The 2024 melting season

[binntho]

Third place in JAXA extent!

This melting season, like all others, can be divided into three phases (originally based on Neven's idea, but expanded with what many others have said in this forum - this is not my theory!)

Three phases, one extreme and two average (so far ...).

First phase "preconditioning" was extreme. By far the strongest we have seen so far. Seemed to be at least partially caused by a new phenomena when an anticyclone brought above-freezing air down on the ice very early in the melting season. The warm air presumably originated in a North American "heat dome".

Second phase, "insolation" was average, not that much clear skies during peek insolation (June + July) but June saw higher air temperatures than normal as many have pointed out.

Third phase, "storminess", is not finished yet but has been average so far, until the last couple of days when large losses have coincided with a largeish storm, and looking at Nullschool, the next 7 days will see more of the same. So we might still be in with a change for 2nd or even first? Although loosing 1.3 million km2 seems somewhat unrealistic.

As Neven used to point out, preconditioning is king. Not perhaps enough to guarantee a new record, but anything a bit above normal during the following phases might well secure a medal at least.

[Niall Dollard]

Arctic ice free in summer is far more then just a symbol. Climatologists expect it could produce a wavier, weaker jet stream.

Leading to a whole host of problems especially to Europe and North America e.g.
More intense persistent heatwaves
More stuck weather patterns. Ridiculous Resilient Ridges 
More intense rainfall events.
More boreal forest fires, moving north.
Rapidly rising summer temps in the Arctic.
More methane release.
All at a much faster pace.

Think of what has happened at Lytton and magnify and spread it further north.

[johnm33]

for what?

The ice is crucial to suppressing waves and surface currents. The physics of ice, seawater and humidity variations are crucial to ice formation, all defenistrated once waves come in to play.
nullschool

[binntho]

for what?

The ice is crucial to suppressing waves and surface currents. The physics of ice, seawater and humidity variations are crucial to ice formation, all defenistrated once waves come in to play.
nullschool

The ice of course suppresses waves, but surface currents not so much - it makes no difference for a current if the top layer is frozen or not. And I don't think anything is being thrown out of the windows. But you may be right in saying that physics are crucial to ice formation.

[bees]

I get the significance of an ice-free or nearly Arctic. It's showing the rapid warming and a truly epic result. But, really and truly, what difference does it make?

TL;DR - Relatively large temperature increases in summer on very large surface area, exact consequences uncertain.

Ice acts as a huge STOP sign to temperature increase, which you could easily see in https://ocean.dmi.dk/arctic/meant80n.uk.php , for example. Extra energy in summer goes to ice melting instead of temperature increase, and top of the graph is almost flat.

When Arctic transitions into ice-free state in summer, then this STOP sign would disappear and rapid temperature increase would be observed, which would be likely even higher in nearby continental landmasses due to them being further south and being land instead of ocean.

When such temperature jump would occur, it likely would trigger significant changes on a large surface area - permafrost melting, vegetation developing, albedo changing, ocean clathrates melting, etc. It would likely be a huge event, but with huge uncertainity of what to expect from it.

Worst (so far) case scenario observed would be so-called "crocodiles and palm trees in the Arctic", see https://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Thermal_Maximum

A preview of what to expect could be found in 2020 Laptev Sea conditions, which featured ~5C warmer sea and occasional t-shirt weather on its shores.

[sadmird]

DMI shows the sea ice volume is consistently ranked #1 lowest, even for August 27:


It's incredible how the supposed "stalling", even during the last week, is not really what it looks like when it comes to volume. It's as if the ice is re-positioning itself to cover the same extent and slowly degrading itself over a vast area while not completely melting out, thus keeping up with the ice area as well. If this is true, ice could simply go poof at some point over large surface area, but we are nearing the end of the melt season, so it may not fully materialize before the refreeze takes over.

[Paul]

Third place in JAXA extent!

This melting season, like all others, can be divided into three phases (originally based on Neven's idea, but expanded with what many others have said in this forum - this is not my theory!)

Three phases, one extreme and two average (so far ...).

First phase "preconditioning" was extreme. By far the strongest we have seen so far. Seemed to be at least partially caused by a new phenomena when an anticyclone brought above-freezing air down on the ice very early in the melting season. The warm air presumably originated in a North American "heat dome".

Second phase, "insolation" was average, not that much clear skies during peek insolation (June + July) but June saw higher air temperatures than normal as many have pointed out.

Third phase, "storminess", is not finished yet but has been average so far, until the last couple of days when large losses have coincided with a largeish storm, and looking at Nullschool, the next 7 days will see more of the same. So we might still be in with a change for 2nd or even first? Although loosing 1.3 million km2 seems somewhat unrealistic.

As Neven used to point out, preconditioning is king. Not perhaps enough to guarantee a new record, but anything a bit above normal during the following phases might well secure a medal at least.

