Latest PIOMAS Volume update

[oren]

Can we stop the OT stuff?

[gerontocrat]

Think one is allowed one howl at what Trump and his merry men seem determined to do to the NOAA and the EPA. I am a Brit but how the USA built the climate science / weather system integrating NOAA / NASA / the military / universities and the private sector is something the world needs to copy.

And now the USA is going to bust it. Second howl of dismay.

[Tigertown]

Think one is allowed one howl at what Trump and his merry men seem determined to do to the NOAA and the EPA. I am a Brit but how the USA built the climate science / weather system integrating NOAA / NASA / the military / universities and the private sector is something the world needs to copy.

And now the USA is going to bust it. Second howl of dismay.

No one is disagreeing with your points in and of themselves, but you just cannot go through the whole forum disrailing the threads. When you comment off topic, others reply and you end up with a series of comments so long that it is hard to go back and find the last post that wasn't off topic and tie back in again. There are a couple threads available about your chosen subject.

[gerontocrat]

Think one is allowed one howl at what Trump and his merry men seem determined to do to the NOAA and the EPA. I am a Brit but how the USA built the climate science / weather system integrating NOAA / NASA / the military / universities and the private sector is something the world needs to copy.

And now the USA is going to bust it. Second howl of dismay.

No one is disagreeing with your points in and of themselves, but you just cannot go through the whole forum disrailing the threads. When you comment off topic, others reply and you end up with a series of comments so long that it is hard to go back and find the last post that wasn't off topic and tie back in again. There are a couple threads available about your chosen subject.

Having howled it is back to the data.
When will Jaxa fix the icedrift graph? Last time I looked sea ice was invading Canada fron the Alaskan border.

[Buddy]

I have a question for you science types....because I want to "get this right".

Am I reading the Piomas chart below correctly....when I say:

1)  The average level of ice during the LOWEST part of melt season during 2000 - 2009 was about 9.2 million cubic kilometers (eyeballing it).

2)  The level of ice volume during the LOWEST part of melt season in 2012 was about 3.8 million cubic kilometers.

3)  Hence.....the loss of ice volume from the average lowest level during the decade of 2000 - 2009......to the level in 2012.....was 59% (the 5.4 cubic kilometers of ice loss is 59% of the 9.2 cubic kilometers average during the decade of 2000 - 2009).

I don't recall seeing any questions on the CPA exam about the thermodynamics of melting ice.  But I KNOW....that it takes a LOT more energy to melt ice, than it does to warm water.

Is it just me.....or is that a STAGGERING AMOUNT of melt in less than a decade?

AND....(more help for the scientifically deficient me)....now that the LEVEL of ICE VOLUME is much lower....can't it "disappear" much faster?  IE.....easier to get rid of 3.8 million cubic kilometers of ice than it is 9.2 kilometers of ice.

I'm a "numbers guy".....and a "visual guy".  Those numbers really "gobsmack" me.....

[Buddy]

Here's another way to look at it.....

1) We "had" an average of 9.2 million cubic kilometers of ice volume during the decade of 2000 - 2009 during peak melt season.

2)  We had about 3.8 million cubic kilometers of ice during the low point of 2012.

3)  From the average of the deacde of 2000 - 2009......WE LOST MORE THAN 140% OF ICE WE ENDED UP WITH IN 2012.  We lost 5.4 cubic kilometers.....and we ended up with 3.8 cubic kilometers. 

 

[binntho]

Not sure, Buddy, but I can see that the exponential trend line for minimum has gone from ~10.300 km3 in 2000 to ~3.200 km3 in 2017, a drop of 69% (adapted from https://sites.google.com/site/arctischepinguin/home/piomas/grf/piomas-trnd2.png)

[Buddy]

And to put one final "point" on it:  It 'aint going to take a lot of melt seasons to get rid of the rest of the ice volume in the Arctic.

Warmer oceans are killing it.....and the warmer atmosphere and feedback mechanisms are not a huge help as well.

We are in the final YEARS (not decades) of the first melting out of ice volume in the Arctic.  And this is why I have maintained that by 2020 almost all (or literally ALL) of it will be good as gone....for the first time during melt season (Sept 2020). 

