First year PIOMAS volume below 1000km^3 poll 2018

[crandles]

This poll was first posted 10 Dec 2014. Over 3 years seemed suitable delay before trying again and after lots of comments on the 'Ice free arctic' thread https://forum.arctic-sea-ice.net/index.php/topic,1886.0.html also seemed suitable.

The original post had

Since 2013 and 2014 minimums were so high, I thought it might be an idea to have another poll to see how much later if at all people think ice free conditions will occur.

Other long term outlooks are welcome. Feel free to describe what you think will happen. If you wish that can include downloading the attachment and drawing what you think is more plausible.

To explain the attached graph:

Blue data is April Average PIOMAS volume
Yellow data is September average PIOMAS volume

Red and green are 4 parameter gompertz fits.

The straight blue line is intended to show acceleration as MYI over 2m thick collapsed due to less area, less age and thinner MYI mainly as the MYI stopped making it around the Beaufort Gyre. Once there was little MYI over 2m thick this accelerated phase dies out so that the thinning was only at a rate consistent with just FYI thinning.

The purple line descends more quickly than the blue line again aiming to be consistent with past. If there is less ice at the start of the season then albedo will be lower allowing more open water to form and more energy to be absorbed so that more ice melts. I have the difference between the two straight lines increasing from 17.8 K Km^3 in 2014 to 18.8 K Km^3 when we reach ice free.

This purple line first goes below 1000 km^3 in 2028.

Also note that the difference between 2012 and 2014 minimum volumes is nearly 3200 Km^3. Therefore while the purple line only gets down to 1000 Km^3 by 2028, it could occur any time after the purple line gets below 2600 km^3 which could be as early as 2022. I am therefore going to average 2022 and 2028 to arrive at 2025.

To this I am adding updated graphs for September and April PIOMAS volume with 4 parameter gompertz fits.

Votes should be changeable until the vote deadline. Also viewable after you have voted.

Anything else I should add? (I haven't put a link to the old poll, think I would prefer people to vote without looking to see how they compare. But open to arguments for doing so.)

Edit: in response to question, I have edited to make clear it is daily minimum per PIOMAS. Note that the graphs are of September average not daily and first year could well be ahead of any trend.

[Tor Bejnar]

The 2014 First Ice free day poll (volume) comments can be reviewed. Voting record below.


An Arctic sea ice free (extent) poll was started in March 2013.  About half of us were wrong (so far). At least one or two of us will undoubtedly be right!  (I'm still in the running.  Boy my thinking changed between this 2013 extent poll and the 2014 volume poll!) This wasn't a volume poll, I know, but I think it is worth reviewing. Voting record below.

[oren]

Crandles just to verify, your poll is about the daily minimum, correct? I am asking as the graphs you posted are for the Sept average.

[Archimid]

Attached is Volume Max with an extended linear trend.

Loss maximum, minimum and average are taken for the 2007-2017 period and drawn on the line

According to that a graph if a maximum loss happened last year volume below 1000km^3  would've been achieved then!

If the average loss remains constant, then the date would be somewhere around 2030.

However because gains are decreasing and temperatures rising I'm going with 2019-2021.

Edit: Replaced graph. Forgot to add 1 to the average

[Dharma Rupa]

This is a crap shoot with real loaded dice.  Loaded dice have a shot of lead inside with something sticky, like wax.  Turn the dice to a particular pair of faces and smack them down hard against the table and now that pair of faces becomes the most likely roll next time.

I don't know which year will be first, but I'm pretty sure the next year will be the same.

[crandles]

Crandles just to verify, your poll is about the daily minimum, correct? I am asking as the graphs you posted are for the Sept average.

Should have known I would miss something obvious. Have edited poll question to add daily and also put in some warning about this issue in the first post.

People should be able to change their vote if they wish.

[oren]

Thanks for the clarification.

[Dave C]

My real answer is "not likely to be soon", but I guess I'll pick 29-33.

Obviously you have to be careful against cherry picking, but the fact is that there has been no volume decline for 7 years now. I don't believe an objective rate of yearly volume decline exists. The rate is entirely dependent on the starting year you pick.
I think the most likely theory is the slow decline one(but still faster than scientific models predicted in the past). It is becoming increasingly likely that the ice dynamics have changed after most of the multi-year ice was eliminated. There is no reason that a trend has to continue. It's quite possible that the usual trend lines referred to will be wrong because the negative feedbacks certain to occur are stronger than predicted.
At least 4 negative feedbacks are certain to occur with less ice. Lower temperatures in ice covered areas, less average insolation, less ice transport and greater chance for refreezing in winter. It's possible that less ice creates more protective cloud cover as well. In the long run the ice is doomed. But in the short run I think these negative feedbacks are likely to prevail.

[crandles]

At least 4 negative feedbacks are certain to occur with less ice. Lower temperatures in ice covered areas, less average insolation, less ice transport and greater chance for refreezing in winter. It's possible that less ice creates more protective cloud cover as well. In the long run the ice is doomed. But in the short run I think these negative feedbacks are likely to prevail.

>"Lower temperatures in ice covered areas"
Why would there be lower temperatures? Surely there are warmer temperatures nearer than previously that can get blown to such positions more easily? Then there is GHG levels.

