Yesterday, I pointed out that despite predictions of an “ice-free summer” in the Arctic by now, Arctic sea ice continues to defy such predictions and ended the 2018 melt season higher that the lowest years of 2012 and 2007:
Ron Clutz writes and provides a graph that suggests the Arctic sea ice has reached a new, but lower, equilibrium point since 2007:
People are overthinking and over-analyzing Arctic Ice extents, and getting wrapped around the axle (or should I say axis). So let’s keep it simple and we can all readily understand what is happening up North.
I will use the ever popular NOAA dataset derived from satellite passive microwave sensors. It sometimes understates the ice extents, but everyone refers to it and it is complete from 1979 to 2017. Here’s what NOAA reports (in M km2):
If I were adding this to the Ice House of Mirrors, the name would be The X-Ray Ice Mirror, because it looks into the structure of the time series. For even more clarity and simplicity, here is the table:
NOAA NH Annual Average Ice Extents (in M km2). Sea Ice Index v2.1 (here)
| Year | Average | Change | Rate of Change |
| 1979 | 12.328 | ||
| 1994 | 12.011 | -0.317 | 0.021 per year |
| 2007 | 10.474 | -1.537 | 0.118 per year |
| 2017 | 10.393 | -0.081 | 0.008 per year |
The satellites involve rocket science, but this does not. There was a small loss of ice extent over the first 15 years, then a dramatic downturn for 13 years, 6 times the rate as before. That was followed by the current plateau with virtually no further loss of ice extent. All the fuss is over that middle period, and we know what caused it. A lot of multi-year ice was flushed out through the Fram Strait, leaving behind more easily melted younger ice. The effects from that natural occurrence bottomed out in 2007.
Kwok et al say this about the Variability of Fram Strait ice flux:
The average winter area flux over the 18-year record (1978–1996) is 670,000 km2, ;7% of the area of the Arctic Ocean. The winter area flux ranges from a minimum of 450,000 km2 in 1984 to a maximum of 906,000 km2 in 1995. . .The average winter volume flux over the winters of October 1990 through May 1995 is 1745 km3 ranging from a low of 1375 km3 in the 1990 flux to a high of 2791 km3 in 1994.
http://www.ccpo.odu.edu/~klinck/Reprints/PDF/kwokJGR99.pdf
Conclusion:
Some complain it is too soon to say Arctic Ice is recovering, or that 2007 is a true change point. The same people were quick to jump on a declining period after 1994 as evidence of a “Death Spiral.”
I think the reason they are wrong is that they cling to their positive feedback “arctic amplification” theory which is proven false by the fact that there isn’t any warming occurring there in the summer when the sun is shining. Even the DMI states that they believe albedo has something to do with warming despite that they are the ones who show temperature data that reveals all the warming is happening in the winter which obviously has nothing to do with the sun. http://ocean.dmi.dk/arctic/meant80n_anomaly.uk.php
http://ocean.dmi.dk/arctic/plus80n/anoplus80N_summer_winter_engelsk.png
The AMO shows up many different ways.
Agreed. But what I want but is the definition for “recovery” as it pertains to Arctic ice! “Recovery” to what and if a parameter is given then why was it selected?
There is little evidence of a persistent ‘recovery’ towards earlier levels of ice area / extent but the fact that the accelerating ice loss seen until 2007 has decelerated to essentially zero net change since 2006 has to be a “recovery” from the OMG, soon there won’t be any ice left, scenario.
I also showed that there was a change in the drift in the date of ice minimum around 2007 which maybe part of this change. (click to see the graph)
https://judithcurry.com/2016/09/18/is-the-arctic-sea-ice-spiral-of-death-dead/
I don’t know what this change in direction “means” but it seems to be part of the changes which occurred around 2007 which refute the simplistic idea of the polar climate being dominated a positive albedo feedback as ice melts.
A decade long pause is not compatible with claims of a positive f/b. It is more indicative of a negative feedback dominating or that changes are driven by other factors.
This is one canary which refuses to die. That would normally be a news worthy event.
http://woodfortrees.org/plot/esrl-amo/from:1980/mean:12/plot/nsidc-seaice-n/from:1980/mean:12/scale:-0.4/offset:4.4
We have much more important things to worry about than this bit of ephemeral wiggle watching….
That goes for the entirety of climate science! Economics has competition as “The Dismal Science”!
