Antarctic Sea Ice Extent

[Entropy]

I think your mis-perceiving a distraction rather than a implied denial of AGW.

I think if people thought this was that big of a deal there would be more analysis on the subject.

And the folks who know the facts of it know the albedo effect is highly diminished because 70% of the ice sheet is under .50-.75M, there was a time when going into the melt season 75% of the arctic ice sheet was 2.5-3.0 meters and 30% was 4M+, which is why losing that kind of pure reflective heat dispersing rock was important and why the outcome has been never before seen warming that has showed no signs of slowing and might be effecting global temps since we have no nino and near record amsu channel 5 temps and and a torching arctic.

The NCEP/NCAR Reanalysis has been called into question in this forum as valid now so we don't have any active data to use for the Antarctic in this forum which is also pretty warm on it's data set, but we do know based on channel 5 and 6 that the Earth is nearing record warmth at the surface because channel 6 is not as warm vs other years as channel 5.

basically the warming is coming from the surface. Outside of the arctic and NH hot spots no one place sticks out, the oceans are generally warming all around. Obviously at some point the "general warmth" will push up and not go back down to previous levels of neutral enso conditions.

With the solar min over for a couple years now, even with a weaker solar max we may be seeing the next push of record warmth, it remains to be seen, this could be a blip in the "cooling' trend. But in the the next 12-24 months I'd hedge my bets with record warmth. If we had a real NINO break out we would likely see 2012 look like 2010 on AMSU going forward the next however many months the nino lasted.

Outside the large area of southern ice. many places of the Southern Ocean are warming.

Take note that on the channel 5 data there is some signs of an early October stair-step a flat-line during the time the arctic sea ice has a more rapid recovery since 2007. It's just a note and has no validity, 2012 might have this, but earlier because there is less ice and the satellites will note a temp differential between the open water and where ice would be. 2007 also had one in late September, who knows.

But these are exciting times of change we can't help now but watch and learn.

Are we sure the NCEP/NCAR reanalysis is wrong? I have a weather and climate related book from 2002 (Blame It on the Weather, Philipps, Parfit & Chisholm) that states: "The frozen continent of Antarctica has warmed a whopping 4.5F in the past 50 years. In the 1970s, glaciologists predicted that melting of the Antarctic ice shelf would be a clear signal of global warming. In 1995, an enormous chunk of ice, 23 by 48 miles in size, broke loose from the western Antarctica ice shelf and floated out to sea. The iceberg was 656 feet thick." I would imagine it would be tough to erase a 4.5F, 50-year warming trend in ten years. I suppose it's also possible that they meant only the West Antarctic peninsula, because there are some errors in the book.

[Jonger]

Are we sure the NCEP/NCAR reanalysis is wrong? I have a weather and climate related book from 2002 (Blame It on the Weather, Philipps, Parfit & Chisholm) that states: "The frozen continent of Antarctica has warmed a whopping 4.5F in the past 50 years. In the 1970s, glaciologists predicted that melting of the Antarctic ice shelf would be a clear signal of global warming. In 1995, an enormous chunk of ice, 23 by 48 miles in size, broke loose from the western Antarctica ice shelf and floated out to sea. The iceberg was 656 feet thick." I would imagine it would be tough to erase a 4.5F, 50-year warming trend in ten years. I suppose it's also possible that they meant only the West Antarctic peninsula, because there are some errors in the book.

50 years ago an iceberg 5 times that size could break off and melt away and nobody would have ever known. That shipping map Vergent posted shows that basically no ships cruise those waters. Observed icebergs in 2012 proves Zippo.

Jon

[ORH_wxman]

This thread has turned into another place for people to "claim" that talking about Antarctic sea ice is "proof" that AGW is not occurring. Its becoming pretty petty.

[weatherwiz]

This thread has turned into another place for people to "claim" that talking about Antarctic sea ice is "proof" that AGW is not occurring. Its becoming pretty petty.

I've never fully understood why people debate over whether or not global warming is occurring. By literally taking the definition of global warming and taking a look at the averaged temperature trends of the Earth over time the Earth has warmed. Then you have issues where people just take one piece of data and use that as a way to prove or disprove global warming.