'Less average insolation' is assuming increased cloud cover? (Not sure there is data showing this or at least isn't very clear.) Then there is lower albedo meaning a higher proportion is absorbed.

'Less ice transport' ice is thinner but moves faster so not sure about less being transported out of arctic. It is possible as ice retreats to smaller area.

But maybe you are talking about, we have cleared ice from area where there is a net movement out of the areas where quick increase in ice free area occurs so readily creating albedo feedback, but when we try to clear area with net movement in the area doesn't clear quickly so the albedo feedback is much slower.

Certainly agree with winter regrowth feedback.

Then there are others like:

Bathymetry: We have cleared the shallow area where warm salty gulf stream water cannot sink.

Distance from land and rivers:
Land warms up fast warming the air and rivers provide fresh water warmed during its journey. As the ice retreats away from these areas it gets harder to melt the ice.

[oren]

Dave C, the slow transition theory postulated a plateau in winter volume, due to fast refreeze of open water and thin ice, and with the freezing season remaining almost the same length, and thus it postulated a slow decline in summer. But instead we got a record low max volume last year, and a number two this year, so I think the theory is flawed, not taking into account very delayed refreeze. I therefore believe only luck prevented new lows in summer volume.

[Tor Bejnar]

Great reply, crandles!  (You wrote everything I was thinking while reading Dave C's post, plus an item or two.)

The Arctic conditions that most support the "slow transition theory", in my opinion, are the bathymetry and distance from coasts concerns.  (I don't think these are really "negative feedbacks" because 'nothing has changed'; years ago I posted, IICR, a concern that ice loss graphs used to predict an ice-free Arctic should use 'only' CAB data.  [I think my concern at the time was the limited 'length of summer' in the high Arctic {late May to mid-September.}  I've learned something along the way!])

[Daniel B.]

At least 4 negative feedbacks are certain to occur with less ice. Lower temperatures in ice covered areas, less average insolation, less ice transport and greater chance for refreezing in winter. It's possible that less ice creates more protective cloud cover as well. In the long run the ice is doomed. But in the short run I think these negative feedbacks are likely to prevail.

>"Lower temperatures in ice covered areas"
Why would there be lower temperatures? Surely there are warmer temperatures nearer than previously that can get blown to such positions more easily? Then there is GHG levels.

'Less average insolation' is assuming increased cloud cover? (Not sure there is data showing this or at least isn't very clear.) Then there is lower albedo meaning a higher proportion is absorbed.

'Less ice transport' ice is thinner but moves faster so not sure about less being transported out of arctic. It is possible as ice retreats to smaller area.

But maybe you are talking about, we have cleared ice from area where there is a net movement out of the areas where quick increase in ice free area occurs so readily creating albedo feedback, but when we try to clear area with net movement in the area doesn't clear quickly so the albedo feedback is much slower.

Certainly agree with winter regrowth feedback.

Then there are others like:

Bathymetry: We have cleared the shallow area where warm salty gulf stream water cannot sink.

Distance from land and rivers:
Land warms up fast warming the air and rivers provide fresh water warmed during its journey. As the ice retreats away from these areas it gets harder to melt the ice.

Dave may not be that far off.  Considers his 4 feedbacks the remaining ice-covered areas. 

1.  Even if the average temperature of the Arctic increases, it will still be substantially colder than the water.  The open water will lose more heat than the ice-covered areas.  This could result in a short-term temperature decrease (at least until most of the ice is lost). 

2.  Less ice transport is most likely to occur, as most of the ice loss occurs in the open ocean where it is much more susceptible to transport, whereas the remaining ice will be tied to land areas.

3.  Yes, the is definitely greater opportunity for refreezing.  This has already occurred during the winters following low summer minima.  This ice is then more likely to melt the following summer.  Not sure that this is a feedback at all.

4.  The ice will not create more cloud cover.  Open water may.  The effect of clouds are two-fold; warmer winters, due to heat retention, and cooler summers, due to solar blockage.  This would be a negative feedback on summer ice loss, but a positive for winter gains.  Overall, clouds tend to reduce temperature extremes; cooling the warmest areas and warming the coldest.  With the Arctic being among the coldest, I would expect a general warming with more cloudiness, even though summer temperatures may decrease slightly.

[litesong]

cherry picking.... has been no volume decline for 7 years..... rate is entirely dependent on the starting year you pick.....most likely theory is the slow decline one..... in the short run I think these negative feedbacks are likely to prevail.

AGW deniers depend on the temporary decrease in solar TSI which has been languid for half a century & low for 11+ years(including a 3+ year period setting a 100 year record low). AGW deniers lock on to anomalous low ice records like 2012(which  decreased greatly in part due to fortuitously directed winds driving much ice out of the arctic). AGW deniers don't mention that present Arctic sea ice ranges from 8000 to 12,000 cubic kilometers LESS than the average of the 1980's, this despite the already mentioned low solar TSI.  AGW deniers are cherry pickers & blame AGW advocates as cherry pickers. 