One other thing to add is sea surface temperatures, higher SSTS can obviously weaken and retreat the ice even more, we saw that to a large extent in 2020 with exceptionally high temperatures on the Siberian side which helped to give one of the most severe retreat of the ice on the Siberian/Atlantic side.

This year we can see the high SSTS affecting the ice on the Atlantic side but ice can hang on in there if SSTS are modest like in the Chukchi for example. The fact in general SSTS are not as exceptional as some years and ice is as low as it is is quite remarkable really.

[Juan C. García]

I get the significance of an ice-free or nearly Arctic. It's showing the rapid warming and a truly epic result. But, really and truly, what difference does it make? Most of ice up, except for strips of multi-year ice along the top of Greenland, is new anyway. In a month or 6 weeks, it will all be frozen over again, and by March, it will all be many meters thick. No (or extremely little) sea-level rise results in lost ocean ice, and I believe it overall a good thing to allow the Arctic ship traffic for small periods in late summer. I don't know, it just seems like every year there's the same hand-ringing and alarm bells...and for what?

Arctic Ocean heat doesn't stay in the ocean. One example: Oh, my God! OMG: Oceans melting Greenland.

https://sealevel.nasa.gov/missions/omg

[oren]

Welcome, bees.

[SteveMDFP]

I get the significance of an ice-free or nearly Arctic. It's showing the rapid warming and a truly epic result. But, really and truly, what difference does it make? Most of ice up, except for strips of multi-year ice along the top of Greenland, is new anyway. In a month or 6 weeks, it will all be frozen over again, and by March, it will all be many meters thick. No (or extremely little) sea-level rise results in lost ocean ice, and I believe it overall a good thing to allow the Arctic ship traffic for small periods in late summer. I don't know, it just seems like every year there's the same hand-ringing and alarm bells...and for what?

Paddy had a good answer above.  But also, consider how much heat energy is absorbed by a meter-thick layer of ice in the Arctic summer.  If that ice is absent, the resulting ambient temperatures would make the Mediterranean Sea seem chilly.  We've seen such a calculation posted somewhere here in the past. 

[Glen Koehler]

<snip> DMI shows the sea ice volume is consistently ranked #1 lowest, even for August 27:

    Indeed, the volume data is striking.  BUT... the DMI chart does not show 2012, 2017, 2019.  I doubt that 2024 is going to reach #1 lowest volume.


https://psc.apl.uw.edu/wordpress/wp-content/uploads/schweiger/ice_volume/BPIOMASIceVolumeAnomalyCurrentV2.1.png

     BUT... as Michael Mann says, the 2024 situation is bad enough without overstating it.  As others have noted, losing the Arctic sea ice cover will change the functions of the planetary energy distribution system.  Open water during the isolation season results in heat energy that would otherwise be reflected back out to space or used up in melting ice (which takes a LOT of energy) being absorbed to accelerate ocean warming.  That additional heat will affect jet stream postiion, weather patterns, permafrost melt, methane release, ecosystem function (many arctic species need ice, including the algae at the base of the food chain) etc. etc.

     For consideration - if the sun was the size of a golf ball, the Earth would have a diameter of about 0.4mm (about the thickness - not length - of a grain of rice) orbiting about 4.6 meters away.  The NEAREST star would be about 1250 km (775 miles) away.  Who knows how far the nearest inhabitable planet would be.  This is the only planet we have.  We are not going to be able to trash this planet and move to the next one over. 

     Paleogeology shows that the climate has been through massive changes throughout Earth's history.  (The one thing climate deniers get right, but they completely miss the point of that fact showing how sensitive the climate system is.)  Humans developed civilization to fit a very stable and favorable Holocene climate.  Messing up the climate is not something we can fix with even our most formidable technology.  Disrupting the geopolitical, economic, food system, and ecological functioning of the planet would have huge and very unpleasant consequences for billions of people.  Our species may not go extinct, but future generations will see us as irresponsible selfish fools if we mess up the climate system.

      This is not a drill folks.  This is for real.  The next couple of decades could set the course for thousands of years of the only known place in the universe to allow human intelligence to survive.  So YES, the state of the Arctic Sea Ice in 2024 is a very big deal. 
      The climate system is an angry beast and we are poking it with sticks
          - Wallace Broecker, 1998.

[Jontenoy]

Every year people are concerned about breaking the 2012 Extent low.  IMHO ice volume is the most important metric as it indicates what buffering there is before a BOE.  We are new the lowest on record for volume. The powers that be (Governments etc) should be shouting this from the rooftops but so far...... nothing !

[Bruce Steele]

Good to see you back Juan ! 

[sadmird]

@Glen Indeed, PIOMAS doesn't rank current year as lowest. But according to DMI, 2024 has been #1 lowest spot since mid-February. 2024 was also rank #1 lowest in terms of average monthly volume during the last 6 months and it is arguably going to rank #1 again in August, or a close second only to 2012. You can see the pictures for both 2024 and 2012 according to PolarPortal's simulation, used by DMI. To me it seems like it fits quite well into a premise that the ice is generally thinner in 2024, although it covers more area and especially more extent for this date, but I might be wrong when judging these two pictures:



If I'd have to make a guess on these two pictures, it seems like volume is a bit lower in 2024 even for august 28, while the sea ice are and extent are lower for 2012.

