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Author Topic: Year-round ice-free Arctic  (Read 12292 times)

Adam Ash

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Re: Year-round ice-free Arctic
« Reply #50 on: August 02, 2017, 11:39:46 AM »
... Head to remote regions. Preferably know where you're heading. Become a part of remote but significantly large regional society before global system fails. ...
Head to remote regions - and promptly starve!  Have you watched a cabbage grow?  It's damn slow compared with the rate of growth of your appetite!  Besides what is 'remote' for you is someone else's back yard, and they are already exploiting it to the max.  If it could be any more productive it would be already.  Instead 'remote regions' are places where humanity has found it impossible to increase the productivity of the land beyond what you see.  They are in balance already.  Adding thousands of hungry city folk will not make the cabbages grow any faster, or at all.  And don't tell me you will hunt to survive.  Better hunters than you will have cleaned the place out long before you get there.  Your risk is that you and yours may become their prey too!

F.Tnioli

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Re: Year-round ice-free Arctic
« Reply #51 on: August 02, 2017, 12:45:57 PM »
Its hard to imagine any scenario that involves an ice free arctic year around.

When was the last time this happened? Right, back then the continents were at quite different positions.

With the current constellation of the land masses there will always be enough cooling during the long dark winters to produce ice and snow.

In fact if the arctic would remain ice free for a winter for whatever strange reason, the lake effect would produce so much snow that there would be no summer the next year.

It's not hard to imagine. Jim White and other gentlemen at Colorado imagined it no problem, and more than imagined - but included into their model, too. Details.

Last time this happened was Pliocene, 3...5 million years ago, they say. So nope, not when continents were at quite different positions. I'd rather say, quite same positions continents were, already.

"Always will be". Such a bold statement. I wouldn't be so sure about "always" part. Lots can change in the future in a way we did not anticipate. And if you'd read through the piece i linked above, you can see that even now some good professors who model Pliocene are doubting that "long dark winter" part in terms of cooling, suggesting thick cloud formations during winter times much prevented said cooling. Cutting edge modern research, too - not some outdated piece out of noone-knows-it institution.

And, you can't deny crocodiles thing. Fossils of those were found in the Arctic. Undeniable proof that (at least big parts of the) Arctic was ice-free year-round in quite recent geological past - despite those very same "long and dark" winters Arctic has today, that is. Waters were warm enough to allow those reptiles to live there, and to me that tells alot.
« Last Edit: August 02, 2017, 02:35:58 PM by F.Tnioli »

F.Tnioli

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Re: Year-round ice-free Arctic
« Reply #52 on: August 02, 2017, 01:06:20 PM »
Head to remote regions - and promptly starve! ...
That 2nd part, i did not propose to do. And certainly it doesn't have to happen, too.

Have you watched a cabbage grow?
Yes. I have 9 years of personal experience working the land, growing all kinds of food relatively organically, from potatoes to strawberries. Including cabbage.

... It's damn slow compared with the rate of growth of your appetite! ...
It's not overnight for sure. Not a reason not to grow cabbage, though. We humans did it in the past, we do it now, and i assure you we will be doing it in the future.

... Besides what is 'remote' for you is someone else's back yard, and they are already exploiting it to the max.  If it could be any more productive it would be already.  Instead 'remote regions' are places where humanity has found it impossible to increase the productivity of the land beyond what you see.  They are in balance already.  Adding thousands of hungry city folk will not make the cabbages grow any faster, or at all.  And don't tell me you will hunt to survive.  Better hunters than you will have cleaned the place out long before you get there.  Your risk is that you and yours may become their prey too!
Not true. Most of the usable land is not exploited to the max because it's not profitable to do so. Moreover, with modern industrial agriculture, there is the tendency to completely abandon vast areas of "suboptimal" soils. But i assure you that when the stakes are higher than getting agricultural business to be profitable, - namely when the stakes are physical survival of the local society, - those lands can produce a whole lot more, and for a long time. Of course, not every country has such lands, and like i said, you gotta know where you're heading, - and why there. In advance.