[crandles]

Comparing a low year like 2012 to an average of a decade might be considered a little odd or even cherry picking. It might be better to compare  a similarly low year like 2007 Sept average of 6.528 to 2012's 3.789 which give a loss of 42% in just 5 years. At that rate it would all go in 7 years from 2012 = 2019, but that is still unfair as 4 years after 2007, 2011 was below the Sept 2007 level but Sept 2016 is above Sept 2012 level so it doesn't seem to be going according to that plan though with maximum volume as low as it is going to be this year it could well get back on track.

now that the LEVEL of ICE VOLUME is much lower....can't it "disappear" much faster?  IE.....easier to get rid of 3.8 million cubic kilometers of ice than it is 9.2 kilometers of ice.

The models also suggest the rate of decline will slow down as zero ice is approached and the pattern of the last 10 years might support this as does a possibility that the fast decline was due to removal of thick MYI which doesn't grow back each year but now we are thinning FYI which does largely grow back each year it could be a slower process.

So when you say "the LEVEL of ICE VOLUME is much lower" it might depend whether you are talking about volume at minimum or volume at maximum. If you are talking of ice volume at maximum, then I would completely agree but that seems different from what you are looking at here.

[wili]

Another way to look at it is that our current (likely) high for the year (Feb. 2017) about matches the volume for the yearly low for the first year recorded in the graph (Sept. 1979)...

[gerontocrat]

Hullo Buddy.

The polar science center explains it something like this.On average, arctic sea ice volume is declining at just under 300 km3 per annum. The energy required to do this is nearly the same as the entire energy output of the USA.

"However, when spread over the area  covered by Arctic sea ice, the additional energy required to melt this much sea ice is actually quite small. It corresponds to about 0.4 Wm-2 . That’s like leaving a very small and dim flashlight bulb continuously burning on every square meter of ice."

Also to remember that this huge number is but a tiny fraction of the energy the sun gives the earth. The earth presents itself to the sun as a small disc 93 million miles away.  The energy the earth receives from the sun is but a minuscule fraction of the energy produced by the sun. We cannot comprehend the enormity of that number. The sun is just a second division sun amongst trillions of others belching out unfathomable quantities of heat.

And yet we are told that despite this the average temperature of the Universe is just 2.73 degrees above absolute zero. (The average surface temperature of our planet is around 287 degrees above absolute zero).

Oh well, off topic again. Sorry

[Pmt111500]

<Buddy> at least you should replace all the 'millions' with 'thousands' when talking of volume... But that's an error seen also done by others... Would have to check your points one by one but yes, the situation is such that if not this year then the next high heat year (my guess 2021-2022), however far in the future the next big release of atmospheric insulators (aka greenhouse gases happens (+++ENSO or some other large ocean surface heat anomaly), the Arctic ocean could have ice only in the form of icebergs and spilled icy drinks from the vessels travelling there.

[Jim Williams]

The models also suggest the rate of decline will slow down as zero ice is approached and the pattern of the last 10 years might support this as does a possibility that the fast decline was due to removal of thick MYI which doesn't grow back each year but now we are thinning FYI which does largely grow back each year it could be a slower process.

Those the same models that predict 2070 for the first Blue Ocean Event?

[Buddy]

Comparing a low year like 2012 to an average of a decade might be considered a little odd or even cherry picking. It might be better to compare  a similarly low year like 2007 Sept average of 6.528 to 2012's 3.789 which give a loss of 42% in just 5 years. At that rate it would all go in 7 years from 2012 = 2019, but that is still unfair as 4 years after 2007, 2011 was below the Sept 2007 level but Sept 2016 is above Sept 2012 level so it doesn't seem to be going according to that plan though with maximum volume as low as it is going to be this year it could well get back on track.

Good points....valid and well taken....and appreciate your time.

The models also suggest the rate of decline will slow down as zero ice is approached and the pattern of the last 10 years might support this as does a possibility that the fast decline was due to removal of thick MYI which doesn't grow back each year but now we are thinning FYI which does largely grow back each year it could be a slower process.

One thing that will help me...is for me to schedule out the ABSOLUTE VALUE of the CUBIC KILOMETERS LOST each year from 2000 onward.....and especially from 2007 onward. 

So when you say "the LEVEL of ICE VOLUME is much lower" it might depend whether you are talking about volume at minimum or volume at maximum. If you are talking of ice volume at maximum, then I would completely agree but that seems different from what you are looking at here.

