IJIS

[EthanOConnor]

That's a pretty amazing fall in 2 days.  Have there ever been century breaks in April?

There have been 18 of them since April 1, 2003. The most extreme occurrence was from April 9 to April 14, 2004:

154,512
129,382
127,666
  70,453
100,826

Just glancing at the maps quickly it looks like the Bering and Barents both saw dramatic retreats across this span. A good reminder that the eye of the needle (the period of lower year-to-year variance) that we pass through in spring reflects in part the transition from peripheral sea melt to basin melt.

I don't have an analysis to back this up, but I'd guess the probability of large declines very early in the season - especially in extent - is lower now than in the past.

[OldLeatherneck]

2012 also had a big string of 100K losses.

2012       SIE (Km²)        Daily Loss (Km²)
 22-Apr      13,849,761    
 23-Apr      13,735,437         114,324
 24-Apr      13,666,921          68,516
 25-Apr      13,560,700         106,221
 26-Apr      13,436,906         123,794
 27-Apr      13,336,421         100,485

[Jim Pettit]

That's a pretty amazing fall in 2 days.  Have there ever been century breaks in April?

There have been a number of them, as noted above: last year saw two, 2014 had one, 2013 had two, 2012 had five, and so on.

2016 has seen April-to-date extent drop by more than was measured in 2014 or 2015, but so far as overall loss, it's still been just about an average month for that metric. Even so, 2016 has been in first place every day this month, and is running some 370k km2 lower than 2nd place 2006:



(Excuse the quick-and-dirty chart.)

[Mark Tough]

April this year is 7th out of 14 according to your chart Jim - just on the high side of average but, as you know, it's where April started and the average daily extent that really scares this community. I know we've hit two and will hit there world record temperature month averages globally but I didn't quite expect where we were going, and quite how quickly.

The DMI is scary, unprecedented! If you aggregate the anomaly quite out of our of all norms. Agree with Sourabh - this is weird and hell is going to break lose (still a frozen hell though) It will be interesting to see if previous years are going to be mirrored and the worm turns - that said the accumulated heat (lack of cold) is there to make this melt season a front row must.

I've been "Master Lurking" here for quite a few years but this year is so different. if Neven graphed the positive/negative/trolling/idiot comments over the years - this is the black swan. The trolls are few and far between (hat tip Neven and good to slay the beasts - they are less by % though), the traditional rationalists are still rational but in our new truth, the game has changed and Friv's scorching events are not just predictions but our realities.

It will be what it is and if the DMI doesn't turn hard right we are in trouble. Of course if the world turns hard right, we are in even more trouble on oh so many levels and that's not a moot point!

[jdallen]

That's a pretty amazing fall in 2 days.  Have there ever been century breaks in April?

There have been 18 of them since April 1, 2003. The most extreme occurrence was from April 9 to April 14, 2004:

154,512
129,382
127,666
  70,453
100,826

Just glancing at the maps quickly it looks like the Bering and Barents both saw dramatic retreats across this span. A good reminder that the eye of the needle (the period of lower year-to-year variance) that we pass through in spring reflects in part the transition from peripheral sea melt to basin melt.

I don't have an analysis to back this up, but I'd guess the probability of large declines very early in the season - especially in extent - is lower now than in the past.

A reasonable conjecture, which is supported by the fact in the past, early extent was much higher and extended deeply into regions which warm earlier.

[charles_oil]

I expect if calculated on a % loss over the month basis this year would rank very high too.

[Magma.]

I don't have an analysis to back this up, but I'd guess the probability of large declines very early in the season - especially in extent - is lower now than in the past.

I think two potentially significant controls early in the melting season could be large areas of ice that may be up to 50 cm thinner than many previous years, and the rapid flushing of first-year and multi-year ice through the Fram Strait. However this is quite far from my own fields of hands-on interest, so take that with a very large grain of salt.

[DavidR]

I expect if calculated on a % loss over the month basis this year would rank very high too.

So far at at  7.78% it rates as the seventh highest percentage out  of 14.

However this only tells half the story as there is a strong correlation between the extent  at the start of the month and the percent  decline. No previous year that  started April with less than 14.2M km^2 has had a rate of decline above 7%. It is also  the equal highest anomaly  from the percentage trend line. The other year being 2003.

