) open water has increased by a marginal 5%, from around 90% to 95%.

The loss of sea ice over the years is therefore basically confined to the summer months. Volatility from year to year is also comparatively low.  These seas are in a stable condition.
__________________________________________________________________________

Group 2 :- the Pacific Gateway, being the Bering and Chukchi seas. (Area 2.0 million Km2)

]The Pacific Gateway allows warm from the Pacific into the Arctic Ocean through the Bering Strait, which is both narrow and shallow.  In theory, increasing warm the in the North Pacific should have leads to loss of ice year round in the Bering Sea, in turn making the Chukchi vulnerable to melting.

Yearly average open water has increased from around just under 60% in 1980 to 70% in 2018, mostly in the last three years

From 1979 in the three minimum ice months of August to October open water has increased from 80% to nearly 100% from 2007. 

Winter sea ice shows and even more dramatic change, open water being at between 30% and 40% from 1980 to 2011, collapsing in 2012 ( the year of massive summer melt) to less than 20%, and then rapidly rising to 50% in 2018.

This is a new development. Is the Bering Sea going through a permanent sea change towards a truly open water maritime climate sea, to be followed by the Chukchi? (Or is this change temporary only)
_____________________________________________________________________
Group 3 :- the Atlantic Gateway, being the Greenland, Barents, Kara & Laptev and seas. (Area 4.2 million Km2)

It is these seas that started the conversation on “Atlantification” of the Arctic. The Atlantic Gateway dwarfs the Pacific Gateway, being many times wider and deeper. As Atlantic Ocean heat content and high latitude air temperatures remorselessly increase, one might expect sea ice in these seas to respond accordingly. Is it the case?

The image attached – from University of Bremen, suggests that this is the case. The numerical analysis supports it.

Yearly average open water has increased from around 45% in 1980 to 60% in 2018, fairly evenly over the years.

In the three minimum ice months of August to October open water has increased from 80% to over 90%, also fairly evenly over the years. 

In the maximum ice month of March open water has increased from 25% to 40%, also fairly evenly over the years. 

The conclusion must be that until now ice has declined in both summer and winter. With summer open water now at well over 90%, the question must be – will winter sea ice continue to decline and at what rate? Winter Sea Ice loss leading to earlier melt and later freeze  in these 4 seas may be the real key to Atlantification of the Arctic Ocean.
_____________________________________________________________

With luck, tomorrow a look at the big beasts - the Beaufort, the ESS and the Central Arctic and then some thoughts, if I am still capable of thought by then

"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #243 on: September 19, 2018, 04:59:41 PM »
OPEN WATER SEAS
A Blue Ocean Event is when the Arctic Seas (even for one day) become an open water sea. We all look at the ice , when perhaps we should be looking at the change to Open Water Seas with a maritime climate as opposed to ice-covered deserts. This is what this series of posts is all about.

The graphs look at open water (i.e. free of ice) as a percentage of the area of each sea. The sea ice measure used is NSIDC ice area

The Arctic Seas are in very different environments. I have invented some rough groupings. This analysis now looks at overall totals for each group
________________________________________________________________________

Group 4 :- the protected seas of the Central Arctic Basin – being the Beaufort, Eastern Siberia and Central Arctic Seas (Area 5.5 million Km2)

Yearly average open water has increased from just under 10% just under 20% from 1980 to date.

In the 3 months of August to October (minimum ice) open water more than doubled from around 20%  to approaching 50 %. In these months volatility from year to year is also very high.

March open water (the month of maximum ice is zero as near as makes no difference, but with a hint of a small increase from 2016 to date to around 5%.

It is therefore entirely a story about summer melting. Even in September, the month of minimum ice, open water only increased to above 50% from 2007, and only exceed 60% in one year – the record melting year of 2012. To approach 100% open water at any time of year looks to be a good many years ahead.

These are still very much “ice desert” seas.

______________________________________________
Group 5 :- Seas south of the Arctic Ocean – being the Okhotsk, and the St. Lawrence (Area 1.9 million Km2)

The Okhotsk Sea, at around 50 North has no connection with the Arctic Ocean, and the St Lawrence, at around 52 North, very little. They form part of the NSIDC analyses and so they are included. Also see the last remark.