Yes...I am talking about minimum's.

[Buddy]

The polar science center explains it something like this.On average, arctic sea ice volume is declining at just under 300 km3 per annum. The energy required to do this is nearly the same as the entire energy output of the USA.

"However, when spread over the area  covered by Arctic sea ice, the additional energy required to melt this much sea ice is actually quite small. It corresponds to about 0.4 Wm-2 . That’s like leaving a very small and dim flashlight bulb continuously burning on every square meter of ice."

I was reading that JUST THIS MORNING.  Now I understand it....thanks.

Also to remember that this huge number is but a tiny fraction of the energy the sun gives the earth. The earth presents itself to the sun as a small disc 93 million miles away.  The energy the earth receives from the sun is but a minuscule fraction of the energy produced by the sun. We cannot comprehend the enormity of that number. The sun is just a second division sun amongst trillions of others belching out unfathomable quantities of heat.

You mean the sun isn't just here for us?  lol.  You're right.  I really never thought about it in that way....great point.

And yet we are told that despite this the average temperature of the Universe is just 2.73 degrees above absolute zero. (The average surface temperature of our planet is around 287 degrees above absolute zero).

This is the trouble with learning.  You start learning....and soon you find out JUST HOW MUCH MORE I DON' T KNOW....

Oh well, off topic again. Sorry

Not at all....I'm here to learn.

[BenB]

Another way to look at it is that our current (likely) high for the year (Feb. 2017) about matches the volume for the yearly low for the first year recorded in the graph (Sept. 1979)...

The average volumes for March and April should be slightly higher than February, so we'll probably be a bit higher than the minimum in 1979, but no doubt we'll get there some year soon.

[rboyd]

The models that assume that the decline in sea ice will slow down as it approaches zero area make the assumption that less sea ice means more reflective clouds. Recent observations though seem to show that there are a lot of other variables that affect cloudiness in the Arctic, and they favour more cloudiness in the Fall and Winter (which will trap heat in the darkness) rather than the Summer.

If the assumptions of extra summer cloudiness do not pan out (therefore the albedo is less), together with the increased ability of heat to enter the Arctic from the south, the trend may simply continue to accelerate to zero. Especially if the refreeze season is increasingly impacted by a cloud blanket, plus storms bringing in more heat and moisture, as well as creating waves and bringing up warmer waters from below.

These factors feel to me like the Sea Ice equivalent  of the "Ice Cliff Collapse" factor for the Antarctic that allowed for a much better fit to the Paleoclimatic records. The models for sea ice loss require a fundamental reworking to reflect the reality that we are seeing.

[LRC1962]

I do not know if the models take it into consideration, but not all ice is equal. The formula for energy needed to melt 1980 ice must be different then that needed for melting 2017 ice. Also impact of waves between 1980 and 2017 is most definitely different. In 1980 waves were hard pressed to get that far into that ice, now a wave can almost travel from one side of the Arctic to the other no matter what ice it faces. On top of that todays ice is far dirtier.
Therefore models can no longer just put sunlight in the equation, they must also put kinetic energy into the frame along with changes in the water column. That is water currents are far warmer and are having a bigger impact, plus all those storms are not only bringing warm water to the surface but adding a huge amount of kinetic energy to the mix that may put more energy into an area what the sun could do in the same amount of time. Granted those storms can go either way in the equation balance sheet.

[Buddy]

These factors feel to me like the Sea Ice equivalent  of the "Ice Cliff Collapse" factor for the Antarctic that allowed for a much better fit to the Paleoclimatic records. The models for sea ice loss require a fundamental reworking to reflect the reality that we are seeing.

And it is interesting to note that the earth now has much less reflective area (ice and snow) than we have had at anytime since 1979 at least.....

Albedo continues to decline.....oceans continue to warm.....ice continues to retreat....and other feedback mechanisms increase.  The physics and science of climate change (in this case anthropogenic global warming).......are colliding with an overhaul in the transportation and energy industries.....and with politics. 

I'll put my money on science and physics for the win.....

[JimboOmega]

The formula for energy needed to melt 1980 ice must be different then that needed for melting 2017 ice.

I can't see why. It's true that of course all the other dynamics you mentioned may be different - more (or less) dark ice as a result of particulates, physically more dispersed ice as a result of it being thinner and subject to wave action, etc. And obviously less of it to start with.