[ORH_wxman]

I've never fully understood why people debate over whether or not global warming is occurring. By literally taking the definition of global warming and taking a look at the averaged temperature trends of the Earth over time the Earth has warmed. Then you have issues where people just take one piece of data and use that as a way to prove or disprove global warming.

Yes..its crap. I agree. Then we have people who point out that we are all in a catastophic tailspin because of arctic sea ice. The whole debate has pretty much become political...which I think is unforutnate.

[weatherwiz]

Yes..its crap. I agree. Then we have people who point out that we are all in a catastophic tailspin because of arctic sea ice. The whole debate has pretty much become political...which I think is unforutnate.

There are some who will just try and grasp at every straw possible to try and prove their point and disprove other's. I used to have major interest in this topic but you're right, this whole debate is pretty much all entirely politically driven now and it's quite unfortunate. While the debate over whether or not the warming or even further increased warming would have major climate impacts is very real, however, even that debate has gotten out of hand. Every time there is an extreme weather event now it gets blamed on global warming.

When it comes to weather and global warming I really don't think there is any room to say "this is happening b/c of global warming or climate change"...how can people make such a claim like that? Especially considering the fact that our records of weather do not date back very far at all.

I always chuckle in the back of my head when I hear people say we'll never have harsh winters again thanks to global warming...we've been in a global cycle which hasn't really favored patterns for harsh winters to be more common here. They will happen again and it could be sooner rather than later.

[Alpha5]

Yes..its crap. I agree. Then we have people who point out that we are all in a catastophic tailspin because of arctic sea ice. The whole debate has pretty much become political...which I think is unforutnate.

Exactly, and the 100 million dead by 2030 is the smoking gun to this end

[The_Global_Warmer]

And she drops as fast as she rises.

2012.7316 1.1447686 16.2041264 15.0593576

2012.7343 1.1654477 16.2217293 15.0562811

2012.7369 1.0325397 16.0858021 15.0532627

2012.7397 0.8711884 15.9102163 15.0390282

2012.7424 0.6993837 15.7249889 15.0256052

2012.7452 0.6460734 15.6567993 15.0107260

2012.7479 0.5578434 15.5598087 15.0019655

[TerryM]

Friv

You're right of course that it's nothing but a distraction, but it's proving to be one that's really making the rounds. I was mentioning ASI the other night and the first response I got was a query as to whether I was aware that Antarctica had "just had the greatest expanse of ice ever recorded". I explained that it was a one day record for that particular day, but my ASI story lost some of it's steam.

I'd been staying out of the fray, but if I get many more feedbacks like that I'll take it more seriously.

Terry

[dabize]

Then we have people who point out that we are all in a catastophic tailspin because of arctic sea ice. The whole debate has pretty much become political...which I think is unforutnate.

The implications of the imminent (within 5 years) loss of most of the summer Arctic SIA before the summer high insolation period is done are indeed catastrophic.

You can say that we are not yet in "a catastrophic tailspin" yet if you like, but you can do the math as well as anyone.

(Significant SIA loss) times (significant proportion of high solar period) = still significant coefficient (10x less surface reflectivity) = massive increase in summer energy absorption. Your coefficient may vary, but not by too much. It's still going to be massive, and it will be in addition to the current (and accelerating) heating directly due to increasing CO2 in the atmosphere.

This addition to ongoing AGW is just starting to occur now. The "catastrophic" part will kick in as soon as we run out of summer SIA entirely and all the additional heat absorption for the season goes into ocean and atmospheric heating instead of into latent heat needed to melt ice.

There's more: (Massive increase in the current rate of AGW) times (significantly altered large scale atmospheric dynamics due to current AGW) = greatly increased risk of predicted AGW changes (drought/heat wave/SLR).

This is going to happen pretty soon, but has not really started yet. The order of magnitude scale is not speculative, even though the exact amount cannot yet be precisely estimated. Serious discussion of the factors that will actually determine the magnitude of these coefficients and/or the time of onset of this dynamic is fine; denying the existence of the problem is lame.