Polarportal's simulation utilizes multiple tools that were also updated recently for a much better approximation. There was a discussion whether it's better than PIOMAS in the approximation and I'd say most posters felt like it was, at least during the melt season that we could observe it, but also during the late melt/early freeze period, since it seems to represent what we observe more faithfully.

I've noticed it also tends to be much better when it comes to displaing or hinting about the "invisible" ice that's seemingly showing and disappearing when it's near or just below the threshold for open water in the satellite view. I came to that conclusion while watching the satellite images and comparing it to Polarportal's model, while also observing the Nortwest Passage thread and it seemed that Polarportal/DMI had a much better representation in that regard as well.

[oren]

DMI shows the sea ice volume is consistently ranked #1 lowest, even for August 27:
[img width=580 It's incredible how the supposed "stalling", even during the last week, is not really what it looks like when it comes to volume. It's as if the ice is re-positioning itself to cover the same extent and slowly degrading itself over a vast area while not completely melting out, thus keeping up with the ice area as well. If this is true, ice could simply go poof at some point over large surface area, but we are nearing the end of the melt season, so it may not fully materialize before the refreeze takes over.

It already happened after a fashion in the ESS arm over the past couple of days (2 frames per day, ending on the 27th). I kind of expected this recently, and am wondering if it can continue further.

* Will the dwindling ESS arm disappear completely? I think we still have some significant extent losses that could happen there.

Edit: the 3-day Bremen animation from Steven's site shows this nicely too.

[El Cid]

I think it is too late for the whole gigantic (almost half the remaining ice !) sloshy soup to go poof. There will be holes but it will hold on like a ragtag band of survivors after zombie apocalypse and then will refreeze quickly. BUT: the refrozen ice will probably be very weak structurally so 2025 could do the real job


...I think all eyes should be on the Atlantic front, SSTs are very high, the melt season could last for 3-4 more weeks there

[IceFloe]

I get the significance of an ice-free or nearly Arctic. It's showing the rapid warming and a truly epic result. But, really and truly, what difference does it make? Most of ice up, except for strips of multi-year ice along the top of Greenland, is new anyway. In a month or 6 weeks, it will all be frozen over again, and by March, it will all be many meters thick. No (or extremely little) sea-level rise results in lost ocean ice, and I believe it overall a good thing to allow the Arctic ship traffic for small periods in late summer. I don't know, it just seems like every year there's the same hand-ringing and alarm bells...and for what?

The big scientists are skeptical about the imminent loss of summer ice. I recently read such a text on the most authoritative source about sea ice in the Arctic.

https://nsidc.org/sea-ice-today/analyses/chill-gone

Passive microwave sensors on satellites provide a long-term, consistent, and near-complete record of sea ice starting in late 1978. Before that, there are gaps in coverage and the data are less consistent. However, in the Arctic, earlier ice charts based on a variety of sources provide a fairly reliable record of the Arctic sea ice extent back to 1953. Before 1953, one must rely on sparse data and reconstructions. Reconstructions are derived by comparing limited observations of sea ice conditions with parameters that influence sea ice, such as air temperatures, sea surface temperatures, and sea level pressure.
A new reconstruction of Arctic sea ice back to 1901 has recently been published (Semenov et al., 2024). This new reconstruction generally compares well with other pre-satellite reconstructions: Sea Ice Back to 1850 (SIBT1850, Walsh et al., 2017) and the Hadley Centre Global Sea Ice and Sea Surface Temperature (HadISST) 1.1 (Rayner et al., 2003). However, the new data set shows more variability in the pre-1953 period. It also depicts lower September extents during the 1930s and 1940s in the western Arctic like the Beaufort and Chukchi Seas. While there are inherent uncertainties in sea ice reconstruction, results from this new approach support the conclusion that the satellite era trend in extent is outside of the range of natural variability. Nevertheless, caution is needed when interpreting these results because of sparse observations of sea surface and air temperatures.

[Chuck]

Every year people are concerned about breaking the 2012 Extent low.  IMHO ice volume is the most important metric as it indicates what buffering there is before a BOE.  We are new the lowest on record for volume. The powers that be (Governments etc) should be shouting this from the rooftops but so far...... nothing !

Volume is arguably a more important metric but since it can’t be accurately measured extent and area are better ways to quantify the state of the ice.

[Steven]

First phase "preconditioning" was extreme. By far the strongest we have seen so far. Seemed to be at least partially caused by a new phenomena when an anticyclone brought above-freezing air down on the ice very early in the melting season.

It depends on how you define preconditioning.  If it's defined as melt ponds, surface wetness and low albedo etc, then I don't think this year was stronger than 2012.  The indicators I've seen for this (NSIDC area, SMOS etc) show stronger preconditioning in 2012 than in 2024 in both June and July when averaged over the month.  Especially in the first half of June, 2012 was way ahead.