[Espen]

IJIS:

12,347,980 km²（April 29, 2016）

[Dorsetmetman]

Long term lurker here (!) and meteorology graduate from several years back. Thanks to Neven and all for this great forum with it's superb technical discussion and analysis and constant supply of new graphs and images. Looking at the average lines from the 80's, 90's and 00's, 2016 is tracking close to the furthest extreme we should come to expect in the 2010's to give a 10's average that follows the approximately linear decrease seen from the others. Once again another clear sign of what the not so distant future has in store.

[Pocampo]

IJIS:

12,347,980 km²（April 29, 2016）

Espen thank you for posting these graphs.   I know having a ICE free Arctic would be historic..  but since we came close to that in 2012.  don't we already know what the impact will be. and even if we lose most of the ice it would only be for a few weeks then we start climbing again.. or is there certain events that will happen ones we lose all the ice.. just seems like there is a lot of doom  that people are waiting for ones the ice is gone even for a few weeks.. so what do I personally watch for ones the ice is gone..  Sorry if I put this post in the wrong spot  Im a newby  thank you Espen  for your hard work

[werther]

Pocampo,
In my opinion the '12 minimum did enhance the climate change-progress. It did in close alliance to the big Greenland Ice Sheet melt that year.
It contributed to changing jet-stream behaviour (as argued by FI Dr. Jennifer Francis), the behaviour of Rossby waves through the NH atmosphere, the North Atlantic 'cold pool' etc etc.

But it doesn't work as a single propagator. It works right in line with a multitude of atmospheric and oceanic changes in a rush never before equalled in the natural history of this planet (with maybe an exception for high impact events from space or the planets' interior...).

[Buddy]

I know having a ICE free Arctic would be historic..  but since we came close to that in 2012.  don't we already know what the impact will be. and even if we lose most of the ice it would only be for a few weeks then we start climbing again.. or is there certain events that will happen ones we lose all the ice.

1)  We went down to 3.14 mill 2k in 2012.  That was the record low THEN.

2)  We will CONTINUE to lose more ice EARLIER and EARLIER as time goes by.

3)  Let's say that this year we go down to 2.5 million 2k (aggressive....but VERY doable).

4)  Then....3 years from now.....we go down to 1.5 million 2k

5)  Then....3 years after THAT...we go to .5 million.....or very close to zero.

The above is ONLY an example (I actually think we will lose ice FASTER than that).  But here is what happens:  Each year....we lose more and more ice......earlier and earlier.  With less snow and ice, we have MORE HEAT ABSORBING DARK BLUE OCEAN that absorbs the SHORT WAVE energy from the sun.....and LESS of the short wave energy gets reflected back out into space (snow and ice can reflect about 80% while the ocean only reflects about 20% or less of the short wave energy back out).  It is ABSORBED....and then turns into LONG WAVE energy which does NOT go back out the atmosphere as easily as the SHORT WAVE radiation came in.

The keys are this:  We continue to put more and more CO2 into the atmosphere.  CO2 has a LONG LIFE in the atmosphere....some of it as much has HUNDREDS OF YEARS.  So it is NOT like "pollution" that clears itself out.

Since we have LESS AND LESS reflective snow and ice on the ice sheets....it will cause us to warm up FASTER than we would otherwise.  We still won't warm up PAST the "equilibrium point"....but we'll get their faster.

And the loss of the Arctic and speeding up of the heating process....also kicks various other "feedback mechanisms" into high gear:  (1)  more heat....means LESS permafrost which then frees MORE CO2 and methane gas into the atmosphere....which causes more heat..and round and round the feedback loop goes.  (2) Same thing with more wild fires.....more heat because of the diminished Arctic ice sheet...means more wildfires....which causes more CO2 to be spewed into the atmosphere....which causes more heat...etc..etc..

The loss of the Arctic ice sheet also will enable the GREEENLAND ICE SHEET to melt sooner.  The warmer the ocean is AROUND Greenland.....the faster it will melt.

Remember.....the Arctic has been losing ice since at least 1980.  Each year....a little bit more dark ocean is available to soak up short wave energy from the sun.....and be turned into long wave energy which does NOT go back OUT the atmosphere as easily as it came in.