The politics is introduced by people who refuse to acknowledge that the problem in the Arctic is serious and attempt to divert public attention to irrelevancies such as the relatively minor changes in Antarctic SIA, which (unlike the Arctic) will not significantly affect the global heat budget. This type of diversion/obfuscation approach has been extensively used by AGW denialisti funded by right wing interest groups (e.g. Heartland) who want to keep making money now at the expense of the public, who will have to face the "catastrophe"in the very near future (i.e. next 10-20 years).

When you insist on doing the same thing as these guys by 1) relentlessly minimizing the importance of the impending Arctic changes, 2) using denialist buzzwords such as "catastrophe" and "alarmist" and 3) spending most of the rest of your time on things like the AMO, PDO and Antarctic SIA changes, you can expect people to draw the obvious conclusion about your motives and resent it.

YOU, not they, have become the problem.

[ORH_wxman]

The implications of the imminent (within 5 years) loss of most of the summer Arctic SIA before the summer high insolation period is done are indeed catastrophic.

You can say that we are not yet in "a catastrophic tailspin" yet if you like, but you can do the math as well as anyone.

(Significant SIA loss) times (significant proportion of high solar period) = still significant coefficient (10x less surface reflectivity) = massive increase in summer energy absorption. Your coefficient may vary, but not by too much. It's still going to be massive, and it will be in addition to the current (and accelerating) heating directly due to increasing CO2 in the atmosphere.

This addition to ongoing AGW is just starting to occur now. The "catastrophic" part will kick in as soon as we run out of summer SIA entirely and all the additional heat absorption for the season goes into ocean and atmospheric heating instead of into latent heat needed to melt ice.

There's more: (Massive increase in the current rate of AGW) times (significantly altered large scale atmospheric dynamics due to current AGW) = greatly increased risk of predicted AGW changes (drought/heat wave/SLR).

This is going to happen pretty soon, but has not really started yet. The order of magnitude scale is not speculative, even though the exact amount cannot yet be precisely estimated. Serious discussion of the factors that will actually determine the magnitude of these coefficients and/or the time of onset of this dynamic is fine; denying the existence of the problem is lame.

The politics is introduced by people who refuse to acknowledge that the problem in the Arctic is serious and attempt to divert public attention to irrelevancies such as the relatively minor changes in Antarctic SIA, which (unlike the Arctic) will not significantly affect the global heat budget. This type of diversion/obfuscation approach has been extensively used by AGW denialisti funded by right wing interest groups (e.g. Heartland) who want to keep making money now at the expense of the public, who will have to face the "catastrophe"in the very near future (i.e. next 10-20 years).

When you insist on doing the same thing as these guys by 1) relentlessly minimizing the importance of the impending Arctic changes, 2) using denialist buzzwords such as "catastrophe" and "alarmist" and 3) spending most of the rest of your time on things like the AMO, PDO and Antarctic SIA changes, you can expect people to draw the obvious conclusion about your motives and resent it.

YOU, not they, have become the problem.

So much of your diatribe here is speculatory its really not worth dissecting. However I bolded a few items that are particularly egregious in their claims as it pertains to mainstream science.

It is also interesting that someone who claims to really understand the need to get the message out on AGW is not really interested in how natural variation may be inhibiting or enhancing any effects from AGW...and such is your penchant to completely marginalize any talk that has to due with our natural climate variability.

[TerryM]

So much of your diatribe here is speculatory its really not worth dissecting. However I bolded a few items that are particularly egregious in their claims as it pertains to mainstream science.

It is also interesting that someone who claims to really understand the need to get the message out on AGW is not really interested in how natural variation may be inhibiting or enhancing any effects from AGW...and such is your penchant to completely marginalize any talk that has to due with our natural climate variability.

I strongly disagree that the above constituted a diatribe, but that aside, you underlined a number of sentences as being outside mainstream science.

Could we start with the first bolded statement,

" loss of most of the summer Arctic SIA before the summer high insolation period is done are indeed catastrophic"

How is this in any way not what "mainstream science" predicts. Science has many branches, but from anthropology to zoology every article I'm familiar with has sounded the alarm.

The so called hard sciences, math & physics point inescapably to a large increase in real heat, as opposed to latent heat that is easily quantifiable as is pointed out in the second bolded section.

"The "catastrophic" part will kick in as soon as we run out of summer SIA entirely and all the additional heat absorption for the season goes into ocean and atmospheric heating instead of into latent heat needed to melt ice."