Indeed. How much of little the sea will rise by 2100 is the least of the worries we have to face right now.
Which wiggles would you wather watch?
A major problem with this dataset is that it is fairly short, so if a longer term cycle is in play, it will not show.
Tom
Yes it will, it will show that during the period covered that it reduced slightly as shown in the chart above.
Regards
Yes, this data set started in 1979, one of the coldest periods in recent times, and a period when arctic sea ice was at a high point, so it is no surprise that arctic sea ice has decreased as the climate warmed from 1979 to the present.
There was less arctic sea ice during the hot 1930’s, than there is today. And it was hotter then than now.
When it warms, arctic sea ice melts. The warming and subsequent arctic sea ice melting in the 1930’s, had little or nothing to do with CO2, even according to the Alarmists, yet more arctic sea ice melted then than today.
And it doesn’t look like CO2 has much to do with arctic sea ice melting today, either, because sea ice is increasing while CO2 increases, which is just the opposite of what should be happening according to the CAGW speculation..
Arctic sea ice is increasing, and temperatures are falling, all while CO2 increases. What’s an Alarmist going to do? Oh, that’s right, the Alamists will do some more temperature chart manipulation.
What will be interesting is to see the response as the AMO enters its cold phase, unlike the warm phase it has been in with corresponding lower ice numbers.
While we know that a lot of multi year ice got flushed out the Fram Straight due to favourable conditions such as storms, winds and a slight warming in the NH over the last 30-35 years, what are other possible sources of any possible human caused influence? One of the things I noticed in the 1980’s and 1990’s was a large acceleration of USSR/Russian and North American ice breaker fleets breaking up the coastal ice which ice had been pinned to coast lines for all of history before that. That ice, had it been unmolested by ice breakers, including ice breakers that were charged with studying global warming and climate change, not busted up that ice so close to thousands of miles of shorelines, it would have been left in-situ melting much later every season. As soon as thousands of miles of shoreline ice are not pinned from shore to the floating ice cap, it is much more susceptible to not only a faster melting, but becomes much more available to the movements of currents and winds when it is just floating with no resistance from ice that previously had been in place and attached to shorelines much later into the season.
While my observations are anecdotal in nature with no corresponding data to suggest such, it is sort of common sense that if you cut off thousands of miles of ice in the Northern Arctic Ocean both on the Siberian side as well as both of Alaska and through the Canadian Archipelago, then there is an potential opposite effect that may accelerate the disappearing ice mystery. Especially in the mid 1980’s to late 1990’s when the ice took extant took such an immediate nose dive and right when large nuclear ice breakers were just making their debut. It seems intuitive to me, but I have seen no significant research on this. But wouldn’t it be ironic if the very ice breakers that are up in the Arctic Ocean, some of which are studying climate change and telling us the Arctic ice is disappearing fast, that they are in part responsible for it.
Earthling,
This would especially be true of the Siberian coast, which was plied by Soviet nuclear-powered ice breakers for decades. Soviet and Russian ballistic missile subs also exploit polynyas, which their presence serves to maintain longer than would naturally be the case.
But the North American Arctic has also suffered such insults in the name of research, often misguided.
Soot from China might also be contributing to Arctic ice melting.
There has also been volcanic activity in the Arctic Ocean in this century and late in the last. I don’t know how normal these eruptions are.
https://www.iceagenow.info/underwater-volcanoes-melting-arctic-ice-says-geologist/
https://www.livescience.com/4992-volcanoes-erupt-beneath-arctic-ice.html
Ah! It’s the Russian who have “interfered” with the Arctic too. They must be stopped. More sanctions must be imposed by Trump.
If you want to follow an ice breaker, you need to stick, close. That ice won’t remain open for long. The Arctic ocean is a BIG place. The chance of altering it with a few ships is like saying a fishing float may be slowing down the flow of a river.
Bingo!
The transits of the northern passages fell off a cliff in the late 80s and early 90s:
http://www.arctic-lio.com/images/transitstatistics01.jpg
I suspect that had something to do with the demise of the USSR but have not looked into it in detail. It may simply be that the sea ice increased although the data does not support that.
The recent data on northern passage transits shows a decline since 2013:
http://www.arctic-lio.com/nsr_transits
So the big saving in shipping costs associated with the northern passages remains wishful thinking.