I did not say a thing about "adding thousands". Indeed, if one moves out by the time thousands others would do so, then it's already too late to move out. One has to become part of the remote low-density population way before any significant refugee wave would hit it. Preferably, it has to be so remote that no "thousands" refugee wave would ever hit it, actually.

Hunting? You're not paying attention; i already mentioned hunting-gathering is not a way forward. Growing cabbages is the way, like it or not. That, or starve to death. I suspect cabbages are the better choice. :D
« Last Edit: August 02, 2017, 02:31:27 PM by F.Tnioli »

Coffee Drinker

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Re: Year-round ice-free Arctic
« Reply #53 on: August 02, 2017, 03:10:38 PM »
Its hard to imagine any scenario that involves an ice free arctic year around.

When was the last time this happened? Right, back then the continents were at quite different positions.

With the current constellation of the land masses there will always be enough cooling during the long dark winters to produce ice and snow.

In fact if the arctic would remain ice free for a winter for whatever strange reason, the lake effect would produce so much snow that there would be no summer the next year.

It's not hard to imagine. Jim White and other gentlemen at Colorado imagined it no problem, and more than imagined - but included into their model, too. Details.

Last time this happened was Pliocene, 3...5 million years ago, they say. So nope, not when continents were at quite different positions. I'd rather say, quite same positions continents were, already.



Isthmus of Panama was open then, allowing a completely different ocean circulation pattern. Very different situation from today.

johnm33

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Re: Year-round ice-free Arctic
« Reply #54 on: August 02, 2017, 03:59:43 PM »
For anyone having difficulty imagining year round ice free conditions this won't help much, I read the whole thing [still got the book] years ago after an Indian [Hindu] workmate said that in their histories there was no ice age, and that the arctic previously had had a climate of permanent springtime. So in essence the book says the vedas were written by a people who lived where there were 6 weeks of darkness and very protracted dawns, hardly imaginable for people used to the 12hr day night cycles of India. With so much going on in the world I wouldn't find the time now to read it but it's worth reading the preface to get the measure of the man. 'The Arctic home in the Vedas'  http://cakravartin.com/wordpress/wp-content/uploads/2007/02/tilak.pdf

F.Tnioli

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Re: Year-round ice-free Arctic
« Reply #55 on: August 02, 2017, 04:05:08 PM »
@Coffee Drinker:

but then nobody is saying, - at least definitely not me, - that we'll have year-round ice-free Arctic with the ocean circulation patterns all being the way they are today, too. You possibly assumed i have that in mind? If so, - incorrect assumption. To me, it's clear that ocean circulation patterns, and especially those which get anywhere close to (and/or into) the Arctic, - many of those, if not all, will change substantially in the period from "today" to the "ice-free for half a year" moment.

Because increasingly ice-free Arctic will affect circulation patterns itself, plus the thing i explained above in the topic about biosphere regulation and expected global surface temperature state change, as predicted by James Lovelock's model.

If to be somewhat blunt, we have not a slightest idea what ocean circulation patterns will be like by the time energy budgets could possibly allow year-round ice-free Arctic.

Take for example the ongoing - for many years, - debate about intensity, speed, and prognoses of/for North Atlantic currents, and in particular about decreasing water temperatures there. Lots of literature on the subject, - but little consensus in lots of significant details. And that's about perhaps the most important for the current civilization state ocean current in the world, - one which directly affects well-being of most of Europe, including all the most "developed" countries of the continent. If that's still in so much doubt, how can we know any well about Arctic circulation, especially decades into the future? We clearly can't.

Besides, yes, it is probably possible Arctic would be "locked up" during winters 2050 and onward, preventing warm waters from coming in and preventing ice formation. But it doesn't really matter, in my book. Arctic ocean is deep enough to store tremendous amount of heat. Once most of it is summer-free starting June, the amount of energy absorbed by its waters during June and remaining summer months will be comparable, per m2 of its surface, to amount of energy absorbed by equatorial waters during ~9 months. That's based on 24/7 sunshine in cloudless areas, and basic features of athmospheric transparency related to how high Sun is above the horizon.