[echoughton]

The freezing season is near the thermometer dropped to -8 at Svartevaeg today

I suspect the holes will begin closing in a few short weeks.

[echoughton]

And I understand what many have said about increased heat when the ice goes poof. It would, but for how long? We're not talking about a long time without ice. If in a year or two, five, whatever, there is a BOE, when, exactly would that occur? It would happen right about now and for a few weeks. Winter would still come...perhaps a bit later with the added heat, but not much longer. It's not at all like there would be ice free Arctic for any period longer than a month to 6 weeks each year. Not this year though. Ice certainly does keep it chilly above 80 north. Indeed, with all the exclaiming on here, one might think the temps have been rising up there unbelievably. Look at it yourselves. Nothing out of the ordinary since April!!!
https://ocean.dmi.dk/arctic/meant80n.uk.php

[Sublime_Rime]

And I understand what many have said about increased heat when the ice goes poof.

I think it's important to not get caught up in BOE vs non-BOE, wvwn before one is officially declared, as well as after. As you say it will begin with only a few days or weeks of ice free and then expand from there. But even before this, we are seeing increasing temps more often late in the season for the whole arctic, and I suspect this is largely driven by open ocean in the basin outside the CAB. You can see this pretty clearly for both 2023 and 2024.

I think this is just as important as changes that occur after a BOE north of 80 deg.

[gerontocrat]

I went on google scholar and searched using "climate impacts of reducing arctic sea ice"

Attached is a screenshot of the first of many results.

Obviously some climate scientists believe it is significant

[binntho]

First phase "preconditioning" was extreme. By far the strongest we have seen so far. Seemed to be at least partially caused by a new phenomena when an anticyclone brought above-freezing air down on the ice very early in the melting season.

It depends on how you define preconditioning.  If it's defined as melt ponds, surface wetness and low albedo etc, then I don't think this year was stronger than 2012.  The indicators I've seen for this (NSIDC area, SMOS etc) show stronger preconditioning in 2012 than in 2024 in both June and July when averaged over the month.  Especially in the first half of June, 2012 was way ahead.

Preconditioning is indeed meltponds and surface wetness - and you need to look at April and May for the preconditioning. June and July are in the second phase, "insolation".

[etienne]

I went on google scholar and searched using "climate impacts of reducing arctic sea ice"

Attached is a screenshot of the first of many results.

Obviously some climate scientists believe it is significant

Of course is a reduced Arctic sea ice significant, but I guess that the question is whether a BOE a tipping point is. IMHO not, more a public relation type of event. But I might be wrong because  the absence of ice could mean that the ocean temperature would increase significantly and delay the freezing season.

[oren]

And I understand what many have said about increased heat when the ice goes poof. It would, but for how long? We're not talking about a long time without ice. If in a year or two, five, whatever, there is a BOE, when, exactly would that occur? It would happen right about now and for a few weeks. Winter would still come...perhaps a bit later with the added heat, but not much longer. It's not at all like there would be ice free Arctic for any period longer than a month to 6 weeks each year. Not this year though. Ice certainly does keep it chilly above 80 north. Indeed, with all the exclaiming on here, one might think the temps have been rising up there unbelievably. Look at it yourselves. Nothing out of the ordinary since April!!!
https://ocean.dmi.dk/arctic/meant80n.uk.php

Please do not derail the melting season thread with these questions. They belong on the "When will the ice go ice free" thread.
BTW the claim that nothing out of the ordinary is happening just because CAB temps are physically stuck to the melting point of ice, is a denier meme, best not bandied about without care. As long as there is ice, temps will not really rise. Does it prove anything? Not much.

[binntho]

Storminess is showing up in the JAXA numbers - we had around 3 days of fairly brisk southerlies from the Atlantic and a moderately deep cyclone over the central Arctic. Relatively quiet yesterday and today, but tomorrow evening will see another stormy intrusion to last for a couple of days. Let's see what that does to extent!

Date	Extent loss	Storminess
Aug-25	27052	Mild
Sep-25	40379	Mild
Oct-25	36560	Mild
Nov-25	63155	Moderate
Dec-25	93688	Moderate
Jan-26	86092	Moderate
Feb-26	44422	Mild

[Yuha]

First phase "preconditioning" was extreme. By far the strongest we have seen so far. Seemed to be at least partially caused by a new phenomena when an anticyclone brought above-freezing air down on the ice very early in the melting season.

It depends on how you define preconditioning.  If it's defined as melt ponds, surface wetness and low albedo etc, then I don't think this year was stronger than 2012.  The indicators I've seen for this (NSIDC area, SMOS etc) show stronger preconditioning in 2012 than in 2024 in both June and July when averaged over the month.  Especially in the first half of June, 2012 was way ahead.

Preconditioning is indeed meltponds and surface wetness - and you need to look at April and May for the preconditioning. June and July are in the second phase, "insolation".