But in the end, other than perhaps slight differences in salinity (especially between MYI and FYI), ice is ice and it takes the same amount of energy to melt. Things like waves and particulates change how the energy is delivered and how much, but it still the same amount is energy.

It'll be very interesting to see how the melt season progresses from such a lower starting point; especially one that implies the ice really is a lot thinner (and should melt faster)

[wehappyfew]

I made another chart:

NCEP arctic temps, annual average anomaly
vs
PIOMAS annual average volume anomaly

...

I think we are likely to hit -8 thousand km^3 for the annual anomaly, implying a record low Sept minimum around 2.5 thousand km^3.

I find it fascinating that the temperature anomaly hit a record high of about 1.3C on 2005, causing a slightly lower record volume low... then the temperature stayed near that plateau for 11 years while volume plummeted.

Now we have jumped to a new record high temp in 2016 and probably in 2017, too. Will the volume repeat the same pattern? Lower and lower volumes over the next decade even if temps plateau?

...

[jdallen]

I made another chart:

NCEP arctic temps, annual average anomaly
vs
PIOMAS annual average volume anomaly

...

I think we are likely to hit -8 thousand km^3 for the annual anomaly, implying a record low Sept minimum around 2.5 thousand km^3.

I find it fascinating that the temperature anomaly hit a record high of about 1.3C on 2005, causing a slightly lower record volume low... then the temperature stayed near that plateau for 11 years while volume plummeted.

Now we have jumped to a new record high temp in 2016 and probably in 2017, too. Will the volume repeat the same pattern? Lower and lower volumes over the next decade even if temps plateau?

...

Interesting chart.  I thjnk the anomaly measure is a proxy for heat flow and to a lesser degree, total system enthalpy.

[Jim Williams]

The formula for energy needed to melt 1980 ice must be different then that needed for melting 2017 ice.

I can't see why. It's true that of course all the other dynamics you mentioned may be different - more (or less) dark ice as a result of particulates, physically more dispersed ice as a result of it being thinner and subject to wave action, etc. And obviously less of it to start with.

But in the end, other than perhaps slight differences in salinity (especially between MYI and FYI), ice is ice and it takes the same amount of energy to melt. Things like waves and particulates change how the energy is delivered and how much, but it still the same amount is energy.

It'll be very interesting to see how the melt season progresses from such a lower starting point; especially one that implies the ice really is a lot thinner (and should melt faster)

Ice with holes in it (or ice cubes) melts faster than a solid block of ice.  It's a simple matter of geometry -- and surface area verses volume.

[wehappyfew]

Interesting chart.  I thjnk the anomaly measure is a proxy for heat flow and to a lesser degree, total system enthalpy.

Thanks.

I agree the cumulative effect of temperatures is most important. FDD captures much of the same information.

...

I forgot to add... 2016 and 2017 are the last two points on the far lower right. 2017 is the rightest and lowest, but it only represents Jan and Feb so far. I can update it throughout the year if it is interesting to anybody.

[Buddy]

Will be interesting to see if the March and April Piomas volume maximum numbers continue to "flatten out" a little earlier this year...and the next couple of years.  I expect that of course...with warmer Arctic air and warmer waters....

What will that max number be this year...and how will it effect the coming melt season.....

[Jim Williams]

Will be interesting to see if the March and April Piomas volume maximum numbers continue to "flatten out" a little earlier this year...and the next couple of years.  I expect that of course...with warmer Arctic air and warmer waters....

We will see about the next couple of years.  I'm betting that at some point the ocean (maritime) climate completely overwhelms the desert climate -- and the Arctic goes from an Ice Cap to basically ice free all winter.  I just don't know exactly when.

At some point the freshwater lens dies along with the thermocline.

[Lord M Vader]

I think we'll see a decent ice growth this March and also in the first half of April which will reduce the gap to the other years. The melting season might surprise us a lot in one or another direction.

[Buddy]

We will see about the next couple of years.

If you look at the lower boundary of the "2 standard deviation" grey area.....you can see "visually" that the lower 2 standard deviations "flattens out slightly" near the peak in March and April (the lower 2 standard deviation area gets "fatter" as the rise slows down March and April).