The loss of the Arctic is only STEP 1.  The loss of the Greenland ice sheet (which has already started and is speeding up) is STEP 2.  And yes....the loss (partial or total) of the Antarctic ice sheet is Step 3.

But the Arctic is the easiest target:  It is at SEA LEVEL....and it is totally a sea based ice sheet (no land like Greenland....and Antarctic is combo of land and water based).

So the loss so far of the Arctic ice sheet is CRUCIAL.  And the continued loss is only going to make things warmer....faster.....as we have now seen over the past decade.

Remember.....the OCEANS are where about 90% of the global warming has gone so far.  They lose their ability to absorb CO2 the warmer they get....and that is very WORRISOME.

Sorry for rambling....hope that helps.

There are MANY good videos from renowned climate scientists (none named Buddy:)....and I would encourage you to watch SEVERAL of those to gain an understanding of the processes involved.

[Buddy]

Pocampo:

Not to beat this horse to death.....but the Arctic ice sheet IS the "linchpin" for the earth.  Here is an article regarding new research on Greenland.  This shows how important the OCEAN TEMPERATURE in the ARCTIC OCEAN is for the melting of Greenland.  So the sooner the Arctic ice sheet goes....the more pressure there will be on melting Greenland (note there already is A LOT...but as the Arctic ice melts......the more heat will be present in the Arctic Ocean....and "attack" the Greenland ice sheet.

https://www.washingtonpost.com/news/energy-environment/wp/2016/04/30/another-typical-day-for-greenland-scientists-find-more-reasons-it-will-melt-faster/

[Pocampo]

Thank you guys for your thoughtful responses.  I don't think that last 3.5 will make that big a difference.. since it will only be that way for a few weeks to start out. If we do lose the last 3.5  it just give us a easier way to show people  how bad it really is..  But you know the deniers they will just make up a another excuse. What hurts are cause is when that Methane Monster 1 you tube Jennifer says  The arctic will be ice free in winter as well as summer.. Im all no don't say that. we know its melting but in the winter as well as the summer next year  we all here know thats not true..  yet she says that. so I think we should just talk about The trend for the arctic is on a down slope.

  so it look like the oceans are taking this warmth right on the chin.. and the jet stream is doing crazy things,, and finally Greenland wow Greenland holds a lot of water. but I just checked the charts it looks rather normal not at all like the Arctic. so at this time it does not looking like there linked together yet. Ok  it looks like the big gorilla in the room is Methane burbs. so my point is even if we have a average year if ice melt does not mean the permafrost is not releasing  huge amounts of  methane  somewhere.  and we would never know it just looking at arctic sea ice charts.  I saw some lady from Russia saying the arctic can release huge amounts of methane so I will try to follow that. but that info is hard to come by. I wish I was smart enough to post a chart of methane releases  Greenland inland ice chart  and arctic sea ice lose..and when all these charts start moving in the same pattern.  we would be able to look at the feedbacks. in real time.  sorry for rambling and I thank Neven for making such a good blog.

[Espen]

IJIS:

 12,293,447 km²（April 30, 2016）

[oren]

This chart is relentless 

[DavidR]

This chart is relentless 

I played around with the various declines in ice extent since 2003 comparing them on a daily basis.
There is a strong tendency in the data for increasing losses in May.

No years had a decline that  would put the June 1 figure above second lowest (11.08M)
Two years put the figure above 11.0 M.
Five years put the figure above the old record of 10.845 M.
Two years lost the record during the month but got it  back by June1.

If the record is lost it doesn't happen before May 20th.

Of the six years that held the record right through May, four ended up with a figure below 10.5 M on Jun 1.  I'd suggest this is the midrange estimate for Jun 1st now.

[DoomInTheUK]

I quite like that graph. It makes the 2016 line so much easier to read.   

[OldLeatherneck]

The above chart is current, with my projections out til the end of May. For 2016 to maintain a substantial lead over 2012 will require well above average losses for the next month.

The below chart is a summary of average daily SIE losses compiled from the ADS-NIPR archived data for years 2003-2015.  What I find most interesting is that from late April through early June there is very little difference in the average daily losses.  It is also interesting to see the drop in late May, where I would have expected to see more of an increase.  Maybe it is just because I only had 13 years of data to work with.  The wide swings between record high and low losses in any period clearly shows the impact of different weather patterns.