[Daniel B.]

cherry picking.... has been no volume decline for 7 years..... rate is entirely dependent on the starting year you pick.....most likely theory is the slow decline one..... in the short run I think these negative feedbacks are likely to prevail.

AGW deniers depend on the temporary decrease in solar TSI which has been languid for half a century & low for 11+ years(including a 3+ year period setting a 100 year record low). AGW deniers lock on to anomalous low ice records like 2012(which  decreased greatly in part due to fortuitously directed winds driving much ice out of the arctic). AGW deniers don't mention that present Arctic sea ice ranges from 8000 to 12,000 cubic kilometers LESS than the average of the 1980's, this despite the already mentioned low solar TSI.  AGW deniers are cherry pickers & blame AGW advocates as cherry pickers.

I would caution against automatically calling it cherry picking.  Only 40 years of data exists, so the analysis is somewhat strained initially.  Overall, the trend over the first and last decades show a slow decline as stated by Dave.  The middle two decades show a large decline.  While the long term decline is definitely apparent, it is difficult to say which trend will continue in the short term.  Obviously you and Dave disagree on which will prevail in the short run.  This does not make either of you cherry pickers.

[Dharma Rupa]

cherry picking.... has been no volume decline for 7 years..... rate is entirely dependent on the starting year you pick.....most likely theory is the slow decline one..... in the short run I think these negative feedbacks are likely to prevail.

AGW deniers depend on the temporary decrease in solar TSI which has been languid for half a century & low for 11+ years(including a 3+ year period setting a 100 year record low). AGW deniers lock on to anomalous low ice records like 2012(which  decreased greatly in part due to fortuitously directed winds driving much ice out of the arctic). AGW deniers don't mention that present Arctic sea ice ranges from 8000 to 12,000 cubic kilometers LESS than the average of the 1980's, this despite the already mentioned low solar TSI.  AGW deniers are cherry pickers & blame AGW advocates as cherry pickers.

I would caution against automatically calling it cherry picking.  Only 40 years of data exists, so the analysis is somewhat strained initially.  Overall, the trend over the first and last decades show a slow decline as stated by Dave.  The middle two decades show a large decline.  While the long term decline is definitely apparent, it is difficult to say which trend will continue in the short term.  Obviously you and Dave disagree on which will prevail in the short run.  This does not make either of you cherry pickers.

Why are you talking decades when the only interesting inflection point is the beginning of the Industrial Age?

We ain't seen nothing yet, and I don't know when the first year will be, but the next year (and many more) will be ice free too.

[litesong]

cherry picking.... has been no volume decline for 7 years..... rate is entirely dependent on the starting year you pick.....most likely theory is the slow decline one..... in the short run I think these negative feedbacks are likely to prevail.

AGW deniers depend on the temporary decrease in solar TSI which has been languid for half a century & low for 11+ years(including a 3+ year period setting a 100 year record low). AGW deniers lock on to anomalous low ice records like 2012(which  decreased greatly in part due to fortuitously directed winds driving much ice out of the arctic). AGW deniers don't mention that present Arctic sea ice ranges from 8000 to 12,000 cubic kilometers LESS than the average of the 1980's, this despite the already mentioned low solar TSI.  AGW deniers are cherry pickers & blame AGW advocates as cherry pickers.

.... cherry picking.  Only 40 years of data exists, so the analysis is somewhat strained initially......last decades show a slow decline as stated by Dave.....Obviously you and Dave disagree

Quoting Dave & giving him cred, while saying its a difference between him & me, tells us where you land.  Stating that there is only 40 years of AGW effects, while AGW denier data is neglected or nil, then landing in the AGW denier nest, also tells us what you are hatching.

[Daniel B.]

cherry picking.... has been no volume decline for 7 years..... rate is entirely dependent on the starting year you pick.....most likely theory is the slow decline one..... in the short run I think these negative feedbacks are likely to prevail.

AGW deniers depend on the temporary decrease in solar TSI which has been languid for half a century & low for 11+ years(including a 3+ year period setting a 100 year record low). AGW deniers lock on to anomalous low ice records like 2012(which  decreased greatly in part due to fortuitously directed winds driving much ice out of the arctic). AGW deniers don't mention that present Arctic sea ice ranges from 8000 to 12,000 cubic kilometers LESS than the average of the 1980's, this despite the already mentioned low solar TSI.  AGW deniers are cherry pickers & blame AGW advocates as cherry pickers.

I would caution against automatically calling it cherry picking.  Only 40 years of data exists, so the analysis is somewhat strained initially.  Overall, the trend over the first and last decades show a slow decline as stated by Dave.  The middle two decades show a large decline.  While the long term decline is definitely apparent, it is difficult to say which trend will continue in the short term.  Obviously you and Dave disagree on which will prevail in the short run.  This does not make either of you cherry pickers.

Why are you talking decades when the only interesting inflection point is the beginning of the Industrial Age?

We ain't seen nothing yet, and I don't know when the first year will be, but the next year (and many more) will be ice free too.

Quite simple.  The satellite data starts in 1979.  There is no good measure of ice volume to that, so anything else is speculation.  Can you state with any certainty the volume of ice in the Arctic at the beginning of the industrial era?  or at any time prior?  I do not know when the first ice-free year will occur either.   However, that does not guarantee that next will be similar. 