The math is rudimentary, and the physics dates back at least as far as Maxwell. Difficult to get more "mainstream" than that.

You claimed to be bolding sections "that are particularly egregious in their claims as it pertains to mainstream science.", yet your third bolded selection has nothing to do with science, rather your own proclivity to address peripheral issues that obfuscate rather than clarify our present circumstances. "mainstream science" has little interest in what is written in this blog by anyone, although a recent article from the UNH does probe the ideological and "belief" factors underlying much of the denier dogma.

Could I ask you what field of "mainstream science" has reviewed these "hard science" facts, and found the results to be less than catastrophic?

Terry

BTW "Catastrophic" is a term I'm loath to use. It was appended to AGM by none other than Frank Lutnz, the super propagandist once employed by W.

[ORH_wxman]

I strongly disagree that the above constituted a diatribe, but that aside, you underlined a number of sentences as being outside mainstream science.

Could we start with the first bolded statement,

" loss of most of the summer Arctic SIA before the summer high insolation period is done are indeed catastrophic"

How is this in any way not what "mainstream science" predicts. Science has many branches, but from anthropology to zoology every article I'm familiar with has sounded the alarm.

The so called hard sciences, math & physics point inescapably to a large increase in real heat, as opposed to latent heat that is easily quantifiable as is pointed out in the second bolded section.

"The "catastrophic" part will kick in as soon as we run out of summer SIA entirely and all the additional heat absorption for the season goes into ocean and atmospheric heating instead of into latent heat needed to melt ice."

The math is rudimentary, and the physics dates back at least as far as Maxwell. Difficult to get more "mainstream" than that.

You claimed to be bolding sections "that are particularly egregious in their claims as it pertains to mainstream science.", yet your third bolded selection has nothing to do with science, rather your own proclivity to address peripheral issues that obfuscate rather than clarify our present circumstances. "mainstream science" has little interest in what is written in this blog by anyone, although a recent article from the UNH does probe the ideological and "belief" factors underlying much of the denier dogma.

Could I ask you what field of "mainstream science" has reviewed these "hard science" facts, and found the results to be less than catastrophic?

Terry

BTW "Catastrophic" is a term I'm loath to use. It was appended to AGM by none other than Frank Lutnz, the super propagandist once employed by W.

No, you haven't proven anything that is supported by mainstream science. You just simply said "math and physics" with no reference to any numbers or specific dire consequences of such math and science.

What exactly in math and physics supports a catstrophic outcome in the arctic both:

1.) Within 5 years

2.) When the sea ice completely melts out in the summer

???

So I'm sorry, until we agree on what consitutes a catastrophic outcome, there is nothing that scientifically backs up either point. Its purely subjective. I'm also not saying that there isn't literature out there that supports dire outcomes, however, such literature is far from certain and open to large standard deviations in their outcomes.

Lastly, talking about an area that is a far greater potential threat to sea level rise than anywhere in the Arctic is not a "peripheral issue", though perhaps you should read up on the land ice mass that Antarctica holds and you would change your mind.

[WeatherRusty]

So much of your diatribe here is speculatory its really not worth dissecting. However I bolded a few items that are particularly egregious in their claims as it pertains to mainstream science.

It is also interesting that someone who claims to really understand the need to get the message out on AGW is not really interested in how natural variation may be inhibiting or enhancing any effects from AGW...and such is your penchant to completely marginalize any talk that has to due with our natural climate variability.

The bolded is the issue I have had with you forever. Natural variation is independent of AGW. Yes there is natural variation exemplified by solar variation, ocean/atmospheric cycles and long standing patterns. Natural variation rides over any longer term trend. A cursory look at the data clearly reveals the ups and downs of natural variation. There is no dispute about that. The longer term trend must be modulated periodically by shorter term trends.

Let's say climate sensitivity is 2.7C per doubling of CO2, the total forcing equals 3.7W/m^2 and the climate system comes into near balance with that forcing over time. The global temperature will oscillate about 2.7C warmer as an average, with natural variability bringing it to ~2.5C to ~2.9C.