This year of course....we are even below the 2 standard deviation line.   My curiosity THIS YEAR....is "how much is that going to flatten out early.....and HOW early is it going to peak?"
 
Down south....in the Antarctic this year....we saw the earliest PEAK to the Antarctic extent (not volume) in late August.  We are continuing to see things that are "out of bounds" so to speak....when it comes to expectations.  I expect those "things" to continue.....unfortunately.

[wili]

BenB wrote: "The average volumes for March and April should be slightly higher than February, so we'll probably be a bit higher than the minimum in 1979, but no doubt we'll get there some year soon."

That's what has happened in the past. But as others have pointed out, things are changing fast now in the Arctic. It certainly looks like melting will predominate in the near term right now: https://robertscribbler.com/2017/03/06/warm-winds-take-aim-at-chukchi-as-arctic-sea-ice-volume-hits-record-lows-during-february-of-2017/

On the 'all ice is not the same' issue...besides increased salinity and reports of even apparently thick ice having approximately the consistency of a slushy, there is the study from a few years back that found that increased atmospheric CO2 concentrations actually directly weakens ice structure (even leaving out it's obvious affect of melting ice through GW).

http://www.smithsonianmag.com/science-nature/bad-news-chemistry-carbon-dioxide-makes-ice-weaker-69767723/

[Jim Williams]

I expect those "things" to continue.....unfortunately.

I also expect them to continue.  I do not place an emotional value upon them.

http://dlkphotography.com/fair-witness/stranger-in-a-strange-land

[Pragma]

And then there is this astonishing bit of "science"

https://phys.org/news/2017-03-arctic-sea-ice-doomed.html

Are these people looking at the same planet that we are?

"Virtually Certain"? Really Who is paying these people?

Words fail me.

[oren]

And then there is this astonishing bit of "science"

https://phys.org/news/2017-03-arctic-sea-ice-doomed.html

Are these people looking at the same planet that we are?

"Virtually Certain"? Really Who is paying these people?

Words fail me.

I'll have some of what they're smoking please.

[gerontocrat]

And then there is this astonishing bit of "science"

https://phys.org/news/2017-03-arctic-sea-ice-doomed.html

Are these people looking at the same planet that we are?

"Virtually Certain"? Really Who is paying these people?

Words fail me.

How I read the article was that while keeping warming to a max of 1.5 is virtually certain to keep some ice it is also virtually certain that warming will be greater than 1.5.

So more about a missed opportunity than an opportunity still available. So expect a little boat to sail over the north pole in the next 5 years ?

[magnamentis]

The formula for energy needed to melt 1980 ice must be different then that needed for melting 2017 ice.

I can't see why. It's true that of course all the other dynamics you mentioned may be different - more (or less) dark ice as a result of particulates, physically more dispersed ice as a result of it being thinner and subject to wave action, etc. And obviously less of it to start with.

But in the end, other than perhaps slight differences in salinity (especially between MYI and FYI), ice is ice and it takes the same amount of energy to melt. Things like waves and particulates change how the energy is delivered and how much, but it still the same amount is energy.

It'll be very interesting to see how the melt season progresses from such a lower starting point; especially one that implies the ice really is a lot thinner (and should melt faster)

Ice with holes in it (or ice cubes) melts faster than a solid block of ice.  It's a simple matter of geometry -- and surface area verses volume.

again that changes how the energy is and/or can be applied according to for example the amount of surface exposed to energy but the amount of energy remains the same. so to melt 1 square meter of ice the amount of energy does not change, while the amount and speed of energy appliance at a given or during a given period of time will change if more surface is exposed, be it to warm waters, warm air or insolation.

this alone was his point, about the amount of energy needed and the factors that could have an impact were mentioned as well.

last but not least a square meter of ice is not always the same amount of ice. ice that has been under high pressure in a glacier will probably be more compact than first year sea ice, with more air pockets bubbles or what ever it might be.

howerver i think that in general, without measuring the smallest differences and going too much into details, the assumption that the same amount of ice will take the same amount of energy, i.e. in joule, to melt.

[Tigertown]

Did anyone catch what the daily average was for February? Just a curiosity, but it also comes in handy for comparison sake.  Neven posted an update (http://neven1.typepad.com/blog/) and said he would add more info later, but not sure what all that entails.

[Pragma]

And then there is this astonishing bit of "science"

https://phys.org/news/2017-03-arctic-sea-ice-doomed.html

Are these people looking at the same planet that we are?