That amount of heat will inevitably warm up Arctic waters down to few hundreds meters depth, especially 0...100m layer, which will warm up dozens degrees celcius. Expanding and becoming substantially less dense, that surface layer will take a LONG time to cool once polar night sets up. Ice will not form on its surface once thin layer of the surface water would cool down to freezing point: instead, that thin layer of water will sink below, being way more dense than still warm layers of water directly below it - and those warm waters will come up. The process will repeat itself over and over, that mixing also equalizing temperatures of nearby layers, too. I.e. complex hydrodynamics in action, but with one clear outcome: ice will not be forming until the point big (upper) part of the water column cools down to temperatures not far from 0C. And given huge thermal capacity of water, that won't happen any quick. Under "not quick" i mean months here, possibly many months, especially if winter-times thick cloud cover would be the new normal feature of ice-free Arctic, as suggested by Jim White.

This is how what we know about Arctic as it is today (and as it was in recent past) is often not applicable when we talk about possibilities of year-round ice-free Arctic ocean. Lots of things will change dramatically, by then. And to be honest, i take pity at my own attempts to imagine how things will look like then; i bet such attempts are very primitive and at best - dramatically incomplete. But i can't help but to try. Because if we don't use even what little knowledge we managed to obtain in order to attempt to imagine the future, then i say there is little point in obtaining knowledge in the 1st place. Right? ;)
« Last Edit: August 02, 2017, 04:19:48 PM by F.Tnioli »

Bill Fothergill

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Re: Year-round ice-free Arctic
« Reply #56 on: August 04, 2017, 12:07:21 PM »
The subject of year-round ice-free Arctic surfaced in the ongoing Melt Season thread, and it is best we continue the discussion in this topic.

... Even with much higher temperatures, there will probably always be freeze in winter, that's why there will probably never exist zero ice all over the year...


What you are discussing is the transition of the Arctic Ocean from being perennially ice covered, through seasonally ice covered, and ending up in a perennially ice free condition.

One such study appeared last year in the Journal of the American Meteorological Society. Their findings, in a nutshell, were that the vast bulk of winter sea ice could be a thing of the past by as soon as ~2130.

I'll put more flesh on this later, but I'm off to sink a few pints.


Bill, excellent spotting about that paper! But i am sure their result is a vast underestimation. I am not familiar with the paper, but i could bet authors did not take the biosphere influence into much consideration when making their calculations. If so, then that is perhaps the biggest flaw of their work. Because, obviously, in real world, we _do_ have the biosphere. So far. Thank God for that, if i might add.
...


Following several beers, here is the additional flesh to which I alluded earlier...

Some time ago, I came across this Ametsoc article titled "On the Potential for Abrupt Arctic Winter Sea Ice Loss".
http://journals.ametsoc.org/doi/full/10.1175/JCLI-D-15-0466.1

The authors used a variety of different models during their work, and largely assumed that CO2 emissions would roughly follow the scenario described by RCP8.5.

One of their most intriguing findings was that, once the conditions in the Arctic Ocean were right - i.e. warm enough - the transition from a seasonally ice free Arctic Ocean to one which is  perennially ice free could occur faster than the phase we are currently in: namely the transition from being perennially ice covered to being seasonally ice covered.

The first couple of paragraphs of their conclusions read as follows...

"We have found that in complex climate models the transition from a seasonally ice-covered Arctic to an ocean without any sea ice year-round occurs faster than the loss of summer sea ice under the same rate of warming. We attribute this effect to the seasonal asymmetry in the ice-thickness distribution. Whereas summer sea ice is too heterogeneous for large-scale rapid shifts in sea ice area to occur over a few years, Arctic winter sea ice is spread out more homogeneously. As long as the winters are cold enough, a thin and relatively homogeneous ice cover still forms each year. Once the water does not cool to the freezing temperature anymore in winter, the small loss of ice volume from one winter to the next is associated with a large ice-area loss. This explanation allows the possibility of abrupt change although it does not rely on any positive feedback because the freezing point constitutes a natural threshold.