If anyone is interested in seeing the raw data I've used, I'd be happy to post it.  Just don't expect it within the next few hours!!

[DavidR]

The above chart is current, with my projections out til the end of May. For 2016 to maintain a substantial lead over 2012 will require well above average losses for the next month.

The smallest  loss in the IJIS record over the next  month is 1.268 million; that  will take IJIS down to almost 11 M well below 2012. Your own graph  has a 10% below average loss at  close to the record set in 2015!  An average loss (1.599 M) will take the loss down to  10.7  million

[Buddy]

I think we're "likely" to fall to the 11.3 - 11.7 area at the end of this month, given the following:

1) slope of the current trend
2)  Temperatures above 80 degrees north latitude are STILL abnormally warm.  We still have NOT crossed below the "normal" (average) temperature on the DMI graph of temperatures above 80 degree latitude.  That has NOT HAPPENED going back AT LEAST to the year 2000.
3)  Temps in northern Canada and northern Russia continue to be higher than normal.
4)  Beaufort continues to break up
5)  Fram continues to flush ice to the north Atlantic.

Not good.....and we're only in early May..

[oren]

I think we're "likely" to fall to the 11.3 - 11.7 area at the end of this month, given the following:

1) slope of the current trend
2)  Temperatures above 80 degrees north latitude are STILL abnormally warm.  We still have NOT crossed below the "normal" (average) temperature on the DMI graph of temperatures above 80 degree latitude.  That has NOT HAPPENED going back AT LEAST to the year 2000.
3)  Temps in northern Canada and northern Russia continue to be higher than normal.
4)  Beaufort continues to break up
5)  Fram continues to flush ice to the north Atlantic.

Not good.....and we're only in early May..

You probably meant 10.3-10.7 ?

[Buddy]

You probably meant 10.3-10.7 ?

YES....my mistake.  Thanks for the catch....

[abbottisgone]

I know having a ICE free Arctic would be historic..  but since we came close to that in 2012.  don't we already know what the impact will be. and even if we lose most of the ice it would only be for a few weeks then we start climbing again.. or is there certain events that will happen ones we lose all the ice.

1)  We went down to 3.14 mill 2k in 2012.  That was the record low THEN.

2)  We will CONTINUE to lose more ice EARLIER and EARLIER as time goes by.

3)  Let's say that this year we go down to 2.5 million 2k (aggressive....but VERY doable).

4)  Then....3 years from now.....we go down to 1.5 million 2k

5)  Then....3 years after THAT...we go to .5 million.....or very close to zero.

The above is ONLY an example (I actually think we will lose ice FASTER than that).  But here is what happens:  Each year....we lose more and more ice......earlier and earlier.  With less snow and ice, we have MORE HEAT ABSORBING DARK BLUE OCEAN that absorbs the SHORT WAVE energy from the sun.....and LESS of the short wave energy gets reflected back out into space (snow and ice can reflect about 80% while the ocean only reflects about 20% or less of the short wave energy back out).  It is ABSORBED....and then turns into LONG WAVE energy which does NOT go back out the atmosphere as easily as the SHORT WAVE radiation came in.

The keys are this:  We continue to put more and more CO2 into the atmosphere.  CO2 has a LONG LIFE in the atmosphere....some of it as much has HUNDREDS OF YEARS.  So it is NOT like "pollution" that clears itself out.

Since we have LESS AND LESS reflective snow and ice on the ice sheets....it will cause us to warm up FASTER than we would otherwise.  We still won't warm up PAST the "equilibrium point"....but we'll get their faster.

And the loss of the Arctic and speeding up of the heating process....also kicks various other "feedback mechanisms" into high gear:  (1)  more heat....means LESS permafrost which then frees MORE CO2 and methane gas into the atmosphere....which causes more heat..and round and round the feedback loop goes.  (2) Same thing with more wild fires.....more heat because of the diminished Arctic ice sheet...means more wildfires....which causes more CO2 to be spewed into the atmosphere....which causes more heat...etc..etc..

The loss of the Arctic ice sheet also will enable the GREEENLAND ICE SHEET to melt sooner.  The warmer the ocean is AROUND Greenland.....the faster it will melt.

Remember.....the Arctic has been losing ice since at least 1980.  Each year....a little bit more dark ocean is available to soak up short wave energy from the sun.....and be turned into long wave energy which does NOT go back OUT the atmosphere as easily as it came in.