You seem to want to ascribe the warming between 1970 and 2000 largely to ocean cycles rather than AGW, with AGW being the lesser of the two contributors. If however, climate sensitivity is 2.3C, then we get 2.3C at equilibrium as a consequence of 3.7W/m^2 radiative forcing. Natural variability is irrelevant to this outcome, unless something very unusual and persistent happens to offset some of it.

[ORH_wxman]

The bolded is the issue I have had with you forever. Natural variation is independent of AGW. Yes there is natural variation exemplified by solar variation, ocean/atmospheric cycles and long standing patterns. Natural variation rides over any longer term trend. A cursory look at the data clearly reveals the ups and downs of natural variation. There is no dispute about that. The longer term trend must be modulated periodically by shorter term trends.

Let's say climate sensitivity is 2.7C per doubling of CO2, the total forcing equals 3.7W/m^2 and the climate system comes into near balance with that forcing over time. The global temperature will oscillate about 2.7C warmer as an average, with natural variability bringing it to ~2.5C to ~2.9C.

You seem to want to ascribe the warming between 1970 and 2000 largely to ocean cycles rather than AGW, with AGW being the lesser of the two contributors. If however, climate sensitivity is 2.3C, then we get 2.3C at equilibrium as a consequence of 3.7W/m^2 radiative forcing. Natural variability is irrelevant to this outcome, unless something very unusual and persistent happens to offset some of it.

I have never said that. I have said that the warming between 1975-2000 very well may have been over estimated as it relates to AGW and not enough emphasis put on ocean cycles. That time period was often used as proof that "warming is accelerating to new levels due to AGW" to paraphrase.

I believe that AGW was the dominant factor in the rise during that period, but not nearly the only significant one.

As per climate sensitivity, natural variation has no bearing on climate sensitivity...I am in agreement with that. It would be silly not to be. But there are two major questions pertaining to climate sensitivity:

1.) What is the actual value?

2.) How long does it take to reach it?

Both are extremely important questions. If the answer to the first question is on the lower end of estimates while the answer to the 2nd question is on the higher end of estimates, then that would actually make natural variation a much larger player in our climate on a decadal scale than what the IPCC currently attributes. It would also be more manageable than if the answers to those two questions were reversed.

[WeatherRusty]

I have never said that. I have said that the warming between 1975-2000 very well may have been over estimated as it relates to AGW and not enough emphasis put on ocean cycles. That time period was often used as proof that "warming is accelerating to new levels due to AGW" to paraphrase.

I believe that AGW was the dominant factor in the rise during that period, but not nearly the only significant one.

As per climate sensitivity, natural variation has no bearing on climate sensitivity...I am in agreement with that. It would be silly not to be. But there are two major questions pertaining to climate sensitivity:

1.) What is the actual value?

2.) How long does it take to reach it?

Both are extremely important questions. If the answer to the first question is on the lower end of estimates while the answer to the 2nd question is on the higher end of estimates, then that would actually make natural variation a much larger player in our climate on a decadal scale than what the IPCC currently attributes. It would also be more manageable than if the answers to those two questions were reversed.

Sorry Will for miss-characterizing your position on the impact of natural variability. I should not have grouped you in with the general skeptical argument as it pertains to the PDO, which is to attribute most of the past warming to natural variability rather than AGW.

I agree to the importance of your two questions, and unfortunately science can not provide the definite answers to either. It is the range of probability which is troubling. I suspect we will be unable to figure out the answers, as each may be unique to the particular circumstances in which they take place. The analog climates applicable to the current set of developing conditions may not be represented by those of the past, from which estimates of climate sensitivity have been estimated.

[TerryM]

No, you haven't proven anything that is supported by mainstream science. You just simply said "math and physics" with no reference to any numbers or specific dire consequences of such math and science.

What exactly in math and physics supports a catstrophic outcome in the arctic both:

1.) Within 5 years

2.) When the sea ice completely melts out in the summer

???

So I'm sorry, until we agree on what consitutes a catastrophic outcome, there is nothing that scientifically backs up either point. Its purely subjective. I'm also not saying that there isn't literature out there that supports dire outcomes, however, such literature is far from certain and open to large standard deviations in their outcomes.

Lastly, talking about an area that is a far greater potential threat to sea level rise than anywhere in the Arctic is not a "peripheral issue", though perhaps you should read up on the land ice mass that Antarctica holds and you would change your mind.