[litesong]

The satellite data starts in 1979.  There is no good measure of ice volume to that, so anything else is speculation.

Much submarine data is available. AGW deniers love to hoot that submarines were surfacing at the North Pole in the 1950's, intimating that 1950's Arctic sea ice was thin. But submarine logs indicate 1950's sea ice was much thicker than today. It took weeks for submarines to find sea ice thin enough, through which submarines could surface. & in weeks previous to that, submarines could not enter the Arctic Ocean from the Bering Strait easily or safely, due to sea ice that was as much as 60 feet thick.
Article about submarine data on sea ice in the 50's & 60's:
http://news.bbc.co.uk/2/hi/science/nature/523065.stm

[litesong]

I don't know when the first year(of month or a few weeks of ice-free) will be, but the next year (and many more) will be ice free too.

The real problem will be 4 or 5 months of ice-free Arctic Ocean waters. An ice free September has the sun low & even below the horizon & ocean waters will not collect much solar energy. But when Arctic Ocean waters are ice-free in May, June, July, & August, with the sun at its highest elevation in the sky, much solar energy will absorbed & will warm Arctic waters. Also, wherever solar energy is absorbed on waters that are on downwellings, much solar energy(previously unavailable) will be transported to continental shelves & even to ocean depths for deep sea storage.
Already, tho NOT ice-free, present Arctic waters have as much as 2 million square kilometers less sea ice as that of the 1980's. & as above, these present clear ice waters ARE gathering solar energy during April, May, June, July & August, that wasn't available before sea ice reductions. 

[Archimid]

Daniel B.'s lies are delicious because by finding what the lie is, you find enlightenment. They are getting very easy to spot though. As climate change advances the evilness of his lies will be evident.

This is one of the best write ups I've seen on Arctic sea ice history. I highly recommended.

https://www.carbonbrief.org/guest-post-piecing-together-arctic-sea-ice-history-1850

This image is from the article.




Daniel B. is right in that the satellite record is very small. Where he is wrong is that when the rest of the evidence is compiled there is reason for alarm.

[Daniel B.]

Daniel B.'s lies are delicious because by finding what the lie is, you find enlightenment. They are getting very easy to spot though. As climate change advances the evilness of his lies will be evident.

This is one of the best write ups I've seen on Arctic sea ice history. I highly recommended.

https://www.carbonbrief.org/guest-post-piecing-together-arctic-sea-ice-history-1850

This image is from the article.




Daniel B. is right in that the satellite record is very small. Where he is wrong is that when the rest of the evidence is compiled there is reason for alarm.

Please leave your false accusations out of this discussion please.  If you wish to present evidence against my claim, at least try to present relative evidence.  We are discussing PIOMAS volume, and you present evidence on extent.  This is similar to the thread on which we were discussing extent, and your refuting evidence was volume.  When you post negative comments about another poster it reflects more on you than the person whom you are attacking.

[Archimid]

Please leave your false accusations out of this discussion please.

Calling you a liar is an accurate description, not an accusation.

If you wish to present evidence against my claim, at least try to present relative evidence

There was twice as much extent for the last 150+years, plenty of anecdotal evidence that it was much thicker and much colder temperatures. The historical data doesn't have the precision and accuracy of the satellite record but it is equally scientific and consistent.
 

We are discussing PIOMAS volume, and you present evidence on extent.

If you are talking about the ice-free thread, this is what I said in regard to extent vs volume

If we were talking about albedo, extent would be a good metric, but we are not talking about albedo. We are talking about when the Arctic will be ice free for the first time. For that the best measure is volume for two good reasons. One, extent has no information about ice content, volume does. The second one is that volume hits 0 first. 0 volume = 0 extent.

But you ignored it and kept using extent without justification for it's use.
 

When you post negative comments about another poster it reflects more on you than the person whom you are attacking.

Yeah, and as climate change gets worse that reflection will improve as the nature of your lies become evident. For now, I'll bite the reputation bullet and treat you like a liar you are, hiding the risks of climate change from others.  Sure my words are rough, and I'm sure nice people everywhere despise me for it but what you are doing is despicable and if no one denounce you, then I will, when I have the strength.

 I'm sorry to the nice people that must read these strong words, but given the nature of the argument and it's consequences I believe it must be done.


To close in a more scientific note:

Can you state with any certainty the volume of ice in the Arctic at the beginning of the industrial era? 

Yes. Given the large extent of the past, lower temperatures of the past and recorded descriptions of the Arctic of the past, as long as the physics are the same as today, the ice was much thicker and the volume much higher to a high degree of certainty. To a very high degree certainty.

However there is always uncertainty. Daniel B. lies uses that fact of life to throw unnecessary uncertainty on the fact that there was much more volume of ice in the past.

[Daniel B.]

Rather odd that you have been arguing on another thread that volume can be less, even though extent is higher.  You seem to be changing your argument to fit your opinion.  I am truly sorry that you think honesty is despicable, and prefer exaggeration to accuracy.  We have argued this previously.  I understand that you are passionate, but your repeated attacks are reflecting poorly on yourself.