The loss of the Arctic is only STEP 1.  The loss of the Greenland ice sheet (which has already started and is speeding up) is STEP 2.  And yes....the loss (partial or total) of the Antarctic ice sheet is Step 3.

But the Arctic is the easiest target:  It is at SEA LEVEL....and it is totally a sea based ice sheet (no land like Greenland....and Antarctic is combo of land and water based).

So the loss so far of the Arctic ice sheet is CRUCIAL.  And the continued loss is only going to make things warmer....faster.....as we have now seen over the past decade.

Remember.....the OCEANS are where about 90% of the global warming has gone so far.  They lose their ability to absorb CO2 the warmer they get....and that is very WORRISOME.

Sorry for rambling....hope that helps.

There are MANY good videos from renowned climate scientists (none named Buddy:)....and I would encourage you to watch SEVERAL of those to gain an understanding of the processes involved.

What sort of 'equilibrium point' are you referring to here can I ask?

[abbottisgone]

You probably meant 10.3-10.7 ?

YES....my mistake.  Thanks for the catch....

Well, here's hoping none if this will come true

[Buddy]

What sort of 'equilibrium point' are you referring to here can I ask?

Equilibrium:  That point in the future where:

Energy coming IN to the atmosphere from the sun = Energy going back OUT of the atmosphere

That "equilibrium" is effected by both NATRUAL and MAN MADE components....including all the "feed back" processes that we (humans) have started.  Those feedback components will take a while to play out.

One of the "problems" that mankind is having with global warming.....is that it is a LONG PROCESS.  Humans aren't good at "looking ahead".  We have trouble looking to next week....let alone 100 years or 1,000 years down the road.

[Buddy]

Well, here's hoping none if this will come true

I think that ALL of us on this site "hope" that doesn't come to fruition.  But this isn't about hope, unfortunately.  This is about physics.  And physics could give a rats ass about hope.

The first thing I look at on this site each morning is the IJIS graph posted by Espen.  It shows me what REALITY IS TODAY....and WHERE IT IS HEADING TOMORROW.  No glitz....no "fluff"....no ambiguity.....no subjectivness.

Others on this site as well post some GREAT graphs/information.  I just think that most of us have trouble "visualizing" where "this train is really headed".  I think WE think about it on "one level".....but truly "feeling" what that future WILL BE in just a SHORT TIME....5 years....10 years....I think some people are going to be very surprised...and not in a good way.  And I say that by LOOKING AT COLD HARD NUMBERS, AND COLD HARD FACTS.

I think the future can be VERY POSITIVE if we get this train turned around in time (it will take decades).  However, if we continue on the path we are on.......and too many people continue to ignore reality, then things could get very ugly indeed.



     

[abbottisgone]

Well, here's hoping none if this will come true

I think that ALL of us on this site "hope" that doesn't come to fruition.  But this isn't about hope, unfortunately.  This is about physics.  And physics could give a rats ass about hope.

The first thing I look at on this site each morning is the IJIS graph posted by Espen.  It shows me what REALITY IS TODAY....and WHERE IT IS HEADING TOMORROW.  No glitz....no "fluff"....no ambiguity.....no subjectivness.

Others on this site as well post some GREAT graphs/information.  I just think that most of us have trouble "visualizing" where "this train is really headed".  I think WE think about it on "one level".....but truly "feeling" what that future WILL BE in just a SHORT TIME....5 years....10 years....I think some people are going to be very surprised...and not in a good way.  And I say that by LOOKING AT COLD HARD NUMBERS, AND COLD HARD FACTS.

I think the future can be VERY POSITIVE if we get this train turned around in time (it will take decades).  However, if we continue on the path we are on.......and too many people continue to ignore reality, then things could get very ugly indeed.



   

I agree: I check espens posts every few days ever since nsidc went down.

I'm from Western Australia and can tell you many people in the government departments are super worried about the multi-year sea ice melting out sooner rather than later.... To me that can't be anything but a bad sign!

Sure everyone's flummoxed about Antarctica but they still take a keen interest on the crazy things happening up there in the top of the world as it just seems like the nightmare is upon us with trends that won't quit!