Well these guys have seem to think that there is some sort of “archived” heat trapped that has the potential to mix with surface waters and melt the whole lot : https://www.sciencedaily.com/releases/2018/08/180829143836.htm
Earthling2,
I myself have often wondered about the effects of ice breakers. I think they likely have an effect when the ice is more rigid, but when the sea-ice wants to move ice-breakers are puny and have little effect.
As an example I’d like to point out the history of the good ship Jeanette, which set out for the North Pole from San Francisco in 1879. They were buoyed by three false hopes.
1.) They believed the North Pole could not be covered by ice, because salt water behaves differently than fresh water. The coldest fresh water rises, and therefore the surface of ponds freeze, but the addition of salt causes the coldest salt water to sink. This is scientific fact. Therefore the waters of the Arctic Sea could never freeze, for such waters would sink as they cooled, and be replaced by warmer waters rising from below.
2.) Sea ice was tested and found to be fresh water. Therefore it could not originate from salt water, and must be due to inflows of fresh water from rivers along arctic coasts. Therefore all sea-ice would be concentrated along arctic coasts, and if you could penetrate that sea-ice you’d find open water off shore
3.) Some whalers had reported landing on Wrangel Island with a lot of open water around, and therefore it seemed Wrangel Island might be a doorway to the open seas beyond.
Wrong. The Jennette was trapped by sea ice short of Wrangle Island, near Herald Island. The sea-ice had increased since the whalers found open seas, and during the following 21 months the sea-ice erratically
took them barely a degree longitude per month to the west. (During this time an icebreaker would have been handy).
But then the sea-ice situation changed radically. The ice began to shift, and the Jeannette was crushed. The 33 members of the crew headed southwest, making it to the New Siberian Islands on ice, but facing open water as they headed to the swamps of the Lena Delta. (Only 13 made it out alive.)
Meanwhile two ships following behind, looking for the lost Jeannette, did not find the Jeannette because they (including the Naturalist John Muir) were able to land upon both Herald Island and Wrangel Island and dilly-dally about surveying both islands. They failed to find the Jeannette but found lots of open water, because the sea-ice was in motion, and moving far faster than it had formally moved.
We know how fast the sea-ice moved, because the crushed Jeannette didn’t sink (though parts of it likely sunk, being iron,) and instead moved, in the next 36 months, more than halfway around the earth, in terms of longitude. The sea-ice the crushed beams and planks were squeezed by moved west along the entire north coasts of Russia and Scandinavia, likely north of Svalbard, and took a left through Fram Strait and then down the entire east coast of Greenland, and then took a sharp right around Cape Farewell and were found nearly three years to the day of when the ship was abandoned, in Baffin Bay off Julianehåb. Miles? You figure it out for me, but the ship was abandoned at 77° 15′ north and 154°59′ east, and the wreckage was found at around 60° 70′ north and 46° 05′ WEST.
Yowza.
This incredible movement of sea-ice in 36 months is what gave Nansen the idea he could park the Fram in Sea Ice in East Siberia and drift across the Pole.
But me? I lack Nansen’s ambition. Instead I sit back and say, “Yowza!” I see that, once sea-ice takes it into its head to move, tremendous forces are involved, and the entire fleet of Russian icebreakers can’t matter much more than fifteen mice standing before an avalanche with stop signs.
And if the mighty Russian ships matter so little before such power, how stupid it is for silly people to think buying curly light bulbs and all other forms of virtue-signaling will have the slightest effect?
Not that we shouldn’t consider ways we might deflect disasters when they are apparent. We should consider spreading black soot on sea-ice the same way we consider seeding hurricanes. However such actions involve at least a basic understanding of the forces we are attempting to influence.
Sad to say, politics has utterly polluted the understanding of many, concerning sea-ice. Unless and until we remove this rot, the subject of sea-ice cannot even reach the level of a basic understanding. Politics is like taking a stupid-pill. It might be screamingly obvious that all mankind would benefit if we spread soot and reduced sea-ice, but political correctness would shout more ice was better.
Caleb,
You wrote:
“The coldest fresh water rises, and therefore the surface of ponds freeze, but the addition of salt causes the coldest salt water to sink. This is scientific fact. Therefore the waters of the Arctic Sea could never freeze, for such waters would sink as they cooled, and be replaced by warmer waters rising from below.”