Preconditioning in regions that are going to melt anyway does not matter much with respect to the minimum area or extent. What matters is preconditioning in the critical regions, which are the regions that may or may not melt, and that happens mostly in June. I agree with Steven that 2012 had stronger critical region preconditioning than this year.

[binntho]

First phase "preconditioning" was extreme. By far the strongest we have seen so far. Seemed to be at least partially caused by a new phenomena when an anticyclone brought above-freezing air down on the ice very early in the melting season.

It depends on how you define preconditioning.  If it's defined as melt ponds, surface wetness and low albedo etc, then I don't think this year was stronger than 2012.  The indicators I've seen for this (NSIDC area, SMOS etc) show stronger preconditioning in 2012 than in 2024 in both June and July when averaged over the month.  Especially in the first half of June, 2012 was way ahead.

Preconditioning is indeed meltponds and surface wetness - and you need to look at April and May for the preconditioning. June and July are in the second phase, "insolation".

Preconditioning in regions that are going to melt anyway does not matter much with respect to the minimum area or extent. What matters is preconditioning in the critical regions, which are the regions that may or may not melt, and that happens mostly in June. I agree with Steven that 2012 had stronger critical region preconditioning than this year.

I do not fully agree with you. I think that the Arctic Basin should be viewed as a whole, and talking about regions that will melt out anyway as irrelevant to the final outcome seems counterintuitive to me.

This is a battle betwene the ice on the defensive, and a multi-pronged energy attack on several fronts. Stronger peripheral defenses will protect the center, so the sooner the "will melt anyway" brigade is out of the way, the sooner the citadel itself is open to direct assault.

Besides, any statements should be backed up by facts. Steven did not say anything about "critical region preconditioning" in spite of you claiming otherwise. He did however compare the "wrong" months - and since I myself am unable to do the comparison, all I am willing to say is that preconditioning this year was extreme, but I don't know if it was more or less than in 2012 or indeed in other extreme melt years.

[be cause]

I found I hadn't posted this last night ..

still no NSIDC figures . 2nd ?
    Laptev side of the Atlantic front is getting hammered . Melt ponds and retreat .
   nullschool had 1m waves at 89'N a few days ago , and wave action from Greenland to Siberia . Johnm33's nullschool images ^^ reveal how weak the remaining ice is beyond the shrinking Canadian and Atlantic wings . Volume must be @ lowest ever . 

  now , after 2 dramatic falls totalling 187k , NSIDC daily area is 2nd . ps .. on polar python it was 4th , i just noticed gero had it at 2nd already . 1st continues to be a strong possibility even as temps drop .

[sadmird]

@Oren: good finding, I completely overlooked it, even though it was also shown on JAXA's images as well and I was checking those images on a daily basis.

By the way, NSIDC's daily sea ice area shows that 2024 has already surpassed the last year's minimum and is only 5k higher than 2020. Rank #1 seems harder to reach now than it was just about a week ago, but it's still has a decent chance, if the weather serves it well in the next 2 weeks, but the season could end at any moment at this point, depending on the weather.

All time low by NSIDC daily sea ice area:
#1   2012   2.2361
#2   2016   2.477
#3   2020   2.633
#4   2024   2.638
#5   2023   2.645
#6   2019   2.900
#7   2011   2.919
#8   2017   3.014
#9   2007   3.031
#10   2008   3.085
#10   2010   3.085
#12   2015   3.142
#13   2021   3.239
#14   2018   3.240
#15   2022   3.248
#16   2009   3.550
#17   2014   3.580
#18   2013   3.615


I'd like to compare and contrast DMI's model for 2012 and 2024 for the August 28 with the JAXA's images for that same date, as well as the date for the final extent of 2012, in order to get the better picture about the likely outcome of sea ice is Chukchi and ESS. It seems like it confirms that almost all of the ice in the ESS and Chukchi should disappear by the end of the season, just like it did in 2012, but it could be just me and regarding self-reporting bias, since I stated that most if not all of that ice should disappear like  6 weeks ago. It proved to be much more resilient, though, and the weather condition also helped it, but it seems that even the strong pack in Chukchi should be gone almost completely by the end of the melt season. Please excuse me for rotating the images for JAXA sea ice concentration for August 28, as well as the image for September 16, 2012. I rotated it solely to be on par for better comparison with polarportal's map:

[oren]

5-day Bremen animation, courtesy of Steven's site (Click).
https://sites.google.com/view/arctic-sea-ice/home/concentration

A few issues I am thinking about:
* Will the dwindling ESS arm disappear completely? I think we still have some significant extent losses that could happen there.
* When will refreeze hit? In 2016 the CAB ice was as rotten as this year, with abundant low concentration in central regions. This brought about an initial refreeze on Sep 9th, 2 weeks from today.
* Can the resilient Chukchi ice at 67-71deg really make it to the end of the season? Refreeze there typically happens in early October (see chart), that's about 6 weeks away. But melting typically stops in about 4 weeks.
* Beaufort ice has taken a deep hit, apparently the poor MYI arm we had last year is all gone. I wonder if there are any updates of the sea ice age product? And can the Beaufort area break the 2012 AMSR2 record of 9765 km2? (See chart, 2012 is in invisible blue).
* The CAA has also had a consistently bad season from the start. Can CAA area break the 2012 AMSR2 record of 109k km2? (See chart).
* The Atlantic side ice edge is showing a persistent march north. Can it make it to 85deg? I would say <50% probability. But certainly >0%.
* Will the Laptev ice edge ever move north before season's end? It's been stuck in the same position for ages now.