"Virtually Certain"? Really Who is paying these people?

Words fail me.

How I read the article was that while keeping warming to a max of 1.5 is virtually certain to keep some ice it is also virtually certain that warming will be greater than 1.5.

So more about a missed opportunity than an opportunity still available. So expect a little boat to sail over the north pole in the next 5 years ?

I suppose that one could read it that way, if one was very generous except that they are playing fast and lose with data. This is disturbing from people who claim to be mathematicians.

First, we are watching an impeding ice free summer at most 5 years out and we are "only" at ~ 1 deg. C. Add to that the 20 to 40 year delay in temperature rise due to ocean thermal mass.

Note that the claim that the 1.5 limit was not attainable was not part of their paper.

They are regarding 2012 as anomalous and widely deviant from the 1979-2000 average, when the record shows a steady, albeit noisy, progression downwards in a time series where virtually every year after 2000 was below the 1981-2010 average and much of it was more than 2 std dev. Further, they make no mention of the loss in volume.

Regardless of whether the 1.5 degree cap is attainable (it isn't), it is amazing that they state:

 'summer ice cover is "virtually certain" to survive' ,

when readily available data strongly suggests that arctic summer sea ice is virtually certain to vanish within 5 years except for perhaps wind driven littoral piles in the CAA, and all at a temperature below what they specify.

I can't read the original paper (paywall) but there are several references to the same, so it doesn't seem to be misinterpreted.

The original posting website appears to be supported by the agricultural industry, but I don't see any obvious signs of denialism, so for now, I chalk it up to some very sloppy math and lazy assumptions. Having such bad science like this "out in the wild" is very disheartening. I also sense that something else is at play here, but it is not obvious.

[crandles]

Did anyone catch what the daily average was for February? Just a curiosity, but it also comes in handy for comparison sake.  Neven posted an update (http://neven1.typepad.com/blog/) and said he would add more info later, but not sure what all that entails.

16.274
16.368
16.455
16.543
16.622
16.708
16.778
16.843
16.888
16.931
16.971
17.05
17.138
17.247
17.376
17.505
17.632
17.758
17.862
17.983
18.076
18.101
18.182
18.284
18.382
18.474
18.544
18.608

Average
17.414

[crandles]

They are regarding 2012 as anomalous and widely deviant from the 1979-2000 average, when the record shows a steady, albeit noisy, progression downwards in a time series where virtually every year after 2000 was below the 1981-2010 average and much of it was more than 2 std dev. Further, they make no mention of the loss in volume.

Regardless of whether the 1.5 degree cap is attainable (it isn't), it is amazing that they state:

 'summer ice cover is "virtually certain" to survive' ,

when readily available data strongly suggests that arctic summer sea ice is virtually certain to vanish within 5 years except for perhaps wind driven littoral piles in the CAA, and all at a temperature below what they specify.

... so for now, I chalk it up to some very sloppy math and lazy assumptions. Having such bad science like this "out in the wild" is very disheartening. I also sense that something else is at play here, but it is not obvious.

The models all say the rate of extent loss will slow down as ice free is approached. It is just this forum where people tend to say things "like summer sea ice is virtually certain to vanish within 5 years" the vast majority of relevant experts are not saying anything like that with 2030 to 2050 being far more common for extent getting down to 1m km².

I expect 2017 is going to be really bad for the ice, but I don't see any reason why 2018 won't get up to ~22k km³ at maximum. A couple more winters with ever lower FDD might change my mind about 5 years to virtually ice free, but the evidence simply isn't there yet. Certainly not in the way you suggest that some simple maths can invalidate the paper.


Having said above, this

The record low of 3.41 million square kilometres (1.32 million square miles) in 2012 was 50 percent less than the 1979-2000 average.

A 1.5 C cap means ice cover would rarely dip below this level, the researchers said.

does surprise me. I would suspect their model tends to create too much ice extent and their modelled ice extent rarely falls below 2012 level but with 1.5C of global warming, I would expect actual ice extent to be less than 2012 level most years.