Just checking what you are saying here. I think you intend to illustrate the error in their thinking? Putting salt onto ice in a fresh water pond will melt the ice and the salty water will be more dense than fresh water, so it will sink. This is the part that you say is scientific fact. To which I agree. But their error is that when the whole bulk of water is uniformly salty, the freezing part is less dense and it also expels the salt forming fresh water ice. So it floats rather than sinking as in their theory.
(If freezing sea water sank, then the north pole would still be frozen over, only it would freeze from the bottom up. )
I guess that in San Francisco in the 1870s they didn’t make ice cream? It’s pretty foolish that they didn’t test their theory in the lab before wasting what must have been millions in today’s money and losing nearly 2/3 of their crew? They could have observed the effect with an ice cream maker filled with sea water. But idle theory is so much easier than experiments I guess.
Kind of like the modern day ship of fools phenomenon except that the crew of the Jeanette didn’t have modern coast guards to bail them out, so they had to pay for their foolishness with their lives. Nowadays we pay for their foolishness with our taxes.
Rich Davis,
I could not see why the arctic ocean didn’t freeze from the bottom up. It gave me a headache trying to think of it.
If you chill some fresh water to 33°F and dye it blue with food coloring, and then use an eyedropper to inject that water into a beaker of fresh water chilled to 35°F, you will see the colder water rises. (At warmer temperatures the colder water will sink. Water is amazing stuff.)
If you do the exact same experiment with salt water at the exact same temperatures the cold water will sink. I’m not sure how much salt it takes to negate the power fresh water has.
So how can salt water freeze? All it takes is a particle of wind-blown spray to freeze, and then it floats, and provides a sort of seed-crystal for further ice growth.
Fishermen have told me that when sea water is extremely cold, below 32°F, falling snow does not melt when it lands on the sea, and in heavy squalls the sea can become snow-covered.
Now, it occurs to me that you may be telling me that salt water becomes fresh before it freezes. I suppose it cold hold less salt, because it is colder and can dissolve less, but sea-water isn’t close to the saturation point where water can’t hold any more salt, is it?
I have my doubts I full understand the dynamics, due to an observation I’ve made on the coast of Maine. When it is extremely cold, and the sea is steaming “sea smoke”, but it is not windy enough to make freezing spray, the sea-water takes on an oily look, before freezing. I wonder what is going on at the very surface that makes it look oily.
Arctic seawater begins to freeze at -1.8C. During the freezing process fractionation occurs due to pure water freezing and saline water forming in ice pockets. Over time the the brine migrates through small channels ing downward. The brine forms microscopic drainage channels in the ice as it migrates back to the ocean. Further cooling from the surface eventually freezes the brine but at much lower salt concentration then the water below.
The process is explained is explained here:
https://nsidc.org/cryosphere/seaice/characteristics/brine_salinity.html
This paper gives measurements over a season:
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011JC007527
Pure water has its maximum density at 4C. Below that temperature it begins to undergo structural changes to crystallize and that has the effect of taking up more space thus lowering density.
Salt depresses the melting/freezing point. For the amount of salt in seawater, it depresses the freezing point by about 2C. So the max density point also drops from 4C to about 2C.
I guess it is no coincidence that the deep ocean is about 2C. Colder water doesn’t sink.
2.1C salt water dropped into 4C salt water would sink while 2.1C fresh water would float on 4C fresh water. However, 0.1C salt water dropped into 2C salt water will float.
Yes the ice becomes freh water as it crystallizes. It has to do with how the water molecules line up and exclude the salt.
If snow (melting point 0C) lands on -0.5C seawater, I guess that it would not melt, at least not immediately until salt diffuses into it. It is also lighter than seawater so it should float on it rather than sinking into the water.
I’m not familiar with the oily appearance you mentioned. Not sure how to explain that.
In calm conditions a certain type of ice forms called ‘frazil’ ice (otherwise known as ‘grease ice’).
https://nsidc.org/cryosphere/glossary/term/grease-ice
I guess that in San Francisco in the 1870s they didn’t make ice cream? It’s pretty foolish that they didn’t test their theory in the lab before wasting what must have been millions in today’s money and losing nearly 2/3 of their crew? They could have observed the effect with an ice cream maker filled with sea water. But idle theory is so much easier than experiments I guess.