After the first issue was confirmed yesterday with the collapse of extent in the ESS arm, today the 4th issue is confirmed, with the Beaufort AWI-AMSR2 area dropping to an all time low of 6932 km2, breaking 2012's long-standing record (in invisible blue). Actually the record was already marginally broken yesterday, for both area and extent according to AWI.

Meanwhile, the CAA appears to be stalling for the moment, and the main party at the CAB is very far from a record. Both Chukchi and Laptev made some strides lower, and the Greenland Sea is nearly down to 2nd place, though still far from 1st.
Atlantic side ice edge is up to ~85.5^o, and Laptev finally managed to advance a bit from 78^o to 80^o.

[Burnrate]

Wow the area posted in the data thread shows only 230k above 2012 if the average loss is followed.

That average loss implies a minimum on the 10th which seems unlikely just due to the what I've read here about possible weather in the coming days and the current way the ice looks and how fast it can vanish in those 3-day median gifs Oren posted above.  Scary year.

[Steven]

Preconditioning is indeed meltponds and surface wetness - and you need to look at April and May for the preconditioning. June and July are in the second phase, "insolation".

April is too early, unless you're including Okhotsk and Labrador Sea or the melting of land snow on the continents (which is a different type of preconditioning, since land heat can affect sea ice later by rivers or winds).  May is more relevant, especially the second half of the month as the snow layer on the sea ice in the Arctic Basin can start to melt.  But as we know from buoys, this is a slow process that takes multiple weeks to complete and real widespread melt pond formation only starts in June.

I wouldn't separate the preconditioning and insolation phases, since they largely overlap in my opinion.  Even in the middle of summer, there can be cyclones dropping new snowfall on the sea ice and increasing the albedo again, and then the whole process starts over again.  Either way, I agree that 2024 had strong preconditioning, although somewhat less strong than 2012.

[NeilT]

Chartic is showing that Extent will cross 2019 into third place tomorrow or the day after.

The continued atlantification and the continued decline of the slushy ice is keeping the losses going.  I'm also guessing there will be one more large drop in extent when temps drop and compaction starts in earnest.

Bremen is showing open water very close to 85n on the Atlantic side.  It is like watching a massive train derailment at 5mph.  It's really slow but the inertia is so huge that stopping it is extremely hard.

[Steven]

All time low by NSIDC daily sea ice area:
#1   2012   2.2361
#2   2016   2.477
#3   2020   2.633
#4   2024   2.638
#5   2023   2.645
#6   2019   2.900
#7   2011   2.919
#8   2017   3.014
#9   2007   3.031
#10   2008   3.085
#10   2010   3.085
#12   2015   3.142
#13   2021   3.239
#14   2018   3.240
#15   2022   3.248
#16   2009   3.550
#17   2014   3.580
#18   2013   3.615

It's a funny coincidence that the top 4 years in this list are all leap years, and the 5th to 8th place are all years just before a leap year*.

*: the 2007 sea ice area in this list is probably biased high somewhat, since the "pole hole" in the NSIDC mask was 10 times larger before 2008 and in the calculations on my website I assume 100% sea ice concentration inside the pole hole, to be consistent with gerontocrat's numbers.  From a quick look at the gridded data, the 2007 minimum would be biased high by about 60k km2 in this list while the years from 2008 onward would have a bias of less than 10k km2, which would mean that 2007 would be at 8th place rather than 9th.

[interstitial]

Lowest NSIDC area is 500,000 km2 away. Average melt is about 12,500 km2 x 14 days or 175,000 km2. Third place is 80,000 km2 of melt. Second place is 240,000 km2 of melt.

[interstitial]

It's a funny coincidence that the top 4 years in this list are all leap years, and the 5th to 8th place are all years just before a leap year*.

Its that extra day of melting.

[sadmird]

Good notice, @Steven. I stand corrected. I know this was mentioned before as well, but I also failed to notice it and put that remark while generating the list. By the way, my guess is  that the list is just a coincidence regarding final results, but it may play a bit of a role on a day-to-day comparison during melt season for a specific date, given that a few days of melt during i.e. June or July make a huge difference, after all.