Regarding the generality of this threshold mechanism, the loss of Arctic summer sea ice in the near future could provide an observational lower limit for the rate of Arctic winter sea ice loss, provided that global warming will continue with a similar rate. Because of the inherent uncertainties in the models, it is difficult to provide a quantitative estimate for the sensitivity of Arctic winter sea ice area. It is plausible that the models with the most sophisticated ice-thickness distribution yield the best estimate of the sensitivity of Arctic winter sea ice area, which is roughly 50% larger than the sensitivity of summer ice area (Fig. 3). We consider the distinctly abrupt Arctic winter ice loss in MPI-ESM and CSIRO to be less realistic due to their simple description of the subgrid-scale thickness distribution.
"

I didn't find the article particularly easy to assimilate (where are the Borg when you need them?) but nevertheless thought that the time was well spent.

One of the diagrams showing the rapidity of change which might occur in the March/April/May average next century is shown below.

By way of comparison, I followed this with simplistic projections based on 1979-2017 PIOMAS and NSIDC monthly averages for March. It is interesting to note that the possible transition period intimated in the study is roughly mid-way between a straight line PIOMAS projection and a 2nd-order polynomial projection of the NSIDC data.


gerontocrat

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Re: Year-round ice-free Arctic
« Reply #57 on: August 04, 2017, 12:31:59 PM »
Hullo Bill,

Volume versus extent.

I have highlighted a quote from that paper that you quoted

"We have found that in complex climate models the transition from a seasonally ice-covered Arctic to an ocean without any sea ice year-round occurs faster than the loss of summer sea ice under the same rate of warming. We attribute this effect to the seasonal asymmetry in the ice-thickness distribution. Whereas summer sea ice is too heterogeneous for large-scale rapid shifts in sea ice area to occur over a few years, Arctic winter sea ice is spread out more homogeneously. As long as the winters are cold enough, a thin and relatively homogeneous ice cover still forms each year."

There is the fact that while summer minimum volume is decreasing at about 20% per decade, extent is reducing at about 12.5% per decade. In 2017 volume loss in spring early summer was extreme while extent loss lagged. Is the above highlighted quote the explanation (or part of it) ?

Bill Fothergill

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Re: Year-round ice-free Arctic
« Reply #58 on: August 04, 2017, 02:18:44 PM »
Whereas summer sea ice is too heterogeneous for large-scale rapid shifts in sea ice area to occur over a few years,
... Is the above highlighted quote the explanation (or part of it) ?

My guess is that the authors are thinking about the cumulative effect of (a) the gradual complete loss of MYI compounded by (b) the even more gradual regression in the date at which re-freeze begins.

Even if we lost all the MYI in the next couple of years, the date at which re-freeze commences isn't going to change much in the short term. The effect of this is that the new ice in some areas will still clock up significant Freezing Degree Days compared to those areas in which the refreeze didn't get going until (say) February.

I think that accounts for the heterogeneity which is being discussed in that quote.

As for this year's varying behaviour viz-a-viz volume & extent, I really wouldn't like to hazard a guess. There's always going to be a certain level of disconnect between these metrics.

I don't know if you noticed, but on the ASIB a couple of months ago, one of the contributors hypothesised that, since PIOMAS and NSIDC gave differing "projection down to zero ice" dates, then one or both had to be in error.

That seemed an astonishing failure to grasp basic maths: if the area is dropping, and the thickness is dropping, then it is axiomatic that the volume should be dropping even faster. Obviously it is physically impossible for matters to continue such that there is zero thickness whilst there is still area present, and vice-versa.

What will happen is that there will be a discontinuity (the rapidity of which will be interesting to learn) in the decline rates of the various metrics. I know you are familiar with all this, but I have appended three simple charts which I knocked up a while ago to demonstrate this effect to someone I know.

In each (extremely simple) case, I have assumed that the length, breadth and thickness of an ice mass each decrease in a perfect linear fashion.

Case (1) has these three values declining such that they would all go to zero in 10 years.