Lab scale experiments such as you suggest wouldn’t have included the pycnocline which is key to the behavior in the arctic. Not sure that it had been discovered or understood at that time.
“The addition of salt to the water lowers the temperature of maximum density, and once the salinity exceeds 24.7 parts per thousand (most Arctic surface water is 30-35), the temperature of maximum density disappears. Cooling of the ocean surface by a cold atmosphere will therefore always make the surface water more dense and will continue to cause convection right down to the freezing point – which itself is depressed by the addition of salt to about -1.8°C for typical sea water. It may seem, then, that the whole water column in an ocean has to be cooled to the freezing point before freezing can begin at the surface, but in fact the Arctic Ocean is composed of layers of water with different properties, and at the base of the surface layer there is a big jump in density (known as a pycnocline), so convection only involves the surface layer down to that level (about 100-150 metres). Even so, it takes some time to cool a heated summer water mass down to the freezing point, and so new sea ice forms on a sea surface later in the autumn than does lake ice in similar climatic conditions.”
https://www.pmel.noaa.gov/arctic-zone/essay_wadhams.html
That’s all very interesting and I’ll have to study it further. However, the original premise was that these explorers believed that sea ice came from fresh water runoff and that sea water cannot freeze on the surface because it would sink before freezing. They had samples of sea ice that they determined to be fresh water ice. If they had put a small amount of sea water into an ice cream churn surrounded by packed ice and rock salt, it would have frozen and they would have produced “fresh water” ice. That would have falsified several of their theories.
However, the original premise was that these explorers believed that sea ice came from fresh water runoff and that sea water cannot freeze on the surface because it would sink before freezing.
Sea water does sink before freezing, the experiment you suggest is not appropriate because you surround the water at all depths with colder than freezing boundaries. If instead you cooled the surface you would find that the water would sink until the water all reached the freezing point. Since the Arctic ocean is over a thousand feet deep it was reasonable to believe that it would take too long to melt. However, since they did not know that there was a shallower layer which inhibited further mixing. See for example from NSIDC:
“In contrast to fresh water, the salt in ocean water causes the density of the water to increase as it nears the freezing point, and very cold ocean water tends to sink. As a result, sea ice forms slowly, compared to freshwater ice, because salt water sinks away from the cold surface before it cools enough to freeze. Furthermore, other factors cause the formation of sea ice to be a slow process. The freezing temperature of salt water is lower than fresh water; ocean temperatures must reach -1.8 degrees Celsius (28.8 degrees Fahrenheit) to freeze. Because oceans are so deep, it takes longer to reach the freezing point, and generally, the top 100 to 150 meters (300 to 450 feet) of water must be cooled to the freezing temperature for ice to form.”
The past history of glaciation should illustrate to us that the climate of the far North exists in a delicate balance. I suspect that balance is largely maintained between the ocean water temperature ( which may be subject to variability from long term ocean currents) and the air temperature which is itself balanced between ice albedo and water surface absorption of solar energy.
The fact that there may be some substantial variation along the line of that balance should actually be expected. To expect that that balance should be precise is pretty ridiculous.
As I’ve asked before, what would be the global temperature anomaly if the far North reverted from its recent marine characteristic back to a “continental” type associated with its being frozen over? Negligible?
I would not call it a delicate balance, which implies tipping points into out of control change. It is certainly a balance of strong opposing forces though. More like a tug of war between well matched teams. It would be absurd to expect a static situation and a back and forth is normal.
Anthony,
Thought I read on this site once that some organization (maybe NSIDC?) stated they were going to recalculate the way they estimate/calculate or measure sea ice extent or area and that this new way would result in slightly lower readings.
Am I correct or am I losing it?
kramer, you are correct. A year ago in October, SII was updated from 2.1 to 3.0. In the post above, I wrongly referred to 2.1. In fact the dataset is SII v3.0 as shown by the link. The numbers in the graph are from that same source.
If you are interested in what was changed and why, here is the report:
https://nsidc.org/sites/nsidc.org/files/files/NSIDC-special-report-19.pdf
They changed the way they averaged the daily data to produce the monthly data, there was no change to the daily data.
Flux is a rate measurement. What is the unit of time in the quoted flux figures?