[jdallen]

People, please chill.  Please don't turn this into a flame war.

[2phil4u]

I read about the negative feedbacks.
This is what i thought about.
We saw better years after low minimums in general and not the opposit, thus winter outperformed the summer because of more heat loss to space.
I only wasnt sure about water temperature in deeper depth, so it could be that even if we have better ice grow after low minimas this is only true for the upper lawyer of the water, but deeper water store energy.
I was not sure, if this is possible or  not.
On the other hand with open water all around the pole there is a small cold surface surrounded by a large area with way above average temperature in summer due to no ice.
So im not sure if there is at least if we dont go up with world temperatures tremendous an area that is absolute safe or not.
But i will vote for last possible options, there is no never ?
 
o.k. that is unlikely to that never before our sun system collapse the global average is high enouph like it was in the past.
So the negative feedbacks but the tremendous amount of warm air in summer if there is only a little core left, hm.

[Archimid]

Rather odd that you have been arguing on another thread that volume can be less, even though extent is higher.

Not only did you ignore my arguments about why volume was obviously higher, you twist my words to fit your lies. This is what I said about volume and extent in the past:

It also works in longer time frames. Volume has been free falling since the beginning of the satellite record but area remained mostly the same for much of it until the 2007 crash. In the colder past when the Arctic was 15m thick I’m sure volume grew yearly but area was limited by export and the Atlantic and Pacific interface.

I told you then, as I tell you now, volume was much higher in the past

You seem to be changing your argument to fit your opinion.

No, you are twisting my words to fit your lies.

I am truly sorry that you think honesty is despicable, and prefer exaggeration to accuracy.

 

Your exaggeration of the uncertainties is despicable. Your exaggerations are already costing lives and property. Your honesty is fake. Fake honesty is a very powerful tool.

I understand that you are passionate, but your repeated attacks are reflecting poorly on yourself.

 I'm telling the harsh truth and your telling comfortable lies. There is no way around it. Calling you a liar is harsh but accurate.

 I could take the Katherine Hayhoe approach, but by doing that I risk understating the risk. While her way is the most effective way of gaining acceptance of climate change (thank goodness for her), my way better depicts the risks we face.

Can you state with any certainty the volume of ice in the Arctic at the beginning of the industrial era?  or at any time prior?

The answer is yes, you can. There are all sorts of proxies confirming that the ice used to be much thicker than it is now.  Expeditions, temperatures, ship logs, sediments, anecdotes and human settlement distribution all point at a consistently thick sea ice sheet and a large extent.

On top of the evidence, the laws of physics ensure that with that much extent there will be more volume.

Your uncertainty argument is false.

[Dave C]

Dave C, the slow transition theory postulated a plateau in winter volume, due to fast refreeze of open water and thin ice, and with the freezing season remaining almost the same length, and thus it postulated a slow decline in summer. But instead we got a record low max volume last year, and a number two this year, so I think the theory is flawed, not taking into account very delayed refreeze. I therefore believe only luck prevented new lows in summer volume.

It seems to be more than luck that the minimum record wasn't broken last year. There is evidence that the arctic is countercyclical to a degree.

I don't know if winter volume has to plateau. It would be enough to slow melting if winter ice gain is increasing, which over the last decade it has on average. It's weird to refer to it as "slow transition theory" though. I am still predicting that the ice will melt way faster than the official IPCC consensus. I just don't think it's going to drop to 1 km^3 in the next decade.

[Dave C]

At least 4 negative feedbacks are certain to occur with less ice. Lower temperatures in ice covered areas, less average insolation, less ice transport and greater chance for refreezing in winter. It's possible that less ice creates more protective cloud cover as well. In the long run the ice is doomed. But in the short run I think these negative feedbacks are likely to prevail.

>"Lower temperatures in ice covered areas"
Why would there be lower temperatures? Surely there are warmer temperatures nearer than previously that can get blown to such positions more easily? Then there is GHG levels.

'Less average insolation' is assuming increased cloud cover? (Not sure there is data showing this or at least isn't very clear.) Then there is lower albedo meaning a higher proportion is absorbed.

'Less ice transport' ice is thinner but moves faster so not sure about less being transported out of arctic. It is possible as ice retreats to smaller area.

But maybe you are talking about, we have cleared ice from area where there is a net movement out of the areas where quick increase in ice free area occurs so readily creating albedo feedback, but when we try to clear area with net movement in the area doesn't clear quickly so the albedo feedback is much slower.

Certainly agree with winter regrowth feedback.

Then there are others like:

Bathymetry: We have cleared the shallow area where warm salty gulf stream water cannot sink.

Distance from land and rivers:
Land warms up fast warming the air and rivers provide fresh water warmed during its journey. As the ice retreats away from these areas it gets harder to melt the ice.

Temperatures would be lower because remaining ice will be further north and further out to sea. I don't think increased weather variability will outweigh that effect. In the long run increased GHG levels will melt the ice, but we are talking about what will happen in the next 20 years.

I'm not talking about cloud cover, but the basic fact that there is less annual insolation the further north you go.

Most ice transport is through the Fram strait. Transport declines significantly in the summer because there is less ice nearby. We can expect that feedback to increase as the ice extent decreases.