To the best of my knowledge the only science that may preclude a catastrophic end to a perennially ice free Arctic would be "political science" - you know - the science that Cheney excelled in after flunking out of the more rigorous courses.

Your professional mag. just published an article describing how education eventually overwhelms the propaganda campaign dedicated to obscuring global warming facts, unfortunately it apparently requires post grad studies before it has much effect on "real" conservatives.

If there is an upside, the article also shows that each year of college level education increases awareness among all other groups. It's probably going to end up like smoking, popular among the least educated and the aged, but the younger and better educated either never got hooked or changed their mind.

If we had enough time, and an educated populace, deniers would die off eventually and the government would be able to take appropriate steps. Unfortunately we don't have the luxury of time, and we don't have an educated populace.

Terry

[dabize]

Terry,

I must thank you for so ably defending the points I was trying to make in my post - you got it exactly right.

I must say I didn't feel up to it myself for personal reasons, and also because of the difficulty inherent in defending any view of the forest from all those trees.

[Snow_Miser]

Scientists generally predicted that we wouldn't see a decline in Antarctic sea ice until later in this century.

What we are seeing there now is pretty consistent with the processes described in this article.

http://blog.chron.co...global-warming/

Actually, the CMIP5 Mean predicted a seasonal decline in Antarctic Sea Ice in upwards of -13% per decade for the summer months over the last few decades.

http://journals.amet...12-00068.1?af=R

We examine the annual cycle and trends in Antarctic sea ice extent (SIE) for 18 Coupled Model Intercomparison Project 5 models that were run with historical forcing for the 1850s to 2005. Many of the models have an annual SIE [sea ice extent] cycle that differs markedly from that observed over the last 30 years. The majority of models have too small a SIE at the minimum in February, while several of the models have less than two thirds of the observed SIE at the September maximum. In contrast to the satellite data, which exhibits a slight increase in SIE, the mean SIE of the models over 1979 - 2005 shows a decrease in each month, with the greatest multi-model mean percentage monthly decline of 13.6% dec^-1 in February and the greatest absolute loss of ice of -0.40 × 10⁶ km² dec^-1 in September. The models have very large differences in SIE over 1860 – 2005. Most of the control runs have statistically significant trends in SIE over their full time span and all the models have a negative trend in SIE since the mid-Nineteenth Century. The negative SIE trends in most of the model runs over 1979 - 2005 are a continuation of an earlier decline, suggesting that the processes responsible for the observed increase over the last 30 years are not being simulated correctly.

[dabize]

Actually, the CMIP5 Mean predicted a seasonal decline in Antarctic Sea Ice in upwards of -13% per decade for the summer months over the last few decades.

Which tells us that this model, like those preceding it, are failing to account for variables that are of fundamental importance to the mechanism responsible for events at both poles.

Interesting that the failures are so reciprocal - suggests that what is missing in the model might involve some teleconnection between the unmodeled increase in the Arctic melt rate and the decrease in that of the Antarctic.

Reminds me of that recent study showing how Arctic deglaciation from the LGM was correlated with events in the South Atlantic

[PhillipS]

Actually, the CMIP5 Mean predicted a seasonal decline in Antarctic Sea Ice in upwards of -13% per decade for the summer months over the last few decades.

http://journals.amet...12-00068.1?af=R

We examine the annual cycle and trends in Antarctic sea ice extent (SIE) for 18 Coupled Model Intercomparison Project 5 models that were run with historical forcing for the 1850s to 2005. Many of the models have an annual SIE [sea ice extent] cycle that differs markedly from that observed over the last 30 years. The majority of models have too small a SIE at the minimum in February, while several of the models have less than two thirds of the observed SIE at the September maximum. In contrast to the satellite data, which exhibits a slight increase in SIE, the mean SIE of the models over 1979 - 2005 shows a decrease in each month, with the greatest multi-model mean percentage monthly decline of 13.6% dec^-1 in February and the greatest absolute loss of ice of -0.40 × 10⁶ km² dec^-1 in September. The models have very large differences in SIE over 1860 – 2005. Most of the control runs have statistically significant trends in SIE over their full time span and all the models have a negative trend in SIE since the mid-Nineteenth Century. The negative SIE trends in most of the model runs over 1979 - 2005 are a continuation of an earlier decline, suggesting that the processes responsible for the observed increase over the last 30 years are not being simulated correctly.