Cases (2) and (3) have the length & breadth (and, consequently, the area as well) decreasing at an unchanged rate. However, in Case (2), the rate of loss of thickness has been decreased, but has been increased for Case (3).

The format of the graphs may look somewhat unusual to some, so a quick explanation may be in order.

The primary Y-axis shows Area, whilst the secondary Y-axis displays volume. The X-axis is used to show thickness. However, as each data point on every data-series is one year apart, the separation of each data point can be considered as being a proxy for the passage of time.

In Case (1), there is no abrupt discontinuity, and the curves for each metric smoothly coalesce at the zero point. However, Case (2) demonstrates a discontinuity in the thickness metric, whilst Case (3) has a similar discontinuity for area.

As mentioned earlier, the physics of the actual ice loss will vary enormously from this simplistic mathematical representation. The losses will be anything but linear - and that's without introducing any noise into the situation.

gerontocrat

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Re: Year-round ice-free Arctic
« Reply #59 on: August 04, 2017, 03:44:50 PM »
Thinking it is a pity that this thread is entitled "Year-round ice-free Arctic". Probably because I think a lot about how it will go from a) now and b)year-round ice-free Arctic.

Will it be a case of a gradually extending blue ocean period or a case of last year's winter being repeated and an accelerating winter ice loss ?

Herewith where we are on volume loss from the PIOMAS site. Linear or what?

DavidR

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Re: Year-round ice-free Arctic
« Reply #60 on: August 05, 2017, 01:56:14 AM »

Herewith where we are on volume loss from the PIOMAS site. Linear or what?

No not linear if you use a line of best fit it  is clearly declining faster now than in the past.

Bill Fothergill

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Re: Year-round ice-free Arctic
« Reply #61 on: August 05, 2017, 01:16:20 PM »
Thinking it is a pity that this thread is entitled "Year-round ice-free Arctic". Probably because I think a lot about how it will go from a) now and b)year-round ice-free Arctic.

Will it be a case of a gradually extending blue ocean period or a case of last year's winter being repeated and an accelerating winter ice loss ? ...

There is an article on the Max Plank website which is complementary (without being unduly complimentary) to the Ametsoc article mentioned upthread.

It contains an interesting animation showing the modelled behaviour of Arctic sea ice for both  March and September. The March animation runs from 2050 to 2200, whilst its September equivalent goes from 1850 till 2100. (The reason for this temporal asymmetry should be obvious, especially after viewing.)

https://www.mpimet.mpg.de/en/communication/news/focus-on-overview/can-arctic-winter-sea-ice-disappear-abruptly/

gerontocrat

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Re: Year-round ice-free Arctic
« Reply #62 on: August 12, 2017, 03:22:13 PM »
Hullo Bill,
That max the plank institute is super-duper. Thanks for the link.
I don't bieve the timing of the summer blue ocean event. Contradicts current trends in volume loss.

Coffee Drinker

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Re: Year-round ice-free Arctic
« Reply #63 on: August 19, 2017, 02:55:20 AM »
@Coffee Drinker:

This is how what we know about Arctic as it is today (and as it was in recent past) is often not applicable when we talk about possibilities of year-round ice-free Arctic ocean. Lots of things will change dramatically, by then. And to be honest, i take pity at my own attempts to imagine how things will look like then; i bet such attempts are very primitive and at best - dramatically incomplete. But i can't help but to try. Because if we don't use even what little knowledge we managed to obtain in order to attempt to imagine the future, then i say there is little point in obtaining knowledge in the 1st place. Right? ;)

Thanks for the coherent reply.

You make good points. I also believe that the future is unpredictable and that there are many important surprises we cant really include in our predictions (super volcano etc).

So I wont exclude the possibility of an ice free arctic. Well of course its possible. Do I believe it will happen? At this stage I have to say no as I think that even an advance of glaciers is more likely than a year around ice free arctic. All it would take is a super volcano eruption or a nuclear winter which I think are possibilities in the longer term.

I talk about believes here as I don't think we have enough knowledge or variable to go beyond believes in this regard.