[magnamentis]

as it happens mostly things did exactly NOT develop like to so called experts said throughout as much time back as i can think (read) with very few exceptions.

in this case as to slowdown or not i clearly lean out of the window and say (to read back later) LOL

it will accelerate and not slow down. the last 1.5 million will vanish within only few years due to feedbacks, like
some kind of devils circle if you excuse the the term (spiral of death)

i'm not trying to convince anyone or argue here, it's my opinion and i shall reserve the right to remind the experts once they have proven wrong to the umpteenth time. experts often (not all) have a narrow focus on their field of work and too often forget or refuse to consider all the other factors from "competing" fields of expertise.

this is agains no-one, just stating an observation (conclusion) from many years of studying stuff like this as a whole, not specifically limited to one or two fields.

let's see what will happen, i'd gladly be wrong in favour of a slower change that would be better than any abrupt changes. i strongly believe that we're in for very unpleasant surprises, not only to polar ice development but especially as far as sea-level rise is concerned, i smell acceleration there as well.

i hope you will take this as what it is, a second opinion, open to see how things go :-) 

[Pragma]

The models all say the rate of extent loss will slow down as ice free is approached. It is just this forum where people tend to say things "like summer sea ice is virtually certain to vanish within 5 years" the vast majority of relevant experts are not saying anything like that with 2030 to 2050 being far more common for extent getting down to 1m km².

Well you certainly have much more experience with this than I do and I have a lot of respect for non-linear systems. I agree there could be many twists and turns ahead.

That said, I still think that the assertion that 2012 was some sort of lower limit is not supported in the data (as you just amended), nor was it that anomalous. I see many mechanisms that would continue and even accelerate the downward slide to effectively zero, but I do not see any obvious mechanisms that would halt the trend, let alone reverse it, even if this winter was one whopper of an outlier. I feel we have seen large enough changes over an extended period, that any negative feedback triggered should be more obvious by now. Of course, that doesn't mean they don't exist.

While this may not be the common consensus, when it comes to climate change, the common consensus has been regularly underestimating the changes and not by a small amount, so I found the phrase "virtually certain" a tad arrogant. True, I used the same phrase for effect, but I'm not publishing papers.

Obviously, we will have to just wait and see.

[DrTskoul]

Ice cover is not a steady state of the system but rather a quasi steady state brought to being by the delicate balance of two opposing forces  freezing and melting.  The forces are always there and their balance produces the ice cover that we observe. 

The obvious result of this is that any change on either forcing is manifested immediately as a changing ice cover. Dynamics are fast, lag is minimal. A few FDD less and the ice decreases, a cold spell and the ice increases.  The trajectory of the balance is set and the outcome inevitable. I would not be surprised if the difference between ice cover and ice free is a mere 0.1 degrees at the ultimate equilibrium point. From 1 to 1.5 we have a long of heat in the system to go.
 
 

[Archimid]

The following chart is the day of the year when Maximum Volume was reached for every year according to PIOMAS.

Average Day of Maximum  was Day 109.421

Latest Day of Maximum was Day 121 in 1983 and 1985
Earliest Day of Maximum was Day 92 in 1995 followed by day 98 in 2007

In 2012 the maximum was on Day 114
In 2016 the Maximum was on Day 112

edit: forgot the chart 

[Darvince]

What is the confidence in the trend? To me it looks quite high but that might also be an artifact of the first years coming late.

[Jim Williams]

And then there is this astonishing bit of "science"

https://phys.org/news/2017-03-arctic-sea-ice-doomed.html

Are these people looking at the same planet that we are?

"Virtually Certain"? Really Who is paying these people?

Words fail me.

My understanding of the Experimental Method, and what Science is includes a requirement for repeatable reproducible experiments.  Models are NOT SCIENCE.

[Peter Ellis]

Models are much more reproducible and repeatable than the real world.  I suggest your understanding of science is quite partial.

[ktonine]

My understanding of the Experimental Method, and what Science is includes a requirement for repeatable reproducible experiments.  Models are NOT SCIENCE.

Straight from the pages of WUWT.

E = mc² is a model.  Every mathematical description of the physical reality around us is a model. 

People that make "models are not science" type statement either don't understand models or they don't understand science.