I wasn't talking about albedo. But speaking of that- If the albedo effect were important then you would expect increased melting in the second half of the summer due to warmer waters. But we see the opposite. Melt at the end of the summer is decreasing and the melt season is increasingly focused around the solstice. Of course the albedo effect still exists on some level, but at least in the short run it appears that the albedo effect is being dominated by the negative feedbacks I have listed.

As for bathymetry, I am skeptical. The ocean map doesn't line up well with this theory. On the Atlantic side it fits well. But on the Alaska/Russian side bathymetry seems like a poor fit for the typical melt shape. See image below.

I agree that distance from land is also likely to be a negative feedback.

http://s16.photobucket.com/user/iciclespike/media/common%20ice%20shape.jpg.html?sort=3&o=0

[litesong]

People, please chill.  Please don't turn this into a flame war.

Addressing the obvious, conscious & determined errors(lies) of a poster is no flame war. If such is NOT opposed from the beginning, THEN more lies will propagate.

[Red]

This may well be of base by many kilometres but the multi-year ice is the most important part of this equation. If the multi-year ice is losing out year on year than volume will be the Arctic Ocean area times the thickness of one winters freeze. One winters freeze tends to turn to water the following season except in the very far north but with the intrusion of the open water on both sides the chances of multi-year ice build up is seemingly impaired by transport out of the arctic. The multi-year ice is the catalyst that was keeping things together, I think. Winter refreeze is the all important variable that seems to be compromised. Remember that the night time lows globally are rising faster than the daytime highs. Well the polar night is the longest night on the planet so it goes to follow that the polar night might just have the time available to creep into heights that not too long ago were unimaginable. Oooh look, I think it just happened in the last couple of years. A few more nights like the last couple and we may well have something here.

[Daniel B.]

People, please chill.  Please don't turn this into a flame war.

Addressing the obvious, conscious & determined errors(lies) of a poster is no flame war. If such is NOT opposed from the beginning, THEN more lies will propagate.

I think that is a given, and often posters will point out glaring errors.  I believe he was referring to actual ad hominem attacks and name calling, instead of countering scientifically.

[jdallen]

People, please chill.  Please don't turn this into a flame war.

Addressing the obvious, conscious & determined errors(lies) of a poster is no flame war. If such is NOT opposed from the beginning, THEN more lies will propagate.

I think that is a given, and often posters will point out glaring errors.  I believe he was referring to actual ad hominem attacks and name calling, instead of countering scientifically.

Precisely.

[icefisher]

I chose 2017 as my first year with area less than 1MM.  After 2007 and 2012, 2017 seemed as likely as not.  Negative reinforcements may delay melting for a few more years or we may have another perfect melting season.  Either way we are already dealing with the effects of global warming.  The future looks unknowable.  Unlike Darth Vader we have already altered it further.

[Archimid]

Ad hominem (Latin for "to the man" or "to the person"[1]), short for argumentum ad hominem, is a fallacious argumentative strategy whereby genuine discussion of the topic at hand is avoided by instead attacking the character, motive, or other attribute of the person making the argument, or persons associated with the argument, rather than attacking the substance of the argument itself

I addressed the discussion at hand and provided evidence. Since his point was false, that would make his statement a lie, making him a liar. Without any context, I didn't perform an ad hominem, however, the rough nature of the words I use make it look like I did. With the context of the climate change debate what I did was way too nice, given the cost in lives and property, present and future.

However I acknowledge that my words have unintended consequences for the good flow of information in a public forum. Thus I pledge to hold strong language back in favor of more  calmed and objective language, even if it understates the nature of these falsehoods.

[crandles]

Temperatures would be lower because remaining ice will be further north and further out to sea. I don't think increased weather variability will outweigh that effect. In the long run increased GHG levels will melt the ice, but we are talking about what will happen in the next 20 years.

I'm not talking about cloud cover, but the basic fact that there is less annual insolation the further north you go.

Most ice transport is through the Fram strait. Transport declines significantly in the summer because there is less ice nearby. We can expect that feedback to increase as the ice extent decreases.

I wasn't talking about albedo. But speaking of that- If the albedo effect were important then you would expect increased melting in the second half of the summer due to warmer waters. But we see the opposite. Melt at the end of the summer is decreasing and the melt season is increasingly focused around the solstice. Of course the albedo effect still exists on some level, but at least in the short run it appears that the albedo effect is being dominated by the negative feedbacks I have listed.

As for bathymetry, I am skeptical. The ocean map doesn't line up well with this theory. On the Atlantic side it fits well. But on the Alaska/Russian side bathymetry seems like a poor fit for the typical melt shape. See image below.

I agree that distance from land is also likely to be a negative feedback.

http://s16.photobucket.com/user/iciclespike/media/common%20ice%20shape.jpg.html?sort=3&o=0

Further north - less insolation.
OK.

I am a little more sceptical of colder temperatures though. In summer temps pegged closely to melting point/freezing point. In winter there is very little insolation and I would expect distance to relatively warm water to be a much more important factor.