[OldLeatherneck]

More Data for IJIS Extent Losses During May

I decided to go ahead and post the detailed Extent loss data that I have used for projecting near-term losses.  The first chart is the average daily losses for each period of the month along with the record maximum and minimum losses.  The second chart is a table of raw data for all years between 2003 and 2015, with record maximum losses highlighted in green and record low losses highlighted in green.  2010 had the record highest loss for the month of May at 2,183,976 KM².  2013 had the record lowest loss for the month of May at 1,210,376 Km².  Average SIE loss for the month of May is 1,555,762 Km².

[Espen]

IJIS:

12,195,413 km²（May 1, 2016）

[DavidR]

That  means we need a record minimum melt in May to not be below 11.0 M on June 1st.

[Juan C. García]

IJIS:

12,195,413 km²（May 1, 2016）

12,293,447 - 12,195,413 = 98,034

With this level of ASI, Wow!
Sounds that we are going to be under 12M on May 4th or May 5th!
That is 1 week before 2015 and 2 weeks+ before 2007 and 2012.

[jdallen]

IJIS:

12,195,413 km²（May 1, 2016）

Might as well be a century break. Only off by 2K.

[abbottisgone]

IJIS:

12,195,413 km²（May 1, 2016）

Speaking roughly:

"..the  figures have not gone down 20% in 30 odd years,.. but the figures are just shy of having gone down 20% in 30 odd years."

Is this a fair comment?

[Espen]

IJIS:

12,164,312 km²（May 2, 2016）

[Juan C. García]

IJIS:

12,164,312 km²（May 2, 2016）

A drop of only 31,101 km². Great!
I rather be wrong about doomsday this year.   

[DungeonMaster]

A drop of only 31,101 km². Great!
I rather be wrong about doomsday this year.   

It recovers! It recovers! 😉

[magnamentis]

that's what we heard a about a week ago and that would be the case if ice conditions of the remaining ice were normal, but it's not much more than an inconsistent patchwork in large areas and the drop will resume like it did several times before this year, let's see.

EDIT: attached 2 pics for area and extent where one can see that area dropped almost like a stone, hence once the winds and currents will compact the ice we shall see a drop ( higher per day drop ) of extent again IMO

[Juan C. García]

A drop of only 31,101 km². Great!
I rather be wrong about doomsday this year.   

It recovers! It recovers! 😉

Not that much!
I'm confident that we will have a 2016 SIE lower than 2007, that will be terrible, from my point of view. But no, I'm not a denier. 
I just hope that we will not break the 2012 record, for the sake of the humanity.

[theoldinsane]

I just hope that we will not break the 2012 record, for the sake of the humanity.


But if we do, I hope it will be with a great margin (no ice in the Arctic) so that the news will reach the general public.

[OldLeatherneck]

I just hope that we will not break the 2012 record, for the sake of the humanity.


But if we do, I hope it will be with a great margin (no ice in the Arctic) so that the news will reach the general public.

I share your feelings.  While 2016 is currently well below 2012, it is far to early to make any meaningful predictions about whether 2016 can or will end up lower than 2012.  Last year, 2015 was 500K Km²below 2012 at the end of May and still ended up by just barely dipping below 2011 for third lowest on record.

As whether an ice-free arctic this season would get much public attention, I'm afraid the US media is so obsessed with the presidential election that any news regarding the Arctic Ocean or AGW in general will get only scant attention.

I'm not going to go off topic and begin a 20 page diatribe about the current state of US politics.  I don't have the time or a 6 month supply of beer!!

[Michael J]

I just hope that we will not break the 2012 record, for the sake of the humanity.


But if we do, I hope it will be with a great margin (no ice in the Arctic) so that the news will reach the general public.

A politician will just say how some city or other had their coldest winter in X years so AGW is a hoax

[Nick_Naylor]

When (not if) the day comes when melting Arctic ice no longer removes heat from the Northern Hemisphere in August, has anyone done the math/modeling to determine what happens to NH temps?

The total heat of fusion absorbed by melting Arctic ice in a season is enough to cool the entire global atmosphere by about 1C. What happens locally when that air conditioning is removed during summer?

[Buddy]

When (not if) the day comes when melting Arctic ice no longer removes heat from the Northern Hemisphere in August

Definitely my #1 concern.  And....as expressed by some of the scientists on this site, it takes a lot more energy to melt ice...than it does to warm water or atmosphere.  So when the ice is gone....seems like things would have to speed up .