An interesting paper - thank you for sharing it with us. Clearly the CMIP5 models aren't the best for antarctic sea ice processes. The models mentioned in Bluewave's post appear to have a much better handle on the Antarctic. That abstract shows the truth in the old saying "All models are wrong, some models are useful". I wonder if the CMIP5 models perform better for other climate change processes or other regions of the Earth.

I do have one question about antarctic sea ice I am interested in your thoughts on - what process is responsible for the increase in the total annual antarctic sea ice melt? As we all know, the Antarctic SIA maximum has increased by roughly 1 M km2 since the instrumental record began in 1979 - but the SIA minimum has been essentially unchanged. For those who need it, here is the CT antarctic SIA plot:

For the maximum area to increase and the minimum area to be stable means that the total annual melt had to increase, too. Otherwise the SIA minimum would have mirrored the SIA maximum and increased too. The 1 M km2 increase in area is a lot of ice, and indicates a corresponding increase in ice volume. Assuming for discussion that the added 1 M km2 of sea ice is 1 m thick, then the added volume would be 1,000 km3. It takes a lot of energy to melt that much ice - if my calculations are right it takes about 334 X 10⁹ Gigajoules to melt 1,000 km3 of ice.

What do you think is source of that additional energy? Since it so closely tracks the increase SIA could one process be responsible for both the increase annual freeze and the increase annual melt? If, as some predict, the trend of increasing antarctic SIA reverses as the ozone hole is reduced, will the increased melt also diminish - or will the annual SIA minimum begin to drop?

[The_Global_Warmer]

An interesting paper - thank you for sharing it with us. Clearly the CMIP5 models aren't the best for antarctic sea ice processes. The models mentioned in Bluewave's post appear to have a much better handle on the Antarctic. That abstract shows the truth in the old saying "All models are wrong, some models are useful". I wonder if the CMIP5 models perform better for other climate change processes or other regions of the Earth.

I do have one question about antarctic sea ice I am interested in your thoughts on - what process is responsible for the increase in the total annual antarctic sea ice melt? As we all know, the Antarctic SIA maximum has increased by roughly 1 M km2 since the instrumental record began in 1979 - but the SIA minimum has been essentially unchanged. For those who need it, here is the CT antarctic SIA plot:

For the maximum area to increase and the minimum area to be stable means that the total annual melt had to increase, too. Otherwise the SIA minimum would have mirrored the SIA maximum and increased too. The 1 M km2 increase in area is a lot of ice, and indicates a corresponding increase in ice volume. Assuming for discussion that the added 1 M km2 of sea ice is 1 m thick, then the added volume would be 1,000 km3. It takes a lot of energy to melt that much ice - if my calculations are right it takes about 334 X 10⁹ Gigajoules to melt 1,000 km3 of ice.

What do you think is source of that additional energy? Since it so closely tracks the increase SIA could one process be responsible for both the increase annual freeze and the increase annual melt? If, as some predict, the trend of increasing antarctic SIA reverses as the ozone hole is reduced, will the increased melt also diminish - or will the annual SIA minimum begin to drop?

Not exactly.

Antarctica's SIA anomaly's are so up and down. Heading into the end of the season it was 750K above normal and in less than 10 days hit normal then in another 10-12 days went up to 1 million, now another 10-14 days goes by and it's getting near normal again.

This is a big time sign a lot of 20-50CM ice is being blown around, mostly outward causing higher SIA with thinner ice. So a smaller change in volume than we would assume like in the arctic.

[Snow_Miser]

For the maximum area to increase and the minimum area to be stable means that the total annual melt had to increase, too. Otherwise the SIA minimum would have mirrored the SIA maximum and increased too. The 1 M km2 increase in area is a lot of ice, and indicates a corresponding increase in ice volume. Assuming for discussion that the added 1 M km2 of sea ice is 1 m thick, then the added volume would be 1,000 km3. It takes a lot of energy to melt that much ice - if my calculations are right it takes about 334 X 10⁹ Gigajoules to melt 1,000 km3 of ice.