Also not sure about your 'further out to sea'. The sea is warm. Secondly i expect wind and currents to keep the last of the ice to hug Greenland and Canadian islands. So for the last of the ice the retreat will be southward not northward. Does that make your insolation effect a positive feedback at the end?

Transport, yes I agree that seems highly probable.

How can the albedo effect not be important? Maybe heat absorbed by ocean doesn't travel far. I would expect winds to pick up this heat but even leaving that out, thin ice has lower albedo and surely that has to be important. But as you say "Melt at the end of the summer is decreasing and the melt season is increasingly focused around the solstice."

How can this be? I suggest it points toward 'distance from land', 'bathymetry' and 'we have done the easy areas where there is net movement of ice out of the area so the albedo effect is artificially enhanced' being important feedbacks.

[litesong]

People, please chill.  Please don't turn this into a flame war.

Addressing the obvious, conscious & determined errors(lies) of a poster is no flame war. If such is NOT opposed from the beginning, THEN more lies will propagate.

I believe he was referring to actual ad hominem attacks and name calling, instead of countering scientifically.

Daniel tries to side-slip away, pretending the following earlier set of posts didn't occur:
///////
Daniel B. wrote: The satellite data starts in 1979.  There is no good measure of ice volume to that, so anything else is speculation.
litesong wrote:
Much submarine data is available. AGW deniers love to hoot that submarines were surfacing at the North Pole in the 1950's, intimating that 1950's Arctic sea ice was thin. But submarine logs indicate 1950's sea ice was much thicker than today. It took weeks for submarines to find sea ice thin enough, through which submarines could surface. & in weeks previous to that, submarines could not enter the Arctic Ocean from the Bering Strait easily or safely, due to sea ice that was as much as 60 feet thick.
Article about submarine data on sea ice in the 50's & 60's:
http://news.bbc.co.uk/2/hi/science/nature/523065.stm 

[Juan C. García]

Last week, I voted for 2029-2033 and today I try to change it to 2034-2039 or even the 2040-49 range, but there is no option to remove my vote [help Neven or DungeonMaster].

Would that make me a denier?   

No way! 

I believe that we are sub estimating the impact that the melting ice on Greenland will have on the process of having an ice-free Arctic. Also, the impact that permafrost melting could have on delaying the ASI melting.

So, we could think that it is good news that the ASI will melt slower than forecasted by some of us, but that will not be true. The problem with AGW is that there are some things going on, that we are not able to see or to measure properly. That is the case of [Oh, my God] “Oceans melting Greenland” (OMG).

https://omg.jpl.nasa.gov/portal/

OMG?...really?

[Daniel B.]

People, please chill.  Please don't turn this into a flame war.

Addressing the obvious, conscious & determined errors(lies) of a poster is no flame war. If such is NOT opposed from the beginning, THEN more lies will propagate.

I believe he was referring to actual ad hominem attacks and name calling, instead of countering scientifically.

Daniel tries to side-slip away, pretending the following earlier set of posts didn't occur:
///////
Daniel B. wrote: The satellite data starts in 1979.  There is no good measure of ice volume to that, so anything else is speculation.
litesong wrote:
Much submarine data is available. AGW deniers love to hoot that submarines were surfacing at the North Pole in the 1950's, intimating that 1950's Arctic sea ice was thin. But submarine logs indicate 1950's sea ice was much thicker than today. It took weeks for submarines to find sea ice thin enough, through which submarines could surface. & in weeks previous to that, submarines could not enter the Arctic Ocean from the Bering Strait easily or safely, due to sea ice that was as much as 60 feet thick.
Article about submarine data on sea ice in the 50's & 60's:
http://news.bbc.co.uk/2/hi/science/nature/523065.stm

I have seen several papers, whereby the scientists try to piece together sea ice extent from various sources.  I have yet to see one detailing volume.  Please post any references.

[Archimid]

I have seen several papers, whereby the scientists try to piece together sea ice extent from various sources.  I have yet to see one detailing volume.  Please post any references.

We know the thickness since the 50's to the 80's was extremely thick, relative to today. We have good proxies for extent that go back centuries that confirm the extent was much higher than now.  We have proxy temperatures that confirm that it was much colder than now that extends for thousands of years.

There is absolutely no indication that the Arctic or the world were as warm as they are today.

You can start here : https://skepticalscience.com/past-Arctic-sea-ice-extent.htm

Evidence was provided that proves Daniel B. statements false. Evidence provided by Daniel B. to justify his uncertainty about volume in the past 0.

[Daniel B.]

I have seen several papers, whereby the scientists try to piece together sea ice extent from various sources.  I have yet to see one detailing volume.  Please post any references.

We know the thickness since the 50's to the 80's was extremely thick, relative to today. We have good proxies for extent that goes back centuries that confirm the extent was much higher than now.  We have proxy temperatures that confirm that it was much colder for than now that extends for thousands of years.

There is absolutely no indication that the Arctic or the world was were as warm as they are today.

You can start here : https://skepticalscience.com/past-Arctic-sea-ice-extent.htm

Evidence was provided that proves Daniel B. statements false. Evidence provided by Daniel B. to justify his uncertainty about volume in the past 0.

Sorry, but inferences do not constitute proof.

[Archimid]

Sorry, but inferences do not constitute proof.