@interstitial you have a point as well. 5-day sliding window for sea ice area by NSIDC is definitely a more reliable way of observing the data. It may not be as accurate for a specific day in terms of raw data, but there are some occasional blips in the data and it helps out to smooth out such inconsistencies. I generated the list using daily sea ice area values by NSIDC and, by such comparison, 2024 is behind 2020 daily sea ice minimum by mere 5,000 km².
For a better overview of condition of the sea ice area, it's more useful to stick with 5-day sliding window and you are right, last year's minimum, by such calculation, is not yet surpassed and it's about 80,000 km2 away.

I spent some time checking on the polarportal's daily and yearly data regarding volume. It seems that 2024 is breaking a new record each day now, because it matched a record low volume from early September 2012 some days ago and it continues with a seemingly very steep loss of volume even for this day of the year. I am posting 2016 for this day, another strong melt year which had one of lowest volume minimums by polarportal, just to signify how destructive this year was (and that graph also has 2012, which held a record low arctic sea ice volume on a daily basis, which gives a good comparison and signals that 2024 melt season is "exploring the uncharted areas" now):



PIOMAS was usually considered as most reliable until this newly updated tool came along and gained traction this summer (or shall I say "recognition"?) on this forum and beyond. It'd be useful to hear new opinions on comparison of different tools for measuring or approximating volume (but not on this thread, of course).

In any case, according to DMI, previous record low daily sea ice volume was held by 2012, but it basically stalled with any volume losses around early September.
These big losses in the ongoing melt season seem to coincide well with models on nullschool and climatereanalyzer, at least from what I had the chance to compare in the last few days. I am not well-versed with posting good animations from nullschool on forum and I didn't save data from climatereanalyzer for previous few days to prove my point. But, from what I see as the forecast for the next few days on climatereeanalyzer, the same situation will continue in the next few days (at it should be fairly reliable forecast), so we can expect DMI's graphs to show even lower sea ice volume over the course of the next couple of days. Let's see just how low can it go before refreeze takes over.

[Paul]

Just amazing at the numbers because this is all despite the lack of high pressure during July and August. Hard to say for sure if the numbers would be worse if we did have a more high pressure dominating July because it would most likely to lead to less dispersion but SSTS around the pack would be much higher than they are now I would of thought.

The Atlantification has been impressive and even more so when you consider in June, extent was high in the Barants and SSTS were running at below normal, such a transformation.

Yet despite it not being a good summer for the ice, refreeze could end up being quite quick if the weather favours it just like it did in 2012.

[John_the_Younger]

Because the sun "goes down" sooner at the north pole, I expect the refreeze - meaning Arctic sea ice area increasing - to start early; the slushy/ice-pondy/disperse ice in the highest Arctic will refreeze and influence the whole Arctic's numbers.  In most years past, this area was mostly pretty solid ice with few openings or ice ponds, so when the sun went down there, that region went from near 100% ice cover to a tiny bit nearer 100% ice cover.

Further south (and bottom melt) ice losses will continue later as our recent normal has determined.

[binntho]

Preconditioning is indeed meltponds and surface wetness - and you need to look at April and May for the preconditioning. June and July are in the second phase, "insolation".

April is too early, unless you're including Okhotsk and Labrador Sea or the melting of land snow on the continents (which is a different type of preconditioning, since land heat can affect sea ice later by rivers or winds).  May is more relevant, especially the second half of the month as the snow layer on the sea ice in the Arctic Basin can start to melt.  But as we know from buoys, this is a slow process that takes multiple weeks to complete and real widespread melt pond formation only starts in June.

I wouldn't separate the preconditioning and insolation phases, since they largely overlap in my opinion.  Even in the middle of summer, there can be cyclones dropping new snowfall on the sea ice and increasing the albedo again, and then the whole process starts over again.  Either way, I agree that 2024 had strong preconditioning, although somewhat less strong than 2012.

You may well be right in saying that April and May are too early, but the whole idea of "preconditioning" is that it sets up the scene for the "insolation" phase. One way to do this is to melt the surface layer even temporarily, which can happen even when the air is below freezing, which lowers albedo and makes the appearnce of melt ponds all that easier later on.

But I had a look back on the timing of the event that I found most interesting this year, and it was indeed early June when the strange phenomena of anti-cyclonic heat dumping happened. At the same time, the entire Arctic became blue indicating extremely widespread meltponding, and ice loss was very rapid.

We tend to think of peak insolation as happening symmetrically around summer solstice, but I seem to remember direct measurements showing it to happen around two weeks later (don't ask me why!).

I have so far avoided setting down timeframes for the putative hypotothetical division into phases, but perhaps we could talk about a transition between preconditioning and insolation in first half of June, and between insolation an storminess at the beginning of August?

[El Cid]

There's been some discussion about how "good" the weather was for Arctic ice loss this year. Let me attach three charts. The first is June Arctic 850 hpa temperatures. 850 hpa temps are significant as they show you how much warm air arrived at the Arctic (2 m temps are more or less fixed due to the presence of ice).

As you can see, 2024 June was the WARMEST. 2nd place: 2020, 3rd: 2012 4th: 2005, 5th: 2007

June heat matters a lot it seems as warm junes correlate quite well with record ice loss years.