Rather than discussing a paper one has never read, one should actually read what it has to say.  In this case it's a letter to Nature Climate Change, Ice-free Arctic at 1.5 °C? James A. Screen & Daniel Williamson, doi:10.1038/nclimate3248

Different climate models give vastly different projections of the lowest sea-ice extent for global warming of less than 1.5 °C (Fig. 1a) or less than 2 °C (Fig. 1b). Models that over-estimate (or underestimate) sea-ice extent in the last ten years are also those that project more ice (or less ice) remaining into the future. This can be summarized mathematically by the strong log-linear relationship (we use logarithms because sea-ice extent cannot physically be less than zero) between model-simulated sea-ice extent averaged for years 2007–2016 and the minimum sea-ice extent for global warming of up to 1.5 °C (Fig. 1a) or up to 2 °C (Fig. 1b). Using the observed sea-ice extent for the last decade (4.8 million km2 ) as a predictor in our simple regression models yields an observationally constrained prediction of 2.9 million km2  (90% credible interval: 2.5–3.4 million km2) for the minimum sea-ice extent if global warming is limited to 1.5 °C (Fig. 1a), or 1.2 million km2 (0.4–4.0 million km2) if global warming remains below 2 °C

We estimate there is less than a 1-in-100,000 (exceptionally unlikely, in IPCC parlance) chance of an ice-free Arctic if global warming stays below 1.5 °C, and around a 1-in-3 chance (39%; about as likely as not, in IPCC parlance) if global warming is limited to 2.0 °C. We suppose then that a summer ice-free Arctic is virtually certain to be avoided if the 1.5 °C target of the Paris Agreement is met. However, the 2 °C target may be insufficient to prevent an ice-free Arctic. Furthermore, our analysis suggests that the Nationally Determined Contributions submitted by countries to support the Paris Agreement (which imply warming of around 3 °C; ref. 10) would likely (in IPCC parlance; 73%) lead to the Arctic becoming ice-free (Fig. 1c).

None of this is at variance with what we know.

[gerontocrat]

And then there is this astonishing bit of "science"

https://phys.org/news/2017-03-arctic-sea-ice-doomed.html

Are these people looking at the same planet that we are?

"Virtually Certain"? Really Who is paying these people?

Words fail me.

My understanding of the Experimental Method, and what Science is includes a requirement for repeatable reproducible experiments.  Models are NOT SCIENCE.

Whoops - you've just torpedoed a largish part of my career below the waterline. In my defence :-

If the model is then tested against the historical record is that not part of the scientific method ?
If that model is then used to make predictions, tested again against those future results, and modified accordingly, is that not science ?

Surely the question is whether the study in question was a lousy piece of work.

[wili]

Yeah, according to JW, then, my friend who went into astrophysics actually went into the arts or humanities rather than into a science, since he can't test repeatedly in a lab his theories about how black holes and white dwarfs etc behave in the universe.

[Jim Williams]

And then there is this astonishing bit of "science"

https://phys.org/news/2017-03-arctic-sea-ice-doomed.html

Are these people looking at the same planet that we are?

"Virtually Certain"? Really Who is paying these people?

Words fail me.

My understanding of the Experimental Method, and what Science is includes a requirement for repeatable reproducible experiments.  Models are NOT SCIENCE.

Whoops - you've just torpedoed a largish part of my career below the waterline. In my defence :-

If the model is then tested against the historical record is that not part of the scientific method ?
If that model is then used to make predictions, tested again against those future results, and modified accordingly, is that not science ?

Surely the question is whether the study in question was a lousy piece of work.

I will grant that since 1979 the weather models have become largely scientific, but PIOMAS is in essence in the last stages of Alchemy, not Science.  And the general circulation models are still simply Alchemy -- no longer quite Astrology.

Call them educated guesses, or call them prognostication -- but they are not science.  They will become science once they are repeatedly reproduced and their predictions have been demonstrated to reliably be correct.

[DrTskoul]

And then there is this astonishing bit of "science"

https://phys.org/news/2017-03-arctic-sea-ice-doomed.html

Are these people looking at the same planet that we are?

"Virtually Certain"? Really Who is paying these people?

Words fail me.

My understanding of the Experimental Method, and what Science is includes a requirement for repeatable reproducible experiments.  Models are NOT SCIENCE.

Are you out of your effing mind???  There goes 100% of my PhD and 12 years of work at the industry - especially since I designed and scaled up a 3000 psi 23 meter tall buvble column reactor with a demonstrated runaway potential solely with computer based and physical modeling . I love your broad strokes. But we can take it at a different thread.