I'm not sure what you mean by this comment. Sea Ice in Antarctica has increased in all four seasons and land ice has thickened.

[TerryM]

I'm not sure what you mean by this comment. Sea Ice in Antarctica has increased in all four seasons and land ice has thickened.

The chart provided above doesn't show that at all.

Where did you get your information that the land ice has been thickening, all I heard about was the winter calving event.

http://glacierchange.wordpress.com/2012/10/08/thwaites-glacier-tongue-major-calving-event-antarctica/

It seems as though calving more glaciers into the ocean might lead to more sea ice?

Terry

[Snow_Miser]

The chart provided above doesn't show that at all.

Where did you get your information that the land ice has been thickening, all I heard about was the winter calving event.

http://glacierchange...ent-antarctica/

It seems as though calving more glaciers into the ocean might lead to more sea ice?

Terry

Eyeballing charts is usually not the best way to determine if a change in a variable is occuring. Statistical analysis is highly prefered by the scientific community.

http://www.the-cryosphere.net/6/871/2012/tc-6-871-2012.pdf

From the abstract of the paper:

When examined

through the annual cycle over the 32-yr period 1979–

2010, the Southern Hemisphere sea ice cover as a whole experienced

positive ice extent trends in every month,

Land Ice has also been thickening in much of Antarctica. This is confirmed by a multitude of studies.

http://www.sciencemag.org/content/331/6024/1592.abstract

http://www.phys.uu.nl/~lenae101/pubs/KMunneke2012.pdf

http://www.nasa.gov/pdf/121648main_ais2.pdf

[The_Global_Warmer]

[Bannor]

New paper in Nature Geoscience:

Wind-driven trends in Antarctic sea-ice drift

The sea-ice cover around Antarctica has experienced a slight expansion in area over the past decades.

This small overall increase is the sum of much larger opposing trends in different sectors that have been

proposed to result from changes in atmospheric temperature or wind stress, precipitation, ocean temperature,

and atmosphere or ocean feedbacks. However, climate models have failed to reproduce the overall increase

in sea ice. Here we present a data set of satellite-tracked sea-ice motion for the period of 1992–2010 that

reveals large and statistically significant trends in Antarctic ice drift, which, in most sectors, can be linked to

local winds. We quantify dynamic and thermodynamic processes in the internal ice pack and show that

wind-driven changes in ice advection are the dominant driver of ice-concentration trends around much of

West Antarctica, whereas wind-driven thermodynamic changes dominate elsewhere. The ice-drift trends also

imply large changes in the surface stress that drives the Antarctic ocean gyres, and in the fluxes of heat and

salt responsible for the production of Antarctic bottom and intermediate waters.

Authors: Paul R. Holland, British Antarctic Survey; Ron Kwok, Jet Propulsion Laboratory, Caltech

http://www.nature.co...l/ngeo1627.html

Quote from UK Guardian article:

[The research] revealed large regional variations. In places where warm winds blowing from the tropics towards

Antarctica had become stronger, sea ice was being lost rapidly. "In some areas, such as the Bellingshausen Sea,

the sea ice is being lost as fast as in the Arctic," said Holland.

But in other areas, sea ice was being added as sea water left behind ice being blown away from the coast froze.

The net effect is that there has been an extra 17,000 sq km of sea ice each year since 1978 – about a tenth of

a percent of the maximum sea ice cover.

Antarctica is a continent surrounded by an ocean, whereas the Arctic is an ocean surrounded by a continent.

For that reason, said Holland, sea ice was not able to expand by the same mechanism in the Arctic as at the

southern pole, because if winds pushed the ice away from the pole it quickly hit land.

http://www.guardian....tarctic-sea-ice

[SVT450R]

Figured this topic could use an update as it's been awhile also noticed this past year looks to be the first time sea ice area anomaly stayed the entire time mostly on the positive side.

[The_Global_Warmer]

Look's like Low Pressure around the Weddell Sea  has helped pull continental cold from the South and spread it N and NE. 

[ineedsnow]

http://arctic.atmos.uiuc.edu/cryosphere/antarctic.sea.ice.interactive.html