Yearly average open water has gradually increased from around 80% to around 90% from 1980 to date.

In the 3 months of August to October (minimum ice) open water is always 100%, often more than 95% open water for more than 6 months.

March open water (maximum ice) has increased from around 45% to around 65%, but volatility from year to year is quite high.

The seas are in the mid-latitudes. Nevertheless, winter sea ice forms substantially. Much has been said about how after a BOE in summer, Arctic winter sea ice would dramatically reduce. Winter sea ice is declining, but not dramatically in these seas, even though they are south of the Arctic in a much milder climatic and ocean environment. So the evidence from these seas contradicts that hypothesis.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #244 on: September 19, 2018, 05:20:07 PM »
OPEN WATER SEAS
A Blue Ocean Event is when the Arctic Seas (even for one day) become an open water sea. We all look at the ice , when perhaps we should be looking at the change to Open Water Seas with a maritime climate as opposed to ice-covered deserts. This is what this series of posts is all about.

The graphs look at open water (i.e. free of ice) as a percentage of the area of each sea. The sea ice measure used is NSIDC ice area

The Arctic Seas are in very different environments. I have invented some rough groupings. This analysis now looks at overall totals for each group
________________________________________________________________________

Summary - Total Arctic Seas Area 17.4 million Km2 (includes some seas outside or partly outside the Arctic Ocean)

The images attached show extent in September 1979 and September 2018, and March 1979 and March 2018 (from NSIDC Spatial Tools). Note that extent covers any water with more than 15% ice, so gives a perhaps exaggerated view of the ice.

It is obvious that reduction in winter ice is low and basically confined to the Bering Sea and Atlantic margin. While summer ice loss is high, it is basically confined to an arc from the Atlantic, along the coast of Siberia, across the Pacific gateway and along the coast to the Alaska – Canada border.

And here is the Open Water Analysis.

Yearly average open water has increased from 40% to 50% from 1980 to date.

In the 3 months of August to October (minimum ice) open water from just over 60%  to just over 80%.

March open water (the month of maximum ice has increased from 20% to just under 30%.

With average open water creeping up to above 50%, can one claim the Arctic Seas in total are on balance now Open Water Seas more than Ice Deserts? A moot point. However, there is a lot more ice to melt for a BOE.

Some individual seas show little or no decrease in winter sea ice, others a lot. It seems to me that their vulnerability to increasing temperatures all depends on their location that determines their climatic environment.

As one can see, the 2012 record melt only had a marginal effect on the open water percentage for the year. Change is gradual – there is no sign of a dramatic change.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Ned W

  • Guest
Re: How soon could we go ice free?
« Reply #245 on: September 19, 2018, 06:08:59 PM »
I think the gridded data IS available from NSIDC, and at least Wipneus and probably some others can analyze it. I fantasize on being able to do it myself at some point.
Yes it is, and I read it up. My fantasy duly evaporated.

Earlier this summer, I used the NSIDC gridded concentration data to recalculate extent using a 30% threshold, 1978-present, to see whether 15% vs 30% made any difference in the trend (it didn't).

gerontocrat

  • Multi-year ice
  • Posts: 20378
    • View Profile
  • Liked: 5289
  • Likes Given: 69
Re: How soon could we go ice free?
« Reply #246 on: September 19, 2018, 06:29:20 PM »
I think the gridded data IS available from NSIDC, and at least Wipneus and probably some others can analyze it. I fantasize on being able to do it myself at some point.
Yes it is, and I read it up. My fantasy duly evaporated.

Earlier this summer, I used the NSIDC gridded concentration data to recalculate extent using a 30% threshold, 1978-present, to see whether 15% vs 30% made any difference in the trend (it didn't).
Arithmetic is a harsh master. It destroys so many hypotheses and gut feelings.

(If I remember rightly the computer works simply by adding and taking away, but very quickly, though in IBM Fortran it added and took away logs).
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)