How do you figure the earth is round without making inferences?

[Daniel B.]

Sorry, but inferences do not constitute proof.

How do you figure the earth is round without making inferences?

We have visual from space for one.

Let's put your inferences to the test.  The rate of average ice loss, in volume, from 1990 to 2010 was about 4000 cubic km per decade.  Let us assume that your inference (based on proxy data) shows that the rate of ice loss prior to the satellite era (1979) was similar to that measured during those two decades.  If we extend that rate back to 1850, that would equate to a volume of ice loss covering the entire Arctic ocean to a depth of 30 meters!  You can infer all you like, but at some point, logic has to step in. 

[slow wing]

Picked 2019-21.

Main contender for me was 2022-2024.

In my humble opinion we are already at the stage where an extreme year could do it.

Superimposed on that is the expectation that the situation is getting progressively worse. But it's problematic to quantify that for Arctic sea ice - the physics is far too complicated & poorly understood, & the constraining observations and measurements are far too few &/or too poor.

I think the year-to-year fluctuations are so big as to be more important than the progressive trend in choosing the first year below 1000 km^3.

It could possibly be this year. But it would take a very bad melt season. The 2018 bin is only 1 year wide so I think it less likely than the 3 year bin afterwards that I did choose.

Competing against the progressive trend, the bins 2022-24 and later are disadvantaged by the possibility that, even if the volume does fall below 1000 km^3, it might have already happened in a prior melt season. That's why I chose 2019-21.

This poll runs for a long time - was it for two months? People voting near the start have less information than those voting later on. Can the close date be made earlier? Also, my preference would be to change the poll settings so we can change our vote.

[Archimid]

How do you figure the earth is round without making inferences?

We have visual from space for one.

There is a staggering amount of inferences that go into placing an object in orbit.

Let's put your inferences to the test.  The rate of average ice loss, in volume, from 1990 to 2010 was about 4000 cubic km per decade.  Let us assume that your inference (based on proxy data) shows that the rate of ice loss prior to the satellite era (1979) was similar to that measured during those two decades.  If we extend that rate back to 1850, that would equate to a volume of ice loss covering the entire Arctic ocean to a depth of 30 meters!  You can infer all you like, but at some point, logic has to step in.

There are inferences and there are false inferences.  For example by assuming continuous volume loss you arrive at a nonsensical result. However a quick look at Arctic temperatures tells you that the losses experienced in the late 20th didn't occur before. Assuming a permanent state of volume loss is a false assumption that leads to nonsensical results.

[litesong]

Let's put your inferences to the test.

Daniel B. put its own IN-ability to infer properly to the test.... & failed its own test.

[Daniel B.]

How do you figure the earth is round without making inferences?

We have visual from space for one.

There is a staggering amount of inferences that go into placing an object in orbit.

Let's put your inferences to the test.  The rate of average ice loss, in volume, from 1990 to 2010 was about 4000 cubic km per decade.  Let us assume that your inference (based on proxy data) shows that the rate of ice loss prior to the satellite era (1979) was similar to that measured during those two decades.  If we extend that rate back to 1850, that would equate to a volume of ice loss covering the entire Arctic ocean to a depth of 30 meters!  You can infer all you like, but at some point, logic has to step in.

There are inferences and there are false inferences.  For example by assuming continuous volume loss you arrive at a nonsensical result. However a quick look at Arctic temperatures tells you that the losses experienced in the late 20th didn't occur before. Assuming a permanent state of volume loss is a false assumption that leads to nonsensical results.

Since you just acknowledged that your previous inference was false, are you now saying that there was no volume loss prior to 1979?  If your new premise is based on rising temperatures resulting in volume loss, how do you explain the volume gains in recent years?  Or are you backtracking now, and supporting my previous contention.

[Iceismylife]

...
 You can infer all you like, but at some point, logic has to step in.

Did you really read what you wrote?

Let us try some logic.

Max volume is dropping.

How long can this be kept up?

really?

Run some numbers.

[oren]

Quite simple.  The satellite data starts in 1979.  There is no good measure of ice volume to that, so anything else is speculation.  Can you state with any certainty the volume of ice in the Arctic at the beginning of the industrial era?  or at any time prior?  I do not know when the first ice-free year will occur either.   However, that does not guarantee that next will be similar.

The classic "argument from ignorance" logical fallacy. There is no good measure of prior ice volume indeed, but it doesn't mean that anything else is speculation. A quick read about Captain Cook's voyage to the Chukchi Sea in mid-August 1778, will reveal that uncertainty is not a good proxy for unknown. The captain's journal describes "ice which was as compact as a wall and seemed to be ten or twelve feet high at least". Compare that to the current ice edge and thickness in mid-August. So yes, anybody can state with certainty that sea ice volume 200 years ago in summer was much higher than today, even though no one can say what the actual volume was.

[Daniel B.]

Of course the ice volume was higher than today.  No one is arguing that.  However, the claim that the volume from past centuries is known, and the recent volume decreases are similar to past is unsupported.  I have been arguing against this “argument from ignorance,” yet others seem to be supportive of it.

[Neven]

Lets not stray too far off-topic, please.