The quoted link http://www.ccpo.odu.edu/~klinck/Reprints/PDF/kwokJGR99.pdf gives me a 404 not found error.
michael, apparently that link is no longer valid. This one allows you to download the Kwok et al study.
https://www.researchgate.net/publication/261010602/download
michael, the quote from Kwok et al refers to the winter flux, which is defined as October through May.
For me at least what’s of far more interest in the study of climate change has been the recent increase in jet stream activity within the Arctic rather then sea ice amounts. The weather in Canada between the 26th and 29th of this month is about to show us why l think that’s the case.
The graphic shows that the late March (max) extent for both 2017 and 2018 was smallest on record thus making the September’s minimum extent more significant for estimating the true near future trend, since the winter – summer difference is getting smaller.
Vukcevic,
…and this graphic shows the August ice extent over time.
Annual ice extent can be misleading because it doesn’t reflect multi-year ice vs. single year, and either cold or precipitation (or both) could affect the numbers. Summer ice extent seems to me a better indicator of change over time, in the absence of volume.
(The graph in the post should have its vertical axis adjusted to show the data more clearly, and no trend lines, which obscure the data. Why do people insist on making arbitrary trend lines?)
Arctic winter ice extent is more dependent on precipitation than the temperature which is always below sea water freezing point. Low precipitation means drier (cooling) conditions.
Therefore, reduction in the winter-summer extent difference is important pointer towards change in the trend prevailing in the last 10-15 years.
(The graph in the post should have its vertical axis adjusted to show the data more clearly, and no trend lines, which obscure the data. Why do people insist on making arbitrary trend lines?)
And those trend lines are very arbitrary, which of course is why the vertical scale was chosen to hide it.
Ice extent is misleading because it is quite possible to have a decrease in extent while having an increase in ice area. If winds and waves break up the edges of the ice pack and scatter the ice about, this can increase the reported extent of ice without any increase in the amount of ice volume or ice area. If winds consolidate the ice, we can see less extent with greater ice area.
Ice volume should be the correct measure but we don’t have actual volume observations, all reported ice volume numbers are model output.
Cross,
Extent isn’t insignificant, since it affects albedo.
Plus more territory upon which polar bears can hunt summer sun-lounging seals.
/Sarc on the latter one.
And heat loss from open water.
Since 2007 the arctic ocean and surrounds have been cooling to depth.
http://www.climate4you.com/ -under oceans “Circum-Arctic” and “North Atlantic (60-0W, 30-65N) heat content 0-700 m depth”.
This will mean less summer melting and easier winter sea ice formation
Bruce,
This could be an effect of the melt, since freshwater is more buoyant than saltwater. Some hypothesize that this is slowing the AMOC.
It looks like the albedo effect for warming as a certain, limited range of operation, and not beyond that. The assumption albedo warming is unlimited was a guess, not science.
“Ron Clutz writes and provides a graph that suggests the Arctic sea ice has reached a new, but lower, equilibrium point since 2007…”
Why would we assume that anything that varies as much as the cryosphere is ever at ‘equilibrium’. The word implies some kind of physical state of balance between natural forces. What it really means is that the quantity we call annual minimal arctic ice extent, hasn’t changed much for 10 years, which may seem significant to humans, but means nothing in Earth science.
We live on a turbulent planet. It has been in a constant state of change for over 4 billion years. The whole nonsense we call modern environmentalism is built on the notions of Edens and equilibriums. Both are myths. Any forecast of some aspect of the physical world, derived from the linear extension of a recent trend, is most assuredly wrong!
A simplistic concept of a static equilibrium state is obviously wrong as you say, but I think that those of us who may have used the term equilibrium have meant the balance of forces that are well-understood to be in constant flux. The idea that the forces are opposing each other is an important insight, because it demonstrates that the system is relatively stable and will never go into a runaway feedback.
The theory of the new lower equilibrium is interesting.
But why is sea ice “extent” a valid metric? Sea ice volume would be a better indicator (if it were measured and not calculated via models.) Sea ice extent (as I understand it) values 15% ice coverage the same as 100% coverage – and ice thickness and age of the ice is not considered in the result. These facts have to mean the stated “extent” needs to be quoted with some significant error bars and uncertainty. Why is that not done? Wind and water currents can have a large impact on “extent” as strong currents can either disperse the ice or pack it together.
Can someone explain to me why my understanding is wrong?
Strongly agree with your objections
Your question is why I use Sea Ice Area for my calculations. Not extents.