As for July, that seems less important but matters still...ranking: 2020,2023, 2022, 1998, 2007, 2024.

Spring also matters a bit (not shown) , 2016 holds the record there.

Last chart is MJJ average anomaly: 2024 is third

My conclusion is that June heat is the most important factor, while spring and July heat is secondary

[NeilT]

Chartic shows 2024 dropped into 3rd place for Extent yesterday.  It might move around a bit over the next few days as 2019 dropped again on the 31st and for the next 2 days.

However it looks like 2024 will end up in third place for extent.  It doesn't look like going below 2023 but that does depend on compaction I guess and also how much more damage that heat in the Atlantic does.

[johnm33]

From nullschool looking at sea temps off Norway, 8-15-22 and 29:08 my thinking is not that the sea is cooling but that the resistance to it penetrating the Arctic is being overcome, hence less kinetic heating locally. Implying accelerated/ing penetration of Atl. waters.
click

[Paul]

There's been some discussion about how "good" the weather was for Arctic ice loss this year. Let me attach three charts. The first is June Arctic 850 hpa temperatures. 850 hpa temps are significant as they show you how much warm air arrived at the Arctic (2 m temps are more or less fixed due to the presence of ice).

As you can see, 2024 June was the WARMEST. 2nd place: 2020, 3rd: 2012 4th: 2005, 5th: 2007

June heat matters a lot it seems as warm junes correlate quite well with record ice loss years.

As for July, that seems less important but matters still...ranking: 2020,2023, 2022, 1998, 2007, 2024.

Spring also matters a bit (not shown) , 2016 holds the record there.

Last chart is MJJ average anomaly: 2024 is third

My conclusion is that June heat is the most important factor, while spring and July heat is secondary

Makes you wonder how things could of ended up if say July was more high pressure dominating but June was definitely notable at the time of how warm the month was for most of the basin.

Unlike last year, there is no real surprises where we are ending up with the extent and maybe the more stormy second part has saved the extent numbers somewhat even if albeit it made the ice pack look pretty ugly visually with all the dispersion there is.

Still nevertheless, it shouldn't take away the trend is still downwards and if we do end up below 4 million on Jaxa then that will be the 3rd time in 6 years that has happened and that should be significant to tell you there is no real stall in the extent numbers and if anything I expect the variability to increase as we get closer to the BOE figure

[SteveMDFP]

There's been some discussion about how "good" the weather was for Arctic ice loss this year. Let me attach three charts. The first is June Arctic 850 hpa temperatures. 850 hpa temps are significant as they show you how much warm air arrived at the Arctic (2 m temps are more or less fixed due to the presence of ice).

As you can see, 2024 June was the WARMEST. 2nd place: 2020, 3rd: 2012 4th: 2005, 5th: 2007

June heat matters a lot it seems as warm junes correlate quite well with record ice loss years.

As for July, that seems less important but matters still...ranking: 2020,2023, 2022, 1998, 2007, 2024.

Spring also matters a bit (not shown) , 2016 holds the record there.

Last chart is MJJ average anomaly: 2024 is third

My conclusion is that June heat is the most important factor, while spring and July heat is secondary

Thanks for this data visualization.  2024 is indeed very notable in terms of early preconditioning/melt.  What's truly alarming about these graphs is the striking trend on display, which is only obvious after 2000. 

Why was such a trend not apparent before 2000?  Why would this be in such contrast to the evolution of the "slow transition"?  Curiouser and curiouser.

[Freegrass]

Latest Five Day Forecast + Last 5 Days
Wind + Temp @ Surface
AMSR2 Central Arctic Leads Animation
Large GIFs!

That storm I was hoping for never came, so I guess we'll have to hope for a massive HPS now to compact the ice. But third place seems to be where we're heading, which is bang on with my prediction. 

[icy voyeur2]

All time low by NSIDC daily sea ice area:
#1   2012   2.2361
#2   2016   2.477
#3   2020   2.633
#4   2024   2.638
#5   2023   2.645
#6   2019   2.900
#7   2011   2.919
 

It's a funny coincidence that the top 4 years in this list are all leap years, and the 5th to 8th place are all years just before a leap year*.

But it's not surprising.
We often get a lot of hot air associated with USA Presidential election years.

 bah dum toosh

I'm sorry, I'm sorry (I'm not sorry)

[The Walrus]

All time low by NSIDC daily sea ice area:
#1   2012   2.2361
#2   2016   2.477
#3   2020   2.633
#4   2024   2.638
#5   2023   2.645
#6   2019   2.900
#7   2011   2.919
 

It's a funny coincidence that the top 4 years in this list are all leap years, and the 5th to 8th place are all years just before a leap year*.

But it's not surprising.
We often get a lot of hot air associated with USA Presidential election years.

 bah dum toosh

I'm sorry, I'm sorry (I'm not sorry)

Good one.  ROFL