[bbr2314]

When (not if) the day comes when melting Arctic ice no longer removes heat from the Northern Hemisphere in August, has anyone done the math/modeling to determine what happens to NH temps?

The total heat of fusion absorbed by melting Arctic ice in a season is enough to cool the entire global atmosphere by about 1C. What happens locally when that air conditioning is removed during summer?

I think something that's overlooked is Greenland's potential to make up for the Arctic deficit. It may sound counterintuitive but the warmer it gets, the more holes open up in the Greenland ice sheet, turning it into a giant sieve that melts ice while also cooling the increasing amounts of warm air overtopping it.

If the volume of air that can filter through the ice sheet can double or triple as its integrity is compromised, wouldn't that create an anomalous amount of low-level cold air?

Perhaps this is another reason we have seen apparent cooling downstream of Greenland, as the stationary Baffin Bay LP dumps Greenland-based airmasses into Hudson Bay & Quebec every few days.

This is a bit wackadoo, but a silly theory: perhaps an ice-free Arctic Ocean is in fact the turning point between warming and ice ages? If an ice-free Arctic leads to Greenland being used more efficiently as a heat sink, the combination of that + freshwater melt wouldn't necessarily make North America much colder in the winter, but summers could become nonexistent over Quebec/Hudson Bay as well as northern Europe/Russia due to the effects of AMOC shutdown on other side of the pond (and a perma-LP SE of Greenland that also delivers low-level cold to Europe).

Once the Arctic becomes ice-free, continental ice sheets begin expanding due to effects of Greenland + remaining mountain-based ice sheets, but the Arctic Ocean remains a heat sink during this time, as ice sheets do not grow quickly. This would happen region by region, not all at once, as we seem to now be seeing in Quebec.

Just a thought...

[ktonine]

When (not if) the day comes when melting Arctic ice no longer removes heat from the Northern Hemisphere in August, has anyone done the math/modeling to determine what happens to NH temps?

The total heat of fusion absorbed by melting Arctic ice in a season is enough to cool the entire global atmosphere by about 1C. What happens locally when that air conditioning is removed during summer?

I think something that's overlooked is Greenland's potential to make up for the Arctic deficit. It may sound counterintuitive but the warmer it gets, the more holes open up in the Greenland ice sheet, turning it into a giant sieve that melts ice while also cooling the increasing amounts of warm air overtopping it.

If I'm not mistaken, this is essentially what Hansen has predicted - short-term global cooling as a result of global warming, thanks to melting Greenland. Predictions Implicit in “Ice Melt” Paper and Global Implications:

What we have is a push and shove match between global warming, which warms the global ocean surface with amplification at high latitudes, and the freshwater stratification effect, which causes ocean surface cooling in the North Atlantic and Southern Oceans. IPCC simulations for the 21st century find a warming Southern Ocean with declining sea ice cover, as freshwater injection is either omitted or small. In contrast, with our assumed rates of freshwater injection, estimated from observations today and extrapolated into the future with several alternative doubling rates, the freshwater cooling effect is already comparable to the greenhouse warming effect in the Southern Ocean, and cooling wins out in our model over the next decade or two.

[jdallen]

If I'm not mistaken, this is essentially what Hansen has predicted - short-term global cooling as a result of global warming, thanks to melting Greenland. Predictions Implicit in “Ice Melt” Paper and Global Implications:

Yes, but localized, and primarily a driver of extreme weather.  Elsewhere, things will still be a hot house.

[JMP]

If I'm not mistaken, this is essentially what Hansen has predicted - short-term global cooling as a result of global warming, thanks to melting Greenland. Predictions Implicit in “Ice Melt” Paper and Global Implications:

Yes, but localized, and primarily a driver of extreme weather.  Elsewhere, things will still be a hot house.

Yes.  Not global.  edit   And, the cooling of the Southern ocean's surface is not so helpful as it might appear since "Antarctic freshwater-induced regional surface cooling yields amplifying feedbacks that melt ice shelves, which is the principal route to increased Antarctic ice sheet mass loss."   (sorry for the tangent - thought it was important to point that out)

[Juan C. García]

Ups...
19,865 !!!
Not even 20k.